Sm Pc78uu-6 Sebm025118.pdf

SEBM025118

MACHINE MODEL

SERIAL NUMBER

PC78UU-6 PC78US-6 PC78US-6

22832 and up 4001 and up 4809 and up (For Norway & EU)

• This shop manual may contain attachments and optional equipment that are not available in your area. Please consult your local Komatsu distributor for those items you may require. Materials and specifications are subject to change without notice. • PC78UU-6, PC78US-6 mounts the 4D95LE-2 and S4D95LE-3-A engine. For details of the engine, see the 95-2 Series and 95-3 Series Engine Shop Manual. • For the PC78US-6 for Norway (Serial No. 4809 and up), the parts which different from the standard model have been put together and added as Section 50. For the common parts, see this manual.

© 2010 All Rights Reserved Printed in Japan 04-10(02)

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CONTENTS

No. of page 01

GENERAL. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 01-1

10

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD . . . . 10-1

20

TESTING AND ADJUSTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-1

30

DISASSEMBLY AND ASSEMBLY . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1

50

OTHER SPECIFICATIONS (PC78US-6 For Norway) . . . . . . . . . . . . 50-1

90

OTHERS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90-1

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PC78US-6

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SAFETY

SAFETY NOTICE

SAFETY SAFETY NOTICE IMPORTANT SAFETY NOTICE Proper service and repair is extremely important for safe machine operation. The service and repair techniques recommended by Komatsu and described in this manual are both effective and safe. Some of these techniques require the use of tools specially designed by Komatsu for the specific purpose. To prevent injury to workers, the symbol k is used to mark safety precautions in this manual. The cautions accompanying these symbols should always be followed carefully. If any dangerous situation arises or may possibly arise, first consider safety, and take the necessary actions to deal with the situation.

GENERAL PRECAUTIONS Mistakes in operation are extremely dangerous. Read the Operation and Maintenance Manual carefully BEFORE operating the machine. 1. Before carrying out any greasing or repairs, read all the precautions given on the decals which are fixed to the machine. 2. When carrying out any operation, always wear safety shoes and helmet. Do not wear loose work clothes, or clothes with buttons missing. • •

Always wear safety glasses when hitting parts with a hammer. Always wear safety glasses when grinding parts with a grinder, etc.

3. If welding repairs are needed, always have a trained, experienced welder carry out the work. When carrying out welding work, always wear welding gloves, apron, hand shield, cap and other clothes suited for welding work. 4. When carrying out any operation with two or more workers, always agree on the operating procedure before starting. Always inform your fellow workers before starting any step of the operation. Before starting work, hang UNDER REPAIR signs on the controls in the operator's compartment. 5. Keep all tools in good condition and learn the correct way to use them.

6. Decide a place in the repair workshop to keep tools and removed parts. Always keep the tools and parts in their correct places. Always keep the work area clean and make sure that there is no dirt or oil on the floor. Smoke only in the areas provided for smoking. Never smoke while working. PREPARATIONS FOR WORK 7. Before adding oil or making any repairs, park the machine on hard, level ground, and block the wheels or tracks to prevent the machine from moving. 8. Before starting work, lower blade, ripper, bucket or any other work equipment to the ground. If this is not possible, insert the safety pin or use blocks to prevent the work equipment from falling. In addition, be sure to lock all the control levers and hang warning signs on them. 9. When disassembling or assembling, support the machine with blocks, jacks or stands before starting work. 10.Remove all mud and oil from the steps or other places used to get on and off the machine. Always use the handrails, ladders or steps when getting on or off the machine. Never jump on or off the machine. If it is impossible to use the handrails, ladders or steps, use a stand to provide safe footing.

00-3

SAFETY

PRECAUTIONS DURING WORK 11. When removing the oil filler cap, drain plug or hydraulic pressure measuring plugs, loosen them slowly to prevent the oil from spurting out. Before disconnecting or removing components of the oil, water or air circuits, first remove the pressure completely from the circuit. 12.The water and oil in the circuits are hot when the engine is stopped, so be careful not to get burned. Wait for the oil and water to cool before carrying out any work on the oil or water circuits. 13.Before starting work, remove the leads from the battery. Always remove the lead from the negative (–) terminal first. 14.When raising heavy components, use a hoist or crane. Check that the wire rope, chains and hooks are free from damage. Always use lifting equipment which has ample capacity. Install the lifting equipment at the correct places. Use a hoist or crane and operate slowly to prevent the component from hitting any other part. Do not work with any part still raised by the hoist or crane. 15.When removing covers which are under internal pressure or under pressure from a spring, always leave two bolts in position on opposite sides. Slowly release the pressure, then slowly loosen the bolts to remove. 16.When removing components, be careful not to break or damage the wiring. Damaged wiring may cause electrical fires. 17.When removing piping, stop the fuel or oil from spilling out. If any fuel or oil drips onto the floor, wipe it up immediately. Fuel or oil on the floor can cause you to slip, or can even start fires. 18.As a general rule, do not use gasoline to wash parts. In particular, use only the minimum of gasoline when washing electrical parts.

00-4

SAFETY NOTICE

19.Be sure to assemble all parts again in their original places. Replace any damaged parts with new parts. • When installing hoses and wires, be sure that they will not be damaged by contact with other parts when the machine is being operated. 20.When installing high pressure hoses, make sure that they are not twisted. Damaged tubes are dangerous, so be extremely careful when installing tubes for high pressure circuits. Also, check that connecting parts are correctly installed. 21.When assembling or installing parts, always use the specified tightening torques. When installing protective parts such as guards, or parts which vibrate violently or rotate at high speed, be particularly careful to check that they are installed correctly. 22.When aligning two holes, never insert your fingers or hand. Be careful not to get your fingers caught in a hole. 23.When measuring hydraulic pressure, check that the measuring tool is correctly assembled before taking any measurements. 24.Take care when removing or installing the tracks of track-type machines. When removing the track, the track separates suddenly, so never let anyone stand at either end of the track.

FOREWORD

GENERAL

FOREWORD GENERAL This shop manual has been prepared as an aid to improve the quality of repairs by giving the serviceman an accurate understanding of the product and by showing him the correct way to perform repairs and make judgements. Make sure you understand the contents of this manual and use it to full effect at every opportunity.

This shop manual mainly contains the necessary technical information for operations performed in a service workshop. For ease of understanding, the manual is divided into the following chapters; these chapters are further divided into the each main group of components.

STRUCTURE AND FUNCTION This section explains the structure and function of each component. It serves not only to give an understanding of the structure, but also serves as reference material for troubleshooting. In addition, this section may contain hydraulic circuit diagrams, electric circuit diagrams, and maintenance standards. TESTING AND ADJUSTING This section explains checks to be made before and after performing repairs, as well as adjustments to be made at completion of the checks and repairs. Troubleshooting charts correlating "Problems" with "Causes" are also included in this section. DISASSEMBLY AND ASSEMBLY This section explains the procedures for removing, installing, disassembling and assembling each component, as well as precautions for them. MAINTENANCE STANDARD This section gives the judgment standards for inspection of disassembled parts. The contents of this section may be described in STRUCTURE AND FUNCTION. OTHERS This section mainly gives hydraulic circuit diagrams and electric circuit diagrams. In addition, this section may give the specifications of attachments and options together.

NOTICE The specifications contained in this shop manual are subject to change at any time and without any advance notice. Use the specifications given in the book with the latest date.

00-5

FOREWORD

HOW TO READ THE SHOP MANUAL

HOW TO READ THE SHOP MANUAL

REVISED EDITION MARK

VOLUMES Shop manuals are issued as a guide to carrying out repairs. They are divided as follows:

When a manual is revised, an edition mark ((1)(2)(3)....) is recorded on the bottom of the pages.

Chassis volume: Issued for every machine model Engine volume: Issued for each engine series Each issued as one Electrical volume: Attachments volume: · volume to cover all models

REVISIONS

}

These various volumes are designed to avoid duplicating the same information. Therefore, to deal with all repairs for any model , it is necessary that chassis, engine, electrical and attachment volumes be available. DISTRIBUTION AND UPDATING Any additions, amendments or other changes will be sent to KOMATSU distributors. Get the most up-todate information before you start any work.

FILING METHOD 1. See the page number on the bottom of the page. File the pages in correct order. 2. Following examples show how to read the page number. Example 1 (Chassis volume): 10 - 3 Item number (10. Structure and Function) Consecutive page number for each item. Example 2 (Engine volume): 12 - 5 Unit number (1. Engine) Item number (2. Testing and Adjusting) Consecutive page number for each item. 3. Additional pages: Additional pages are indicated by a hyphen (-) and number after the page number. File as in the example. Example: 12-203 10-4 12-203-1 10-4-1 Added pages 12-203-2 10-4-2 12-204 10-5

00-6

Revised pages are shown in the LIST OF REVISED PAGES next to the CONTENTS page.

SYMBOLS So that the shop manual can be of ample practical use, important safety and quality portions are marked with the following symbols.

Symbol

Item

Remarks

k

Safety

Special safety precautions are necessary when performing the work.

Caution

Special technical precautions or other precautions for preserving standards are necessary when performing the work.

Weight

Weight of parts of systems. Caution necessary when selecting hoisting wire, or when working posture is important, etc.

Tightening torque

Places that require special attention for the tightening torque during assembly.

Coat

Places to be coated with adhesives and lubricants, etc.

5

Oil, water

Places where oil, water or fuel must be added, and the capacity.

6

Drain

Places where oil or water m u s t b e d r a i n ed , a n d quantity to be drained.

a

4

3 2

FOREWORD

HOISTING INSTRUCTIONS

HOISTING INSTRUCTIONS HOISTING k Heavy parts (25 kg or more) must be lifted with a hoist, etc. In the DISASSEMBLY AND ASSEMBLY section, every part weighing 25 kg or more is indicated clearly with the symbol 4 •

If a part cannot be smoothly removed from the machine by hoisting, the following checks should be made: 1) Check for removal of all bolts fastening the part to the relative parts. 2) Check for existence of another part causing interference with the part to be removed.

WIRE ROPES 1) Use adequate ropes depending on the weight of parts to be hoisted, referring to the table below: Wire ropes (Standard "Z" or "S" twist ropes without galvanizing) Rope diameter

Allowable load

mm

kN

tons

10 11.5 12.5 14 16 18 20 22.4 30 40 50 60

9.8 13.7 15.7 21.6 27.5 35.3 43.1 54.9 98.1 176.5 274.6 392.2

1.0 1.4 1.6 2.2 2.8 3.6 4.4 5.6 10.0 18.0 28.0 40.0

Slinging near the edge of the hook may cause the rope to slip off the hook during hoisting, and a serious accident can result. Hooks have maximum strength at the middle portion.

100%

88%

79%

71%

41% SAD00479

3) Do not sling a heavy load with one rope alone, but sling with two or more ropes symmetrically wound onto the load.

k Slinging with one rope may cause turning of the load during hoisting, untwisting of the rope, or slipping of the rope from its original winding position on the load, which can result in a dangerous accident.

4) Do not sling a heavy load with ropes forming a wide hanging angle from the hook. When hoisting a load with two or more ropes, the force subjected to each rope will increase with the hanging angles. The table below shows the variation of allowable load kN {kg} when hoisting is made with two ropes, each of which is allowed to sling up to 9.8 kN {1000 kg} vertically, at various hanging angles. When two ropes sling a load vertically, up to 19.6 kN {2000 kg} of total weight can be suspended. This weight becomes 9.8 kN {1000 kg} when two ropes make a 120° hanging angle. On the other hand, two ropes are subjected to an excessive force as large as 39.2 kN {4000 kg} if they sling a 19.6 kN {2000 kg} load at a lifting angle of 150°.

! The allowable load value is estimated to be onesixth or one-seventh of the breaking strength of the rope used. 2) Sling wire ropes from the middle portion of the hook.

00-7

FOREWORD

METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER

METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER k Before carrying out the following work, release the residual pressure from the hydraulic tank. For details, see TESTING AND ADJUSTING, Releasing residual pressure from hydraulic tank. k Even if the residual pressure is released from the hydraulic tank, some hydraulic oil flows out when the hose is disconnected. Accordingly, prepare an oil receiving container. Disconnection 1) Release the residual pressure from the hydraulic tank. For details, see TESTING AND ADJUSTING, Releasing residual pressure from hydraulic tank. 2) Hold adapter (1) and push hose joint (2) into mating adapter (3). (See Fig. 1) ! The adapter can be pushed in about 3.5 mm. ! Do not hold rubber cap portion (4). 3) After hose joint (2) is pushed into adapter (3), press rubber cap portion (4) against (3) until it clicks. (See Fig. 2) 4) Hold hose adapter (1) or hose (5) and pull it out. (See Fig. 3) ! Since some hydraulic oil flows out, prepare an oil receiving container. Connection 1) Hold hose adapter (1) or hose (5) and insert it in mating adapter (3), aligning them with each other. (See Fig. 4) ! Do not hold rubber cap portion (4). 2) After inserting the hose in the mating adapter perfectly, pull it back to check its connecting condition. (See Fig. 5) ! When the hose is pulled back, the rubber cap portion moves toward the hose about 3.5 mm. This does not indicate abnormality, however.

00-8

Type 1

FOREWORD

METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER

Type 3

1) Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end.

1) Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end.

2) Hold in the condition in Step 1), and turn lever (4) to the right (clockwise).

2) Hold in the condition in Step 1), and push until cover (3) contacts contact surface a of the hexagonal portion at the male end.

3) Hold in the condition in Steps 1) and 2), and pull out whole body (2) to disconnect it.

3) Hold in the condition in Steps 1) and 2), and pull out whole body (2) to disconnect it.

•

•

Disassembly

Type 2

Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end to connect it.

Connection

Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end to connect it.

00-9

FOREWORD

COATING MATERIALS

COATING MATERIALS ! The recommended coating materials such as adhesives, gasket sealants and greases used for disassembly and assembly are listed below. ! For coating materials not listed below, use the equivalent of products shown in this list. Category

Komatsu code

Part No.

LT-1A

790-129-9030

LT-1B

790-129-9050

LT-2

09940-00030

LT-3

790-129-9060 (Set of adhesive and hardening agent)

LT-4

790-129-9040

Holtz MH 705

790-126-9120

Three bond 1735

790-129-9140

Aron-alpha 201

790-129-9130

Loctite 648-50

79A-129-9110

LG-1

790-129-9010

LG-5

790-129-9080

LG-6

790-129-9020

LG-7

790-129-9070

Three bond 1211

790-129-9090

Three bond 1207B

419-15-18131

Adhesives

Gasket sealant

00-10

Q’ty

Container

Main applications, features

• Used to prevent rubber gaskets, rubber cushions, and cock plug from coming out. • Used in places requiring an immediately effective, strong adhesive. Used for plastics (except polyethylene, 20 g Polyethylene polyprophylene, tetrafluoroethlene and (2 pcs.) container vinyl chloride), rubber, metal and nonmetal. • Features: Resistance to heat and chemicals Polyethylene 50 g • Used for anti-loosening and sealant container purpose for bolts and plugs. • Used as adhesive or sealant for metal, Adhesive: glass and plastic. 1 kg Hardening Can agent: 500 g Polyethylene • Used as sealant for machined holes. 250 g container • Used as heat-resisting sealant for 75 g Tube repairing engine. • Quick hardening type adhesive Polyethylene • Cure time: within 5 sec. to 3 min. 50 g container • Used mainly for adhesion of metals, rubbers, plastics and woods. • Quick hardening type adhesive • Quick cure type Polyethylene (max. strength after 30 minutes) 2g container • Used mainly for adhesion of rubbers, plastics and metals. • Resistance to heat, chemicals Polyethylene • Used at joint portions subject to high 50 cc container temperatures. • Used as adhesive or sealant for gaskets 200 g Tube and packing of power train case, etc. • Used as sealant for various threads, pipe joints, flanges. 1 kg Can • Used as sealant for tapered plugs, elbows, nipples of hydraulic piping. • Features: Silicon based, resistance to heat, cold 200 g Tube • Used as sealant for flange surface, tread. • Used as sealant for oil pan, final drive case, etc. • Features: Silicon based, quick hardening type • Used as sealant for flywheel housing, 1 kg Tube intake manifold, oil pan, thermostat housing, etc. • Used as heat-resisting sealant for 100 g Tube repairing engine. • Features: Silicone type, heat resistant, vibration resistant, and impact resistant 100 g Tube sealing material • Used as sealing material for transfer case 150 g

Tube

FOREWORD

Molybdenum disulphide lubricant

Komatsu code

Part No.

Q’ty

Container

LM-G

09940-00051

60 g

Can

LM-P

09940-00040

200 g

Tube

Various

Various

G2-LI

G2-CA

Grease

Primer

Adhesive

Caulking material

SYG2-400LI SYG2-350LI SYG2-400LI-A SYG2-160LI SYGA-160CNLI SYG2-400CA SYG2-350CA SYG2-400CA-A SYG2-160CA SYGA-160CNCA

Molybdenum disulphide grease LM-G (G2-M) Hyper White Grease G2-T G0-T (*) *: For use in cold district Biogrease G2B G2-BT (*) *: For high temperature and large load SUNSTAR PAINT PRIMER 580 SUPER SUNSTAR GLASS PRIMER 580 SUPER SUNSTAR PAINT PRIMER 435-95

SYG2-400B SYGA-16CNB SYG2-400BT (*) SYGA-16CNBT (*)

SUNSTAR GLASS PRIMER 435-41 SUNSTAR SASH PRIMER GP-402 SUNSTAR PENGUINE SUPER 560 SUNSTAR PENGUINE SEAL 580 SUPER “S” or “W” Sika Japan, Sikaflex 256HV SUNSTAR PENGUINE SEAL No. 2505 SEKISUI SILICONE SEALANT GE TOSHIBA SILICONES TOSSEAL 381

SYG2-400M SYG2-400M-A SYGA-16CNM SYG2-400T-A SYG2-16CNT SYG0-400T-A (*) SYG0-16CNT (*)

Various

Various

400 g × 10 Bellows type 400 g × 20 Bellows type 16 kg Can

400 g 16 kg

400 g 16 kg

Main applications, features • Used as lubricant for sliding portion (to prevent from squeaking). • Used to prevent seizure or scuffling of the thread when press fitting or shrink fitting. • Used as lubricant for linkage, bearings, etc. • General purpose type

• Used for normal temperature, light load bearing at places in contact with water or steam.

• Used for heavy load portion

• Seizure resistance and heat resistance higher than molybdenum disulfide grease Bellows type • Since this grease is white, it does not Can stand out against machine body. • Since this grease is decomposed by bacteria in short period, it has less effects Bellows type on microorganisms, animals, and plants. Can

20 ml

Glass container

20 ml

Glass container

22M-54-27230

20 ml

Glass container

22M-54-27240

150 ml

Can

22M-54-27250

20 ml

Glass container

22M-54-27210

320 ml

Ecocart (Special container)

• Used as primer for cab side (Using limit: 4 months)

417-926-3910

417-926-3910

320 ml

Polyethylene container

20Y-54-39850

310 ml

Polyethylene container

417-926-3920

320 ml

Polyethylene container

20Y-54-55130

333 ml

Polyethylene container

22M-54-27220

333 ml

Cartridge

• Used as primer for glass side (Using limit: 4 months)

Adhesive for cab glass

Category

COATING MATERIALS

• Used as primer for painted surface on cab side (Using limit: 4 months) • Used as primer for black ceramiccoated surface on glass side and for hard polycarbonate-coated surface (Using limit: 4 months) • Used as primer for sash (Alumite). (Using limit: 4 months) • Used as adhesive for glass. (Using limit: 6 months) • “S” is used for high-temperature season (April - October) and “W” for low-temperature season (November April) as adhesive for glass. (Using limit: 4 months) • Used as adhesive for glass. (Using limit: 6 months) • Used to seal joints of glass parts. (Using limit: 4 months) • Used to seal front window. (Using limit: 6 months) • Used to seal joint of glasses. Translucent white seal. (Using limit: 12 months)

00-11

FOREWORD

STANDARD TIGHTENING TORQUE

STANDARD TIGHTENING TORQUE STANDARD TIGHTENING TORQUE TABLE (WHEN USING TORQUE WRENCH) ! In the case of metric nuts and bolts for which there is no special instruction, tighten to the torque given in the table below. Tightening torque Thread diameter of bolt

Width across flats

mm

mm

Nm

kgm

6 8 10 12 14

10 13 17 19 22

11.8 – 14.7 27 – 34 59 – 74 98 – 123 153 – 190

1.2 – 1.5 2.8 – 3.5 6 – 7.5 10 – 12.5 15.5 – 19.5

16 18 20 22 24

24 27 30 32 36

235 – 285 320 – 400 455 – 565 610 – 765 785 – 980

23.5 – 29.5 33 – 41 46.5 – 58 62.5 – 78 80 – 100

27 30 33 36 39

41 46 50 55 60

1150 – 1440 1520 – 1910 1960 – 2450 2450 – 3040 2890 – 3630

118 – 147 155 – 195 200 – 250 250 – 310 295 – 370

Thread diameter of bolt

Width across flats

mm

mm

Nm

kgm

6 8 10 12

10 13 14 27

5.9 – 9.8 13.7 – 23.5 34.3 – 46.1 74.5 – 90.2

0.6 – 1.0 1.4 – 2.4 3.5 – 4.7 7.6 – 9.2

Tightening torque

Sealing surface

TABLE OF TIGHTENING TORQUES FOR FLARED NUTS ! In the case of flared nuts for which there is no special instruction, tighten to the torque given in the table below.

SAD00483

Thread diameter

Width across flat

mm

mm

Nm

kgm

14 18 22 24 30 33 36 42

19 24 27 32 36 41 46 55

24.5 ± 4.9 49 ± 19.6 78.5 ± 19.6 137.3 ± 29.4 176.5 ± 29.4 196.1 ± 49 245.2 ± 49 294.2 ± 49

2.5 ± 0.5 5±2 8±2 14 ± 3 18 ± 3 20 ± 5 25 ± 5 30 ± 5

00-12

Tightening torque

FOREWORD

STANDARD TIGHTENING TORQUE

TABLE OF TIGHTENING TORQUES FOR SPLIT FLANGE BOLTS ! In the case of split flange bolts for which there is no special instruction, tighten to the torque given in the table below.

Thread diameter

Width across flat

Tightening torque

mm

mm

Nm

kgm

10 12 16

14 17 22

59 – 74 98 – 123 235 – 285

6 – 7.5 10 – 12.5 23.5 – 29.5

TABLE OF TIGHTENING TORQUES FOR O-RING BOSS PIPING JOINTS ! Unless there are special instructions, tighten the O-ring boss piping joints to the torque below.

Thread diameter

Width across flat

mm

mm

14 20 24 33 42

Varies depending on type of connector.

Tightening torque (Nm {kgm})

Norminal No.

02 03, 04 05, 06 10, 12 14

Range 35 – 63 84 – 132 128 – 186 363 – 480 746 – 1010

{3.5 – 6.5} {8.5 – 13.5} {13.0 – 19.0} {37.0 – 49.0} {76.0 – 103}

Target 44 {4.5} 103 {10.5} 157 {16.0} 422 {43.0} 883 {90.0}

TABLE OF TIGHTENING TORQUES FOR O-RING BOSS PLUGS ! Unless there are special instructions, tighten the O-ring boss plugs to the torque below.

Thread diameter

Width across flat

mm

mm

08 10 12 14 16 18 20 24 30 33 36 42 52

14 17 19 22 24 27 30 32 32 — 36 — —

Tightening torque (Nm {kgm})

Norminal No.

08 10 12 14 16 18 20 24 30 33 36 42 52

Range 5.88 – 8.82 9.8 – 12.74 14.7 – 19.6 19.6 – 24.5 24.5 – 34.3 34.3 – 44.1 44.1 – 53.9 58.8 – 78.4 93.1 – 122.5 107.8 – 147.0 127.4 – 176.4 181.3 – 240.1 274.4 – 367.5

{0.6 – 0.9} {1.0 – 1.3} {1.5 – 2.0} {2.0 – 2.5} {2.5 – 3.5} {3.5 – 4.5} {4.5 – 5.5} {6.0 – 8.0} {9.5 – 12.5} {11.0 – 15.0} {13.0 – 18.0} {18.5 – 24.5} {28.0 – 37.5}

Target 7.35 {0.75} 11.27 {1.15} 17.64 {1.8} 22.54 {2.3} 29.4 {3.0} 39.2 {4.0} 49.0 {5.0} 68.6 {7.0} 107.8 {11.0} 124.4 {13.0} 151.9 {15.5} 210.7 {21.5} 323.4 {33.0}

00-13

FOREWORD

STANDARD TIGHTENING TORQUE

TIGHTENING TORQUE FOR 102 AND 114 ENGINE SERIES 1) BOLT AND NUTS Use these torques for bolts and nuts (unit: mm) of Cummins Engine. Thread diameter

Tightening torque

mm

Nm

kgm

6 8 10 12

10 ± 2 24 ± 4 43 ± 6 77 ± 12

1.02 ± 0.20 2.45 ± 0.41 4.38 ± 0.61 7.85 ± 1.22

2) EYE JOINTS Use these torques for eye joints (unit: mm) of Cummins Engine. Thread diameter

Tightening torque

mm

Nm

kgm

6 8 10 12 14

8±2 10 ± 2 12 ± 2 24 ± 4 36 ± 5

0.81 ± 0.20 1.02 ± 0.20 1.22 ± 0.20 2.45 ± 0.41 3.67 ± 0.51

3) TAPERED SCREWS Use these torques for tapered screws (unit: inch) of Cummins Engine. Thread diameter

Tightening torque

inch

Nm

kgm

1 / 16 1/8 1/4 3/8 1/2 3/4 1

3±1 8±2 12 ± 2 15 ± 2 24 ± 4 36 ± 5 60 ± 9

0.31 ± 0.10 0.81 ± 0.20 1.22 ± 0.20 1.53 ± 0.20 2.45 ± 0.41 3.67 ± 0.51 6.12 ± 0.92

TIGHTENING TORQUE TABLE FOR HOSES (TAPER SEAL TYPE AND FACE SEAL TYPE) ! Tighten the hoses (taper seal type and face seal type) to the following torque, unless otherwise specified. ! Apply the following torque when the threads are coated (wet) with engine oil. Tightening torque (Nm {kgm}) Nominal size Width across of hose flats

Taper seal type

Face seal type

Thread size Nominal thread Root diameter size - Threads per (mm) (Reference) (mm) inch, Thread series

Range

Target

34 – 54 {3.5 – 5.5}

44 {4.5}

–

9 — – 18UN 16

14.3

34 – 63 {3.5 – 6.5}

44 {4.5}

14

–

–

22

54 – 93 {5.5 – 9.5}

74 {7.5}

–

11 — – 16UN 16

17.5

24

59 – 98 {6.0 – 10.0}

78 {8.0}

18

–

–

04

27

84 – 132 {8.5 – 13.5}

103 {10.5}

22

13 — – 16UN 16

20.6

05

32

128 – 186 {13.0 – 19.0}

157 {16.0}

24

1 – 14UNS

25.4

06

36

177 – 245 {18.0 – 25.0}

216 {22.0}

30

3 1 — – 12UN 16

30.2

(10)

41

177 – 245 {18.0 – 25.0}

216 {22.0}

33

–

–

(12)

46

197 – 294 {20.0 – 30.0}

245 {25.0}

36

–

–

(14)

55

246 – 343 {25.0 – 35.0}

294 {30.0}

42

–

–

02

03

00-14

19

FOREWORD

ELECTRIC WIRE CODE

ELECTRIC WIRE CODE In the wiring diagrams, various colors and symbols are employed to indicate the thickness of wires. This wire code table will help you understand WIRING DIAGRAMS. Example: 5WB indicates a cable having a nominal number 5 and white coating with black stripe.

CLASSIFICATION BY THICKNESS Copper wire Cable O.D. (mm)

Current rating (A)

Applicable circuit

0.88

2.4

12

Starting, lighting, signal etc.

0.32

2.09

3.1

20

Lighting, signal etc.

65

0.32

5.23

4.6

37

Charging and signal

15

84

0.45

13.36

7.0

59

Starting (Glow plug)

40

85

0.80

42.73

11.4

135

Starting

60

127

0.80

63.84

13.6

178

Starting

100

217

0.80

109.1

17.6

230

Starting

Norminal number

Number of strands

Dia. of strands (mm2)

Cross section (mm2)

0.85

11

0.32

2

26

5

CLASSIFICATION BY COLOR AND CODE Circuits Priority Classification

1

Primary

Charging

Ground

Starting

Lighting

Instrument

Signal

Other

Code

W

B

B

R

Y

G

L

Color

White

Black

Black

Red

Yellow

Green

Blue

Code

WR

—

BW

RW

YR

GW

LW

2 Color White & Red

—

Code

—

WB

White & Black Red & White Rellow & Red Green & White Blue & White BY

RB

YB

GR

LR

3

4

Auxiliary

Color White & Black

—

Code

—

WL

Black & Yellow Red & Black Yellow & Black Green & Red Blue & Yellow BR

Color White & Blue

—

Code

—

—

Color White & Green

—

—

Code

—

—

—

Color

—

—

—

WG

RY

Black & Red Red & Yellow RG

YG

GY

LY

Yellow & Green

Green & Yellow

Blue & Yellow

YL

GB

LB

5 Red & Green Yellow & Blue Green & Black Blue & Black RL

YW

GL

—

6 Red & Blue Yellow & White Green & Blue

—

00-15

FOREWORD

CONVERSION TABLE

CONVERSION TABLE METHOD OF USING THE CONVERSION TABLE The Conversion Table in this section is provided to enable simple conversion of figures. For details of the method of using the Conversion Table, see the example given below.

EXAMPLE • Method of using the Conversion Table to convert from millimeters to inches 1. Convert 55 mm into inches. (1) Locate the number 50 in the vertical column at the left side, take this as (A), then draw a horizontal line from (A). (2) Locate the number 5 in the row across the top, take this as (B), then draw a perpendicular line down from (B). (3) Take the point where the two lines cross as (C). This point (C) gives the value when converting from millimeters to inches. Therefore, 55 mm = 2.165 inches. 2. Convert 550 mm into inches. (1) The number 550 does not appear in the table, so divide by 10 (move the decimal point one place to the left) to convert it to 55 mm. (2) Carry out the same procedure as above to convert 55 mm to 2.165 inches. (3) The original value (550 mm) was divided by 10, so multiply 2.165 inches by 10 (move the decimal point one place to the right) to return to the original value. This gives 550 mm = 21.65 inches. (B) Millimeters to inches 1 mm = 0.03937 in

(A)

00-16

0

1

2

3

4

0 10 20 30 40

0 0.394 0.787 1.181 1.575

0.039 0.433 0.827 1.220 1.614

0.079 0.472 0.866 1.260 1.654

0.118 0.512 0.906 1.299 1.693

0.157 0.551 0.945 1.339 1.732

50 60 70 80 90

1.969 2.362 2.756 3.150 3.543

2.008 2.402 2.795 3.189 3.583

2.047 2.441 2.835 3.228 3.622

2.087 2.480 2.874 3.268 3.661

2.126 2.520 2.913 3.307 3.701

5 0.197 0.591 0.984 1.378 1.772 (C) 2.165 2.559 2.953 3.346 3.740

6

7

8

9

0.236 0.630 1.024 1.417 1.811

0.276 0.669 1.063 1.457 1.850

0.315 0.709 1.102 1.496 1.890

0.354 0.748 1.142 1.536 1.929

2.205 2.598 2.992 3.386 3.780

2.244 2.638 3.032 3.425 3.819

2.283 2.677 3.071 3.465 3.858

2.323 2.717 3.110 3.504 3.898

FOREWORD

CONVERSION TABLE

Millimeters to Inches 1 mm = 0.03937 in

0

1

2

3

4

5

6

7

8

9

0

0.039

0.079

0.118

0.157

0.197

0.236

0.276

0.315

0.354

10

0.394

0.433

0.472

0.512

0.551

0.591

0.630

0.669

0.709

0.748

20

0.787

0.827

0.866

0.906

0.945

0.984

1.024

1.063

1.102

1.142

30

1.181

1.220

1.260

1.299

1.339

1.378

1.417

1.457

1.496

1.536

40

1.575

1.614

1.654

1.693

1.732

1.772

1.811

1.850

1.890

1.929

50

1.969

2.008

2.047

2.087

2.126

2.165

2.205

2.244

2.283

2.323

60

2.362

2.402

2.441

2.480

2.520

2.559

2.598

2.638

2.677

2.717

70

2.756

2.795

2.835

2.874

2.913

2.953

2.992

3.032

3.071

3.110

80

3.150

3.189

3.228

3.268

3.307

3.346

3.386

3.425

3.465

3.504

90

3.543

3.583

3.622

3.661

3.701

3.740

3.780

3.819

3.858

3.898

0

Kilogram to Pound 1 kg = 2.2046 lb

0 0

0

1

2

3

4

5

6

7

8

9

2.20

4.41

6.61

8.82

11.02

13.23

15.43

17.64

19.84

10

22.05

24.25

26.46

28.66

30.86

33.07

35.27

37.48

39.68

41.89

20

44.09

46.30

48.50

50.71

51.91

55.12

57.32

59.53

61.73

63.93

30

66.14

68.34

70.55

72.75

74.96

77.16

79.37

81.57

83.78

85.98

40

88.18

90.39

92.59

94.80

97.00

99.21

101.41

103.62

105.82

108.03

50

110.23

112.44

114.64

116.85

119.05

121.25

123.46

125.66

127.87

130.07

60

132.28

134.48

136.69

138.89

141.10

143.30

145.51

147.71

149.91

152.12

70

154.32

156.53

158.73

160.94

163.14

165.35

167.55

169.76

171.96

174.17

80

176.37

178.57

180.78

182.98

185.19

187.39

189.60

191.80

194.01

196.21

90

198.42

200.62

202.83

205.03

207.24

209.44

211.64

213.85

216.05

218.26

00-17

FOREWORD

CONVERSION TABLE

Liter to U.S. Gallon 1l = 0.2642 U.S. Gal

0

1

2

3

4

5

6

7

8

9

0

0.264

0.528

0.793

1.057

1.321

1.585

1.849

2.113

2.378

10

2.642

2.906

3.170

3.434

3.698

3.963

4.227

4.491

4.755

5.019

20

5.283

5.548

5.812

6.076

6.340

6.604

6.869

7.133

7.397

7.661

30

7.925

8.189

8.454

8.718

8.982

9.246

9.510

9.774

10.039

10.303

40

10.567

10.831

11.095

11.359

11.624

11.888

12.152

12.416

12.680

12.944

50

13.209

13.473

13.737

14.001

14.265

14.529

14.795

15.058

15.322

15.586

60

15.850

16.115

16.379

16.643

16.907

17.171

17.435

17.700

17.964

18.228

70

18.492

18.756

19.020

19.285

19.549

19.813

20.077

20.341

20.605

20.870

80

21.134

21.398

21.662

21.926

22.190

22.455

22.719

22.983

23.247

23.511

90

23.775

24.040

24.304

24.568

24.832

25.096

25.361

25.625

25.889

26.153

0

Liter to U.K. Gallon 1l = 0.21997 U.K. Gal

0

1

2

3

4

5

6

7

8

9

0

0.220

0.440

0.660

0.880

1.100

1.320

1.540

1.760

1.980

10

2.200

2.420

2.640

2.860

3.080

3.300

3.520

3.740

3.950

4.179

20

4.399

4.619

4.839

5.059

5.279

5.499

5.719

5.939

6.159

6.379

30

6.599

6.819

7.039

7.259

7.479

7.969

7.919

8.139

8.359

8.579

40

8.799

9.019

9.239

9.459

9.679

9.899

10.119

10.339

10.559

10.778

50

10.998

11.281

11.438

11.658

11.878

12.098

12.318

12.528

12.758

12.978

60

13.198

13.418

13.638

13.858

14.078

14.298

14.518

14.738

14.958

15.178

70

15.398

15.618

15.838

16.058

16.278

16.498

16.718

16.938

17.158

17.378

80

17.598

17.818

18.037

18.257

18.477

18.697

18.917

19.137

19.357

19.577

90

19.797

20.017

20.237

20.457

20.677

20.897

21.117

21.337

21.557

21.777

0

00-18

FOREWORD

CONVERSION TABLE

kgm to ft. lb 1 kgm = 7.233 ft. lb

0

1

2

3

4

5

6

7

8

9

0

0

7.2

14.5

21.7

28.9

36.2

43.4

50.6

57.9

65.1

10

72.3

79.6

86.8

94.0

101.3

108.5

115.7

123.0

130.2

137.4

20

144.7

151.9

159.1

166.4

173.6

180.8

188.1

195.3

202.5

209.8

30

217.0

224.2

231.5

238.7

245.9

253.2

260.4

267.6

274.9

282.1

40

289.3

296.6

303.8

311.0

318.3

325.5

332.7

340.0

347.2

354.4

50

361.7

368.9

376.1

383.4

390.6

397.8

405.1

412.3

419.5

426.8

60

434.0

441.2

448.5

455.7

462.9

470.2

477.4

484.6

491.8

499.1

70

506.3

513.5

520.8

528.0

535.2

542.5

549.7

556.9

564.2

571.4

80

578.6

585.9

593.1

600.3

607.6

614.8

622.0

629.3

636.5

643.7

90

651.0

658.2

665.4

672.7

679.9

687.1

694.4

701.6

708.8

716.1

100

723.3

730.5

737.8

745.0

752.2

759.5

766.7

773.9

781.2

788.4

110

795.6

802.9

810.1

817.3

824.6

831.8

839.0

846.3

853.5

860.7

120

868.0

875.2

882.4

889.7

896.9

904.1

911.4

918.6

925.8

933.1

130

940.3

947.5

954.8

962.0

969.2

976.5

983.7

990.9

998.2

1005.4

140

1012.6

1019.9

1027.1

1034.3

1041.5

1048.8

1056.0

1063.2

1070.5

1077.7

150

1084.9

1092.2

1099.4

1106.6

1113.9

1121.1

1128.3

1135.6

1142.8

1150.0

160

1157.3

1164.5

1171.7

1179.0

1186.2

1193.4

1200.7

1207.9

1215.1

1222.4

170

1129.6

1236.8

1244.1

1251.3

1258.5

1265.8

1273.0

1280.1

1287.5

1294.7

180

1301.9

1309.2

1316.4

1323.6

1330.9

1338.1

1345.3

1352.6

1359.8

1367.0

190

1374.3

1381.5

1388.7

1396.0

1403.2

1410.4

1417.7

1424.9

1432.1

1439.4

00-19

FOREWORD

CONVERSION TABLE

kg/cm2 to lb/in2 1kg/cm2 = 14.2233 lb/in2

0

1

2

3

4

5

6

7

8

9

0

0

14.2

28.4

42.7

56.9

71.1

85.3

99.6

113.8

128.0

10

142.2

156.5

170.7

184.9

199.1

213.4

227.6

241.8

256.0

270.2

20

284.5

298.7

312.9

327.1

341.4

355.6

369.8

384.0

398.3

412.5

30

426.7

440.9

455.1

469.4

483.6

497.8

512.0

526.3

540.5

554.7

40

568.9

583.2

597.4

611.6

625.8

640.1

654.3

668.5

682.7

696.9

50

711.2

725.4

739.6

753.8

768.1

782.3

796.5

810.7

825.0

839.2

60

853.4

867.6

881.8

896.1

910.3

924.5

938.7

953.0

967.2

981.4

70

995.6

1010

1024

1038

1053

1067

1081

1095

1109

1124

80

1138

1152

1166

1181

1195

1209

1223

1237

1252

1266

90

1280

1294

1309

1323

1337

1351

1365

1380

1394

1408

100

1422

1437

1451

1465

1479

1493

1508

1522

1536

1550

110

1565

1579

1593

1607

1621

1636

1650

1664

1678

1693

120

1707

1721

1735

1749

1764

1778

1792

1806

1821

1835

130

1849

1863

1877

1892

1906

1920

1934

1949

1963

1977

140

1991

2005

2020

2034

2048

2062

2077

2091

2105

2119

150

2134

2148

2162

2176

2190

2205

2219

2233

2247

2262

160

2276

2290

2304

2318

2333

2347

2361

2375

2389

2404

170

2418

2432

2446

2460

2475

2489

2503

2518

2532

2546

180

2560

2574

2589

2603

2617

2631

2646

2660

2674

2688

190

2702

2717

2731

2745

2759

2773

2788

2802

2816

2830

200

2845

2859

2873

2887

2901

2916

2930

2944

2958

2973

210

2987

3001

3015

3030

3044

3058

3072

3086

3101

3115

220

3129

3143

3158

3172

3186

3200

3214

3229

3243

3257

230

3271

3286

3300

3314

3328

3343

3357

3371

3385

3399

240

3414

3428

3442

3456

3470

3485

3499

3513

3527

3542

00-20

FOREWORD

CONVERSION TABLE

Temperature Fahrenheit-Centigrade Conversion ; a simple way to convert a Fahrenheit temperature reading into a Centigrade temperature reading or vice versa is to enter the accompanying table in the center or boldface column of figures. These figures refer to the temperature in either Fahrenheit or Centigrade degrees. If it is desired to convert from Fahrenheit to Centigrade degrees, consider the center column as a table of Fahrenheit temperatures and read the corresponding Centigrade temperature in the column at the left. If it is desired to convert from Centigrade to Fahrenheit degrees, consider the center column as a table of Centigrade values, and read the corresponding Fahrenheit temperature on the right. 1°C = 33.8°F

°C

°F

°C

°F

°C

°F

°C

°F

–40.4 –37.2 –34.4 –31.7 –28.9

–40 –35 –30 –25 –20

–40.0 –31.0 –22.0 –13.0 –4.0

–11.7 –11.1 –10.6 –10.0 –9.4

11 12 13 14 15

51.8 53.6 55.4 57.2 59.0

7.8 8.3 8.9 9.4 10.0

46 47 48 49 50

114.8 116.6 118.4 120.2 122.0

27.2 27.8 28.3 28.9 29.4

81 82 83 84 85

117.8 179.6 181.4 183.2 185.0

–28.3 –27.8 –27.2 –26.7 –26.1

–19 –18 –17 –16 –15

–2.2 –0.4 1.4 3.2 5.0

–8.9 –8.3 –7.8 –7.2 –6.7

16 17 18 19 20

60.8 62.6 64.4 66.2 68.0

10.6 11.1 11.7 12.2 12.8

51 52 53 54 55

123.8 125.6 127.4 129.2 131.0

30.0 30.6 31.1 31.7 32.2

86 87 88 89 90

186.8 188.6 190.4 192.2 194.0

–25.6 –25.0 –24.4 –23.9 –23.3

–14 –13 –12 –11 –10

6.8 8.6 10.4 12.2 14.0

–6.1 –5.6 –5.0 –4.4 –3.9

21 22 23 24 25

69.8 71.6 73.4 75.2 77.0

13.3 13.9 14.4 15.0 15.6

56 57 58 59 0

132.8 134.6 136.4 138.2 140.0

32.8 33.3 33.9 34.4 35.0

91 92 93 94 95

195.8 197.6 199.4 201.2 203.0

–22.8 –22.2 –21.7 –21.1 –20.6

–9 –8 –7 –6 –5

15.8 17.6 19.4 21.2 23.0

–3.3 –2.8 –2.2 –1.7 –1.1

26 27 28 29 30

78.8 80.6 82.4 84.2 86.0

16.1 16.7 17.2 17.8 18.3

61 62 63 64 65

141.8 143.6 145.4 147.2 149.0

35.6 36.1 36.7 37.2 37.8

96 97 98 99 100

204.8 206.6 208.4 210.2 212.0

–20.0 –19.4 –18.9 –18.3 –17.8

–4 –3 –2 –1 0

24.8 26.6 28.4 30.2 32.0

–0.6 0 0.6 1.1 1.7

31 32 33 34 35

87.8 89.6 91.4 93.2 95.0

18.9 19.4 20.0 20.6 21.1

66 67 68 69 70

150.8 152.6 154.4 156.2 158.0

40.6 43.3 46.1 48.9 51.7

105 110 115 120 125

221.0 230.0 239.0 248.0 257.0

–17.2 –16.7 –16.1 –15.6 –15.0

1 2 3 4 5

33.8 35.6 37.4 39.2 41.0

2.2 2.8 3.3 3.9 4.4

36 37 38 39 40

96.8 98.6 100.4 102.2 104.0

21.7 22.2 22.8 23.3 23.9

71 72 73 74 75

159.8 161.6 163.4 165.2 167.0

54.4 57.2 60.0 62.7 65.6

130 135 140 145 150

266.0 275.0 284.0 293.0 302.0

–14.4 –13.9 –13.3 –12.8 –12.2

6 7 8 9 10

42.8 44.6 46.4 48.2 50.0

5.0 5.6 6.1 6.7 7.2

41 42 43 44 45

105.8 107.6 109.4 111.2 113.0

24.4 25.0 25.6 26.1 26.7

76 77 78 79 80

168.8 170.6 172.4 174.2 176.0

68.3 71.1 73.9 76.7 79.4

155 160 165 170 175

311.0 320.0 329.0 338.0 347.0

00-21

FOREWORD

UNITS

UNITS In this manual, the measuring units are indicated with Internatinal System of units (SI). As for reference, conventionally used Gravitational System of units are indicated in parentheses {

}.

Example: N {kg} Nm {kgm} MPa {kg/cm2} kPa {mmH2O} kPa {mmHg} kW/rpm {HP/rpm} g/kWh {g/HPh}

00-22

04-05

01 GENERAL Specifiaction dimensions drawing ............... 01- 2 Working range drawing ................................. 01- 4 Specifications ................................................. 01- 6 Weight table ................................................... 01-18 List of lubricants and coolant ........................ 01-22

PC78US-6

01-1

GENERAL

SPECIFICATION DIMENSIONS DRAWING

12

SPECIFICATION DIMENSIONS DRAWING PC78US-6

Item Machine weight

Unit

Standard spec. Blade sped.

Bucket capacity Engine model Rated engine output

kg

PC78US-6 Steel shoe spec.

Road liner spec.

Rubber shoe spec.

6,850

6,880

6,780

7,190

7,220

7,120

m³ *1 *2

0.28 KOMATSU 4D95LE-2 Diesel engine

—

KOMATSU S4D95LE-3-A Diesel engine

kW {HP}/rpm

40.5 {54.0}/1,850

A

Overall length

mm

5,770

B

Overall height

mm

C

Overall width

mm

2,730

2,750

2,730

2,330

D

Shoe width

mm

450

E

Tail swing radius

mm

1,240

F

Overall length of track

mm

2,840

2,900

2,880

G

Distance between tumbler centers

mm

2,235

2,235

2,265

Minimum ground clearance

mm

360

400

380

Travel speed (Low/High)

km/h

Continuous swing speed

rpm

3.0/4.5

3.2/4.8 10.0

*1. Serial No.: 4001 – 5500 *2. Serial No.: 5501 and up

01-2

PC78US-6

GENERAL

SPECIFICATION DIMENSIONS DRAWING

PC78UU-6

Item

Unit

Machine weight

kg

Bucket capacity Engine model Rated engine output

PC78UU-6 Road liner spec.

Rubber shoe spec.

Steel shoe spec.

7,700

7,600

7,670

m³ *1 *2

0.28 KOMATSU 4D95LE-2 Diesel engine

—

KOMATSU S4D95LE-3-A Diesel engine

kW {HP}/rpm

40.5 {54.0}/1,850 6,060

A

Overall length

mm

B

Overall height

mm

2,750

2,730

2,730

C

Overall width

mm

2,330

D

Shoe width

mm

450

E

Tail swing radius

mm

1,240

F

Overall length of track

mm

2,900

2,880

2,840

G

Distance between tumbler centers

mm

2,235

2,265

2,235

Minimum ground clearance

mm

400

380

360

Travel speed (Low/High)

km/h

3.0/4.5

3.2/4.8

3.0/4.5

Continuous swing speed

rpm

10.0

*1. Serial No.: 22832 – 23500 *2. Serial No.: 23501 and up

PC78US-6

01-3

GENERAL

WORKING RANGE DRAWING

WORKING RANGE DRAWING

Working range (mm)

PC78US-6

PC78UU-6

A

Max. digging reach

6,380

6,400

B

Max. digging depth

4,100

4,200

C

Max. digging height

7,300

7,360

D

Max. vertical wall depth

3,610

3,160

E

Max. dumping height

5,180

5,290

F

Min. swing radius of work equipment

1,750

1,200

G

Max. reach at ground level

6,240

6,240

H

Max. blade lifting height

380

415

I

Max. blade lowering depth

245

210

01-4

PC78US-6

GENERAL

SPECIFICATIONS

SPECIFICATIONS PC78US-6 PC78US-6

Machine model

Blade-less specification

Serial Number 0.28

0.28

kg

6,850 (6,880) [6,780]

7,190 (7,220) [7,120]

Max. digging depth

mm

4,100

4,100

Max. vertical wall depth

mm

3,610

3,610

Max. digging reach

mm

6,380

6,380

Max. reach at ground level

mm

6,240

6,240

Max. digging height

mm

7,300

7,300

Max. dumping height

mm

5,180

5,180

Max. blade lifting height

mm

–

Working range

Machine weight

Performance

4001 – 5500 m3

Bucket capacity

Max. blade lowering depth Max. digging force (Bucket) Continuous swing speed

380

mm

–

kN {kg}

61.29 {6,250}

61.29 {6,250}

rpm

10.0

10.0

245

Max. slope angle for swing

deg.

20.0

19.0

Travel speed (Low/High)

km/h

3.0/4.5 [3.2/4.8]

3.0/4.5 [3.2/4.8]

Gradeability

deg.

35

35

kPa {kg/cm2}

30.4 {0.31}

32.4 {0.33}

Overall length (for transport)

mm

5,770

5,770

Ground pressure

Dimension

Blade specification

Overall width

mm

2,330

2,330

Overall height (for transport)

mm

2,730 (2,750)

2,730 (2,750)

Overall height (for operation)

mm

2,710 (2,750 [2,730]

2,710 (2,750) [2,730]

Ground clearance of counterweight

mm

735 (780) [760]

735 (780) [760]

Min. ground clearance

mm

360 (400) [380]

360 (400) [380]

Tail swing radius

mm

1,240

1,240

Min. swing radius of work equipment

mm

1,750

1,750

Height of work equipment at min. swing radius

mm

5,570 (5,590)

5,570 (5,590)

Overall width of track

mm

2,320

2,320

Overall length track

mm

2,840 (2,900) [2,880]

2,840 (2,900) [2,880]

Distance between tumbler centers

mm

2,235 [2,265]

2,235 [2,265]

Track gauge

mm

1,870

1,870

Machine cab height

mm

1,745 (1,795) [1,775]

1,745 (1,795) [1,775]

Blade width × height

mm

–

2,320 × 470

Figures (steel shoe specification) are common to the all specifications unless otherwise specified. ( ) Figures in ( ): Road liner specification [ ] Figures in [ ]: Rubber shoe specification

01-6

PC78US-6

GENERAL

SPECIFICATIONS

PC78US-6 Blade-less specification

Blade specification

5501 and up 0.28

0.28

6,850 (6,880) [6,780]

7,190 (7,220) [7,120]

4,100

4,100

3,610

3,610

6,380

6,380

6,240

6,240

7,300

7,300

5,180

5,180

– –

380 245

61.29 {6,250}

61.29 {6,250}

10.0

10.0

20.0

19.0

3.0/4.5 [3.2/4.8]

3.0/4.5 [3.2/4.8]

35

35

30.4 {0.31}

32.4 {0.33}

5,770

5,770

2,330

2,330

2,730 (2,750)

2,730 (2,750)

2,710 (2,750 [2,730]

2,710 (2,750) [2,730]

735 (780) [760]

735 (780) [760]

360 (400) [380]

360 (400) [380]

1,240

1,240

1,750

1,750

5,570 (5,590)

5,570 (5,590)

2,320

2,320

2,840 (2,900) [2,880]

2,840 (2,900) [2,880]

2,235 [2,265]

2,235 [2,265]

1,870

1,870

1,745 (1,795) [1,775]

1,745 (1,795) [1,775]

–

2,320 × 470

PC78US-6

01-7

GENERAL

SPECIFICATIONS

PC78US-6

Machine model

Blade-less specification

Serial Number

4D95LE-2

Type

4-cycle, water-cooled, in-line vertical type, direct injection mm

4-95 × 115

{cc} kW/rpm {HP/rpm} Nm/rpm {kgm/rpm}

3.26 {3,260} 40.5/1,850 {54.0/1,850} 226/1,500 {23.0/1,500}

Max. speed at no load

rpm

2,020

Min. speed at no load

rpm

1,130

Min. fuel consumption

g/kWh {g/HPh}

231 {172}

Total displacement

Performance

Rated output Engine

4001 – 5500

Model

No. of cylinders - bore × stroke

Max. torque

Starting motor

24 V, 3.0 kw 24 V, 25 A

Alternator Battery (*1)

12 V, 48 Ah × 2

Undercarriage

Type of radiator core

CF29-3

Carrier roller

1 on each side

Track roller

5 on each side

Track shoe (Steel shoe) (Road liner) (Rubber shoe)

Hydraulic motor Control valve

Hydraulic pump

Type × No.

Hydraulic system

Blade specification

Discharge Set pressures *2 (Work equipment, swing, travel) *3 (Work equipment, travel) *3. (Swing, blade) (Control)

{cc}

MPa {kg/cm2}

Type × No. Control method

Assembly-type triple grouser, 39 on each side Assembly-type road liner, 39 on each side Unit-type rubber crawler Variable-capacity piston pump Variable-capacity piston pump ×1 ×1 Gear pump × 1 Gear pump × 2 80× 2+12.7 80× 2+60+12.7

26.5 {270} – – 3.1 {32}

– 26.5 {270} 21.1 {215} 3.1 {32}

6-spool type × 1

7-spool type × 1

Hydraulically assisted

Hydraulically assisted

Travel motor

Variable-capacity piston motor (with brake valve, parking brake) × 2

Swing motor

Fixed-capacity piston motor (with safety valve, pivot shaft brake) × 1

Hydraulic tank Hydraulic oil filter Oil cooler

Box-shaped, open Tank return side Air-cooled (CF40-1)

*1: Battery capacity (Ah) shows the rate of 5 hours. *2: Blade-less specification *3: Blade specification

01-8 (13)

PC78US-6

GENERAL

SPECIFICATIONS

PC78US-6 Blade-less specification

PC78US-6 Blade specification

Blade-less specification

6501 and up

Blade specification

5501 – 6500

S4D95LE-3-A

S4D95LE-3-A

4-cycle, water-cooled, in-line vertical type, direct injection, with turbocharger

4-cycle, water-cooled, in-line vertical type, direct injection, with turbocharger

4-95 × 115

4-95 × 115

3.26 {3,260}

3.26 {3,260}

40.5/1,850 {54.0/1,850} 237/1,500 {24.2/1,500}

40.5/1,850 {54.0/1,850} 237/1,500 {24.2/1,500}

2,020

2,020

1,130

1,130

227 {169}

227 {169}

24 V, 3.0 kw

24 V, 3.0 kw

24 V, 25 A

24 V, 25 A

12 V, 48 Ah × 2

12 V, 48 Ah × 2

ALW-4

CF29-3

1 on each side

1 on each side

5 on each side

5 on each side

Assembly-type triple grouser, 39 on each side Assembly-type triple grouser, 39 on each side Assembly-type road liner, 39 on each side Assembly-type road liner, 39 on each side Unit-type rubber crawler Unit-type rubber crawler Variable-capacity piston pump Variable-capacity piston pump Variable-capacity piston pump Variable-capacity piston pump ×1 ×1 ×1 ×1 Gear pump × 1 Gear pump × 2 Gear pump × 1 Gear pump × 2 80× 2+12.7 80× 2+60+12.7 80× 2+12.7 80× 2+60+12.7

26.5 {270} – – 3.1 {32}

– 26.5 {270} 21.1 {215} 3.1 {32}

26.5 {270} – – 3.1 {32}

– 26.5 {270} 21.1 {215} 3.1 {32}

6-spool type × 1

7-spool type × 1

6-spool type × 1

7-spool type × 1

Hydraulically assisted

Hydraulically assisted

Hydraulically assisted

Hydraulically assisted

Variable-capacity piston motor (with brake valve, parking brake) × 2

Variable-capacity piston motor (with brake valve, parking brake) × 2

Fixed-capacity piston motor (with safety valve, pivot shaft brake) × 1

Fixed-capacity piston motor (with safety valve, pivot shaft brake) × 1

Box-shaped, open

Box-shaped, open

Tank return side

Tank return side

Air-cooled (CF42)

Air-cooled (CF40-1)

PC78US-6

01-9 (13)

GENERAL

SPECIFICATIONS

PC78US-6

Machine model

Blade-less specification

Serial Number

4001 – 5500

Boom cylinder

Type

ø 115

ø 115

Diameter of piston rod

mm

ø 65

ø 65

Stroke

mm

858

858

Max. distance between pins

mm

2,143

2,143

Min. distance between pins

mm

1,285

1,285

Reciprocating piston

Reciprocating piston

Arm cylinder

Inside diameter of cylinder

mm

ø 100

ø 100

Diameter of piston rod

mm

ø 60

ø 60

Stroke

mm

865

865

Max. distance between pins

mm

2,193

2,193

Min. distance between pins

mm

1,328

1,328

Reciprocating piston

Reciprocating piston

Inside diameter of cylinder

mm

ø 90

ø 90

Diameter of piston rod

mm

ø 55

ø 55

Stroke

mm

710

710

Max. distance between pins

mm

1,765

1,765

Min. distance between pins

mm

1,055

1,055

–

Reciprocating piston

Type Blade cylinder

Reciprocating piston

mm

Type Bucket cylinder

Work equipment cylinder

Hydraulic system

Reciprocating piston

Inside diameter of cylinder

Type

01-10

Blade specification

Inside diameter of cylinder

mm

–

ø 130

Diameter of piston rod

mm

–

ø 65

Stroke

mm

–

130

Max. distance between pins

mm

–

679

Min. distance between pins

mm

–

549

PC78US-6

GENERAL

SPECIFICATIONS

PC78US-6 Blade-less specification

Blade specification

5501 and up Reciprocating piston

Reciprocating piston

ø 115

ø 115

ø 65

ø 65

858

858

2,143

2,143

1,285

1,285

Reciprocating piston

Reciprocating piston

ø 100

ø 100

ø 60

ø 60

865

865

2,193

2,193

1,328

1,328

Reciprocating piston

Reciprocating piston

ø 90

ø 90

ø 55

ø 55

710

710

1,765

1,765

1,055

1,055

–

Reciprocating piston

–

ø 130

–

ø 65

–

130

–

679

–

549

PC78US-6

01-11

GENERAL

SPECIFICATIONS

PC78UU-6 PC78UU-6

Machine model

— m3

0.28

Machine weight

kg

7,700 (7,600) [7,670]

Max. digging depth

mm

4,200

Max. vertical wall depth

mm

3,160

Max. digging reach

mm

6,400

Max. reach at ground level

mm

6,240

Max. digging height

mm

7,360

Max. dumping height

mm

5,290

Boom offset (left side/right sede)

mm

1,030/1,065

Max. blade lifting height

mm

415

Max. blade lowering depth

mm

210

kN {kg}

61.3 {6,250}

Continuous swing speed

rpm

10.0

Max. slope angle for swing

deg.

13.0

Travel speed (Low/High)

km/h

3.0/4.5 (3.2/4.8)

Gradeability

deg.

35

Ground pressure

{kg/cm2}

Max. digging force (Bucket)

Dimension

22832 – 23500

Bucket capacity

Working range

Performance

Serial Number

kPa

34.3 {0.35}

Overall length (for transport)

mm

6,060

Overall width

mm

2,330

Overall height (for transport)

mm

2,750 (2,730) [2,730]

Overall height (for operation)

mm

2,750 (2,730) [2,710]

Ground clearance of counterweight

mm

780 (760) [735]

Min. ground clearance

mm

400 (380) [360]

Tail swing radius

mm

1,240

mm

1,200

mm

5,490 (5,470) [5,470]

Overall width of track

mm

2,320

Overall length track

mm

2,900 (2,880) [2,840]

Distance between tumbler centers

mm

2,235 (2,265)

Track gauge

mm

1,870

Machine cab height

mm

1,795 (1,775) [1,745]

Blade width × height

mm

2,320 x 470

Min. swing radius of work equipment (at boom offset) Height of work equipment at min. swing radius

Figures (Road liner specification) are common to the all specifications unless otherwise specified. ( ) Figures in ( ): Rubber shoe specification [ ] Figures in [ ]: Steel shoe specification

01-12

PC78US-6

GENERAL

SPECIFICATIONS

PC78UU-6 — 23501 and up 0.28 7,700 (7,600) [7,670] 4,200 3,160 6,400 6,240 7,360 5,290 1,030/1,065 415 210 61.3 {6,250} 10.0 13.0 3.0/4.5 (3.2/4.8) 35 34.3 {0.35} 6,060 2,330 2,750 (2,730) [2,730] 2,750 (2,730) [2,710] 780 (760) [735] 400 (380) [360] 1,240 1,200 5,490 (5,470) [5,470] 2,320 2,900 (2,880) [2,840] 2,235 (2,265) 1,870 1,795 (1,775) [1,745] 2,320 x 470

PC78US-6

01-13

GENERAL

SPECIFICATIONS

PC78UU-6

Machine model

—

Serial Number Model

4D95LE-2

Type

4-cycle, water-cooled, in-line vertical type, direct injection

No. of cylinders - bore × stroke

mm

4–95 × 115

{cc} kW/rpm {HP/rpm} Nm/rpm {kgm/rpm}

3.260 {3,260}

Max. speed at no load

rpm

2,020

Min. speed at no load

rpm

1,130

Min. fuel consumption

g/kWh {g/HPh}

231 {172}

Total displacement

Performance

Rated output Engine

22832 – 23500

Max. torque

Starting motor

24 V, 3.0 kw

Alternator

24 V, 25 A

Battery (*1)

12 V, 48 Ah × 2

Undercarriage

Type of radiator core

CF29-3

Carrier roller

1 on each side

Track roller

5 on each side

Hydraulic pump

Track shoe (Steel shoe) (Road liner) (Rubber shoe)

Hydraulic motor Control valve

Hydraulic system

40.5/1,850 {54.0/1,850} 226/1,500 {23.0/1,500}

Assembly-type triple grouser, 39 on each side Assembly-type road liner, 39 on each side Unit-type rubber crawler

Type × No. Discharge Set pressures (Work equipment, travel) (Swing, blade) (Control)

Variable-capacity piston pump × 1 {cc} MPa {kg/cm2}

Type × No. Control method

Gear pump × 2 80× 2+60+12.7 26.5 {270} 21.1 {215} 3.1 {32} 8-spool type × 1 Hydraulically assisted

Travel motor

Variable-capacity piston motor (with brake valve, parking brake) × 2

Swing motor

Fixed-capacity piston motor (with safety valve, pivot shaft brake) × 1

Hydraulic tank Hydraulic oil filter Oil cooler

Box-shaped, open Tank return side Air-cooled (CF40-1)

*1: Battery capacity (Ah) shows the rate of 5 hours.

01-14 (13)

PC78US-6

GENERAL

SPECIFICATIONS

PC78UU-6 — 23501 and up S4D95LE-3-A 4-cycle, water-cooled, in-line vertical type, direct injection, with turbocharger 4–95 × 115 3.260 {3,260} 40.5/1,850 {54.0/1,850} 237/1,500 {24.2/1,500} 2,020 1,130 227 {169} 24 V, 3.0 kw 24 V, 25 A 12 V, 48 Ah × 2 CF29-3 1 on each side 5 on each side Assembly-type triple grouser, 39 on each side Assembly-type road liner, 39 on each side Unit-type rubber crawler Variable-capacity piston pump × 1 Gear pump × 2 80× 2+60+12.7 26.5 {270} 21.1 {215} 3.1 {32} 8-spool type × 1 Hydraulically assisted Variable-capacity piston motor (with brake valve, parking brake) × 2 Fixed-capacity piston motor (with safety valve, pivot shaft brake) × 1 Box-shaped, open Tank return side Air-cooled (CF40-1)

PC78US-6

01-15 (13)

GENERAL

SPECIFICATIONS

PC78UU-6

Machine model

—

Serial Number

22832 – 23500

Boom cylinder

Type

Reciprocating piston

Inside diameter of cylinder

mm

ø 120

Diameter of piston rod

mm

ø 70

Stroke

mm

1,015

Max. distance between pins

mm

2,436.5

Min. distance between pins

mm

1,421.5 Reciprocating piston

Inside diameter of cylinder

mm

ø 110

Diameter of piston rod

mm

ø 65

Stroke

mm

715

Max. distance between pins

mm

955

Min. distance between pins

mm

240

Type Bucket cylinder

Work equipment cylinder

Hydraulic system

Arm cylinder

Type

Reciprocating piston

Inside diameter of cylinder

mm

ø 90

Diameter of piston rod

mm

ø 55

Stroke

mm

710

Max. distance between pins

mm

1,765

Min. distance between pins

mm

1,055

Offset cylinder

Type

Reciprocating piston

Inside diameter of cylinder

mm

ø 110

Diameter of piston rod

mm

ø 55

Stroke

mm

350

Max. distance between pins

mm

1,500

Min. distance between pins

mm

1,150

Blade cylinder

Type

01-16

Reciprocating piston

Inside diameter of cylinder

mm

ø 130

Diameter of piston rod

mm

ø 65

Stroke

mm

130

Max. distance between pins

mm

679

Min. distance between pins

mm

549

PC78US-6

GENERAL

SPECIFICATIONS

PC78UU-6 — 23501 and up Reciprocating piston

ø 120 ø 70 1,015 2,436.5 1,421.5 Reciprocating piston

ø 110 ø 65 715 955 240 Reciprocating piston

ø 90 ø 55 710 1,765 1,055 Reciprocating piston

ø 110 ø 55 350 1,500 1,150 Reciprocating piston

ø 130 ø 65 130 679 549

PC78US-6

01-17

GENERAL

WEIGHT TABLE

WEIGHT TABLE

k This mass list is for reference in handling or transporting these components. PC78US-6

PC78UU-6

Machine model Blade-less specification Serial Number

Blade specification

4001 – 5500

— 22832 – 23500

Engine assembly (without water and oil)

400

403

403

• Engine (without water and oil)

300

300

300

• Engine mount

30

30

30

• PTO

7

7

7

• Hydraulic pump

63

66

66

Cooling assembly (without coolant and oil)

29

29

29

• Radiator (without coolant)

6.3

6.3

6.3

• Oil cooler (without oil)

5.2

5.2

5.2

Revolving frame

930

930

930

Operator's cab

260

260

260

Operator's seat

18

18

18

Fuel tank (without fuel)

11

11

11

Hydraulic tank (without hydraulic oil)

75

75

75

Control valve

56

58

60

Counterweight

950

800

800

Swing motor (Including brake valve)

22

22

22

Swing circle

104

104

104

Swing machinery

47

47

47

Center swivel joint

16

17

17

1,067 [1,048]

1,142 [1,123]

1,142 [1,123]

704

779

779

• Idler assembly

54 x 2

54 x 2

54 x 2

• Recoil spring assembly

40 x 2

40 x 2

40 x 2

• Carrier roller

3.4 x 2

3.4 x 2

3.4 x 2

• Track roller

13 x 10

13 x 10

13 x 10

• Travel motor (with reduction gears)

81 x 2

81 x 2

81 x 2

• Sprocket

19 x 2

19 x 2

19 x 2

Track frame assembly (without track shoe) • Track frame

Figures (steel shoe specification) are common to the all specifications unless otherwise specified. [ ] Figures in [ ]: Rubber shoe specification

01-18 (13)

PC78US-6

GENERAL

WEIGHT TABLE

Unit: kg PC78US-6 Blade-less specification

PC78US-6

Blade specification

Blade-less specification

5501 – 6500

*1. *2. *3. *4.

PC78UU-6

Blade specification

6501 and up

— 23501 and up

401

404

401

404

404

300

300

300

300

300

30

30

30

30

30

7

7

7

7

7

64

67

64

67

67

29

29

29

29

29

6.3

6.3

5.8

5.8

6.3

5.2

5.2

5.5

5.5

5.2

930

930

984

984

930

260

260

260

260

260

18

18

18

18

18

11

11

48

48

(*3) 11 (*4) 17

75

75

70

70

75

56

58

56

58

60

950

800

885

732

800

22

22

22

22

22

104

104

104

104

104

47

47

46

46

47

16

17

16

17

17

1,067 [1,048]

1,142 [1,123]

1,067 [1,048]

1,142 [1,123]

1,142 [1,123]

704

779

704

779

779

54 x 2

54 x 2

54 x 2

54 x 2

54 x 2

39 x 2

39 x 2

39 x 2

39 x 2

39 x 2

3.4 x 2

3.4 x 2

3.4 x 2

3.4 x 2

3.4 x 2

13 x 10

13 x 10

12.4 x 10

12.4 x 10

81 x 2

81 x 2

81 x 2

81 x 2

81 x 2

19 x 2

19 x 2

19 x 2

19 x 2

19 x 2

PC78UU-6 PC78UU-6 PC78UU-6 PC78UU-6

PC78US-6

(*1) 13 x 10 (*2) 12.4 x 10

(Serial No.: 23501 – 24066) (Serial No.: 24067 and up) (Serial No.: 23501 – 24085) (Serial No.: 24086 and up)

01-19 (13)

GENERAL

WEIGHT TABLE

Machine model

PC78US-6 Blade-less specification

Serial Number

PC78UU-6

Blade specification

4001 – 5500

— 22832 – 23500

Track shoe assembly • City pad shoe (450 mm)

410 X 2

410 X 2

410 X 2

• Road liner (450 mm)

450 X 2

450 X 2

450 X 2

• Rubber shoe (450 mm)

385 X 2

385 X 2

385 X 2

• Triple grouser (600 m)

495 X 2

495 X 2

–

418

418

731

• 1st boom

–

–

293

• 2nd boom

–

–

177

• 3rd bracket

–

–

135

• Sublink

–

–

27

Arm assembly

147

147

165

Bucket link assembly

56

56

56

Bucket assembly (with side cutter)

210

210

210

Blade assembly

–

374

374

Boom cylinder assembly

86

86

107

Arm cylinder assembly

72

72

87

Bucket cylinder assembly

51

51

51

Offset cylinder assembly

–

–

47

Blade cylinder assembly

–

46

46

Boom assembly

Figures are common to the all specifications unless otherwise specified.

01-20 (6)

PC78US-6

GENERAL

WEIGHT TABLE

Unit: kg PC78US-6 Blade-less specification

PC78US-6

Blade specification

Blade-less specification

5501 – 6500

PC78UU-6

Blade specification

6501 and up

— 23501 and up

410 X 2

410 X 2

410 X 2

410 X 2

410 X 2

450 X 2

450 X 2

450 X 2

450 X 2

450 X 2

385 X 2

385 X 2

385 X 2

385 X 2

385 X 2

495 X 2

495 X 2

495 X 2

495 X 2

–

418

418

418

418

731

–

–

–

–

293

–

–

–

–

177

–

–

–

–

135

–

–

–

–

27

147

147

147

147

165

56

56

54

54

56

210

210

204

204

210

–

374

–

358

374

86

86

86

86

107

72

72

72

72

87

51

51

51

51

51

–

–

–

–

47

–

46

–

46

46

PC78US-6

01-21 (10)

GENERAL

LIST OF LUBRICANTS AND COOLANT

LIST OF LUBRICANTS AND COOLANT

RESERVOIR

KIND OF FLUID

AMBIENT TEMPERATURE –22 –30

–4 –20

14 –10

32 0

50 10

68 20

86 30

104 40

122˚F 50˚C

SAE 30 SAE 10W

Engine oil pan

SAE 10W-30 SAE 15W-40 Swing machinery case Final drive case PTO gear case

Engine oil SAE 30

SAE 10 Hydraulic system SAE 10W-30 SAE 15W-40

ASTM D975 No. 2 Diesel fuel

Fuel tank

ASTM D975 No. 1

Greasing system

Grease

Cooling system

Coolant

NLGI No. 2 Add antifreeze

Unit: l PC78US-6

Reservoir

PC78UU-6

Specified capacity

Refill capacity

Specified capacity

Refill capacity

Engine oil pan

7.5

7.0

7.5

7.0

PTO gear case

0.4

0.4

0.4

0.4

Swing machinery case

2.0

2.0

2.0

2.0

Final drive case (each)

1.3

1.3

1.3

1.3

(*1)

110

64

(*2)

102

56

120

64

125

—

125

—

(*1)

10.5

—

(*2)

11.8

—

10.5

—

Hydraulic system Fuel tank Cooling system

*1. PC78US-6 (Serial No.: 4001 – 6500) *2. PC78US-6 (Serial No.: 6501 and up)

01-22 (10)

PC78US-6

10 STRUCTURE, FUNCTION AND MAINTENANCE STANDARD PTO ........................................................................... 10- 2 Cooling system .......................................................... 10- 4 Power train system .................................................... 10- 6 Swing circle ............................................................... 10- 8 Swing machinery ....................................................... 10-10 Track frame and idler cushion ................................... 10-14 Idler ........................................................................... 10-16 Track roller................................................................. 10-17 Carrier roller .............................................................. 10-19 Sprocket .................................................................... 10-20 Track shoe................................................................. 10-21 Arrangement of hydraulic components...................... 10-26 Hydraulic tank and oil filter ........................................ 10-29 Center swivel joint ..................................................... 10-31 Travel motor .............................................................. 10-33 Work equipment cylinder ........................................... 10-41 Solenoid valve ........................................................... 10-46 Multi-control valve ..................................................... 10-53 Accumulator for braker .............................................. 10-54 Hydraulic pump ......................................................... 10-55 Control valve ............................................................. 10-80 CLSS ....................................................................... 10-120 Swing motor ............................................................ 10-158 Work equipment and swing PPC valve ................... 10-166 Travel PPC valve..................................................... 10-172 Offset PPC valve , attachment PPC valve, blade PPC valve...................................................... 10-176 Work equipment ...................................................... 10-180 Dimensions of each part of work equipment ........... 10-186 Air conditioner piping (OPTIONAL) ......................... 10-192 Electric control system ............................................ 10-195 System components ................................................ 10-252 Monitor system ........................................................ 10-265 Sensors ................................................................... 10-271

PC78US-6

10-1 (14)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

PTO

PTO PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up

1. 2. 3. 4. 5. 6. 7.

Drain plug Coupling Flywheel Pump case Cage Level plug Breather/Oil filler plug

10-2 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

PTO

PC78US-6 Serial No.: 6501 and up

1. 2. 3. 4. 5. 6.

Drain plug Coupling Flywheel Pump case Level plug Breather/Oil filler plug

PC78US-6

10-3 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

COOLING SYSTEM

COOLING SYSTEM PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Fan guard Radiator inlet hose Drain valve Radiator outlet hose Radiator cap Oil cooler Radiator Shroud Oil cooler inlet Reservoir tank Oil cooler outlet

10-4 (10)

SPECIFICATIONS Radiator

Oil cooler

Type of core

CF29-3

CF40-1

Fin pitch (mm)

4.0/2

4.5/2

Total heat dissipation area (m2)

16.53

6.15

Pressure valve cracking pressure (kPa {kg/cm2})

88.3±14.7 (0.9±0.15)

–

Vacuum valve cracking pressure (kPa {kg/cm2})

4.9 (0.05)

–

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

COOLING SYSTEM

PC78US-6 Serial No.: 6501 and up

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Fan guard Radiator inlet hose Drain valve Radiator outlet hose Radiator cap Oil cooler Radiator Shroud Oil cooler inlet Reservoir tank Oil cooler outlet

PC78US-6

SPECIFICATIONS Radiator

Oil cooler

Type of core

ALW-4

CF42

Fin pitch (mm)

3.5/2

3.5/2

Total heat dissipation area (m2)

16.04

5.96

Pressure valve cracking pressure (kPa {kg/cm2})

49 (0.5)

–

Vacuum valve cracking pressure (kPa {kg/cm2})

4.9 (0.05)

–

10-5 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

POWER TRAIN SYSTEM

POWER TRAIN SYSTEM PC78US-6

1. 2. 3. 4. 5. 6. 7.

Idler Control valve Center swivel joint Swing motor Travel motor Control pump (for pilot control) Hydraulic pump (for swing and blade) [Installed to only blade specification]

10-6 (10)

8. Hydraulic pump (Blade-less specification: For travel, swing, and work equipment) (Blade specification: For travel and work equipment) 9. Engine 10. Swing holding brake solenoid valve 11. 2-stage travel speed selector solenoid valve 12. PPC lock solenoid valve 13. Swing machinery 14. Swing circle

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

POWER TRAIN SYSTEM

PC78UU-6

1. 2. 3. 4. 5. 6. 7. 8.

Idler Control valve Center swivel joint Swing motor Travel motor Control pump (for pilot control) Hydraulic pump (for swing and blade) Hydraulic pump (For travel and work equipment) 9. Engine

PC78US-6

10. 11. 12. 13. 14. 15. 16. 17.

Boom RAISE stop EPC valve Arm IN stop EPC valve Left offset stop EPC vaolve Swing holding brake solenoid valve 2-stage travel speed selector solenoid valve PPC lock solenoid valve Swing machinery Swing circle

10-7 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SWING CIRCLE

SWING CIRCLE

Unit: mm

2. 3. 4. 5. 6. 7.

No.

Item

1

Clearance between bearing and circle

Greasing for swing circle bearing Greasing for swing circle pinion Outer race Inner race Ball Seal

10-8 (10)

Criteria

Remedy

Standard clearance

Allowable clearance

0.3 – 1.2

2.0

Replace

a. Position of inner race soft zone b. Position of outer race soft zone Specifications Reduction ratio

80/10=8.0

Grease

G2-LI

Quantity of grease (l)

5.5

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SWING MACHINERY

SWING MACHINERY PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Swing pinion (Number of teeth: 10) Swing machinery case No. 2 planetary carrier Ring gear (Number of teeth: 58) No. 2 sun gear (Number of teeth: 14) No. 1 planetary carrier No. 1 sun gear (Number of teeth: 14) Swing motor Oil filler Level gauge No. 1 planetary gear (Number of teeth: 22) No. 2 planetary gear (Number of teeth: 22) Drain plug

10-10 (10)

Specification Reduction ratio

(14+58)/14X(14+58)/14 = 26.45

Swing reduction ratio

26.45X8.0 = 211.59

Swing speed (rpm)

10

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SWING MACHINERY

Unit: mm No.

Item

1

Backlash between swing motor shaft and No. 1 sun gear

2

Criteria

Remedy

Standard clearance

Allowable clearance

0.03 – 0.11

—

Backlash between No. 1 sun gear and No. 1 planetary gear

0.10 – 0.27

0.6

3

Backlash between No. 1 planetary gear and ring gear

0.12 – 0.38

0.6

4

Backlash between No. 1 planetary carrier and No. 2 sun gear

0.10 – 0.25

—

5

Backlash between No. 2 sun gear and No. 2 planetary gear

0.10 – 0.27

0.6

6

Backlash between No. 2 planetary gear and ring gear

0.12 – 0.38

0.6

7

Backlash between No. 2 planetary carrier and swing pinion

0.07 – 0.21

—

8

Backlash between swing pinion and swing circle

0.27 – 0.83

2.0

9

Wear of sliding surface of swing pinion collar against oil seal

PC78US-6

Basic dimension 75

Allowance 0 - 0.074

Replace

Allowable Limit 74.8

Plating with hard chromium or replace

10-11 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SWING MACHINERY

PC78US-6 Serial No.: 6501 and up

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Swing pinion (Number of teeth: 10) Swing machinery case No. 2 planetary carrier Ring gear (Number of teeth: 58) No. 2 sun gear (Number of teeth: 14) No. 1 planetary carrier No. 1 sun gear (Number of teeth: 14) Swing motor Oil filler Level gauge No. 1 planetary gear (Number of teeth: 22) No. 2 planetary gear (Number of teeth: 22) Drain plug

10-12 (10)

Specification Reduction ratio

(14+58)/14X(14+58)/14 = 26.45

Swing reduction ratio

26.45X8.0 = 211.59

Swing speed (rpm)

10

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SWING MACHINERY

Unit: mm No.

Item

1

Backlash between swing motor shaft and No. 1 sun gear

2

Criteria

Remedy

Standard clearance

Allowable clearance

0.03 – 0.11

—

Backlash between No. 1 sun gear and No. 1 planetary gear

0.10 – 0.27

0.6

3

Backlash between No. 1 planetary gear and ring gear

0.12 – 0.37

0.6

4

Backlash between No. 1 planetary carrier and No. 2 sun gear

0.10 – 0.25

—

5

Backlash between No. 2 sun gear and No. 2 planetary gear

0.10 – 0.27

0.6

6

Backlash between No. 2 planetary gear and ring gear

0.12 – 0.37

0.6

7

Backlash between No. 2 planetary carrier and swing pinion

0.009 – 0.117

—

8

Backlash between swing pinion and swing circle

0.27 – 0.83

2.0

9

Wear of sliding surface of swing pinion collar against oil seal

PC78US-6

Basic dimension 75

Allowance 0 - 0.074

Replace

Allowable Limit 74.8

Plating with hard chromium or replace

10-13 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRACK FRAME AND IDLER CUSHION

TRACK FRAME AND IDLER CUSHION

10-14 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRACK FRAME AND IDLER CUSHION

Unit: mm No.

1

2

Item

Vertical width of idler guide

Lateral width of idler guide

Criteria Basic dimension

Allowable limit

Track frame

74

78

Idler support

73

69

Overlay or replace

Track frame

158

162

Overlay

Idler support

156

152

Overlay or replace

Basic dimension

3

Recoil spring

*1. PC78US-6 PC78UU-6 *2. PC78US-6 PC78UU-6

Remedy Overlay

Allowable limit

Free length

Installed length

Installed load

Free length

Installed load

(*1) Road liner, steel shoe

410

323

47.4 kN {4,837 kg}

400

42.2 kN {4,305 kg}

(*1) Rubber shoe

410

283

69.2 kN {7,061 kg}

400

61.6 kN Replace {6,284 kg}

(*2) Road liner, steel shoe

412

323

47.4 kN {4,837 kg}

402

42.2 kN {4,305 kg}

(*2) Rubber shoe

412

283

69.2 kN {7,061 kg}

402

61.6 kN {6,284 kg}

Serial No.: 4001 – 5500 Serial No.: 22832 – 23500 Serial No.: 5501 and up Serial No.: 23501 and up

4. 5. 6. 7. 8. 9. 10. 11.

Idler Track frame Carrier roller Travel motor Sprocket Track roller Track shoe Idler cushion 11a. Support 11b. Yoke 11c. Recoil spring 11d. Cylinder 11e. Collar 11f. Lubricator 12. Idler guard (Road liner specification, steel shoe specification) 13. Bracket to secure machine body for transportation (for USA spec. only) Specification Grease

G2-LI

Quantity of grease (cc)

96 (Steel shoe, road liner) 233 (Rubber shoe)

PC78US-6

10-15 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

IDLER

IDLER

Unit: mm No. 1

Item Outside diameter of projected part

2

Outside diameter of tread

3

Depth of tread

4

Criteria Basic dimension

Remedy Allowable limit

460

—

415

407

22.5

26.5

Width of projected part

43

37

5

Overall width

100

92

6

Width of tread

28.5

7

Clearance between idler shaft and bushing

Basic dimension 44

8

9

Interference between idler and bushing Side clearance of idler (Each side)

10

Thickness of tread (at center of width of tread)

—

Quantity of oil

10-16 (10)

Basic dimension 50

Overlay or replace

32 Allowance

Shaft

Hole

Standard clearance

Allowable clearance

-0.250 -0.290

+0.062 0

0.250 – 0.352

1.5

Allowance Shaft

Hole

+0.117 +0.087

+0.025 0

Standard clearance

Standard Allowable Replace interference interference 0.062 – 0.117

—

Allowable clearance

0.190 – 0.395

1.5

Basic dimension

Allowable limit

13.8

9.8

60 cc (Engine oil: SAE30CD)

Overlay or replace —

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRACK ROLLER

TRACK ROLLER PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 – 24066

Unit: mm No.

Item

1

Outside diameter of projected part

2

Criteria Basic dimension

Remedy Allowable limit

149

—

Outside diameter of tread

120

113

3

Width of flange

43

36.6

4

Overall width

129

—

5

Width of tread

43

47.3

6

Clearance between shaft and bushing

Basic dimension 38

7

Interference between roller and bushing

Basic dimension 48

8

Side clearance of track roller (Each side)

9

Thickness of tread (at center of width of tread)

—

Quantity of oil

PC78US-6

Allowance

Overlay or replace

— Overlay or replace

Shaft

Hole

Standard clearance

Allowable clearance

-0.250 -0.270

+0.075 - 0.025

0.225 – 0.345

1.5

Allowance Shaft

Hole

+0.117 +0.087

+0.030 0

Standard Allowable interference interference Replace 0.057 – 0.117

—

Standard clearance

Allowable clearance

0.38 – 0.73

1.5

Basic dimension

Allowable limit

36

32.5

210 – 230 cc (Gear oil: G0140)

Overlay or replace —

10-17 (13)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRACK ROLLER

PC78US-6 Serial No.: 6501 and up PC78UU-6 Serial No.: 24067 and up

Unit: mm No.

Item

1

Outside diameter of projected part

2

Criteria Basic dimension

Remedy Allowable limit

139

—

Outside diameter of tread

110

103

3

Width of flange

43

36.6

4

Overall width

136.6

—

5

Width of tread

46.8

51.1

6

Clearance between shaft and bushing

Basic dimension 40

7

Interference between roller and bushing

Basic dimension 44

8

Side clearance of track roller (Each side)

9

Thickness of tread (at center of width of tread)

—

Quantity of oil

10-18 (13)

Allowance

Overlay or replace

— Overlay or replace

Shaft

Hole

Standard clearance

Allowable clearance

-0.250 -0.270

+0.165 - 0.020

0.230 – 0.435

1.5

Allowance Shaft

Hole

+0.150 +0.100

+0.025 - 0.020

Standard Allowable interference interference Replace 0.075 – 0.170

—

Standard clearance

Allowable clearance

0.53 – 1.06

1.5

Basic dimension

Allowable limit

33

29.5

160 – 180 cc (Gear oil: G0140)

Overlay or replace —

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CARRIER ROLLER

CARRIER ROLLER

Unit: mm No.

Item

1

Outside diameter of tread

2

Width of tread

3

4

Interference between shaft and bearing Interference between roller and bearing

5

Thickness of tread

—

Quantity of oil

PC78US-6

Criteria Basic dimension

Allowable limit

82

Overlay or replace

72

100 Basic dimension

Remedy

— Allowance

—

Standard Allowable interference interference

Shaft

Hole

30

+0.009 - 0.004

0 - 0.010

-0.004 – 0.019

—

62

0 - 0.013

+0.018 - 0.012

-0.031 – 0.012

—

Basic dimension

Allowable limit

10

5

47 – 52 cc (Grease: ALVANIA EP-2)

Replace

Overlay or replace —

10-19 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SPROCKET

SPROCKET

Unit: mm No.

Item

Criteria Basic dimension

1

Wear of root diameter

2

Allowance

Remedy Allowable limit

433.004

+1.0 - 2.0

421

Wear of tip diameter

483.7

±2.0

472

3

Wear of dip width

28

—

23

4

Wear of root width

38

+0.5 - 2.5

33

5

Thickness of root

84.002

+0.475 - 1.150

78

10-20 (10)

Overlay or replace

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRACK SHOE

TRACK SHOE CITY PAD SHOE, ROAD LINER, AND TRIPLE SHOE

1. City pad shoe (PC78US: STD, PC78UU: OPT) Triple shoe (PC78US: OPT) 2. Road liner (PC78US: OPT, PC78UU: STD) a Part P is the link on the press fitting side of bushing.

PC78US-6

10-21 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRACK SHOE

Unit: mm No.

Item

Criteria

1

Link pitch

2

Outside diameter of bushing

3

Height of link

4

Thickness of link (Press fitting part of bushing)

Basic dimension

Allowable limit

154.25

157.25

41.2

37.2

74

70

20

16 89

Shoe bolt pitch

73

7

Link

10

Inside width

45

Overall width

30

Width of tread

26.3

11

Projection of pin

12

Projection of regular bushing

3.15

13

Overall length of pin

131

14

Overall length of bushing (Master bushing)

74.6

Thickness of bushing

16

Thickness of spacer

17 Press fitting pressure

(*1) 19

Repair or replace

3

15

18

Replace

57

8 9

Reverse or replace

Repair or replace

5 6

Remedy

Adjust or replace

Basic dimension

Allowable limit

8.4

4.4 —

Bushing

19.6 – 98.1 kN {2 – 10 ton}

Regular pin

49.0 – 117.7 kN {5 – 12 ton}

Master pin

39.2 – 78.5 kN {4 – 8 ton}

—

*1. For dry track.

10-22 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRACK SHOE

Unit: mm No.

Item

Criteria Tightening torque (Nm {kgm}) • City pad a. Regular link • Triple

Shoe bolt

Retightening angle (deg.)

117.7 ± 19.6 {12 ± 2}

90 ± 10

• Road liner

117.7 ± 19.6 {12 ± 2}

60 ± 10 (Torque after retightening) Min. 343 Nm {35 kgm}

Tightening torque

Retightening angle (deg.)

Lower limit torque

—

—

—

20 b. Master link Number of shoes (Each side)

21

39

Number of shoes (Each side) Interference between regular pin and link

23

Clearance between regular pin and bushing

(*1) Interference between master pin 24 and link

(*1) Clearance between master pin 25 and bushing

Height of grouser

Road liner

Standard interference

Shaft

Hole

41

+0.214 +0.174

+0.062 0

0.112 – 0.214

24

+0.150 0

-0.198 -0.250

0.198 – 0.400

Allowance

Basic dimension 24

Shaft

Hole

+0.150 0

+0.830 +0.330

Standard clearance 0.180 – 0.830 Adjust or replace

Allowance

Basic dimension 24

Shaft

Hole

+0.020 -0.020

-0.198 -0.250

Standard interference 0.178 – 0.270

Allowance

Basic dimension 24

Retighten

—

Allowance

Basic dimension

22

26

Remedy

Shaft

Hole

-0.150 -0.250

+0.630 +0.230

Standard clearance 0.380 – 0.880

Basic dimension

Allowable limit

42

19

Replace

*1. For dry track.

PC78US-6

10-23 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRACK SHOE

TRIPLE SHOE AND CITY PAD SHOE

Unit: mm No.

Item

1

Height of grouser

2

Overall height of shoe

3

Thickness of plate

4 5

Remedy

Basic dimension

Allowable limit

20

12

26

18 6

Overlay or replace

14 Length of upper side of grouser

6

10-24 (10)

Criteria

10 12

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRACK SHOE

RUBBER SHOE (OPTIONAL)

Unit: mm No.

Item

1

Wear of lug height

2

Wear of roller guide

3

Wear of meshing part of sprocket

PC78US-6

Criteria

Remedy

Basic dimension

Allowable limit

30

5

42

58

Replace

Basic dimension

Allowance

Allowable limit

22.5

±0.5

27

10-25 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ARRANGEMENT OF HYDRAULIC COMPONENTS

ARRANGEMENT OF HYDRAULIC COMPONENTS PC78US-6 Serial No.: 4001 – 6500

1. 2. 3. 4. 5. 6. 7. 8. 9.

Bucket cylinder Arm cylinder Boom cylinder Hydraulic tank Control valve Swing motor Hydraulic pump Oil cooler Travel motor

10-26 (10)

10. 11. 12. 13. 14. 15. 16.

Left work equipment PPC valve Blade PPC valve (Blade specification) Right work equipment PPC valve Center swivel joint Travel PPC valve 3-spool solenoid valve Service PPC valve (Machine to which attachments can be installed) 17. Blade cylinder (Blade specification)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ARRANGEMENT OF HYDRAULIC COMPONENTS

PC78US-6 Serial No.: 6501 and up

1. 2. 3. 4. 5. 6. 7. 8. 9.

Bucket cylinder Arm cylinder Boom cylinder Hydraulic tank Control valve Swing motor Hydraulic pump Oil cooler Travel motor

PC78US-6

10. 11. 12. 13. 14. 15. 16.

Left work equipment PPC valve Blade PPC valve (Blade specification) Right work equipment PPC valve Center swivel joint Travel PPC valve 3-spool solenoid valve Service PPC valve (Machine to which attachments can be installed) 17. Blade cylinder (Blade specification)

10-27 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ARRANGEMENT OF HYDRAULIC COMPONENTS

PC78UU-6

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Bucket cylinder Arm cylinder Offset cylinder Boom cylinder Hydraulic tank Control valve Swing motor Hydraulic pump Oil cooler Travel motor

10-28 (10)

11. 12. 13. 14. 15. 16. 17. 18. 19.

Left work equipment PPC valve Blade PPC valve Right work equipment PPC valve Center swivel joint Service PPC valve (Machine to which attachments can be installed) Travel PPC valve 6-spool solenoid valve Offset PPC valve Blade cylinder

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC TANK AND OIL FILTER

HYDRAULIC TANK AND OIL FILTER PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up

1. 2. 3. 4. 5. 6. 7.

Hydraulic tank Sight gauge Strainer Drain plug Filter Bypass valve Oil filler cap

PC78US-6

Specification Tank capacity ( )

80

Quantity of oil in tank ( )

64

Bypass valve set pressure (kPa {kg/cm²})

0.15 ± 0.03 {1.53 ± 0.3}

Pressure valve cracking pressure (kPa {kg/cm²})

38 ± 15 {0.39 ± 0.15}

Vacuum valve cracking pressure (kPa {kg/cm²})

0–5 {0 – 0.05}

10-29 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC TANK AND OIL FILTER

PC78US-6 Serial No.: 6501 and up

1. 2. 3. 4. 5. 6. 7.

Hydraulic tank Sight gauge Strainer Drain plug Filter Bypass valve Oil filler cap

10-30 (10)

Specification Tank capacity ( )

70

Quantity of oil in tank ( )

56

Bypass valve set pressure (kPa {kg/cm²})

0.15 ± 0.03 {1.53 ± 0.3}

Pressure valve cracking pressure (kPa {kg/cm²})

38 ± 15 {0.39 ± 0.15}

Vacuum valve cracking pressure (kPa {kg/cm²})

0–5 {0 – 0.05}

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CENTER SWIVEL JOINT

CENTER SWIVEL JOINT PC78US-6 (Blade-less specification)

A1: From right travel control valve

A2: To right travel motor

B1: From right travel control valve

B2: To right travel motor

C1: From left travel control valve

C2: To left travel motor

D1: From left travel control valve

D2: To left travel motor

E1: From 2-stage travel speed selector solenoid valve

E2: To 2-stage travel speed selector solenoid valve

DR1: To tank

DR2: From travel motor drain port

1. Cover 2. Rotor

3. Slipper seal 4. Shaft Unit: mm

No.

5

Item Clearance between rotor and shaft

PC78US-6

Criteria Basic dimension 60

Remedy

Standard clearance Allowable clearance 0.056 – 0.105

0.111

Replace

10-31 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CENTER SWIVEL JOINT

PC78US-6 (Blade specification) PC78UU-6

A1: From right travel control valve

A2: To right travel motor

B1: From right travel control valve

B2: To right travel motor

C1: From left travel control valve

C2: To left travel motor

D1: From left travel control valve

D2: To left travel motor

E1: From blade control valve

E2: To blade cylinder bottom

F1: From blade control valve

F2: To blade cylinder head

G1: From 2-stage travel speed selector solenoid valve

G2: To 2-stage travel speed selector solenoid valve

DR1: To tank

DR2: From travel motor drain port

1. Cover 2. Rotor

3. Slipper seal 4. Shaft Unit: mm

No.

5

Item Clearance between rotor and shaft

10-32 (10)

Criteria Basic dimension 70

Remedy

Standard clearance Allowable clearance 0.056 – 0.105

0.111

Replace

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRAVEL MOTOR

TRAVEL MOTOR

A. B. D. P.

From travel control valve From travel control valve To tank From 2-stage travel speed selector solenoid valve

PC78US-6

10-33 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Check valve Counterbalance valve Valve plate Cylinder Brake piston Plate Disc Piston Swash plate Regulator piston RV gear RV gear Case

10-34 (10)

TRAVEL MOTOR

14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.

Shaft Drive gear Cover Crankshaft Drain plug Driven gear Pivot Spindle Floating seal End cover Regulator valve Check valve

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRAVEL MOTOR

Specification Model Theoretical displacement (cm³/rev) Rated speed

GM09VN-E Hi

24.1

Lo

36.3

Hi

3,211

Lo

2,154

Brake releasing pressure (MPa {kg/cm²})

0.47 {4.8}

Speed changeover pressure (MPa {kg/cm²})

2.94 {30}

Reduction ratio

66.5

Outline

1. Reduction gears The reduction gears consists of spur gear unit (1a) and differential gear unit (1b) which uses pericycloid gears and converts the high speed revolution of the hydraulic motor into low-speed and high-torque revolution. 2. Hydraulic motor The hydraulic motor is a swash plate-type axial piston motor, which converts the power of the hydraulic oil sent from the hydraulic pump into revolution.

4. 2-stage travel speed changeover mechanism The 2-stage travel speed changing mechanism consists of a changeover valve and a piston, which change the displacement of the hydraulic motor to either of 2 stages. 5. Parking brake The parking brake is a friction plate brake, which is built as a part of the hydraulic motor.

3. Brake valve The brake valve consists of various valves and has functions of stopping the hydraulic motor smoothly, preventing the hydraulic motor from running away, and preventing generation of abnormally high pressure when the hydraulic motor is stopped suddenly.

PC78US-6

10-35 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRAVEL MOTOR

OPERATION Operation of motor At low speed (With swash plate angle at maximum)

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

2-stage travel speed selector solenoid valve Regulator valve Spring Check valve End cover Regulator piston Swash plate Pump merge-divider valve Travel control valve Brake valve

• • •

• •

10-36 (10)

Since 2-stage travel speed selector solenoid valve (1) is de-energized, the hydraulic oil from the control pump does not flow into port Pi. Accordingly, regulator valve (2) is pressed to the left by spring (3). Under this condition, the main hydraulic oil from the control valve pushes check valve (4) and flows into end cover (5) and then is shut off by regulator valve (2). The hydraulic oil in control chamber (a) flows through passage (b) of regulator valve (2) into the motor case. As a result, swash plate (7) is pushed toward the maximum swash plate angle by the main hydraulic oil in chamber (P) of the cylinder and the motor capacity is increased to the maximum and the travel speed lowers.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRAVEL MOTOR

At high speed (With swash plate angle at minimum)

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

2-stage travel speed selector solenoid valve Regulator valve Spring Check valve End cover Regulator piston Swash plate Pump merge-divider valve Travel control valve Brake valve

PC78US-6

•

•

•

If 2-stage travel speed selector solenoid valve (1) is energized, the pilot pressure from the control pump flows into port Pi and pushes regulator valve (2) to the right. Accordingly, the main hydraulic oil from the control valve flows through passage (c) of regulator valve (2) into control chamber (a) and pushes regulator piston (6) to the left. As a result, swash plate (7) is pushed toward the minimum swash plate angle and the motor capacity is decreased to the minimum and the travel speed rises.

10-37 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

Operation of brake valve • The brake valve consists of check valves (1a) and (1b) and counterbalance valve spool (2) as shown in the following figure.

TRAVEL MOTOR

Operation when oil is supplied • If the travel lever is operated, the hydraulic oil from the control valve flows in port PA, pushes valve (1a) open, and flows through motor input port MA to motor outlet port MB. At the same time, the hydraulic oil also flows through orifice c of spool (2) to chamber D. If its pressure becomes higher than the pressure of spring (3), spool (2) is pushed to the left. As a result, port MB is connected to port PB and the motor outlet side opens and the motor starts revolution. Since port PA is connected to port E, too, the hydraulic oil operates parking brake piston (4) to release the parking brake force.

Function • When the machine travels downhill, its speed may become higher than the motor speed because of its momentum. If the engine speed is low at this time, the motor runs idle and the machine runs away, and this situation is very dangerous. The brake valve prevents this phenomenon and limits the travel speed according to the engine speed (pump discharge).

10-38 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

Operation when oil is shut off • If the control lever is returned to neutral, the hydraulic oil from the control valve is shut off and spool (2) is returned to the right by the reaction force of spring (3). At this time, the oil flows through orifice (c) of chamber D into port PA and back pressure is generated by the throttle effect of orifice (c). This back pressure controls the speed of spool (2) returning to the right. Even after the hydraulic oil in port PA is shut off, the motor continues revolution by inertia. At this time, the returning oil is reduced gradually according to the changing speed and shape of spool (2) to stop the motor smoothly. The motor continues revolution by inertia and can cause cavitation. Since valve (1a) is operated by very slight negative pressure, however, it opens ports PA and MA to prevent cavitation.

PC78US-6

TRAVEL MOTOR

Operation of brake during downhill travel • If the machine starts running away while traveling downhill, the motor revolves idle and the pressure on the motor inlets side lowers, then the pressure in chamber D also lowers through orifice (c). If the pressure in chamber D lowers below the pressure of spring (3), spool (2) is pushed back to the right. At this time, the oil in chamber G flows through orifice (f) into port PB. The throttle effect of orifice (f) generates back pressure, and spool (2) returns to the right to control the returning speed of spool (2). Port MB on the outlet side is narrowed. As a result, the pressure on the outlet side rises and revolving resistance is generated in the motor to prevent the machine from running away. To put it concretely, spool (2) moves to a position at which the machine weight and the pressure on the inlet side are balanced with the pressure at port MB on the outlet side to narrow the outlet circuit. Consequently, the speed is controlled according to the pump discharge.

10-39 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

Operation of parking brake When travel lever is operated • If the travel lever is operated, the hydraulic oil from the pump moves spool (1) to the left and flows through port E into chamber A of brake piston (2), then pushes brake piston (2) to the left. As a result, the pressing force of spring (5) given to plate (3) and disc (4) is lost, then plate (3) and disc (4) are separated and the brake force is released.

10-40 (10)

TRAVEL MOTOR

When travel lever is set to neutral position • If the travel lever is set to the neutral position, the hydraulic oil from the pump is shut off. The hydraulic oil in chamber (a) of brake piston (2) is drained into the case and piston (2) is pushed to the right by spring (5). As a result, plate (3) and disc (4) are pressed and the braking force is applied.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

WORK EQUIPMENT CYLINDER

WORK EQUIPMENT CYLINDER PC78US-6 Boom cylinder

Arm cylinder

Bucket cylinder

PC78US-6

10-41 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

WORK EQUIPMENT CYLINDER

Blade cylinder

Unit: mm No.

Item

Criteria Cylinder name

1

2

3

Clearance between piston rod and bushing

Clearance between piston rod support shaft and bushing

Clearance between cylinder bottom support shaft and bushing

5

Tightening torque of cylinder piston

10-42 (10)

Shaft

Hole

Standard clearance

Allowable clearance

65

-0.030 -0.104

+0.250 +0.055

0.085 – 0.354

0.654

Arm

60

-0.030 -0.104

+0.163 +0.006

0.036 – 0.267

0.567

Bucket

55

-0.030 -0.104

+0.163 +0.006

0.036 – 0.267

0.567

Blade

65

-0.030 -0.104

+0.250 +0.055

0.085 – 0.354

0.654

Boom

60

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Arm

60

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Bucket

60

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Blade

70

-0.030 -0.104

+0.174 +0.100

0.130 – 0.278

1.0

Boom

65

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Arm

55

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Bucket

50

-0.030 -0.100

+0.142 +0.080

0.110 – 0.242

1.0

Blade

70

-0.030 -0.104

+0.174 +0.100

0.130 – 0.274

1.0

Arm Tightening torque of cylinder head

Allowance

Boom

Boom

4

Basic dimension

Remedy

Bucket

Replace bushing

Replace pin and bushing

961 ± 96.1 Nm {98 ± 9.8 kgm} 785 ± 78.5 Nm {80 ± 8.0 kgm} Procedure 1) Tighten to 1.18 – 1.37 kNm {120 – 140 kgm}. 2) Loosen to 0 Nm {0 kgm}. 3) Tighten to 0.39 kNm {40 kgm}. 4) Control tightening of cylinder head by turning angle (Turning distance: 3.5 – 4.5 mm).

Blade

1.030 ± 103.0 Nm {105 ± 10.5 kgm}

Boom

2.60 ± 0.26 kNm {265 ± 26.5 kgm} (2 Width across flats : 70 mm)

Arm

2.65 ± 0.26 kNm {270 ± 27.0 kgm} (2 Width across flats : 65 mm)

Bucket

2.16 ± 0.22 kNm {220 ± 22.0 kgm} (2 Width across flats : 60 mm)

Blade

3.14 ± 0.31 kNm {320 ± 32.0 kgm} (2 Width across flats : 75 mm)

Retighten

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

WORK EQUIPMENT CYLINDER

PC78UU-6 Boom cylinder

Arm cylinder

Bucket cylinder

PC78US-6

10-43 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

WORK EQUIPMENT CYLINDER

Offset cylinder

Blade cylinder

10-44 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

WORK EQUIPMENT CYLINDER

Unit: mm No.

Item

Criteria Cylinder name

1

2

3

Clearance between piston rod and bushing

Clearance between piston rod support shaft and bushing

Clearance between cylinder bottom support shaft and bushing

Clearance between trunnion support shaft bushing

5

PC78US-6

Standard clearance

Allowable clearance

-0.030 -0.104

+0.271 +0.075

0.105 – 0.375

0.675

Arm

65

-0.030 -0.104

+0.262 +0.067

0.097 – 0.366

0.666

Bucket

55

-0.030 -0.104

+0.163 +0.006

0.036 – 0.267

0.567

Offset

55

-0.030 -0.104

+0.163 +0.006

0.036 – 0.267

0.567

Blade

65

-0.030 -0.104

+0.250 +0.055

0.085 – 0.354

0.654

Boom

65

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Arm

60

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Bucket

60

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Offset

55

-0.030 -0.076

+0.174 +0.100

0.130 – 0.250

1.0

Blade

70

-0.030 -0.104

+0.174 +0.100

0.130 – 0.278

1.0

Boom

65

-0.030 -0.100

+0.174 +0.100

0.130 – 0.274

1.0

Bucket

50

-0.025 -0.064

+0.142 +0.080

0.105 – 0.206

1.0

Offset

55

-0.030 -0.076

+0.174 +0.100

0.130 – 0.250

1.0

Blade

70

-0.030 -0.104

+0.174 +0.100

0.130 – 0.274

1.0

Arm

65

-0.080 -0.126

+0.124 +0.050

0.130 – 0.250

1.0

Bucket

Offset

Tightening torque of cylinder piston

Hole

70

Arm Tightening torque of cylinder head

Allowance Shaft

Boom

Boom

4

Basic dimension

Remedy

Replace bushing

Replace pin and bushing

980 ± 98.0 Nm {100 ± 10.0 kgm} 1,107 ± 116.7 Nm {113 ± 11.3 kgm} Procedure 1) Tighten to 1.18 – 1.37 kNm {120 – 140 kgm}. 2) Loosen to 0 Nm {0 kgm}. 3) Tighten to 0.39 kNm {40 kgm}. 4) Control tightening of cylinder head by turning angle (Turning distance: 3.5 – 4.5 mm). 931 ± 93.1 Nm {95 ± 9.5 kgm}

Blade

1.030 ± 103.0 Nm {105 ± 10.5 kgm}

Boom

3.97 ± 0.40 kNm {405 ± 40.5 kgm} (2 Width across flats : 80 mm)

Arm

4.12 ± 0.41 kNm {420 ± 42.0 kgm} (2 Width across flats : 75 mm)

Bucket

2.16 ± 0.22 kNm {220 ± 22.0 kgm} (2 Width across flats : 60 mm)

Offset

1.42 ± 0.14 kNm {145 ± 14.5 kgm} (2 Width across flats : 55 mm)

Blade

3.14 ± 0.31 kNm {320 ± 32.0 kgm} (2 Width across flats : 75 mm)

Retighten

10-45 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SOLENOID VALVE

SOLENOID VALVE PC78US-6

10-46 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

A: B1: B2: B3: T:

SOLENOID VALVE

From control pump To PPC valve To 2nd travel speed selection valve To swing holding brake To hydraulic tank

1. Swing holding brake solenoid valve 2. 2-stage travel speed selector solenoid valve 3. PPC lock solenoid valve Solenoid valve 4. Coil (ON-OFF type) 5. Push pin 6. Valve spool 7. Return spring 8. Valve body Control relief valve 9. Adjustment screw 10. Locknut 11. Guide 12. Return spring 13. Valve spool

PC78US-6

10-47 (14)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SOLENOID VALVE

PC78UU-6

10-48 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

A: A4: A5: A6: B1: B2: B3: B4: B5: B6: T: 1. 2. 3. 4. 5. 6.

SOLENOID VALVE

From control pump From offset PPC valve "LEFT OFFSET" From left work equipment PPC valve "ARM IN" From right work equipment PPC valve "BOOM RAISE" To PPC valve To 2-stage travel speed selection valve To swing holding brake To control valve "LEFT OFFSET" To control valve "ARM IN" To control valve "BOOM RAISE" To hydraulic tank Boom raise stop EPC valve Arm in stop EPC valve Left offset stop EPC valve Swing holding brake solenoid valve 2-stage travel speed selector solenoid valve PPC lock solenoid valve

Solenoid valve 7. Coil (ON-OFF type) 8. Push pin 9. Valve spool 10. Return spring 11. Valve body EPC valve 12. Return spring 13. Guide 14. Valve spool 15. Push pin 16. Coil (Proportional) Check valve 17. Plug 18. Spring 19. Ball Control relief valve 20. Adjustment screw 21. Locknut 22. Guide 23. Return spring 24. Valve spool

PC78US-6

10-49 (14)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SOLENOID VALVE

PPC LOCK SOLENOID VALVE 2-STAGE TRAVEL SPEED SELECTOR SOLENOID VALVE SWING HOLDING BRAKE SOLENOID VALVE Operation When solenoid is de-energized (circuit is broken) • While a signal current does not flow from the PPC hydraulic lock switch or travel speed boost pedal, solenoid (1) is de-energized. Accordingly, spool (2) is pressed up by spring (3). • Under this condition, port A is closed and the pilot hydraulic oil does not flow into the actuator. At the same time, the oil from the actuator is drained through ports B and T into the tank.

10-50 (10)

When solenoid is energized (circuit is made) • If a signal current flows from the PPC hydraulic lock switch or travel speed boost pedal to solenoid (1), solenoid (1) is energized. • Accordingly, spool (2) is pushed down by push pin (4). • Under this condition, the pilot hydraulic oil flows through port A, spool (2), and port B into the actuator. At the same time, port T is closed and the oil does not flow into the tank.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SOLENOID VALVE

BOOM RAISE STOP EPC VALVE ARM IN STOP EPC VALVE LEFT OFFSET STOP EPC VALVE Operation When signal current is maximum (When coil is energized and circuit pressure is maximum) • If the signal current flows from the controller into coil (1), coil (1) is energized. At this time, the thrust of coil (1) is maximum. • As a result, spool (2) is pushed down by push pin (3). • Accordingly, all the pressurized oil from the PPC valve flows through port A, spool (2), and port B to the control valve. At this time, port T is closed and any oil does not flow in the tank.

PC78US-6

When signal current is reduced (When coil is energized and circuit pressure is low) • If the signal current flowing from the controller into coil (1) is reduced, coil (1) is still energized but its thrust is lowered in proportion to the signal current. • As a result, push pin (3) pushes down spool (2) and the pressurized oil from port A flows to port B. • If the pressure in port B rises and the force applied to face "a" of spool (2) becomes larger than the thrust of coil (1), spool (2) is pushed up and port A is disconnected from port B and connected to port T. • Accordingly, spool (2) moves up and down so that the thrust of coil (1) will be balanced with the pressure in port B. • As a result, the circuit pressure between the PPC valve and control valve is controlled in proportion to the signal current.

10-51 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

When signal current is 0 (When coil is de-energized and circuit cut out) • If the signal current flowing from the controller into coil (1) becomes 0, coil (1) is deenergized. • As a result, spool (2) is pressed up by return spring (4). • Accordingly, port A is closed and the pressurized oil from the PPC valve does not flow into the control valve. At this time, the oil from the control valve is drained through ports B and T into the tank.

SOLENOID VALVE

Control relief valve •

If the pressure of the hydraulic oil from the control pump rises, the oil in port A pushes spool (1). The reaction force of spool (1) compresses spring (2) and moves spool (1) to the right to open ports A and T to relieve the circuit. Set pressure: 3.1 MPa {32 kg/cm²}

Signal current is 0 o increased o maximum • The valve operates in the order of 3, 2, and 1 explained above.

10-52 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

MULTI-CONTROL VALVE

MULTI-CONTROL VALVE (OPTIONAL)

(1) JIS Pattern (2) Backhoe Pattern a Operation pattern selection drawing (Port names correspond to symbols in drawing)

PC78US-6

10-53 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ACCUMULATOR FOR BRAKER

ACCUMULATOR FOR BRAKER (OPTIONAL)

1. 2. 3. 4. 5. 6.

Cap Core Guard rubber Lid Plug Shell

10-54 (14)

Specification Type of gas

Nitrogen Gas

Gas volume ( )

0.48

Sealed gas pressure (MPa {kg/cm²})

0.1 {1} (at 80 °C)

Max. actuating pressure (MPa {kg/cm²})

6.86 {70}

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

HYDRAULIC PUMP PC78US-6 (with blade) Serial No.: 4001 – 5500 PC78UU-6 (with blade) Serial No.: 22832 – 23500 Model: LPD45 + 45

P1 : Pump discharge P2 : Pump discharge P3 : Gear pump discharge P4 : Pilot pump discharge P5 : Gear pump pressure pickup port PD : Drain PM : PC mode changeover pressure pickup port P1T : Travel deviation adjustment orifice P2T : Travel deviation adjustment orifice

PC78US-6

PD2 : Pump drain (plug) PDA: Air bleeder PEN: Control pressure pickup port PGS: Gear pump suction PLS : LS pressure input (From control valve) PPT : PTO oil filler PS1 : Main pump suction PEPC: EPC main pressure pickup port PPLS : Pump pressure input (From control valve)

10-55 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

PC78US-6 (without blade) Serial No.: 4001 – 5500 Model: LPD45 + 45

P1 : Pump discharge P2 : Pump discharge P4 : Pilot pump discharge PD : Drain PM : PC mode changeover pressure pickup port P1T : Travel deviation adjustment orifice P2T : Travel deviation adjustment orifice PD2 : Pump drain (plug)

10-56 (10)

PDA: Air bleeder PEN: Control pressure pickup port PLS : LS pressure input (From control valve) PPT : PTO oil filler PS1 : Main pump suction PEPC: EPC main pressure pickup port PPLS : Pump pressure input (From control valve)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

T : Drain P1 : Pump discharge P2 : Pump discharge P3 : Gear pump pressure input PD : Drain PH : Pump shuttle PAV : Pump average pressure

PC78US-6

HYDRAULIC PUMP

PD2 : Drain (Plug) PDE: EPC drain PEN: Control pressure input PPT : PTO oil filler PS1 : Pump suction PEPC: EPC main pressure pickup port

10-57 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

HYDRAULIC PUMP

Shaft Flange Case Rocker cam Shoe Piston Cylinder block Valve plate Servo piston Oil seal

10-58 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

PDE: EPC drain 1. EPC valve PC valve T: Drain P3: Gear pump pressure input PH: Pump shuttle pressure PAV: Pump average pressure PPL: PC valve output pressure PEPCOUT: EPC output pressure 2. Lever 3. Spring

PC78US-6

4. Retainer 5. Seat 6. Spool 7. Sleeve 8. Piston 9. Seal 10. Piston 11. Plug

LS valve PE: Control piston pressure PH: Pump shuttle pressure PLS: LS pressure input PPL: PC valve output pressure PPLS: LS pump pressure input 12. Spool 13. Plug

14. Seat 15. Spring 16. Seat 17. O-ring 18. Backup ring 19. Nut 20. Plug

10-59 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

PC78US-6 (with blade) Serial No.: 5501 – 6500 PC78UU-6 (with blade) Serial No.: 23501 and up Model: LPD45 + 45

P1 : Pump discharge P2 : Pump discharge P3 : Gear pump discharge P4 : Pilot pump discharge P5 : Gear pump pressure pickup port PD : Drain PM : PC mode changeover pressure pickup port P1T : Travel deviation adjustment orifice P2T : Travel deviation adjustment orifice

10-60 (10)

PD2 : Pump drain (plug) PDA: Air bleeder PEN: Control pressure pickup port PGS: Gear pump suction PLS : LS pressure input (From control valve) PPT : PTO oil filler PS1 : Main pump suction PEPC: EPC main pressure pickup port PPLS : Pump pressure input (From control valve)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

T P1 P2 P3 P5 PD PH

: Drain : Pump discharge : Pump discharge : Gear pump pressure input : Gear pump pressure pickup port : Drain : Pump shuttle

PC78US-6

HYDRAULIC PUMP

PAV : Pump average pressure PD2 : Drain (Plug) PDE: EPC drain PEN: Control pressure input PPT : PTO oil filler PS1 : Pump suction PEPC: EPC main pressure pickup port

10-61 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

PC78US-6 (without blade) Serial No.: 5501 – 6500 Model: LPD45 + 45

P1 : Pump discharge P2 : Pump discharge P4 : Pilot pump discharge PD : Drain PM : PC mode changeover pressure pickup port P1T : Travel deviation adjustment orifice P2T : Travel deviation adjustment orifice PD2 : Pump drain (plug)

10-62 (10)

PDA: Air bleeder PEN: Control pressure pickup port PLS : LS pressure input (From control valve) PPT : PTO oil filler PS1 : Main pump suction PEPC: EPC main pressure pickup port PPLS : Pump pressure input (From control valve)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

T : Drain P1 : Pump discharge P2 : Pump discharge PD : Drain PH : Pump shuttle PAV : Pump average pressure PD2 : Drain (Plug)

PC78US-6

HYDRAULIC PUMP

PD3 : Drain PDE: EPC drain PEN: Control pressure input PPT : PTO oil filler PS1 : Pump suction PEPC: EPC main pressure pickup port

10-63 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

HYDRAULIC PUMP

Shaft Flange Case Rocker cam Shoe Piston Cylinder block Valve plate Servo piston Oil seal

10-64 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

PDE: EPC drain 1. EPC valve PC valve T: Drain P3: Gear pump pressure input PH: Pump shuttle pressure PAV: Pump average pressure PPL: PC valve output pressure PEPCOUT: EPC output pressure 2. Lever 3. Spring

PC78US-6

4. Retainer 5. Seat 6. Spool 7. Sleeve 8. Piston 9. Seal 10. Piston 11. Plug

LS valve PE: Control piston pressure PH: Pump shuttle pressure PLS: LS pressure input PPL: PC valve output pressure PPLS: LS pump pressure input 12. Spool 13. Plug

14. Seat 15. Spring 16. Seat 17. O-ring 18. Backup ring 19. Nut 20. Plug

10-65 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

PC78US-6 (with blade) Serial No.: 6501 and up Model: LPD45 + 45

P1 : Pump discharge P2 : Pump discharge P3 : Gear pump discharge P4 : Pilot pump discharge P5 : Gear pump pressure pickup port PD : Drain PM : PC mode changeover pressure pickup port P1T : Travel deviation adjustment orifice P2T : Travel deviation adjustment orifice

10-66 (10)

PD2 : Pump drain (plug) PDA: Air bleeder PEN: Control pressure pickup port PGS: Gear pump suction PLS : LS pressure input (From control valve) PPT : PTO oil filler PS1 : Main pump suction PEPC: EPC main pressure pickup port PPLS : Pump pressure input (From control valve)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

T P1 P2 P3 P5 PD PH

: Drain : Pump discharge : Pump discharge : Gear pump pressure input : Gear pump pressure pickup port : Drain : Pump shuttle

PC78US-6

HYDRAULIC PUMP

PAV : Pump average pressure PD2 : Drain (Plug) PDE: EPC drain PEN: Control pressure input PPT : PTO oil filler PS1 : Pump suction PEPC: EPC main pressure pickup port

10-67 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

PC78US-6 (without blade) Serial No.: 6501 and up Model: LPD45 + 45

P1 : Pump discharge P2 : Pump discharge P4 : Pilot pump discharge PD : Drain PM : PC mode changeover pressure pickup port P1T : Travel deviation adjustment orifice P2T : Travel deviation adjustment orifice PD2 : Pump drain (plug)

10-68 (10)

PDA: Air bleeder PEN: Control pressure pickup port PLS : LS pressure input (From control valve) PPT : PTO oil filler PS1 : Main pump suction PEPC: EPC main pressure pickup port PPLS : Pump pressure input (From control valve)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

T : Drain P1 : Pump discharge P2 : Pump discharge PD : Drain PH : Pump shuttle PAV : Pump average pressure PD2 : Drain (Plug)

PC78US-6

HYDRAULIC PUMP

PD3 : Drain PDE: EPC drain PEN: Control pressure input PPT : PTO oil filler PS1 : Pump suction PEPC: EPC main pressure pickup port

10-69 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

HYDRAULIC PUMP

Shaft Flange Case Rocker cam Shoe Piston Cylinder block Valve plate Servo piston Oil seal

10-70 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

PDE: EPC drain 1. EPC valve PC valve T: Drain P3: Gear pump pressure input PH: Pump shuttle pressure PAV: Pump average pressure PPL: PC valve output pressure PEPCOUT: EPC output pressure 2. Lever 3. Spring

PC78US-6

4. Retainer 5. Seat 6. Spool 7. Sleeve 8. Piston 9. Seal 10. Piston 11. Plug

LS valve PE: Control piston pressure PH: Pump shuttle pressure PLS: LS pressure input PPL: PC valve output pressure PPLS: LS pump pressure input 12. Spool 13. Plug

14. Seat 15. Spring 16. Seat 17. O-ring 18. Backup ring 19. Nut 20. Plug

10-71 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

Function • This pump converts the revolution and torque of the engine transmitted to its shaft into hydraulic energy and discharges hydraulic oil according to the load. • The discharge can be changed by changing the swash plate angle.

HYDRAULIC PUMP

•

The oil in each cylinder of cylinder block (7) can be drawn and discharged through valve plate (8).

Structure • Cylinder block (7) is supported on shaft (1) through spline a. Shaft (1) is supported on the front and rear bearings. • The end of piston (6) is a concave sphere, which holds shoe (5) as a spherical bearing. • Rocker cam (4) has plane A. Shoe (5) is kept pressed against plane A and slid circularly. Rocker cam (4) is supported on flange (2) and ball (12) fixed to the case and slides on the formed static pressure bearing and high-pressure oil. • Piston (6) moves axially and relatively in each cylinder of cylinder block (7). • Cylinder block (7) revolves relatively against valve plate (8), sealing the hydraulic oil. The hydraulic pressure on the revolving surface of the cylinder block is balanced properly.

10-72 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

Operation

HYDRAULIC PUMP

•

1. Operation of pump •

• •

•

Shaft (1) and cylinder block (7) revolve together and shoe (5) slides on plane A. As rocker cam (4) slants around ball (12) at this time, angle ( ) between the center line X of rocker cam (4) and axis of cylinder block (7) changes. Angle ( ) is called the swash plate angle.

• •

If center line X of rocker cam (4) is in the direction of the axis of cylinder block (7) (Swash plate angle = 0), the difference between volumes E and F in cylinder block (7) is 0 and oil is not sucked or discharged (The swash plate angle is not reduced to 0 actually, however). In short, swash plate angle ( ) is in proportion to the discharge of the pump. The number of holes on cylinder block (7) is even 10 and every second one of them is fitted to 2 grooves of valve plate (8). The quantity of the oil equivalent to 5 pistons is discharged to each of P1 and P2.

If the angle between the center line X of rocker cam (4) and the axis of cylinder block (7) is a, plane A works as a cam for shoe (5). Accordingly, piston (6) slides inside cylinder block (7) and makes difference between volumes E and F in cylinder block (7) and the oil is drawn and discharged by the difference. In short, if cylinder block (7) revolves and volume of chamber E is reduced, the oil is discharged. On the other hand, the volume of chamber F is increased and the oil is sucked. (The figure shows the end of suction process of chamber F and the end of discharge process of chamber E.)

PC78US-6

10-73 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

2. Control of discharge

LS valve

•

Function • The LS valve controls the discharge of the pump according to the stroke of the control lever, or the demand flow for the actuator. • The LS valve calculates the demand flow for the actuator fr om differential pr essure PLS between inlet pressure PPLS and outlet pressure PLS of the control valve, and controls discharge Q of the main pump. (PPLS is called the LS pump pressure, PLS the LS pressure, and PLS the LS differential pressure.) • That is, the discharge of the pump is controlled according to the demand flow for the actuator by the following method; The pressure loss made when the oil flows through the opening of the control valve spool (LS differential pressure PLS) is sensed and discharge Q of the pump is so controlled that the pressure loss will be constant. • The LS valve receives main pump discharge pressure PP, LS pump pressure (PPLS), and LS pressure PLS. The relationship between the LS differential pressure ( PLS) and pump discharge Q changes as shown below.

•

If swash plate angle ( ) is increased, the difference between volumes E and F, or discharge Q, is increased. Swash plate angle ( ) is changed with servo piston (11). Servo piston (11) is reciprocated linearly by the signal pressure of PC and LS valves. This linear motion is transmitted to rocker cam (4) supported on flange (2) through ball (12). Then, rocker cam (4) slides in the revolutionary direction.

10-74 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

PC valve Function • The PC valve limits the oil flow to a certain level (according to the discharge pressure) even if the stroke of the control valve is increased so that the horsepower absorbed by the pump will not exceed the engine horsepower, as long as pump discharge pressure PP is high. That is, the PC valve performs constant-horsepower control. • In other words, the PC valve decreases the pump discharge when the load is increased and the pump discharge pressure rises and increases it when the pump discharge pressure lowers. • This pump has 2 discharge openings and the average of discharge pressures P1 and P2 at those openings is sensed. The average of P1 and P2 is called the PAVE. The relationship between this average and pump discharge (discharge from the 2 discharge openings) is shown below.

Operation 1. PC78UU, 78US-6 (With blade) (1) Function of spring • The spring load of spring (2) at the PC valve is decided by the position of the swash plate. • If servo piston (6) moves to the right, spring (2) is compressed through lever (1) and its spring load changes. The spring constant of this spring changes to 2 levels. (2) When pump pressure PAVE is low • The pressure of spool (4) is decreased and spool (3) is a little to the right (Fig. 1 and Fig. 4). At this time, ports C and D are connected to each other and the pressure in the LS valve is drain pressure PT.

PC78US-6

HYDRAULIC PUMP

•

• •

•

At this time, ports F and G of the LS valve are connected to each other. As a result, the pressure in port J becomes drain pressure PT and servo piston (6) moves to the left. Consequently, the pump discharge is increased. As servo piston (6) moves, lever (1) moves to the left and spring (2) expands and its spring load is decreased. Consequently, spool (3) moves to the left to break the connection of ports C and D, and then pump discharge ports B and C are connected. As a result, the pressure in port C rises and the piston pressure is increased and servo piston (6) stops moving to the left.

(3) When pump pressure PAVE is high • The pressure of spool (4) is increased and spool (3) is a little to the left (Fig. 2 and Fig. 5). At this time, ports C and B are connected to each other and the pressure in the LS valve is pump pressure PP. • At this time, ports F and G of the LS valve are connected to each other. As a result, the pressure in port J becomes pump pressure PP and servo piston (6) moves to the right. • Consequently, the pump discharge is decreased. • As servo piston (6) moves, lever (1) moves to the right and spring (2) is compressed and its spring load is increased. Consequently, spool (3) moves to the right to break the connection of ports C and B, and then drain pressure ports D and C are connected. • As a result, the pressure in port C lowers and the piston pressure is decreased and servo piston (6) stops moving to the right. • Accordingly, the stopping position (= pump discharge) of servo piston (6) is decided by the position where the pressure caused by pressure PP applied to spool (4) is balanced with the force of spring (2) applied through spool (3) (Fig. 3 and Fig. 6). (4) When swing gear pump pressure rises/lowers • The pressure of spool (4) changes and the pump discharge changes similarly to the case where the PAVE rises/lowers. • The PC-EPC valve changes the output pressure according to the input current from the controller, then the pressure of spool (5) changes and the pump discharge changes similarly to the case where the PAVE rises/lowers.

10-75 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

When load is light

When load is heavy

10-76 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

When balanced

2. PC78US-6 (Without blade) • Although the swing gear pump is not mounted, the theory of operation of this model is the same as that of the machine equipped with the swing gear pump. When load is light

PC78US-6

10-77 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

HYDRAULIC PUMP

When load is heavy

When balanced

10-78 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

CONTROL VALVE Outline a The control valves of the following types are set. PC78US-6 • • • • • •

Blade-less, without service valve Blade-less, with 1 service valve Blade-less, with 2 service valve With blade, without service valve With blade and 1 service valve With blade and 2 service valve

PC78UU-6 • Without service valve • 1 service valve • 2 service valve a Since each service valve is of add-on type, it can be added or removed later.

1. PC78US-6 blade-less and with 1 service valve (1) Outside view A1: To swing motor A2: To left travel motor A3: To right travel motor A4: To boom cylinder bottom A5: To arm cylinder head A6: To bucket cylinder head A7: To attachment 1 B1: To swing motor B2: To left travel motor B3: To right travel motor B4: To boom cylinder head B5: To arm cylinder bottom B6: To bucket cylinder bottom B7: To attachment 1 BP: From boom RAISE PPC valve LS: To pump LS valve (LS pressure input) P1: From main pump P2: From main pump PP: To pump LS valve (Pump pressure input) PS: From swing holding brake reset solenoid valve

10-80 (10)

PT: To travel pressure switch TB: To tank TC: To oil cooler TS: To tank PA1: From swing right PPC valve PA2: From left travel reverse PPC valve PA3: From right travel reverse PPC valve PA4: From boom raise PPC valve PA5: From arm out PPC valve PA6: From bucket dump PPC valve PA7: From service 1 PPC valve PB1: From swing left PPC valve PB2: From left travel forward PPC valve PB3: From right travel forward PPC valve PB4: From boom lower PPC valve PB5: From arm in PPC valve PB6: From bucket curl PPC valve PB7: From service 1 PPC valve TSW: To swing motor

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(PC78US-6 blade-less and with 1 service valve)

PC78US-6

10-81 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(2) Sectional view Serial No.: 4001 – 6500 (1/4)

(PC78US-6 blade-less and with 1 service valve)

10-82 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

Serial No.: 6501 and up (1/4)

(PC78US-6 blade-less and with 1 service valve)

PC78US-6

10-83 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28.

Suction valve (Left travel) Suction valve (Right travel) Main relief valve Suction valve (Boom bottom) Suction valve (Arm head) Suction valve (Bucket head) Suction valve (Attachment) Safety valve Suction valve (Attachment) Suction valve (Bucket bottom) Suction valve (Arm bottom) Suction valve (Boom head) Lift check valve Cooler bypass valve Suction valve (Right travel) Suction valve (Left travel) Spool (Swing) Spool (Left travel) Spool (Right travel) Unload valve (P1) Unload valve (P2) Spool (Boom) Spool (Arm) Spool (Bucket) Spool (Attachment) LS pressure pickup plug (LS2) LS pressure pickup plug (LS1) Spool (LS selector)

CONTROL VALVE

29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52.

Pressure compensation valve F (Swing) Pressure compensation valve F (Left travel) Pressure compensation valve F (Right travel) Pressure compensation valve F (Boom) Pressure compensation valve F (Arm) Pressure compensation valve F (Bucket) Pressure compensation valve F (Attachment) Pump pressure pickup plug (P2) LS pressure pickup plug (LS3) Pressure compensation valve R (Attachment) Pressure compensation valve R (Bucket) Pressure compensation valve R (Arm) Pressure compensation valve R (Boom) LS bypass plug (LS2) Logic valve Spool (Pump merge-divider valve) Pressure compensation valve R (Right travel) Pressure compensation valve R (Left travel) Pressure compensation valve R (Swing) Check valve (Attachment) Check valve (Bucket) Check valve (Arm) Boom hydraulic drift prevention valve Check valve (Boom bottom)

F: Flow control valve R: Pressure reducing valve

(PC78US-6 blade-less and with 1 service valve)

10-84 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

Unit: mm No.

Item

Criteria Basic dimensions

53

Lift check valve spring

Remedy Allowable limit

Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

58.1 X 17.0

36

59.6 N {5.8 kg}

—

47.7 N {4.64 kg}

54

Cooler bypass valve spring

34.5 X 17.7

25

73.5 N {7.5 kg}

—

58.8 N {6.0 kg}

55

Spool return spring (Swing)

29.2 X 17.5

28.5

28.3 N {2.89 kg}

—

22.6 N {2.31 kg}

56

Spool return spring (Travel)

29.0 X 17.5

28.5

22.6 N {2.3 kg}

—

18.1 N {1.84 kg}

57

Spool return spring (Arm in)

41.1 X 19.3

40.5

43.1 N {4.4 kg}

—

34.5 N {3.52 kg}

58

Spool return spring (Work equipment)

41.1 X 19.3

40.5

34.3 N {3.5 kg}

—

27.4 N {2.8 kg}

59

Spool return spring (Arm out)

42.3 X 19.2

40.5

54.9 N {5.6 kg}

—

43.9 N {4.49 kg}

60

Unload valve spring

40.9 X 15.1

33.5

129 N {13.2 kg}

—

103 N {10.6 kg}

61

LS selector valve spring

16.6 X 13.0

13

11.2 N {1.14 kg}

—

8.96 N {0.91 kg}

62

Pressure compensation valve spring

15.4 X 6.0

8

7.45 N {0.76 kg}

—

5.96 N {0.61 kg}

63

Pump merge-divider valve spool return spring

33.2 X 14.2

22.5

49.0 N {5.0 kg}

—

39.2 N {4.0 kg}

64

Pressure compensation valve spring

30.9 X 5.2

20

27.7 N {2.82 kg}

—

22.2 M {2.26 kg}

65

Pressure compensation valve spring

28.0 X 14.4

14.5

13.7 N {1.4 kg}

—

11.0 N {1.12 kg}

66

Pressure compensation valve spring

33.4 X 14.4

21.5

55.9 N {5.7 kg}

—

44.7 N {4.56 kg}

67

Pressure compensation valve spring

20.0 X 8.4

12

6.86 N {0.7 kg}

—

5.49 N {0.56 kg}

68

Pressure compensation valve spring

23.0 X 8.4

15

6.86 N {0.7 kg}

—

5.49 N {0.56 kg}

69

Check valve spring

12.3 X 11.4

10.5

3.92 N {0.4 kg}

—

3.14 N {0.32 kg}

70

Check valve spring

27.2 X 6.9

22

3.92 N {0.4 kg}

—

3.14 N {0.32 kg}

If damaged or deformed, replace spring.

(PC78US-6 blade-less and with 1 service valve)

PC78US-6

10-85 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

Serial No.: 4001 – 6500 (2/4)

(PC78US-6 blade-less and with 1 service valve)

10-86 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

Serial No.: 6501 and up (2/4)

(PC78US-6 blade-less and with 1 service valve)

PC78US-6

10-87 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24.

CONTROL VALVE

Spool (LS selector) Spool (Swing) Pressure compensation valve R (Swing) Pressure compensation valve F (Swing) Pressure compensation valve F (Left travel) Suction valve (Left travel) Spool (Left travel) Suction valve (Left travel) Pressure compensation valve R (Left travel) LS bleed valve Pressure compensation valve F (Right travel) Suction valve (Right travel) Spool (Right travel) Suction valve (Right travel) Pressure compensation valve R (Right travel) Travel junction valve, LS bleed valve Pump pressure pickup plug (P1) Spool (Pump merge-divider valve) Unload valve (P1) Check valve (P1) Cooler bypass valve LS pressure pickup plug (LS1) LS bypass plug (LS1) Logic valve

F: Flow control valve R: Pressure reducing valve

Unit: mm No.

Item

Criteria Basic dimensions

25

Check valve spring

Remedy Allowable limit

Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

21.9 X 5.0

15.8

1.96 N {0.2 kg}

—

1.57 N {0.16 kg}

26

Travel junction valve spring

19.3 X 7.5

14

15.7 N {1.6 kg}

—

12.6 N {1.28 kg}

27

Check valve spring

13.0 X 6.5

9

2.26 N {0.23 kg}

—

1.81 N {0.18}

If damaged or deformed, replace spring.

(PC78US-6 blade-less and with 1 service valve)

10-88 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(3/4)

(PC78US-6 blade-less and with 1 service valve)

10-90 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31.

CONTROL VALVE

Unload valve (P2) Main relief valve Check valve (P2) Lift check valve LS pressure pickup plug (LS2) LS bypass plug (LS2) Pressure compensation valve F (Boom) Suction valve (Boom bottom) Boom hydraulic drift prevention valve Suction valve (Boom head) Spool (Boom) Pressure compensation valve R (Boom) Suction valve (Arm head) Spool (Arm) Suction valve (Arm bottom) Pressure compensation valve R (Arm) Pressure compensation valve F (Arm) Suction valve (Bucket head) Spool (Bucket) Suction valve (Bucket bottom) Pressure compensation valve R (Bucket) Pressure compensation valve F (Bucket) Suction valve (Attachment) Spool (Attachment) Suction valve (Attachment) Pressure compensation valve R (Attachment) Pressure compensation valve F (Attachment) Pump pressure pickup plug (P2) Safety valve Pressure release plug LS pressure pickup plug (LS3)

F: Flow control valve R: Pressure reducing valve

Unit: mm No.

Item

Criteria Basic dimensions

32

Check valve spring

Remedy Allowable limit

Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

13.0 X 6.5

9

2.26 N {0.23 kg}

—

1.81 N {0.18}

33

Hydraulic drift prevention valve spring

16.6 X 13.0

13

11.2 N {1.14 kg}

—

8.96 N {0.91 kg}

34

Hydraulic drift prevention valve spring

13.0 X 8.8

7.7

10.8 N {1.1 kg}

—

8.64 N {0.88 kg}

If damaged or deformed, replace spring.

(PC78US-6 blade-less and with 1 service valve)

PC78US-6

10-91 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(4/4)

(PC78US-6 blade-less and with 1 service valve)

10-92 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4.

CONTROL VALVE

Travel junction valve, LS bleed valve LS bleed valve Check valve (Boom head) Logic valve

Unit: mm No.

Item

Criteria Basic dimensions

5

6

Check valve spring

Logic valve spring

Remedy Allowable limit

Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

27.2 X 6.9

22

3.92 N {0.4 kg}

—

3.14 N {0.32 kg}

11.0 X 6.2

9.5

5.5 N {0.56 kg}

—

4.4 N {0.45 kg}

If damaged or deformed, replace spring.

(PC78US-6 blade-less and with 1 service valve)

PC78US-6

10-93 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

2. PC78US-6 with blade and 1 service valve (1) Outside view A1: To blade cylinder head A2: To swing motor A3: To left travel motor A4: To right travel motor A5: To offset cylinder head A6: To boom cylinder bottom A7: To arm cylinder head A8: To bucket cylinder head B1: To blade cylinder bottom B2: To swing motor B3: To left travel motor B4: To right travel motor B5: To offset cylinder bottom B6: To boom cylinder head B7: To arm cylinder bottom B8: To bucket cylinder bottom BP: From boom RAISE PPC valve LS: To pump LS valve (LS pressure input) P1: From main pump P2: From main pump P3: From gear pump PP: To pump LS valve (LS pressure input) PT: To travel pressure switch TB: To tank TC: To oil cooler TS: To tank PA1: From blade raise PPC valve PA2: From swing right PPC valve PA3: From left travel reverse PPC valve PA4: From right travel reverse PPC valve PA5: From offset right PPC valve PA6: From boom raise PPC valve PA7: From arm out PPC valve PA8: From bucket dump PPC valve PB1: From blade lower PPC valve PB2: From swing left PPC valve PB3: From left travel forward PPC valve PB4: From right travel forward PPC valve PB5: From offset left PPC valve PB6: From boom lower PPC valve PB7: From arm in PPC valve PB8: From bucket curl PPC valve TSW: To swing motor

10-94 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(PC78US-6 with blade and 1 service valve)

PC78US-6

10-95 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(2) Sectional view Serial No.: 4001 – 6500 (1/4)

(PC78US-6 with blade and 1 service valve)

10-96 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

Serial No.: 6501 and up (1/4)

(PC78US-6 with blade and 1 service valve)

PC78US-6

10-97 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30.

Safety-suction valve (Blade head) Suction valve (Left travel) Suction valve (Right travel) Main relief valve Suction valve (Boom bottom) Suction valve (Arm head) Suction valve (Bucket head) Suction valve (Attachment) Safety valve Suction valve (Attachment) Suction valve (Bucket bottom) Suction valve (Arm bottom) Suction valve (Boom head) Cooler bypass valve Suction valve (Right travel) Suction valve (Left travel) Suction valve (Blade bottom) Gear pump relief valve Spool (Boom raise merge) Spool (Blade) Spool (Swing) Spool (Left travel) Spool (Right travel) Unload valve (P1) Unload valve (P2) Spool (Boom) Spool (Arm) Spool (Bucket) Spool (Attachment) LS pressure pickup plug (LS2)

CONTROL VALVE

31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54. 55. 56. 57.

LS pressure pickup plug (LS1) Pressure compensation valve F (Left travel) Pressure compensation valve F (Right travel) Pressure compensation valve F (Boom) Pressure compensation valve F (Arm) Pressure compensation valve F (Bucket) Pressure compensation valve F (Attachment) Pump pressure pickup plug (P2) LS pressure pickup plug (LS3) Pressure compensation valve R (Attachment) Pressure compensation valve R (Bucket) Pressure compensation valve R (Arm) Pressure compensation valve R (Boom) LS bypass plug (LS2) Logic valve Spool (Pump merge-divider valve) Pressure compensation valve R (Right travel) Pressure compensation valve R (Left travel) Check valve (Swing) LS bleed valve Travel junction valve, LS bleed valve Check valve (Attachment) Check valve (Bucket) Check valve (Arm) Boom hydraulic drift prevention valve Check valve (Boom bottom) Check valve (Blade)

F: Flow control valve R: Pressure reducing valve

(PC78US-6 with blade and 1 service valve)

10-98 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

Unit: mm No.

Item

Criteria

Remedy

Basic dimensions 58

Cooler bypass valve spring

Allowable limit

Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

34.5 X 17.7

25

73.5 N {7.5 kg}

—

58.8 N {6.0 kg}

59

Spool return spring (Blade, swing)

29.0 X 18.3

27.5

89.5 N {9.1 kg}

—

71.6 N {7.28 kg}

60

Spool return spring (Travel)

29.0 X 17.5

28.5

22.6 N {2.3 kg}

—

18.1 N {1.84 kg}

61

Spool return spring (Arm in)

41.1 X 19.3

40.5

43.1 N {4.4 kg}

—

34.5 N {3.52 kg}

62

Spool return spring (Work equipment)

41.1 X 19.3

40.5

34.3 N {3.5 kg}

—

27.4 N {2.8 kg}

63

Spool return spring (Arm out)

42.3 X 19.2

40.5

54.9 N {5.6 kg}

—

43.9 N {4.49 kg}

64

Unload valve spring

40.9 X 15.1

33.5

129 N {13.2 kg}

—

103 N {10.6 kg}

65

Boom RAISE merge valve spring

16.6 X 13.0

13

11.2 N {1.14 kg}

—

8.96 N {0.91 kg}

66

Pump merge-divider valve spool return spring

33.2 X 14.2

22.5

49.0 N {5.0 kg}

—

39.2 N {4.0 kg}

67

Pressure compensation valve spring

30.9 X 5.2

20

27.7 N {2.82 kg}

—

22.2 M {2.26 kg}

68

Pressure compensation valve spring

28.0 X 14.4

14.5

13.7 N {1.4 kg}

—

11.0 N {1.12 kg}

69

Pressure compensation valve spring

33.4 X 14.4

21.5

55.9 N {5.7 kg}

—

44.7 N {4.56 kg}

70

Pressure compensation valve spring

20.0 X 8.4

12

6.86 N {0.7 kg}

—

5.49 N {0.56 kg}

71

Check valve spring

13.0 X 6.5

9

2.26 N {0.23 kg}

—

1.81 N {0.18}

72

Check valve spring

27.2 X 6.9

22

3.92 N {0.4 kg}

—

3.14 N {0.32 kg}

73

Check valve spring

12.3 X 11.4

10.5

3.92 N {0.4 kg}

—

3.14 N {0.32 kg}

74

Check valve spring

21.9 X 5.0

15.8

1.96 N {0.2 kg}

—

1.57 N {0.16 kg}

75

Spool return spring (Boom)

41.13 X 19.3

38.5

136.41 N {13.91 kg}

—

109 N {11.1 kg}

76

Spool return spring (Blade)

29.01 X 18.3

27.5

89.5 N {9.1 kg}

—

71.6 N {7.3 kg}

If damaged or deformed, replace spring.

(PC78US-6 with blade and 1 service valve)

PC78US-6

10-99 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

Serial No.: 4001 – 6500 (2/4)

(PC78US-6 with blade and 1 service valve)

10-100 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

Serial No.: 6501 and up (2/4)

(PC78US-6 with blade and 1 service valve)

PC78US-6

10-101 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28.

CONTROL VALVE

Spool (Boom raise merge) Gear pump relief valve Safety-suction valve (Blade head) Suction valve (Blade bottom) Spool (Blade) Check valve (Blade) Spool (Swing) Check valve (Swing) Pressure compensation valve F (Left travel) Suction valve (Left travel) Spool (Left travel) Suction valve (Left travel) Pressure compensation valve R (Left travel) LS bleed valve Pressure compensation valve F (Right travel) Suction valve (Right travel) Spool (Right travel) Suction valve (Right travel) Pressure compensation valve R (Right travel) Travel junction valve, LS bleed valve Pump pressure pickup plug (P1) Unload valve (P1) Check valve (P1) Cooler bypass valve LS pressure pickup plug (LS1) LS bypass plug (LS1) Logic valve Spool (Pump merge-divider valve)

F: Flow control valve R: Pressure reducing valve

Unit: mm No.

Item

Criteria

Remedy

Basic dimensions 29

Check valve spring

Allowable limit

Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

21.9 X 5.0

15.8

1.96 N {0.2 kg}

—

1.57 N {0.16 kg}

30

Travel junction valve spring

19.3 X 7.5

14

15.7 N {1.6 kg}

—

12.6 N {1.28 kg}

31

Check valve spring

13.0 X 6.5

9

2.26 N {0.23 kg}

—

1.81 N {0.18}

If damaged or deformed, replace spring.

(PC78US-6 with blade and 1 service valve)

10-102 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(3/4)

(PC78US-6 with blade and 1 service valve)

10-104 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27.

CONTROL VALVE

Logic valve Unload valve (P2) Main relief valve Check valve (P2) LS pressure pickup plug (LS2) LS bypass plug (LS2) Suction valve (Boom bottom) Boom hydraulic drift prevention valve Suction valve (Boom head) Spool (Boom) Pressure compensation valve R (Boom) Pressure compensation valve F (Boom) Suction valve (Arm head) Spool (Arm) Suction valve (Arm bottom) Pressure compensation valve R (Arm) Pressure compensation valve F (Arm) Suction valve (Bucket head) Spool (Bucket) Suction valve (Bucket bottom) Pressure compensation valve R (Bucket) Pressure compensation valve F (Bucket) Suction valve (Attachment) Spool (Attachment) Suction valve (Attachment) Pressure compensation valve R (Attachment) Pressure compensation valve F (Attachment)

F: Flow control valve R: Pressure reducing valve

Unit: mm No.

Item

Criteria

Remedy

Basic dimensions 28

Check valve spring

Allowable limit

Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

13.0 X 6.5

9

2.26 N {0.23 kg}

—

1.81 N {0.18}

29

Hydraulic drift prevention valve spring

16.6 X 13.0

13

11.2 N {1.14 kg}

—

8.96 N {0.91 kg}

30

Hydraulic drift prevention valve spring

13.0 X 8.8

7.7

10.8 N {1.1 kg}

—

8.64 N {0.88 kg}

If damaged or deformed, replace spring.

(PC78US-6 with blade and 1 service valve)

PC78US-6

10-105 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(4/4)

(PC78US-6 with blade and 1 service valve)

10-106 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9.

CONTROL VALVE

Pump pressure pickup plug (P2) Safety valve Pressure release plug LS pressure pickup plug (LS3) LS bleed valve Travel junction valve, LS bleed valve Check valve (Boom head) Boom hydraulic drift prevention valve Logic valve

Unit: mm No.

Item

Criteria

Remedy

Basic dimensions 10

11

Check valve spring

Logic valve spring

Allowable limit

Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

27.2 X 6.9

22

3.92 N {0.4 kg}

—

3.14 N {0.32 kg}

11.0 X 6.2

9.5

5.5 N {0.56 kg}

—

4.4 N {0.45 kg}

If damaged or deformed, replace spring.

(PC78US-6 with blade and 1 service valve)

PC78US-6

10-107 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

3. PC78UU-6 without service valve (1) Outside view A1: To blade cylinder head A2: To swing motor A3: To left travel motor A4: To right travel motor A5: To offset cylinder head A6: To boom cylinder bottom A7: To arm cylinder head A8: To bucket cylinder head B1: To blade cylinder bottom B2: To swing motor B3: To left travel motor B4: To right travel motor B5: To offset cylinder bottom B6: To boom cylinder head B7: To arm cylinder bottom B8: To bucket cylinder bottom BP: From boom RAISE PPC valve LS: To pump LS valve (LS pressure input) P1: From main pump P2: From main pump P3: From gear pump PP: To pump LS valve (Pump pressure input) PT: To travel pressure switch TB: To tank TC: To oil cooler TS: To tank PA1: From blade raise PPC valve PA2: From swing right PPC valve PA3: From left travel reverse PPC valve PA4: From right travel reverse PPC valve PA5: From offset right PPC valve PA6: From boom raise PPC valve PA7: From arm out PPC valve PA8: From bucket dump PPC valve PB1: From blade lower PPC valve PB2: From swing left PPC valve PB3: From left travel forward PPC valve PB4: From right travel forward PPC valve PB5: From offset left PPC valve PB6: From boom lower PPC valve PB7: From arm in PPC valve PB8: From bucket curl PPC valve TSW: To swing motor

10-108 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(PC78UU-6 without service valve)

PC78US-6

10-109 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(2) Sectional view (1/4)

(PC78UU-6 without service valve)

10-110 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29.

Safety-suction valve (Blade head) Suction valve (Left travel) Suction valve (Right travel) Suction valve (Offset head) Main relief valve Suction valve (Boom bottom) Suction valve (Arm head) Suction valve (Bucket head) Safety valve Suction valve (Bucket bottom) Suction valve (Arm bottom) Suction valve (Boom head) Cooler bypass valve Suction valve (Right travel) Suction valve (Left travel) Suction valve (Blade bottom) Gear pump relief valve Spool (Boom raise merge) Spool (Blade) Spool (Swing) Spool (Left travel) Spool (Right travel) Spool (Offset) Unload valve (P1) Unload valve (P2) Spool (Boom) Spool (Arm) Spool (Bucket) LS pressure pickup plug (LS2)

CONTROL VALVE

30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. 54.

LS pressure pickup plug (LS1) Pressure compensation valve F (Left travel) Pressure compensation valve F (Right travel) Pressure compensation valve F (Offset) Pressure compensation valve F (Boom) Pressure compensation valve F (Arm) Pressure compensation valve F (Bucket) Pump pressure pickup plug (P2) LS pressure pickup plug (LS3) Pressure compensation valve R (Bucket) Pressure compensation valve R (Arm) Pressure compensation valve R (Boom) LS bypass plug (LS2) Logic valve Spool (Pump merge-divider valve) Pressure compensation valve R (Offset) Pressure compensation valve R (Right travel) Pressure compensation valve R (Left travel) Check valve (Blade) Check valve (Swing) LS bleed valve Travel junction valve, LS bleed valve Check valve (Bucket) Check valve (Arm) Check valve (Boom bottom)

F: Flow control valve R: Pressure reducing valve

(PC78UU-6 without service valve)

PC78US-6

10-111 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

Unit: mm No.

Item

Criteria Basic dimensions

55

Cooler bypass valve spring

Remedy Allowable limit

Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

34.5 X 17.7

25

73.5 N {7.5 kg}

–

58.8 N {6.0 kg}

56

Spool return spring (Blade, swing)

29.0 X 18.3

27.5

89.5 N {9.1 kg}

–

71.6 N {7.28 kg}

57

Spool return spring (Travel, offset)

29.0 X 17.5

28.5

22.6 N {2.3 kg}

–

18.1 N {1.84 kg}

58

Spool return spring (Work equipment)

41.1 X 19.3

40.5

34.3 N {3.5 kg}

–

27.4 N {2.8 kg}

59

Spool return spring (Arm out)

42.3 X 19.2

40.5

54.9 N {5.6 kg}

–

43.9 N {4.48 kg}

60

Unload valve spring

40.9 X 15.1

33.5

129 N {13.2 kg}

–

103 N {10.6 kg}

61

Boom RAISE merge valve spring

16.6 X 13.0

13

11.2 N {1.14 kg}

–

8.96 N {0.91 kg}

62

Pump merge-divider valve spool return spring

33.2 X 14.2

22.5

49.0 N {5.0 kg}

–

39.2 N {4.0 kg}

63

Pressure compensation valve spring

30.9 X 5.2

20

27.7 N {2.82 kg}

–

22.2 M {2.26 kg}

64

Pressure compensation valve spring

28.0 X 14.4

14.5

13.7 N {1.4 kg}

–

11.0 N {1.12 kg}

65

Pressure compensation valve spring

33.4 X 14.4

21.5

55.9 N {5.7 kg}

–

44.7 N {4.56 kg}

66

Pressure compensation valve spring

20.0 X 8.4

12

6.86 N {0.7 kg}

–

5.49 N {0.56 kg}

67

Check valve spring

13.0 X 6.5

9

2.26 N {0.23 kg}

–

1.81 N {0.18}

68

Check valve spring

27.2 X 6.9

22

3.92 N {0.4 kg}

–

3.14 N {0.32 kg}

69

Check valve spring

12.3 X 11.4

10.5

3.92 N {0.4 kg}

–

3.14 N {0.32 kg}

70

Check valve spring

21.9 X 5.0

15.8

1.96 N {0.2 kg}

–

1.57 N {0.16 kg}

If damaged or deformed, replace spring.

(PC78UU-6 without service valve)

10-112 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(2/4)

(PC78UU-6 without service valve)

10-114 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24.

CONTROL VALVE

Spool (Boom raise merge) Gear pump relief valve Safety-suction valve (Blade head) Suction valve (Blade bottom) Spool (Blade) Check valve (Blade) Spool (Swing) Check valve (Swing) Suction valve (Left travel) Spool (Left travel) Suction valve (Left travel) Pressure compensation valve R (Left travel) LS bleed valve Pressure compensation valve F (Left travel) Suction valve (Right travel) Spool (Right travel) Suction valve (Right travel) Pressure compensation valve R (Right travel) Travel junction valve, LS bleed valve Pressure compensation valve F (Right travel) Suction valve (Offset head) Spool (Offset) Pressure compensation valve R (Offset) Pressure compensation valve F (Offset)

F: Flow control valve R: Pressure reducing valve

Unit: mm No.

Item

Criteria Basic dimensions

25

26

Check valve spring

Travel junction valve spring

Remedy Allowable limit

Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

21.9 X 5.0

15.8

1.96 N {0.2 kg}

—

1.57 N {0.16 kg}

19.3 X 7.5

14

15.7 N {1.6 kg}

—

12.6 N {1.28 kg}

If damaged or deformed, replace spring.

(PC78UU-6 without service valve)

PC78US-6

10-115 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(3/4)

(PC78UU-6 without service valve)

10-116 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29.

CONTROL VALVE

Unload valve (P1) Check valve (P1) LS pressure pickup plug (LS1) Cooler bypass valve Logic valve LS bypass plug (LS1) Spool (Pump merge-divider valve) Pump pressure pickup plug (P1) Main relief valve Check valve (P2) LS pressure pickup plug (LS2) LS bypass plug (LS2) Unload valve (P2) Suction valve (Boom bottom) Boom hydraulic drift prevention valve Suction valve (Boom head) Spool (Boom) Pressure compensation valve R (Boom) Pressure compensation valve F (Boom) Suction valve (Arm head) Spool (Arm) Suction valve (Arm bottom) Pressure compensation valve R (Arm) Pressure compensation valve F (Arm) Suction valve (Bucket head) Spool (Bucket) Suction valve (Bucket bottom) Pressure compensation valve R (Bucket) Pressure compensation valve F (Bucket)

F: Flow control valve R: Pressure reducing valve

Unit: mm No.

Item

Criteria Basic dimensions

30

Check valve spring

Remedy Allowable limit

Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

13.0 X 6.5

9

2.26 N {0.23 kg}

—

1.81 N {0.18}

31

Hydraulic drift prevention valve spring

16.6 X 13.0

13

11.2 N {1.14 kg}

—

8.96 N {0.91 kg}

32

Hydraulic drift prevention valve spring

13.0 X 8.8

7.7

10.8 N {1.1 kg}

—

8.64 N {0.88 kg}

If damaged or deformed, replace spring.

(PC78UU-6 without service valve)

PC78US-6

10-117 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CONTROL VALVE

(4/4)

(PC78UU-6 without service valve)

10-118 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9.

CONTROL VALVE

Safety valve Pressure release plug LS pressure pickup plug (LS3) Pump pressure pickup plug (P2) LS bleed valve Travel junction valve, LS bleed valve Boom hydraulic drift prevention valve Check valve (Boom head) Logic valve

F: Flow control valve R: Pressure reducing valve Unit: mm No.

Item

Criteria Basic dimensions

10

11

Check valve spring

Logic valve spring

Remedy Allowable limit

Free length x Outside diameter

Installed length

Installed load

Free length

Installed load

27.2 X 6.9

22

3.92 N {0.4 kg}

—

3.14 N {0.32 kg}

11.0 X 6.2

9.5

5.5 N {0.56 kg}

—

4.4 N {0.45 kg}

If damaged or deformed, replace spring.

(PC78UU-6 without service valve)

PC78US-6

10-119 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

CLSS OUTLINE OF CLSS Features CLSS stands for Closed center Load Sensing System, and has the following featues. • Fine control not influenced by load • Control enabling digging even with fine control • Ease of compound operation ensured by flow divider function using area of opening of spoll during compund operations • Energy saving using variable pump control

10-120 (10)

Structure • The CLSS consists of a variable capacity single piston pump, control valve, and actuators. • The pump body consists of the main pump, PC valve and LS valve.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

BASIC PRINCIPLE 1. Control of pump swash plate angle • The pump swash plate angle (pump discharge amount) is controlled so that LS differential pressure PLS (the difference between pump (discharge) pressure PP and control valve outlet port LS pressure PLS) load pressure of actuator) is constant. (LS pressure PLS=Pump discharge pressure PP–LS pressure PLS)

•

If LS differential pressure PLS becomes lower than the set pressure of the LS valve (when the actuator load pressure is high), the pump swash plate moves towards the maximum position; if the set pressure becomes higher than the set pressure of the LS valve (when the actuator load pressure is low), the pump swash plate moves towards the minimum position. a For details of the operation, see HYDRAULIC PUMP.

PC78US-6

10-121 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

2. Pressure compensation control • A pressure compensation valve is installed to the inlet port side of the control valve spool to balance the load. When to actuators are operated together, this valve acts to make pressure difference P

10-122 (10)

CLSS

between the upstream (inlet port) and downstream (outlet port) the same, regardless of the size of the load (pressure). In this way, the flow of oil from the pump is divided (compensated) in proportion to the area of openings S1 and S2 of each valve when it is operated.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

OPERATION FOR EACH FUNCTION AND VALVE Hydraulic circuit diagram and name of valves (PC78US-6 Blade-less, 1 service valve)

10-124 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

1. Unload valve (P1) Set pressure: LS pressure + 2.45 MPa {25 kg/cm2} 2. Unload valve (P2) Set pressure: LS pressure + 2.45 MPa {25 kg/cm2} 3. Main relief valve Set pressure: 26.5 MPa {270 kg/cm2} 4. Lift check valve 5. Cooler bypass valve 6. Suction valve 7. Safety valve Set pressure: 27.9 MPa {285 kg/cm2} 8. Pressure compensation valve 9. LS bypass plug (P1) 10. LS bypass plug (P2) 11. LS selector valve 12. LS bleed valve 13. Travel junction valve, LS bleed valve 14. Logic valve 15. Boom hydraulic drift prevention valve

PC78US-6

10-125 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

(PC78US-6 with blade and 1 service valve)

10-126 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

1. Unload valve (P1) Set pressure: LS pressure + 2.45 MPa {25 kg/cm2} 2. Unload valve (P2) Set pressure: LS pressure + 2.45 MPa {25 kg/cm2} 3. Main relief valve Set pressure: 26.5 MPa {270 kg/cm2} 4. Gear pump relief valve Set pressure: 21.1 MPa {215 kg/cm2} 5. Cooler bypass valve 6. Suction valve 7. Safety-suction valve Set pressure: 9.8 MPa {100 kg/cm2} 8. Safety valve Set pressure: 27.9 MPa {285 kg/cm2} 9. Pressure compensation valve 10. LS bypass plug (P1) 11. LS bypass plug (P2) 12. Boom raise merge valve 13. LS bleed valve 14. Travel junction valve, LS bleed valve 15. Logic valve 16. Boom hydraulic drift prevention valve

PC78US-6

10-127 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

(PC78US-6 without service valve)

10-128 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

1. Unload valve (P1) Set pressure: LS pressure + 2.45 MPa {25 kg/cm2} 2. Unload valve (P2) Set pressure: LS pressure + 2.45 MPa {25 kg/cm2} 3. Main relief valve Set pressure: 26.5 MPa {270 kg/cm2} 4. Gear pump relief valve Set pressure: 21.1 MPa {215 kg/cm2} 5. Cooler bypass valve 6. Suction valve 7. Safety-suction valve Set pressure: 9.8 MPa {100 kg/cm2} 8. Safety valve Set pressure: 27.9 MPa {285 kg/cm2} 9. Pressure compensation valve 10. LS bypass plug (P1) 11. LS bypass plug (P2) 12. Boom raise merge valve 13. LS bleed valve 14. Travel junction valve, LS bleed valve 15. Logic valve 16. Boom hydraulic drift prevention valve (PC78UU-6 without service valve)

PC78US-6

10-129 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

Unload valve 1. When control valve is at HOLD

Function • When the control valve is at HOLD, pump discharge amount Q discharged by the minimum swash plate angle is released to the tank circuit. At this time, pump discharge pressure PP1/PP2 is set at 2.45 MPa {25.0 kg/cm2} by spring (2) in the valve. (LS pressure PLS1/PLS2: 0 MPa {0 kg/cm2}) • Since the pump merge-divider valve is at the merge position, pump discharge pressures PP1 and PP2 are merged. LS pressures PLS1, PLS2, and PLS3 are also merged.

•

•

•

When the control valve is at HOLD, LS pressures PLS1 and PLS2 are not generated, so only pump discharge pressures PP1 and PP2 act, and PP1 and PP2 are set by only the load of spring (2). As pump discharge pressure PP1/PP2 rises and reaches the load of spring (2) (2.45 MPa {25.0 kg/cm2}), spool (1) is moved to the right. Pump discharge pressures PP1 and PP2 are connected to tank circuit T through the cut of spool (1) As a result, pump discharge pressure PP1/PP2 is set to 2.45 MPa {25.0 kg/cm2}.

Operation • Pump discharge pressures PP1 and PP2 are acting on the left end of unload spool (1) and LS pressures PLS1 and PLS2 are acting on the right end. (PP1 = PP2, PLS1 = PLS2)

10-130 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

2. During fine control of work equipment valve Work equipment valve: Swing (PC78US-6 without blade), boom, arm, bucket, or attachment.

Function • During fine control of the work equipment valve, when the demand flow for the actuator is within the amount discharged by the minimum swash plate angle of the pump, pump discharge pressure PP1/PP2 is set to LS pressure PLS1/PLS2 + 2.45 MPa {25.0 kg/cm2}. When the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 reaches the load of spring (2) (2.45 MPa {25.0 kg/cm 2 }), unload spool (1) opens, so LS differential pressure PLS becomes 2.45 MPa {25 kg/cm2}. • Since the pump merge-divider valve is at the merge position, pump discharge pressures PP1 and PP2 are merged. LS pressures PLS1, PLS2, and PLS3 are also merged.

PC78US-6

Operation • When fine control is carried out on the work equipment valve, LS pressures PLS1 and PLS2 are generated and act on the right end of spool (1) (PP1 = PP2, PLS1 = PLS2). When this happens, the area of the opening of the work equipment valve spool is small, so LS pressures PLS1 and PLS2 are very different from pump discharge pressures PP1 and PP2. • When the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 reaches the load of spring (2) (2.45 MPa {25.0 kg/cm2}), spool (1) moves to the right, and pump discharge pressures PP1 and PP2 are connected to tank circuit T. • In other words, pump discharge pressure PP1/ PP2 is set to the spring force (2.45 MPa {25.0 kg/cm2}) + LS pressure PLS1/PLS2, and LS differential pressure PLS becomes 2.45 MPa {25.0 kg/cm2}.

10-131 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

3. When work equipment valve is operated Work equipment valve: Swing (PC78US-6 without blade), boom, arm, bucket, or attachment

Function • When any work equipment valve is operated if the demand flow for the actuator becomes greater than the pump discharge from the minimum swash plate angle, the oil flow to tank circuit T is cut off, and all pump discharge amount Q flows to the actuator circuit. • Since the pump merge-divider valve is at the merge position, pump discharge pressures PP1 and PP2 are merged. LS pressures PLS1, PLS2, and PLS3 are also merged.

•

•

For this reason, the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 does not reach the load of spring (2) (2.45 MPa {25.0 kg/cm2}), so spool (1) is pushed to the left by spring (2). As a result, pump discharge pressures PP1 and PP2 and tank circuit T are shut off, and all pump discharge amount Q flows to the actuator circuit.

Operation • When any work equipment valve is operated for a long stroke, LS pressures PLS1 and PLS2 are generated and act on the right end of unload spool (1) (PP1 = PP2, PLS1 = PLS2). When this happens, the area of the opening of the work equipment valve spool is large, so LS pressures PLS1 and PLS2 are not so different from pump discharge pressures PP1 and PP2.

10-132 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

4. During fine control of both travel valves

Function • During fine control of both travel valves, when the demand flow is below the maximum pump discharge amount, pump discharge pressure PP1/PP2 is set to LS pressure PLS1/PLS2 + 2.45 MPa {25.0 kg/cm2}. • When the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 reaches the load of spring (2) (2.45 MPa {25.0 kg/cm2}), unload spool (1) opens, so excessive oil (maximum pump discharge mount – demand flow) flows into the tank circuit. • Since the pump merge-divider valve is at the separate position, pump discharge pressures PP1 and PP2 are separated. LS pressures PLS1 and PLS2 are also separated. • The swash plate angle of the pump becomes maximum, so the pump discharge amount becomes maximum. (For details, see the sections on the pump merge-divider valve and logic valve.)

PC78US-6

Operation • When fine control is carried out on both travel valves, LS pressures PLS1 and PLS2 are generated and act on the right end of spool (1) (PP1, PP2, PLS1, and PLS2 are separated). • When this happens, the area of the opening of both travel valve spools is small, so LS pressures PLS1 and PLS2 are very different from pump discharge pressures PP1 and PP2. • When the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 reaches the load of spring (2) (2.45 MPa {25.0 kg/cm2}), spool (1) moves to the right, and pump discharge pressures PP1 and PP2 are connected to tank circuit T and the excessive oil (maximum pump discharge mount – demand flow) flows. • In other words, the excessive oil (maximum pump discharge mount – demand flow) above the strokes of both travel valves flows into tank circuit T.

10-133 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

5. When both travel valves are operated

Function • During operation of both travel valves, when the demand flow becomes maximum, the oil flow to tank circuit T is cut off, and all pump discharge amount Q flows to both travel circuits. • Since the pump merge-divider valve is at the separate position, pump discharge pressures PP1 and PP2 are separated. LS pressures PLS1 and PLS2 are also separated. • The swash plate angle of the pump becomes maximum, so the pump discharge amount becomes maximum. (For details, see the sections on the pump merge-divider valve and logic valve.)

•

•

•

When this happens, the area of the openings of both travel valve spools is large, so LS pressures PLS1 and PLS2 are not so different from pump discharge pressures PP1 and PP2. For this reason, the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 does not reach the load of spring (2) (2.45 MPa {25.0 kg/cm2}), so spool (1) is pushed to the left by spring (2). As a result, pump discharge pressures PP1 and PP2 and tank circuit T are shut off, and all pump discharge amount Q flows to the actuator circuit.

Operation • When both travel valves are operated to the stroke ends, LS pressures PLS1 and PLS2 are generated and act on the right end of unload spool (1) (PP1, PP2, PLS1, and PLS2 are separated).

10-134 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

6. When either travel valve is operated

Function • The demand flow decided by the valve stroke is sent to the travel circuit on the operated travel valve side and the all pump discharge amount is sent to the tank circuit on the non-operated travel valve side. • Since the pump merge-divider valve is at the separate position, pump discharge pressures PP1 and PP2 are separated. LS pressures PLS1 and PLS2 are also separated. • The swash plate angle of the pump becomes maximum, so the pump discharge amount becomes maximum. (For details, see the sections on the pump merge-divider valve and logic valve.)

•

Operation When left travel valve is operated to stroke end and right one is at HOLD. • When the left travel valve is operated to the stroke end, LS pressure PLS1 is generated and acts on the right end of unload spool (1).

•

PC78US-6

•

•

•

When this happens, the area of the openings of both travel valve spools is large, so LS pressures PLS1 is not so different from pump discharge pressures PP1. For this reason, the difference between pump discharge pressure PP1 and LS pressure PLS1 does not reach the load of spring (2) (2.45 MPa {25.0 kg/cm2}), so spool (1) is pushed to the left by spring (2). As a result, pump discharge pressures PP1 and tank circuit T are shut off, and all pump discharge amount QP1 on the P1 side flows to the left travel circuit. Since the right travel valve is at HOLD, LS pressure PLS2 is not generated, so only pump discharge pressure PP2 acts. When pump discharge pressure PP2 reaches the load of spring (4) (2.45 MPa {25.0 kg cm2}), spool (3) moves to the right, and all pump discharge amount QP2 on the P2 side flows into tank circuit T.

10-135 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

Pump merge-divider valve and logic valve 1. When control valve is at HOLD

Function • Pump merge-divider valve spool (3) merges pump discharge pressures PP1 and PP2 and LS pressures PLS1, PLS2, and PLS3 respectively. Operation • When the control valve is at HOLD, changeover pressure is not generated on logic spool (1), so spring (2) pushes spool (1) to the left. • Since both travel valves are at HOLD, changeover pressure is not generated on the pump mergedivider spool. • When the control valve is at HOLD, changeover pressure is not generated on the pump mergedivider spool, so spring (4) pushes spool (3) to the right. • Pump discharge pressures PP1 and PP2 and LS pressures PLS1, PLS2, and PLS3 are merged respectively (PP1 = PP2, PLS1 = PLS2 = PLS3).

10-136 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

2. When work equipment valve is operated (including compound operation of work equipment + travel). Work equipment valve: Swing (PC78US-6 without blade), boom, arm, bucket, or attachment.

Function • Pump merge-divider valve spool (3) merges pump discharge pressures PP1 and PP2 and LS pressures PLS1, PLS2, and PLS3 respectively. • As the LS pressure, PLS1, PLS2, and PLS3 are output.

• •

When the work equipment valve is operated, changeover pressure for spool (3) is not generated, so spring (4) pushes spool (3) to the right. Pump discharge pressures PP1 and PP2 are merged. LS pressures PLS1, PLS2, and PLS3 are also merged (PP1 = PP2, PLS1 = PLS2 = PLS3).

Operation • When any work equipment valve is operated, the work equipment PPC pressure or the swing holding brake release pressure is introduced in the left chamber of logic spool (1) to change over spool (1). • When the load of spring (2) reaches 0.6 MPa {6 kg/cm2}, spool (1) moves to the right. • As a result, the right chamber of spool (3) is connected to tank circuit T and changeover pressure for spool (3) is not generated.

PC78US-6

10-137 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

3. When either or both travel valves are operated

Function • Pump merge-divider valve spool (3) separates pump discharge pressures PP1 and PP2 and LS pressures PLS1, PLS2, and PLS3 respectively. • As the LS pressure, higher pressure of PP1 and PP2 is output. Operation • Since the all work equipment valves are at HOLD, changeover pressure for logic spool (1) is not generated, spring (2) pushes spool (1) to the left. • When both travel valves are operated, travel PPC pressure is introduced as changeover pressure for spool (3) through spool (1) into the right chamber of spool (3). • When the load of spring (4) reaches 0.49 MPa {5 kg/cm2}, spool (3) is pushed to the left. • As a result, pump discharge pressures PP1 and PP2 and LS pressures PLS1 and PLS2 are separated respectively.

10-138 (10)

• •

Furthermore, PP1 and PLS1 are separated for the left travel circuit and PP2 and PLS2 are separated for the right travel circuit. The higher pressure of pump discharge pressures PP1 and PP2 is output as the LS pressure and the swash plate angle of the pump becomes maximum, so the pump discharge amount becomes maximum.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

Introduction of LS pressure 1. Work equipment valve: Swing (PC78US-6 without blade), boom, arm, bucket, or attachment

Function • The LS pressure is the actuator load pressure at the outlet port end of the control valve. • Actually, pump discharge pressure PP is reduced by reducing valve (3) of the pressure compensation valve to the same pressure as actuator circuit pressure A and sent to LS circuit PLS. • In the travel valve, actuator circuit pressure A is directly introduced to LS circuit PLS. Operation • When spool (1) is operated, pump discharge pressure PP flows from flow control valve (2) through notch (a) in the spool and bridge passage (b) to actuator circuit A. • At the same time, reducing valve (3) also moves to the right, so pump discharge pressure PP is reduced by the pressure loss at notch (c). It goes to LS circuit PLS, and then goes to spring chamber PLSS.

PC78US-6

• •

•

When this happens, LS circuit PLS is connected to tank circuit T from LS bypass plug (4) (See the section on the LS bypass plug). The areas at both ends of reducing valve (3) are the same (SA = SLS), and actuator circuit pressure PA acts on the SA end. The reduced pump discharge pressure PP acts on SLS at the other end. As a result, reducing valve (3) is balanced at a position where actuator circuit pressure PA and the pressure of spring chamber PLSS are the same. Pump discharge pressure PP reduced at notch (c) becomes actuator pressure A and is introduced into LS circuit PLS.

10-139 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

2. Travel valve

Operation • When spool (1) is operated, pump discharge pressure PP flows from flow control valve (2) through notch (a) in the spool and bridge passage (b) to actuator circuit A. • At the same time, reducing valve (3) is moved to the right by actuator circuit pressure PA, and notch (c) and notch (d) are interconnected respectively with travel junction circuit (e) and LS circuit PLS. • As a result, actuator circuit pressure PA (= A) is introduced from notch (c) through the internal check valve and notch (d) into LS circuit PLS. a The travel circuit is different from the work equipment circuit: actuator circuit pressure PA is directly introduced into LS circuit PLS.

10-140 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

LS bypass plug When work equipment valve is operated

When both travel valves are operated

Function • The LS bypass plug releases the residual pressure of LS pressure PLS. • This lowers the rising speed of LS pressure PLS. In addition, the discarded throttled flow causes a pressure loss in the throttled flow in the reducing valve, and that lowers the effective LS differential pressure to improve the stability. Operation 1. When work equipment valve is operated (including compound operation of work equipment + travel) • Since pump merge-divider spool (1) is at the merge position, the hydraulic oil in LS circuits PC78US-6

PLS1, PLS2, and PLS3 flows from tip filter (a) of LS bypass plug (2) through orifice (b) to tank circuit T. 2. When either or both travel valves are operated • Since pump merge-divider spool (1) is at the separate position, LS circuits PLS1, PLS2, and PLS3 are separated. • The hydraulic oil PLS1 flows from tip filter (a) of LS bypass plug (3) on the P1 side through orifice (b) to tank circuit T. • The hydraulic oil PLS2 flows from tip filter (a) of LS bypass plug (2) on the P2 side through orifice (b) to tank circuit T.

10-141 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

LS selector valve (only PC78US-6 without blade) Function • When the machine swings and the boom is raised simultaneously, this valve prevents the high-pressure swing LS pressure from entering LS circuit PLS and secures sufficient pump discharge amount to keep the boom raising speed. Operation 1. During normal operation

• •

When the boom is not raised, the pilot pressure is not applied to pilot port BP. Under this condition, pump discharge pressure PP is introduced through the internal passage of spool (1) into reducing valve (3) of the swing valve. When the swing lever is operated, LS pressure PLS is generated according to the load pressure and sent to the pump LS valve.

10-142 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

2. When machine swings and boom is raised simultaneously.

• •

•

•

When the machine swings and boom is raised simultaneously, the signal pressure of the boom RAISE PPC circuit is applied to pilot port BP. When pilot pressure BP acts on spool (1) and increases above the force of spring (2), spool is pushed to the right and the internal passage is closed, then pump discharge pressure PP does not flow into reducing valve (3) of the swing valve. As a result, swing LS pressure PLS is not generated and only the boom RAISE LS pressure is introduced in the pump LS valve to control the pump discharge amount. The level of pilot pressure BP is decided by the stroke of the control lever (Boom RAISE)

PC78US-6

10-143 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

Boom raise merge valve (PC78US-6 with blade, PC78UU-6) During normal operation

When machine swings and boom is raised simultaneously

Function • When the machine swings and the boom is raised simultaneously, this valve merges discharge amount of the gear pump into that of main pump to heighten the boom raising speed. Operation 1. During normal operation • When the boom is not raised, the pilot pressure is not applied to pilot port BP. • Under this condition, gear pump circuit P3 and main pump circuit PP are shut off by spool (1), so oil in gear circuit P3 is not merged into that of main pump circuit PP.

10-144 (10)

2. When machine swings and boom is raised simultaneously • When the machine swings and boom is raised simultaneously, the signal pressure of the boom RAISE PPC circuit is applied to pilot port BP. • When pilot pressure BP acts on spool (1) and increases above the force of spring (2), spool is pushed to the right. Then, check valve (3) in spool (1) is pushed open and oil in gear pump circuit P3 is merged into that in main pump circuit PP to heighten the boom raising speed.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

Area ratio of pressure compensation valve

Function • The pressure compensation valve determines the compensation characteristics by carrying out fine adjustment of the area r atio (S2/S1) between (left) area S1 of flow control valve (2) and (right) area S2 of reducing valve (1) to match the characteristics of each actuator. S1: Area of flow control valve (2) – area of piston (3) S2: Area of reducing valve (1) – area of piston (3)

PC78US-6

Area ratio (S1:S2) and compensation characteristics • When ratio is 1.00: [Pump discharge pressure PP – spool notch upstream pressure PPB] = [LS circuit pressure PLS – actuator circuit pressure PA (= A)] and oil flow is divided in proportion to area of opening of spool. • When ratio is more than 1.00:PP – PPB > PLS – PA ( = A) and oil fl ow i s divided in a proportion less tha n ar ea of ope ning of spool. • When ratio is less than 1.00:PP – PPB < PLS – PA ( = A) and oil fl ow i s divided in a proportion more tha n ar ea of ope ning of spool.

10-145 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

Pressure compensation valve

Function • During compound operations, if the load pressure on either actuator becomes lower than the other actuator and the oil flow is about to increase, compensation is made. [When this happens, the other actuator being used for compound operation (right side) is at a high load than the actuator on this side (left side).] Operation • When the load pressure on the other actuator (right side) becomes higher during compound operations, the oil flow in actuator circuit A on this side (left side) starts increasing. • When this happens, the LS pressure PLS on the other actuator acts on spring chamber PLSS, and reducing valve (1) and flow control valve (2) are pushed to the left. • Flow control valve (2) throttles the area of opening between pump circuit PP and spool upstream PPA to cause a pressure loss between PP and PPA.

10-146 (10)

•

•

Flow control valve (2) and reducing valve (1) are balanced in a position where the difference between PLS and PA acting on both ends of reducing valve (1) and the pressure loss made between PP and PPA on the sides of flow control valve (2) will be the same. In this way, the pressure difference between upstream pressure PPA and downstream pressure PA of both spools used during compound operations is the same, so the pump flow is divided in proportion to the area of opening of notch (a) of each spool.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

Boom hydraulic drift prevention valve Function • This valve prevents the oil in the boom cylinder bottom from leaking through spool (1) to cause hydraulic drift of the boom while the boom control lever is not operated. 1. When boom is raised

Operation • When the boom is "raised", the main pressure from the control valve pushes up puppet (2). As a result, the hydraulic oil from the control valve flows through the valve into the boom cylinder bottom.

PC78US-6

10-147 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

2. When boom is held

•

When the boom control lever is returned to the neutral position after the boom is raised, the holding pressure on the boom cylinder bottom side is closed by puppet (2) and the hydraulic oil that flowed through orifices (a1) and (a2) is closed by pilot spool (3). Accordingly, the boom is held.

10-148 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

3. When boom is lowered

•

•

•

When the boom is lowered, pilot pressure P1 from the PPC valve pushes pilot spool (3) and the hydraulic oil in chamber (b) in the puppet is drained. The pressure in port (Ab) is heightened by the hydraulic oil from the boom cylinder bottom, but the pressure in chamber (b) is lowered by orifices (a1) and (a2). When the pressure in chamber b lowers below that in port (Ab), puppet (2) opens and the hydraulic oil from port (Ab) flows through port (Aa) into the control valve.

PC78US-6

10-149 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

Boom regeneration circuit 1. When boom is lowered by its weight.

Function • While the boom is being lowered by its weight, if bottom pressure A of cylinder (1) is higher than head pressure B, this circuit sends the return oil on the bottom side to the head side to increase the cylinder speed by that amount.

•

•

When this happens, a part of the return oil on the bottom side flows through regeneration passages (a) of bottom spool (2), pushes check valve (3) open, and flows into the head side. As a result, the boom lowering speed is heightened.

Operation • While the boom is being lowered by its weight, pressure A on the bottom side of boom cylinder (1) is higher than pressure B on the head side.

10-150 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

2. When boom is lowered under a load.

Function • While the boom is being lowered under a load, if head pressure B of cylinder (1) is higher than bottom pressure A, check valve (3) is closed to shut off the head side and bottom side from each other. Operation • While the boom is being lowered under a load, pressure B on the head side of boom cylinder (1) is higher than pressure A on the bottom side. • When this happens, check valve (3) is closed by pressure B on the head side and spring (4) to shut off the head side and bottom side from each other.

PC78US-6

10-151 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

Travel junction valve (L.H., R.H. travel junction circuit) 1. When traveling in a straight line

10-152 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

2. When steered during travel

PC78US-6

10-153 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

Function • To compensate for any difference in the oil flow in the left and right travel circuits while machine travels in a straight line, the junction circuit opens when the left and right travel spools are operated. • In this way, the flow rates of oil to the left and right travel motors are almost the same when the machine travels in a straight line, so the machine deviates less. • When the machine is steered, the junction circuit opens. Since opening (b) of travel junction valve spool (3) is small, however, the junction circuit does not affect the steering performance. Operation 1. When traveling in a straight line • Since only both travel valves are operated and any work equipment valve is not operated, pump discharge circuits PP1 and PP2 and LS circuits PLS1 and PLS2 are separated by the pump merge-divider spool. (See the section on the LS bypass plug). • When both travel spools (1) are operated, the oil from the pump flows from pump discharge circuits PP1 and PP2 through actuator circuit PB to B. • When the machine travels in straight line, both reducing valves (2) are pushed to the right and notch (a) and travel junction circuit are opened. • The right end of travel junction spool (3) is the work equipment PPC pressure circuit. Since the work equipment valve is not operated at this time, however, any pressure is not generated. • In this way, both travel actuator circuits are interconnected by the travel junction circuit. If any difference occurs in the flow of oil to both travel motors, the difference is compensated to reduce travel deviation. 2. When steered during travel • Since only both travel valves are operated and any work equipment valve is not operated, pump discharge circuits PP1 and PP2 and LS circuits PLS1 and PLS2 are separated by the pump merge-divider spool. (See the section on the LS bypass plug). • The machine is steered by supplying the demand flow to the actuator circuit according to the strokes of both travel spools. (See the section on the unload valve.) • While the machine is traveling in a straight line, if the right travel spool (right 1) is returned to the neutral position and the machine is steered, a difference (left B > right B) is made between the load pressures in both travel actuator circuits PB.

10-154 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

Travel LS bleed circuit and travel junction valve 1. During normal operation

PC78US-6

10-155 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

CLSS

2. When travel actuator and another actuator are operated

10-156 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

Function • When the travel actuator and another actuator are operated at the same time, the amount of oil discarded through the throttle in LS circuit PLS increases and the pressure compensation precision of the travel circuit is lowered to reduce the drop of the travel speed. • When the travel actuator or any other actuator is operated singly, the LS bleed circuit is closed. • Travel junction valve spool (5) is set to open (b) (small) or open (c) (large) by the boom PPC pressure so that the difference between the flow rates in both travel circuits can be corrected easily.

CLSS

•

•

As a result, reducing valve (2) moves to the left and LS pressure PLS flows through check valves (3) and (4) and notch (a) of reducing valve (2) to travel circuit PB. For this reason, LS circuit pressure PLS, which is the same pressure as boom circuit pressure A, flows to travel circuit B to reduce the pressure.

Operation 1. During normal operation • When boom spool (1) is operated, LS circuit PLS becomes the same pressure as boom circuit pressure A. • Since the work equipment valve is operated, pump discharge pressures PP1 and PP2 are merged by the pump merge-divider valve spool. LS pressures PLS1, PLS2, and PLS3 are also merged. (See the sections on the pump merge-divider valve and logic valve.) • At the same time, LS pressure PLS also goes to spring chamber PLSS of reducing valve (2) of the travel valve. • Since the travel valve spool is not operated, notch (a) of reducing valve (2) is closed, and check valves (3) and (4) of the bleed circuit are also closed. • As a result, when the boom is operated singly, the travel LS bypass circuit is closed. 2. When travel actuator and another actuator are operated • When boom spool (1) is operated, LS circuit PLS becomes the same pressure as boom circuit pressure A. • Since the work equipment valve is operated, pump discharge pressures PP1 and PP2 are merged by the pump merge-divider valve spool. LS pressures PLS1, PLS2, and PLS3 are also merged. (See the sections on the pump merge-divider valve and logic valve.) • As for the actuator circuit pressure, the boom RAISE pressure is normally higher than the travel pressure (A > B), so the pressure in spring chamber PLSS inside reducing valve (2) of the travel valve is higher than travel circuit pressure PB.

PC78US-6

10-157 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SWING MOTOR

SWING MOTOR Model: LMF30AEL

B: From swing brake solenoid valve S: From tank T: To tank MA: From control valve MB: From control valve

Specifications Model: LMF30AEL Capacity: 31 cm3/rev Set pressure of safety valve: 21 MPa {210 kg/cm2} Cracking pressure of check valve: Max. 0.03 MPa {0.30 kg/cm2}

1. Reverse prevention valve

10-158 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8.

SWING MOTOR

Output shaft Housing Shoe Piston Cylinder block Valve plate Center spring Swash plate

9. 10. 11. 12. 13. 14. 15.

Safety valve Check valve Check valve spring Brake spring Brake piston Disc Plate

Unit: mm No.

Item

Criteria Basic dimension

A

B

Check valve spring

Allowable limit

Free length × Outside diameter

Installed length

Installed load

Free length

Installed load

15.5 × 9.0

11.5

0.9 N {0.09 kg}

—

0.69 N {0.07 kg}

33 × 13.8

19.5

1.8 N {0.18 kg}

—

1.41 N {0.14 kg}

Valve return spring

PC78US-6

Remedy

If damaged or deformed, replace spring.

10-159 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

BRAKE VALVE Outline • The brake valve consists of a check valve and a safety valve. Function • When the machine stops swinging, control valve (1) closes the outlet circuit of the motor. Since the motor continues revolving because of the inertia, the motor output pressure rises abnormally to break the motor. Accordingly, the abnormally high pressure is released through the outlet (high pressure side) of the motor to protect the motor. Operation 1. When machine starts swinging • When the swing control lever is operated to swing to the left, the hydraulic oil from the pump flows through control valve (1) into port MB. As a result, the pressure in port MB rises and the starting torque is generated in the motor and the motor starts revolution. The oil from the motor outlet returns from port MA through control valve (1) to the tank.

10-160 (10)

SWING MOTOR

2. When machine stops swinging • If the swing control lever is returned to the neutral position, oil is not supplied from the pump to port MB any more. Since the return circuit for the oil from the motor outlet to the tank is closed by control valve (1), the pressure in port MA rises and revolution resistance is generated in the motor, then the motor is braked. • The pressure in port MA rises to the set pressure of the safety valve. As a result, high braking torque is generated in the motor, then the motor stops. • While the safety valve is operating, the oil discharged from the safety valve and the oil from port S are supplied through check valve CB to port MB so that cavitation will not occur in port MB.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SWING MOTOR

MODULATING RELIEF VALVE Function The relief valve for the swing motor prevents the relief pressure from rising sharply to reduce shocks when the machine starts and stops swinging.

Operation 1. When circuit pressure is P0 • The relief valve does not operate. 2. When circuit pressure rises sharply • When circuit pressure rises to P1, the hydraulic pressure acts on the area difference between D1 and D3 (D1 > D3) and pushes spring (4) to open valve (3). • At this time, pressure acts on the area difference between D1 and D2 (D2 > D1), so seat (1) follows valve (3). • As seat (1) moves, the passage for the pressurized oil in chamber (a) to flow into port S is narrowed by ball (2). Accordingly, seat (1) does not move so fast as valve (3). • As a result, the relief pressure rises gradually from P1 to P2 while seat (1) is moving to sleeve (5).

PC78US-6

10-161 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SWING MOTOR

SWING BRAKE

2. When solenoid valve is energized

1. When solenoid valve is de-energized

Operation • When the solenoid valve of the swing brake is energized, the valve is changed and hydraulic oil from the self-pressure reducing valve flows through port B into brake chamber A. • The hydraulic oil in chamber A pushes brake spring (12) and brake piston (13) moves down. As a result, disc (14) and plate (15) are separated and the brake is released.

Operation • When the solenoid valve of the swing brake is de-energized, the hydraulic oil from the selfpressure reducing valve is shut off and port B is connected to the tank circuit. • As a result, brake piston (13) is pushed up by brake spring (12) to press disc (14) and disc (15) to apply the brake.

10-162 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SWING MOTOR

REVERSE ROTATION PREVENTION LEVEL

MA : MB : T1 : T2 :

Port Port Port Port

PC78US-6

1. 2. 3. 4. 5. 6. 7.

Valve Body Spool (MA end) Spring (MA end) Plug (MA end) Spool (MB end) Spring (MB end) Plug (MB end)

10-163 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SWING MOTOR

EFFECT EXPLANATION DRAWING

10-164 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SWING MOTOR

Function • This valve reduces the swing back generated in the swing body by the inertia of the swing body, the backlash and rigidity of the machinery system, and the compression of the hydraulic oil when the swing is stopped. • This is effective in preventing spillage of the load when stopping the swing and reducing the cycle time (the positioning ability is good and it is possible to move swiftly to the next job).

1. When brake pressure is being generated at port MB Operation • Pressure MB passes through the notch and goes to chamber d, spool (5) compresses spring (6) according to the difference in area D1 > D2, moves to the left, and MB o e is connected. • When this happens, pressure MA is below the set pressure of spring (3), so spool (2) does not move. For this reason, the pressure oil is closed, and the braking force is ensured.

2. After motor stops Operation • The motor is reversed by the closing pressure generated at port MB. (1st reversal) • When this happens, reversal pressure is generated at port MA. Pressure MA goes to chamber a, compresses spring (3), spool (2) moves to the right, and MA o b is connected. • At the same time, b o f is connected through the drill hole in spool (5), so the reversal pressure at port MA is bypassed to port T to prevent the 2nd reversal.

PC78US-6

10-165 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

WORK EQUIPMENT AND SWING PPC VALVE

WORK EQUIPMENT AND SWING PPC VALVE PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up

P : T : P1 : P2 : P3 : P4 :

From main pump To tank Left - Arm OUT/Right - Boom LOWER Left - Arm IN/Right - Boom RAISE Left - Swing RIGHT/Right - Bucket CURL Left - Swing LEFT/Right - Bucket DUMP

10-166 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6.

WORK EQUIPMENT AND SWING PPC VALVE

Spool Metering spring Centering spring Piston Disc Nut (For connection of lever)

7. 8. 9. 10. 11.

Joint Plate Retainer Body Filter

Unit: mm No.

Item

Criteria Basic dimension

12

13 14

Centering spring (For ports P3 and P4)

Centering spring (For ports P1 and P2) Metering spring

PC78US-6

Remedy Allowable limit

Free length × Outside diameter

Installed length

Installed load

Free length

Installed load

42.4 × 15.5

34.0

17.7 N {1.80 kg}

—

13.7 N {1.40 kg}

44.4 × 15.5

34.0

29.4 N {3.0 kg}

—

23.5 N {2.40 kg}

26.5 × 8.15

24.9

16.7 N {1.70 kg}

—

13.7 N {1.40 kg}

If damaged or deformed, replace spring.

10-167 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

WORK EQUIPMENT AND SWING PPC VALVE

PC78US-6 Serial No.: 6501 and up

P T P1 P2 P3 P4

: : : : : :

From main pump To tank Left - Arm OUT/Right - Boom LOWER Left - Arm IN/Right - Boom RAISE Left - Swing RIGHT/Right - Bucket CURL Left - Swing LEFT/Right - Bucket DUMP

10-168 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6.

WORK EQUIPMENT AND SWING PPC VALVE

Spool Metering spring Centering spring Piston Disc Nut (For connection of lever)

7. 8. 9. 10. 11.

Joint Plate Retainer Body Filter

Unit: mm No.

Item

Criteria Basic dimension

12

13 14

Centering spring (For ports P3 and P4)

Centering spring (For ports P1 and P2) Metering spring

PC78US-6

Remedy Allowable limit

Free length × Outside diameter

Installed length

Installed load

Free length

Installed load

42.5 × 15.5

32.0

21.8 N {2.22 kg}

—

15.7 N {1.6 kg}

44.5 × 15.5

32.0

35.0 N {3.57 kg}

—

24.5 N {2.5 kg}

26.5 × 8.15

24.9

16.7 N {1.70 kg}

—

11.8 N {1.2 kg}

If damaged or deformed, replace spring.

10-169 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

WORK EQUIPMENT AND SWING PPC VALVE

OPERATION 1. At neutral • Ports A and B of the control valve and ports P1 and P2 of the PPC valve are connected to drain chamber D through fine control hole f in spool (1). (Fig. 1)

2. During fine control (neutral o fine control) • When piston (4) starts to be pushed by disc (5), retainer (9) is pushed; spool (1) is also pushed by metering spring (2), and moves down. • When this happens, fine control hole f is shut off from drain chamber D, and at almost the same time, it is connected to pump pressure chamber PP, so pilot pressure oil from the main pump passes through fine control hole f and goes from port P1 to port A. • When the pressure at port P1 becomes higher, spool (1) is pushed back and fine control hole f is shut off from pump pressure chamber PP. At almost the same time, it is connected to drain chamber D to release the pressure at port P1. • When this happens, spool (1) moves up or down so that the force of metering spring (2) is balanced with the pressure at port P1. The relationship in the position of spool (1) and body (10) (fine control hole f is at a point midway between drain hole D and pump pressure chamber PP) does not change until retainer (9) contacts spool (1). • Therefore, metering spring (2) is compressed proportionally to the amount of movement of the control lever, so the pressure at port P1 also rises in proportion to the travel of the control lever. • In this way, the control valve spool moves to a position where the pressure in chamber A (the same as the pressure at port P1) and the force of the control valve spool return spring are balanced. (Fig. 2)

10-170 (13)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

WORK EQUIPMENT AND SWING PPC VALVE

3. During fine control (when control lever is returned) • When disc (5) starts to be returned, spool (1) is pushed up by the force of centering spring (3) and the pressure at port P1. • When this happens, fine control hole f is connected to drain chamber D and the pressure oil at port P1 is released. • If the pressure at port P1 drops too far, spool (1) is pushed down by metering spring (2), and fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, and the pump pressure is supplied until the pressure at port P1 recovers to a pressure that corresponds to the lever position. • When the spool of the control valve returns, oil in drain chamber D flows in from fine control hole f ' in the valve on the side that is not working. The oil passes through port P2 and enters chamber B to fill the chamber with oil. (Fig. 3)

4. At full stroke • When disc (5) pushes down piston (4), and retainer (9) pushes down spool (1), fine control hole f is shut off from drain chamber D, and is connected with pump pressure chamber PP. • Therefore, the pilot pressure oil from the main pump passes through fine control hole f and flows to chamber A from port P1, and pushes the control valve spool. • The oil returning from chamber B passes from port P2 through fine control hole f ' and flows to drain chamber D. (fig. 4)

PC78US-6

10-171 (13)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRAVEL PPC VALVE

TRAVEL PPC VALVE

P : T : P1 : P2 : P3 : P4 :

From main pump To tank Left travel reverse Left travel forward Right travel reverse Right travel forward

10-172 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4.

TRAVEL PPC VALVE

5. 6. 7. 8.

Plate Body Piston Collar

Metering spring Centering spring Valve Bolt Unit: mm

No.

Item

Criteria Basic dimension

A

B

Metering spring

Centering spring

PC78US-6

Remedy Allowable limit

Free length × Outside diameter

Installed length

Installed load

Free length

Installed load

26.5 × 8.15

24.9

16.7 N {1.70 kg}

—

13.7 N {1.40 kg}

52.06 × 15.5

32.1

134 N {13.67 kg}

—

107 N {10.94 kg}

If damaged or deformed, replace spring.

10-173 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRAVEL PPC VALVE

OPERATION 1. At neutral • Ports A and B of the control valve and ports P1 and P2 of the PPC valve are connected to drain chamber D through fine control hole f in spool (1). (Fig. 1)

2. During fine control (neutral o fine control) • When piston (4) starts to be pushed by disc (5), retainer (9) is pushed; spool (1) is also pushed by metering spring (2), and moves down. • When this happens, fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, and the pilot pressure of the main pump is sent from port A through fine control hole f to port P1 . • When the pressure at port P1 rises, spool (1) is pushed back. Fine control hole f is shut off from pump pressure chamber PP. At almost the same time, it is connected to drain chamber D to release the pressure at port P1. • As a result, spool (1) moves up and down until the force of metering spool (2) is balanced with the pressure of port P1. • The relationship in the position of spool (1) and body (10) (fine control hole f is in the middle between drain hole D and pump pressure chamber PP) does not change until retainer (9) contacts spool (1). • Therefore, metering spring (2) is compressed in proportion to the travel of the control lever, so the pressure at port P1 also rises in proportion to the travel of the control lever. • In this way, the control valve spool moves to a position where the pressure of chamber A (same as pressure at port P1) and the force of the return spring of the control valve spool are balanced. (Fig. 2)

10-174 (13)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

TRAVEL PPC VALVE

3. Fine control (control lever returned) • When disc (5) starts to be returned, spool (1) is pushed up by the force of centering spring (3) and the pressure at port P1. • Because of this, fine control hole f is connected to drain chamber D, and the pressurized oil at port P1 is released. • If the pressure at port P1 drops too much, spool (1) is pushed up by metering spring (2), so fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, so the pressure at port P1 supplies the pump pressure until the pressure recovers to a pressure equivalent to the position of the lever. • When the control valve returns, oil in drain chamber D flows in from fine control hole f ' of the valve on the side that is not moving. It passes through port P2 and enters chamber B to fill the chamber with oil. (Fig. 3)

4. At full stroke • Disc (5) pushes down piston (4), and retainer (9) pushes down spool (1). Fine control hole f is shut off from drain chamber D, and is connected to pump pressure chamber PP. • Therefore, the pilot pressure oil from the main pump passes through fine control hole f and flows to chamber A from port P1 to push the control valve spool. • The return oil chamber B passes from port P2 through fine control hole f ' and flows to drain chamber D. (fig. 4)

PC78US-6

10-175 (13)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

OFFSET PPC VALVE, ATTACHMENT PPC VALVE, BLADE PPC VALVE

OFFSET PPC VALVE (PC78UU-6) ATTACHMENT PPC VALVE (PC78US-6) BLADE PPC VALVE (PC78UU, PC78US-6)

T P P1 P2

: : : :

To tank From main pump To attachment/blade valve To attachment/blade valve

1. 2. 3. 4. 5.

Spool Metering spring Centering spring Piston Lever

6. 7. 8. 9.

Plate Retainer Body Filter

Offset/for attachment

10-176 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ATTACHMENT AND BLADE PPC VALVA

For Attachment Unit: mm No.

Item

Criteria Basic dimension

A

B

Centering spring

Metering spring

Remedy Allowable limit

Free length × Outside diameter

Installed length

Installed load

Free length

Installed load

33.9 × 15.3

28.4

125 N {12.7 kg}

—

100 N {10.2 kg}

22.7 × 8.10

22.0

16.7 N {1.70 kg}

—

13.3 N {1.36 kg}

If damaged or deformed, replace spring.

For Blade Unit: mm No.

Item

Criteria Basic dimension

A

B

Centering spring

Metering spring

PC78US-6

Remedy Allowable limit

Free length × Outside diameter

Installed length

Installed load

Free length

Installed load

42.36 × 15.5

28.4

207.8 N {21.2 kg}

—

166.3 N {16.96 kg}

22.73 × 8.1

22.0

16.67 N {1.7 kg}

—

13.7 N {1.4 kg}

If damaged or deformed, replace spring.

10-177 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ATTACHMENT AND BLADE PPC VALVA

Operation 1. In the neutral mode • P1 and P2 ports of the operation valves A, B and PPC valve are connected to drain room D via the fine control hole f on the spool (1).

2. In the fine control mode (Neutral o fine control) • As the piston (4) is pushed by disk (5), the retainer (7) is pushed too. At the same time, the spool (1) is also pushed down via the metering spring (2). • By this move, connection of the fine control hole f is switched from the drain room D to the pump pressure room PP, and pilot pressure oil for the control pump is conducted from P1 port to A port. • As P1 port pressure increases, the spool (1) is pushed back. By this move, connection of the fine control hole f is switched from the pump pressure room PP to the drain room D, thereby relieving P1 port pressure. • As the result, the spool (1) moves up and down so that force of the metering spring (2) and P1 port pressure may be balanced. • Positional relationship between the spool (1) and body (8) (fine control hole f is situated at mid point between the drain room D and pump pressure room PP) remains unchanged until the retainer (7) is contacted against the spool (1). • The metering spring (2) is, therefore, compressed in proportion to strokes of the operation lever. Thus, the P1 port pressure too, increases in proportion to strokes of the operation lever. • As the result, the operation valve spool moves to the position where the pressure of A room (the same as P1 port pressure) is balanced against force of the operation valve spool return spring.

10-178 (13)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ATTACHMENT AND BLADE PPC VALVA

3. In the fine control mode (when the operation lever is shifted back to its original position) • As the lever (5) starts returning, the spool (1) is pushed up by force of the centering spring (3) and P1 port pressure. By this move, the fine control hole f is connected to the drain room D and relieves pressurized oil of P1 port to it. • If P1 port pressure goes excessively low, the spool (1) is pushed down by the metering spring (2), and passage between fine control hole f and drain room D is shut down. And, almost at the same time, the hole is connected to the pump pressure room PP and starts supplying pump the pressure. This supply continues until the P1 port pressure is recovered to the level equivalent to the lever position. • When the operation valve spool returns, oil in the drain room D flows in through the fine control hole f ' on the not moving side valve. Oil is then conducted via P2 port to the room B to fill it up.

4. In the full stroke mode • When the disk (5) pushes down piston (4) and the retainer (7) pushes down the spool (1), connection of the fine control hole f is switched from the drain room D, to the pump pressure room PP. • Thus, pilot pressurized oil from the control pump passes through fine control hole f and conducted to A room via P1 port to push the operation valve spool. • Return oil from B room is conducted from P2 port to the drain room D via the fine control hole f '.

PC78US-6

10-179 (13)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

WORK EQUIPMENT

WORK EQUIPMENT PC78US-6

Unit: mm No.

1

Item

Clearance between mounting pin and bushing of boom and revolving frame

Criteria Basic dimension

Allowance

Remedy

Shaft

Hole

Standard clearance

Allowable clearance

65

-0.030 -0.100

+0.174 +0.100

0.130– 0.274

1.0

2

Clearance between mounting pin and bushing of boom and arm

60

-0.030 -0.100

+0.174 +0.100

0.130– 0.274

1.0

3

Clearance between mounting pin and bushing of arm and bucket

50

-0.225 -0.285

-0.062 -0.120

0.105– 0.233

1.0

4

Clearance between mounting pin and bushing of arm and link

50

-0.225 -0.285

-0.062 -0.120

0.105– 0.233

1.0

5

Clearance between mounting pin and bushing of link and link

60

-0.030 -0.100

+0.173 +0.100

0.130– 0.273

1.0

6

Clearance between mounting pin and bushing of bucket and link

50

-0.225 -0.285

-0.040 -0.094

0.131– 0.245

1.0

7

Clearance between mounting pin and bushing of blade and track frame (Blade specification)

50

-0.025 -0.087

-0.142 -0.080

0.1050.229

1.0

10-180 (10)

Replace pin and bushing

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

PC78US-6

WORK EQUIPMENT

10-181 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

WORK EQUIPMENT

PC78UU-6

PC78US-6

10-183 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

10-184 (10)

WORK EQUIPMENT

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

WORK EQUIPMENT

Unit: mm No.

1

2

3

4

5

6

7

Item

Clearance between 1st boom and revolving frame mounting pin and bushing Clearance between 1st boom and 2nd boom mounting pin and bushing Clearance between 1st boom and sub-link mounting pin and bushing Clearance between 2nd boom and 3rd bracket mounting pin and bushing Clearance between 3rd bracket and sub-link mounting pin and bushing Clearance between 3rd bracket and arm mounting pin and bushing Clearance between arm and bucket mounting pin and bushing

Criteria Basic dimension

Allowance

Remedy

Shaft

Hole

Standard clearance

Allowable clearance

65

- 0.030 - 0.100

+0.174 +0.100

0.130– 0.274

1.0

100

- 0.036 - 0.090

+0.207 +0.120

0.156– 0.297

1.0

50

- 0.025 - 0.087

+0.142 +0.080

0.105– 0.229

1.0

100

- 0.036 - 0.090

+0.207 +0.120

0.156– 0.297

1.0

50

- 0.025 - 0.087

+0.142 +0.080

0.105– 0.229

1.0

65

- 0.280 - 0.350

- 0.082 - 0.150

0.130– 0.268

1.0

50

- 0.225 - 0.285

- 0.062 - 0.120

0.105– 0.223

1.0

8

Clearance between arm and link mounting pin and bushing

50

- 0.225 - 0.285

- 0.062 - 0.120

0.105– 0.223

1.0

9

Clearance between link and link mounting pin and bushing

60

- 0.030 - 0.100

+0.173 +0.100

0.130– 0.273

1.0

50

- 0.225 - 0.285

- 0.040 - 0.094

0.131– 0.245

1.0

50

- 0.025 - 0.087

+0.142 +0.080

0.105– 0.229

1.0

10

11

Clearance between link and bucket mounting pin and bushing Clearance between blade and track frame mounting pin and bushing

PC78US-6

Replace pin and bushing

10-185 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

DIMENSIONS OF EACH PART OF WORK EQUIPMENT

DIMENSIONS OF EACH PART OF WORK EQUIPMENT 1. ARM SECTION PC78US-6

*1. Serial No.: 4001 – 4927

10-186 (13)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

DIMENSIONS OF EACH PART OF WORK EQUIPMENT

Unit: mm PC78US-6 No.

Allowance Measuring point

1

– Arm side

Basic dimension 60

Shaft

Hole

- 0.030 - 0.100

+0.100 0

71.5

+1.0 0

70

±1.2

2 Cylinder head side 3

–

60

- 0.030 - 0.100

+0.100 0

Boom side

220

+0.5 0

Arm side

220

- 0.5 - 1.0

4

5

–

142.4

±2.0

6

–

218.8

±1.0

7

–

458.6

±1.0

8

–

1,650

–

9

–

2,093.9

±3.0

10

–

1,661.2

±1.3

11

–

258.7

±0.3

12

–

15.1

±1.0

13

–

395.1

±0.1

14

–

342

±0.1

15

–

312.2

–

16

–

1,066.9

–

17

–

50

- 0.225 - 0.285

0 - 0.150

Link side

200

- 1.0 - 2.0

Bucket side

200

+2.0 0

19

–

50

20

Arm as individual part

188

- 0.5 - 1.0

21

When pressfitting bushing

200

- 0.5 - 1.4

Min.

1,055

±1.5

Max.

1,765

–

18

- 0.225 - 0.285

0 - 0.150

22

PC78US-6

10-187 (13)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

DIMENSIONS OF EACH PART OF WORK EQUIPMENT

PC78UU-6

10-188 (13)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

DIMENSIONS OF EACH PART OF WORK EQUIPMENT

Unit: mm PC78UU-6 No.

Allowance Measuring point

1

– Arm side

Basic dimension 60

Shaft

Hole

- 0.030 - 0.100

+0.100 0

78.5

+2.0 0

70

0 - 0.5

2 Cylinder head side 3

–

65

- 0.280 - 0.350

+0.100 0

Boom side

225

+0.5 0

Arm side

220

- 0.5 - 1.0

4

5

–

192.6

±2.0

6

–

235

±1.0 0

7

–

335.7

±1.0 0

8

–

1,720

–

9

–

2,039.6

±3.0

10

–

1,660.3

±2.0

11

–

258.8

±1.0

12

–

11.3

±1.0

13

–

395.1

±0.1

14

–

342

±0.1

15

–

312.2

–

16

–

1,066.9

–

17

–

50

- 0.225 - 0.285

0 - 0.150

Link side

200

- 1.0 - 2.0

Bucket side

200

+2.0 0

19

–

50

20

Arm as individual part

188

- 0.5 - 1.0

21

When pressfitting bushing

200

- 0.5 - 1.4

Min.

1,055

±1.5

Max.

1,765

–

18

- 0.225 - 0.285

0 - 0.150

22

PC78US-6

10-189 (13)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

DIMENSIONS OF EACH PART OF WORK EQUIPMENT

2. BUCKET PORTION

*1. PC78US-6 Serial No.: 6501 and up

10-190 (13)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

DIMENSIONS OF EACH PART OF WORK EQUIPMENT

Unit: mm PC78US-6, PC78UU-6 No. Measuring point

Basic dimension

Allowance

1

–

309.8

±0.5

2

–

38.6

±0.5

3

–

97.1°

–

4

–

312.2

–

5

–

1,057.2

–

6

–

143.7

–

7

–

8°

–

8

–

5.2°

–

9

–

50

10

–

60

–

11

–

70

+0.2 0

12

–

200

+2.0 0

13

–

40

–

14

–

71

–

15

–

296

+1.0 0

16

–

18

–

17

–

100

–

18

–

115

–

19

–

95

–

20

–

211

+3.0 0

21

–

40

–

22

–

24

–

23

–

89.3

–

24

–

87.9

–

25

–

60

–

26

–

66

–

PC78US-6

0 - 0.15

10-191 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

AIR CONDITIONER PIPING (OPTIONAL)

AIR CONDITIONER PIPING (OPTIONAL) PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up

A: Hot/Cool air outlet B: Inside air circulation opening C: Fresh air inlet

10-192 (10)

1. 2. 3. 4. 5. 6. 7. 8.

Hot water take-out piping Air conditioner compressor Hot water return piping Refrigerant piping Condenser Receiver drier Air conditioner unit Duct

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

AIR CONDITIONER PIPING (OPTIONAL)

PC78US-6 Serial No.: 6501 and up

A: B: C: D:

Hot/Cool air outlet Inside air circulation opening Fresh air inlet Refrigerant checking port

PC78US-6

1. 2. 3. 4. 5. 6. 7. 8.

Hot water take-out piping Air conditioner compressor Hot water return piping Refrigerant piping Condenser Receiver drier Air conditioner unit Duct

10-193 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

ELECTRIC CONTROL SYSTEM Engine control function Engine and pump compound control function Overheat prevention function

Swing control function

Travel control function

PPC lock function (*1) Automatic gear shift system Electric control system

Seed reducing function

(*1) Turbocharger protection function

Stop/Alarm function (*2) Interference prevention system

Emergency stop/Alarm function

Cancel function

Reset function Depth – from – Ground – Level display function

(*2) Depth measuring system

Depth – from – Datum – Plane display function (*2) Automatic height stop system

Height setup function

(*2) Boom end cushion function (*2) Arm end cushion function

Error code display and alarm function Self-diagnosis function Error code memory function

* 1 For PC78US-6 Serial No. 6501 and up * 2 For PC78UU-6 machine only.

PC78US-6

10-195 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

GENERAL SYSTEM DIAGRAM PC78US-6 Serial No.: 4001 – 5500 a This drawing shows the PC78US-6 of blade specification.

10-196 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39.

Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency pump drive switch Swing holding brake release switch Resistor (For emergency pump drive) Safety lock lever PPC lock switch Starting motor cut relay Safety relay One-touch deceleration switch Fuel control motor relay (For drive) Fuel control motor relay (For accelerator) Fuel control motor relay (For deceleration) Fuel control dial Fuel control motor Monitor panel Travel speed boost pedal [Blade specification] Travel alarm (If equipped) PPC lock solenoid valve 2-stage travel speed selector solenoid valve Swing holding brake solenoid valve TVC-EPC valve Right work equipment PPC valve Travel PPC valve Left work equipment PPC valve Blade PPC valve [Blade specification] Boom RAISE PPC oil pressure switch Travel PPC oil pressure switch Arm IN PPC oil pressure switch Swing PPC oil pressure switch Engine stop solenoid Starting motor Engine speed sensor Coolant temperature sensor Hydraulic pump 39a. Servo piston 39b. LS valve 39c. TVC valve 40. Control valve 40a. Pump merge-divider valve 41. Travel motor 42. Swing motor

PC78US-6

10-197 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No.: 5501 – 6500 a This drawing shows the PC78US-6 of blade specification.

10-198 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39.

Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency pump drive switch Swing holding brake release switch Resistor (For emergency pump drive) Safety lock lever PPC lock switch Starting motor cut relay Safety relay One-touch deceleration switch Fuel control motor relay (For accelerator) Fuel control motor relay (For deceleration) Fuel control dial Fuel control motor Monitor panel Travel speed boost pedal (Blade specification) Travel alarm (If equipped) PPC lock solenoid valve 2-stage travel speed selector solenoid valve Swing holding brake solenoid valve TVC-EPC valve Right work equipment PPC valve Travel PPC valve Left work equipment PPC valve Blade PPC valve (Blade specification) Boom RAISE PPC oil pressure switch Travel PPC oil pressure switch Arm IN PPC oil pressure switch Swing PPC oil pressure switch Engine stop solenoid Engine stop solenoid relay Starting motor Engine speed sensor Coolant temperature sensor Hydraulic pump 39a. Servo piston 39b. LS valve 39c. TVC valve 40. Control valve 40a. Pump merge-divider valve 41. Travel motor 42. Swing motor

PC78US-6

10-199 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No.: 6501 and up a This drawing shows the PC78US-6 of blade specification.

10-200 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39.

40. 41. 42. 43.

ELECTRIC CONTROL SYSTEM

Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency pump drive switch Swing holding brake release switch Resistor (For emergency pump drive) Safety lock lever PPC lock switch Starting motor cut relay Safety relay One-touch deceleration switch Fuel control motor relay (For accelerator) Fuel control motor relay (For deceleration) Fuel control dial Fuel control motor Monitor panel Hydraulic pump pressure sensor Travel alarm (If equipped) PPC lock solenoid valve 2-stage travel speed selector solenoid valve Swing holding brake solenoid valve TVC-EPC valve Right work equipment PPC valve Travel PPC valve Left work equipment PPC valve Blade PPC valve (Blade specification) Boom RAISE PPC oil pressure switch Travel PPC oil pressure switch Arm IN PPC oil pressure switch Swing PPC oil pressure switch Engine stop solenoid Engine stop solenoid relay Starting motor Engine speed sensor Coolant temperature sensor Hydraulic pump 39a. Servo piston 39b. LS valve 39c. TVC valve Control valve 40a. Pump merge-divider valve Travel motor Swing motor Travel alarm drive relay

PC78US-6

10-201 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78UU-6 Serial No.: 22832 – 23500

10-202 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49.

50. 51. 52.

ELECTRIC CONTROL SYSTEM

Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency work equipment operating switch Emergency pump drive switch Swing holding brake release switch Resistor (For emergency work equipment operating) Resistor (For emergency pump drive) Safety lock lever PPC lock switch PPC lock cut relay Starting motor cut relay Safety relay One-touch deceleration switch Fuel control motor relay (For drive) Fuel control motor relay (For accelerator) Fuel control motor relay (For deceleration) Fuel control dial Fuel control motor Monitor panel Travel speed boost pedal Travel alarm (If equipped) PPC lock solenoid valve 2-stage travel speed selector solenoid valve Swing holding brake solenoid valve Boom RAISE stop EPC valve Arm IN stop EPC valve Left offset stop EPC valve TVC-EPC valve Right work equipment PPC valve Travel PPC valve Left work equipment PPC valve Offset PPC valve Blade PPC valve Boom RAISE PPC oil pressure switch Travel PPC oil pressure switch Arm IN PPC oil pressure switch Swing PPC oil pressure switch Boom potentiometer Offset potentiometer Arm potentiometer Engine stop solenoid Starting motor Engine speed sensor Coolant temperature sensor Hydraulic pump 49a. Servo piston 49b. LS valve 49c. TVC valve Control valve 50a. Pump merge-divider valve Travel motor Swing motor

PC78US-6

10-203 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78UU-6 Serial No.: 23501 and up

10-204 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49.

50. 51. 52.

ELECTRIC CONTROL SYSTEM

Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency work equipment operating switch Emergency pump drive switch Swing holding brake release switch Resistor (For emergency work equipment operating) Resistor (For emergency pump drive) Safety lock lever PPC lock switch PPC lock cut relay Starting motor cut relay Safety relay One-touch deceleration switch Fuel control motor relay (For accelerator) Fuel control motor relay (For deceleration) Fuel control dial Fuel control motor Monitor panel Travel speed boost pedal Travel alarm (If equipped) PPC lock solenoid valve 2-stage travel speed selector solenoid valve Swing holding brake solenoid valve Boom RAISE stop EPC valve Arm IN stop EPC valve Left offset stop EPC valve TVC-EPC valve Right work equipment PPC valve Travel PPC valve Left work equipment PPC valve Offset PPC valve Blade PPC valve Boom RAISE PPC oil pressure switch Travel PPC oil pressure switch Arm IN PPC oil pressure switch Swing PPC oil pressure switch Boom potentiometer Offset potentiometer Arm potentiometer Engine stop solenoid Engine stop solenoid relay Starting motor Engine speed sensor Coolant temperature sensor Hydraulic pump 49a. Servo piston 49b. LS valve 49c. TVC valve Control valve 50a. Pump merge-divider valve Travel motor Swing motor

PC78US-6

10-205 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

ENGINE CONTROL FUNCTION PC78US-6 Serial No.: 4001 – 5500

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19.

Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch Starting motor cut relay Safety relay Fuel control dial Fuel control motor Fuel control motor relay (For drive) Fuel control motor relay (For accelerator) Fuel control motor relay (For deceleration) One-touch deceleration switch Monitor panel Engine stop solenoid Starting motor

10-206 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

Starting engine • If starting switch (4) is turned to the ON position, engine stop solenoid (18) moves governor stop lever to the "RUN" side. Accordingly, if the electric system has any trouble, the engine stops, that is, a fail-safe mechanism is formed. • If starting switch (4) is turned to the START position while safety lock lever (7) is at the "LOCK" position, the start signal flows to starting motor (19) and the engine starts. If safety lock lever (7) is at the "FREE" position, the start signal to starting motor (19) is cut out by starting motor cut relay (9) and the engine cannot start. • At this time, since fuel control motor (12) is linked with fuel control dial (11), the engine speed is fixed to the speed set with fuel control dial (11). Controlling engine speed • Fuel control motor (12) outputs the acceleration (engine speed raising) signal and deceleration (engine speed lowering) signal to controller (6) according to the position of fuel control dial (11). • Upon receiving the signal, controller (6) outputs the drive signal through fuel control motor relays (13), (14), and (15) to fuel control motor (12). • Fuel control motor (12) lengthens or shortens the cable to control the engine speed according to the drive signal.

ELECTRIC CONTROL SYSTEM

One-touch deceleration • If one-touch deceleration switch (16) is pressed, the deceleration signal is output to controller (6). • Controller (6) turns on the one-touch deceleration monitor of monitor panel (17) and drives fuel control motor (12) to lower the engine speed to low idling. • If one-touch deceleration switch (16) is pressed while the engine is being started, the engine speed is set to low idling. If it is pressed again, the engine speed returns to the speed set with fuel control dial (11). a Even if the engine is stopped while the onetouch deceleration system is turned on, the latter is turned off when the engine is started next time (the engine speed is set the speed set with the fuel control dial). a Even if the fuel control dial is operated while the one-touch deceleration system is turned on, the engine speed is kept at low idling. a If the fuel control dial is at low idling, the engine speed does not lower any more even if the onetouch deceleration switch is pressed.

Stopping engine • If starting switch (4) is turned to the OFF position, engine stop solenoid (18) moves the governor stop lever to the STOP side and the engine stops.

A: B: C: D: E:

PC78US-6

One-touch deceleration switch [ON] One-touch deceleration switch [OFF] Engine speed set with fuel control dial Low idling Max. 1 sec

10-207 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No.: 5501 – 6500

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19.

Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch Starting motor cut relay Safety relay Fuel control dial Fuel control motor Fuel control motor relay (For accelerator) Fuel control motor relay (For deceleration) One-touch deceleration switch Monitor panel Engine stop solenoid Engine stop solenoid relay Starting motor

10-208 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No.: 6501 and up

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19.

Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch Starting motor cut relay Safety relay Fuel control dial Fuel control motor Fuel control motor relay (For accelerator) Fuel control motor relay (For deceleration) One-touch deceleration switch Monitor panel Engine stop solenoid Engine stop solenoid relay Starting motor

PC78US-6

10-209 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

Starting engine • If starting switch (4) is turned to the ON position, engine stop solenoid (17) moves governor stop lever to the "RUN" side. Accordingly, if the electric system has any trouble, the engine stops, that is, a fail-safe mechanism is formed. • If starting switch (4) is turned to the START position while safety lock lever (7) is at the "LOCK" position, the start signal flows to starting motor (19) and the engine starts. If safety lock lever (7) is at the "FREE" position, the start signal to starting motor (19) is cut out by starting motor cut relay (9) and the engine cannot start. • At this time, since fuel control motor (12) is linked with fuel control dial (11), the engine speed is fixed to the speed set with fuel control dial (11). Controlling engine speed • Fuel control dial (11) outputs the potentiometer voltage to controller (6) according to its position. • Upon receiving the signal, controller (6) outputs the drive signal through fuel control motor relays (13) and (14) to fuel control motor (12). • Fuel control motor (12) lengthens or shortens the cable to control the engine speed according to the drive signal.

10-210 (10)

ELECTRIC CONTROL SYSTEM

Function of preventing engine stop solenoid from burning • Engine stop solenoid relay (18) is installed to prevent engine stop solenoid (17) from burning. • The time to supply the suction current is limited to 3 seconds after starting switch (4) is turned to the ON position by replacing the 2-wire engine stop solenoid (17) (which uses the same wire for the suction and holding currents) with the 3-wire one (which uses independent wires for the suction and holding currents) and adding a timer function and engine stop solenoid relay (18) to controller (6).

A: B: C: t:

Operation of starting switch Suction coil current Holding coil current 3 seconds

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

Stopping engine • If starting switch (4) is turned to the OFF position, engine stop solenoid (17) moves the governor stop lever to the STOP side and the engine stops. One-touch deceleration • If one-touch deceleration switch (16) is pressed, the deceleration signal is output to controller (6). • Controller (6) turns on the one-touch deceleration monitor of monitor panel (16) and drives fuel control motor (12) to lower the engine speed to low idling. • If one-touch deceleration switch (15) is pressed while the engine is being started, the engine speed is set to low idling. If it is pressed again, the engine speed returns to the speed set with fuel control dial (11). a Even if the engine is stopped while the onetouch deceleration system is turned on, the latter is turned off when the engine is started next time (the engine speed is set the speed set with the fuel control dial). a Even if the fuel control dial is operated while the one-touch deceleration system is turned on, the engine speed is kept at low idling. a If the fuel control dial is at low idling, the engine speed does not lower any more even if the onetouch deceleration switch is pressed.

A: B: C: D: E:

One-touch deceleration switch [ON] One-touch deceleration switch [OFF] Engine speed set with fuel control dial Low idling Max. 1 sec

PC78US-6

10-211 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No.: 6501 and up Turbocharger protection function • When the engine is started at low temperature, if the engine speed is increased sharply, the turbocharger may be seized. The turbocharger protection function prevents this trouble.

A: B: C: D: E: F:

Start of engine Turbocharger protection time (Approx. 0.6 sec) Modulation time (Approx. 1.4 sec) 1,000 rpm 1,200 rpm 2,020 rpm Operating condition

Coolant temperature: Max. 30° Engine speed sensor: Normal

10-212 (10)

o

Operation Protection of turbocharger (See above figure)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78UU-6 Serial No.: 22832 – 23500

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21.

Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch Starting motor cut relay Safety relay Fuel control dial Fuel control motor Fuel control motor relay (For drive) Fuel control motor relay (For accelerator) Fuel control motor relay (For deceleration) One-touch deceleration switch Monitor panel Engine stop solenoid Starting motor Emergency work equipment operating switch PPC lock cut relay

PC78US-6

10-213 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

Starting engine • If starting switch (4) is turned to the ON position, engine stop solenoid (18) moves governor stop lever to the "RUN" side. Accordingly, if the electric system has any trouble, the engine stops, that is, a fail-safe mechanism is formed. • If starting switch (4) is turned to the START position while safety lock lever (7) is at the "LOCK" position, the start signal flows to starting motor (19) and the engine starts. If safety lock lever (7) is at the "FREE" position, the start signal to starting motor (19) is cut out by starting motor cut relay (9) and the engine cannot start. • At this time, since fuel control motor (12) is linked with fuel control dial (11), the engine speed is fixed to the speed set with fuel control dial (11). Controlling engine speed • Fuel control motor (12) outputs the acceleration (engine speed raising) signal and deceleration (engine speed lowering) signal to controller (6) according to the position of fuel control dial (11). • Upon receiving the signal, controller (6) outputs the drive signal through fuel control motor relays (13), (14), and (15) to fuel control motor (12). • Fuel control motor (12) lengthens or shortens the cable to control the engine speed according to the drive signal.

ELECTRIC CONTROL SYSTEM

One-touch deceleration • If one-touch deceleration switch (16) is pressed, the deceleration signal is output to controller (6). • Controller (6) turns on the one-touch deceleration monitor of monitor panel (17) and drives fuel control motor (12) to lower the engine speed to low idling. • If one-touch deceleration switch (16) is pressed while the engine is being started, the engine speed is set to low idling. If it is pressed again, the engine speed returns to the speed set with fuel control dial (11). a Even if the engine is stopped while the onetouch deceleration system is turned on, the latter is turned off when the engine is started next time (the engine speed is set the speed set with the fuel control dial). a Even if the fuel control dial is operated while the one-touch deceleration system is turned on, the engine speed is kept at low idling. a If the fuel control dial is at low idling, the engine speed does not lower any more even if the onetouch deceleration switch is pressed.

Stopping engine • If starting switch (4) is turned to the OFF position, engine stop solenoid (18) moves the governor stop lever to the STOP side and the engine stops.

A: B: C: D: E:

10-214 (10)

One-touch deceleration switch [ON] One-touch deceleration switch [OFF] Engine speed set with fuel control dial Low idling Max. 1 sec

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78UU-6 Serial No.: 23501 and up

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21.

Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch Starting motor cut relay Safety relay Fuel control dial Fuel control motor Fuel control motor relay (For accelerator) Fuel control motor relay (For deceleration) One-touch deceleration switch Monitor panel Engine stop solenoid Engine stop solenoid relay Starting motor Emergency work equipment operating switch PPC lock cut relay

PC78US-6

10-215 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

Starting engine • If starting switch (4) is turned to the ON position, engine stop solenoid (17) moves governor stop lever to the "RUN" side. Accordingly, if the electric system has any trouble, the engine stops, that is, a fail-safe mechanism is formed. • If starting switch (4) is turned to the START position while safety lock lever (7) is at the "LOCK" position, the start signal flows to starting motor (19) and the engine starts. If safety lock lever (7) is at the "FREE" position, the start signal to starting motor (19) is cut out by starting motor cut relay (9) and the engine cannot start. • At this time, since fuel control motor (12) is linked with fuel control dial (11), the engine speed is fixed to the speed set with fuel control dial (11). Controlling engine speed • Fuel control motor (12) outputs the acceleration (engine speed raising) signal and deceleration (engine speed lowering) signal to controller (6) according to the position of fuel control dial (11). • Upon receiving the signal, controller (6) outputs the drive signal through fuel control motor relays (13) and (14) to fuel control motor (12). • Fuel control motor (12) lengthens or shortens the cable to control the engine speed according to the drive signal.

10-216 (10)

ELECTRIC CONTROL SYSTEM

Function of preventing engine stop solenoid from burning • Engine stop solenoid relay (18) is installed to prevent engine stop solenoid (17) from burning. • The time to supply the suction current is limited to 3 seconds after starting switch (4) is turned to the ON position by replacing the 2-wire engine stop solenoid (17) (which uses the same wire for the suction and holding currents) with the 3-wire one (which uses independent wires for the suction and holding currents) and adding a timer function and engine stop solenoid relay (18) to controller (6).

A: B: C: t:

Operation of starting switch Suction coil current Holding coil current 3 seconds

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

Stopping engine • If starting switch (4) is turned to the OFF position, engine stop solenoid (17) moves the governor stop lever to the STOP side and the engine stops. One-touch deceleration • If one-touch deceleration switch (16) is pressed, the deceleration signal is output to controller (6). • Controller (6) turns on the one-touch deceleration monitor of monitor panel (16) and drives fuel control motor (12) to lower the engine speed to low idling. • If one-touch deceleration switch (15) is pressed while the engine is being started, the engine speed is set to low idling. If it is pressed again, the engine speed returns to the speed set with fuel control dial (11). a Even if the engine is stopped while the onetouch deceleration system is turned on, the latter is turned off when the engine is started next time (the engine speed is set the speed set with the fuel control dial). a Even if the fuel control dial is operated while the one-touch deceleration system is turned on, the engine speed is kept at low idling. a If the fuel control dial is at low idling, the engine speed does not lower any more even if the onetouch deceleration switch is pressed.

A: B: C: D: E:

One-touch deceleration switch [ON] One-touch deceleration switch [OFF] Engine speed set with fuel control dial Low idling Max. 1 sec

PC78US-6

10-217 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

ENGINE AND PUMP COMPOUND CONTROL FUNCTION PC78US-6 Serial No. 4001 – 6500 (Blade-less specification)

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency pump drive switch Resistor (For emergency pump drive) Monitor panel TVC-EPC valve Engine speed sensor Coolant temperature sensor Control valve 13a. Pump merge-divider valve 14. Hydraulic pump 14a. Servo piston 14b. LS valve 14c. TVC valve

10-218 (10)

Input/Output signals a. Controller power source b. Solenoid power source c. Monitor panel power source d. S-NET signal e. Coolant temperature signal f. Engine speed signal g. EPC valve drive signal

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No. 6501 and up (Blade-less specification)

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency pump drive switch Resistor (For emergency pump drive) Monitor panel TVC-EPC valve Engine speed sensor Coolant temperature sensor Control valve 13a. Pump merge-divider valve 14. Hydraulic pump 14a. Servo piston 14b. LS valve 14c. TVC valve

PC78US-6

Input/Output signals a. Controller power source b. Solenoid power source c. Monitor panel power source d. S-NET signal e. Coolant temperature signal f. Engine speed signal g. EPC valve drive signal

10-219 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No. 4001 – 6500 (Blade specification) PC78UU-6 Serial No. 22832 and up

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency pump drive switch Resistor (For emergency pump drive) Monitor panel TVC-EPC valve Engine speed sensor Coolant temperature sensor Control valve 13a. Pump merge-divider valve 14. Hydraulic pump 14a. Servo piston 14b. LS valve 14c. TVC valve

10-220 (10)

Input/Output signals a. Controller power source b. Solenoid power source c. Monitor panel power source d. S-NET signal e. Coolant temperature signal f. Engine speed signal g. EPC valve drive signal

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No. 6501 and up (Blade specification)

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.

Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency pump drive switch Resistor (For emergency pump drive) Monitor panel TVC-EPC valve Engine speed sensor Coolant temperature sensor Control valve 13a. Pump merge-divider valve 14. Hydraulic pump 14a. Servo piston 14b. LS valve 14c. TVC valve

PC78US-6

Input/Output signals a. Controller power source b. Solenoid power source c. Monitor panel power source d. S-NET signal e. Coolant temperature signal f. Engine speed signal g. EPC valve drive signal

10-221 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

Functions • The "active" or "E" mode is selected with the working mode selection switch on the monitor panel. In each mode, proper engine torque and pump absorption torque are selected according to the contents of work. • The controller detects the engine governor speed set with the fuel control dial and the actual engine speed and controls the hydraulic system so that the pump will absorb the all torque at each output point of the engine, according to the pump absorption torque set for each mode. • If the engine speed is lowered, the pump absorption torque is reduced to prevent the engine from stopping.

10-222 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

Control method in each mode Active mode • Matching point of active mode:

•

Model

PC78US-6, PC78UU-6

Active mode

40.5 kw / 1.850 rpm {54.0 HP / 1.850 rpm}

If the pump load increases and the pressure rises, engine speed lowers. At this time, the pump discharge is reduced to heighten the engine speed to near the full output point. On the other hand, if the pressure lowers, engine speed is heightened to near the full output point to increase the pump discharge. The engine is constantly used near the full output point by repeating this control.

PC78US-6

10-223 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

E mode • Matching point of E mode: 85% partial output point of active mode Model E mode

•

PC78US-6, PC78UU-6 37.5 kw / 1.660 rpm {50.0 HP / 1,660 rpm}

In this mode, the engine speed is lowered along the constant horsepower curve of the engine, keeping the pump absorption torque at a constant level. The engine is used in the high fuel efficiency area by this control method.

10-224 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

Driving pump in an emergency • Even if the controller, etc. has a problem and the hydraulic pump does not operate normally, the operator can work temporarily by operating the emergency pump drive switch (S). (1) Auto: Normal state (2) Cancel: Abnormal state a The emergency pump drive switch (S) is of alternative type. If it is set to the "CANCEL (2)" position while the machine is normal, user code "E02" is displayed on the display unit. PC78US-6 Serial No. 4001 – 6500 PC78UU-6

PC78US-6 Serial No. 6501 and up

OVERHEAT PREVENTION FUNCTION a For the system circuit diagram, see "Engine and pump compound control function". •

If the coolant temperature rises too high, the pump load is lowered to prevent the engine from overheating. Operating condition Coolant temperature is above 99°C

PC78US-6

Operation

o

• Pump absorption torque is reduced according to torque control system to reduce engine load. (Matching point: 90% partial output point) • Engine speed is kept as it is.

Resetting condition

o Coolant temperature is below 95°C

10-225 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

SWING CONTROL FUNCTION PC78US-6 Serial No. 4001 – 6500 a This drawing shows PC78US-6 of the blade-less specification.

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

Battery Battery relay Fusible link Starting switch Fuse box Controller Swing holding brake release switch Swing holding brake solenoid valve Swing motor Left work equipment PPC valve Arm IN PPC oil pressure switch Swing PPC oil pressure switch Engine Hydraulic pump Control valve 15a. Pump merge-divider valve

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Input/Output signals a. Controller power source b. Solenoid power source c. Solenoid valve drive signal d. Swing PPC oil pressure switch signal e. Arm IN PPC oil pressure switch signal

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No. 6501 and up a This drawing shows PC78US-6 of the blade-less specification.

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

Battery Battery relay Fusible link Starting switch Fuse box Controller Swing holding brake release switch Swing holding brake solenoid valve Swing motor Left work equipment PPC valve Arm IN PPC oil pressure switch Swing PPC oil pressure switch Engine Hydraulic pump Control valve 15a. Pump merge-divider valve

PC78US-6

Input/Output signals a. Controller power source b. Solenoid power source c. Solenoid valve drive signal d. Swing PPC oil pressure switch signal e. Arm IN PPC oil pressure switch signal

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STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78UU-6

1. Battery 2. Battery relay 3. Fusible link 4. Starting switch 5. Fuse box 6. Controller 7. Swing holding brake release switch 8. Swing holding brake solenoid valve 9. Swing motor 10. Left work equipment PPC valve 11. Arm IN PPC oil pressure switch 12. Swing PPC oil pressure switch 13. Engine 14. Hydraulic pump 15. Control valve 15a. Pump merge-divider valve 16. Offset potentiometer

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Input/Output signals a. Controller power source b. Solenoid power source c. Solenoid valve drive signal d. Swing PPC oil pressure switch signal e. Arm IN PPC oil pressure switch signal f. Offset potentiometer signal

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

Function Swing holding brake • When the machine stops swinging, the swing holding brake is applied automatically to prevent hydraulic drift on a slope, etc. • When the arm is moved in, the swing holding brake is released to reduce the load on the swing unit during digging work. • If the offset operation is turned ON, the swing holding brake is released to reduce the shocks made when the offset operation is started and stopped. (PC78UU) a If the swing holding brake is released, only the hydraulic brake of the safety valve is used to stop swinging. Accordingly, if the machine stops swinging on a slope, etc. the boom may drift hydraulically. Take care. Releasing swing holding brake • Even if the controller, etc. has a problem and the swing holding brake does not operate normally and the machine does not swing, the operator can swing the machine by releasing the swing holding brake with the swing holding brake cancel switch (S). (1) Auto: Normal state (2) Cancel: Abnormal state a Emergency swing holding brake cancel switch (S) is of alternative type. If it is set to the "CANCEL (2)" position while the machine is normal, user code "E03" is displayed on the display unit.

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No. 6501 and up

Relationship between swing holding brake cancel switch and swing holding brake Swing holding brake cancel switch

Operation

• If swing control lever or arm IN lever is set to neutral position, swing holding Auto brake is applied about 5 seconds later. (Normal state) • If swing control lever or arm IN lever is operated, swing holding brake is released and machine can swing freely.

Cancel (Abnormal state)

• When swing holding brake system has trouble, if swing holding brake cancel switch (S) is set to "Cancel (2)", swing holding brake is released and machine can swing. • Even if swing control lever or arm IN lever is set to neutral position, swing holding brake does not operate, however.

Time chart of input and output signals PC78US-6 Serial No. 4001 – 6500 PC78UU-6

PC78US-6

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STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

TRAVEL CONTROL FUNCTION PC78US-6 Serial No. 4001 – 6500 (Blade-less specification)

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Battery Battery relay Fusible link Starting switch Fuse box Controller Monitor panel 2-stage travel speed selector solenoid valve Left travel motor Right travel motor Travel PPC valve Travel PPC oil pressure switch Travel alarm (If equipped) Engine Hydraulic pump Control valve 16a. Pump merge-divider valve

Function Changing travel speed • If the travel speed boost selector switch is operated, the motor capacity changes to change the travel speed. a When the engine is started, the travel speed boost selector switch is set to the low speed position automatically. Travel speed boost selector switch

Lo lamp lights Hi lamp lights up up (Low speed) (High speed)

Motor capacity (cc/rev)

36.3

24.1

Travel speed (km/h)

3.0

4.5

Swash plate angle of travel motor

Max.

Min.

Input/Output signals a. Controller power source b. Solenoid power source c. Monitor panel power source d. S-NET drive signal e. Solenoid valve drive signal f. Travel PPC oil pressure switch signal g. Travel alarm drive signal

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PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No. 4001 – 6500 (Blade specification) PC78UU-6 Serial No. 22832 and up

PC78US-6

a When the engine is started, the travel speed boost selector switch is set to the low speed position automatically. aThe travel speed boost pedal is effective only while the "Lo" lamp of the travel speed boost selector switch is lighting. Even if the pedal is pressed while the "Hi" lamp is lighting up, the travel speed does not change. Travel speed boost selector switch

Released

Input/Output signals a. Controller power source b. Solenoid power source c. Monitor panel power source d. S-NET drive signal e. Solenoid valve drive signal f. Travel PPC oil pressure switch signal g. Travel alarm drive signal h. 2nd travel speed selection signal

Function Changing travel speed • If the travel speed boost selector switch is operated or the travel speed boost pedal is pressed, the motor capacity changes to change the travel speed.

Pressed

Battery Battery relay Fusible link Starting switch Fuse box Controller Monitor panel 2-stage travel speed selector solenoid valve Left travel motor Right travel motor Travel PPC valve Travel PPC oil pressure switch Travel alarm (If equipped) Engine Hydraulic pump Control valve 16a. Pump merge-divider valve 17. Travel speed boost pedal

Travel speed boost pedal

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Motor capacity (cc/rev) Travel speed (km/h) Swash plate angle of travel motor Motor capacity (cc/rev) Travel speed (km/h) Swash plate angle of travel motor

Lo lamp Hi lamp lights up lights up (Low speed) (High speed) 36.3

24.1

3.0

4.5

Max.

Min.

24.1

24.1

4.5

4.5

Min.

Min.

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STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No. 6501 and up (Blade-less specification)

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Battery Battery relay Fusible link Starting switch Fuse box Controller Monitor panel 2-stage travel speed selector solenoid valve Left travel motor Right travel motor Travel PPC valve Travel PPC oil pressure switch Travel alarm (If equipped) Engine Hydraulic pump Control valve 16a. Pump merge-divider valve 17. Hydraulic pump pressure sensor 18. Travel alarm drive relay

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Input/Output signals a. Controller power source b. Solenoid power source c. Monitor panel power source d. S-NET drive signal e. Solenoid valve drive signal f. Travel PPC oil pressure switch signal g. Travel alarm drive signal

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No. 6501 and up (Blade specification)

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.

Battery Battery relay Fusible link Starting switch Fuse box Controller Monitor panel 2-stage travel speed selector solenoid valve Left travel motor Right travel motor Travel PPC valve Travel PPC oil pressure switch Travel alarm (If equipped) Engine Hydraulic pump Control valve 16a. Pump merge-divider valve 17. Hydraulic pump pressure sensor 18. Travel alarm drive relay

PC78US-6

Input/Output signals a. Controller power source b. Solenoid power source c. Monitor panel power source d. S-NET drive signal e. Solenoid valve drive signal f. Travel PPC oil pressure switch signal g. Travel alarm drive signal

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STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

Function 1. Changing travel speed • If the travel speed boost selector switch is operated, the motor capacity changes to change the travel speed. a When the engine is started, the travel speed boost selector switch is set to the low speed position automatically. Travel speed boost selector switch

Lo lamp lights Hi lamp lights up up (Low speed) (High speed)

Motor capacity (cc/rev)

36.3

24.1

Travel speed (km/h)

3.0

4.5

Swash plate angle of travel motor

Max.

Min.

2) Automatic selection corresponding to discharge pressure of pump • If travel pressure of 23.0MPa {235 kg/ cm 2 } or higher continues for 0.02 seconds or more when travel speed selector switch is in HIGH, travel speed changes to LOW automatically. • If travel pressure of 13.2MPa {135 kg/ cm2} or lower continues for 0.1 seconds or more when travel speed selector switch is in HIGH, travel speed changes to HIGH automatically. a If travel speed selector switch is in LOW, travel speed is not changed automatically.

2. "Automatic"change of travel speed 1) Automatic selection corresponding to engine speed • If engine speed drops to 1,350 rpm or less when travel speed selector switch is in HIGH and travel speed is HIGH, travel speed changes to LOW automatically. • If engine speed becomes 1,550 rpm or less when travel speed selector switch is in HIGH and travel speed is LOW, travel speed changes to HIGH automatically. a If travel speed selector switch is in LOW, travel speed is not changed automatically.

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PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PPC LOCK FUNCTION PC78US-6 Serial No.: 4001 – 5500 a This drawing shows PC78US-6 of the blade specification.

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch PPC lock solenoid valve Left work equipment PPC valve Right work equipment PPC valve Travel PPC valve Blade PPC valve (Blade specification) Engine Hydraulic pump

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Input/Output signals a. Controller power source b. Solenoid power source c. Solenoid valve drive signal Function • The PPC lock switch is linked with the safety lock lever. If the safety lock lever is set to the LOCK position, the PPC lock switch is turned OFF. • If the PPC lock switch is turned OFF, the current to the PPC lock solenoid valve is cut out and the work equipment does not move any more even if the work equipment control lever is operated.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78US-6 Serial No.: 5501 and up a This drawing shows PC78US-6 of the blade specification.

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.

Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch PPC lock solenoid valve Left work equipment PPC valve Right work equipment PPC valve Travel PPC valve Blade PPC valve (Blade specification) Engine Hydraulic pump

PC78US-6

Input/Output signals a. Controller power source b. Solenoid power source c. Solenoid valve drive signal Function • The PPC lock switch is linked with the safety lock lever. If the safety lock lever is set to the LOCK position, the PPC lock switch is turned OFF. • If the PPC lock switch is turned OFF, the current to the PPC lock solenoid valve is cut out and the work equipment does not move any more even if the work equipment control lever is operated.

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STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78UU-6 Serial No.: 22832 – 23500

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18.

Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch PPC lock solenoid valve Left work equipment PPC valve Right work equipment PPC valve Travel PPC valve Blade PPC valve Engine Hydraulic pump Emergency work equipment operating switch Offset PPC valve PPC lock cut relay

10-238 (10)

Input/Output signals a. Controller power source b. Solenoid power source c. Solenoid valve drive signal Function • The PPC lock switch is linked with the safety lock lever. If the safety lock lever is set to the LOCK position, the PPC lock switch is turned OFF. • If the PPC lock switch is turned OFF, the current to the PPC lock solenoid valve is cut out and the work equipment does not move any more even if the work equipment control lever is operated.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

PC78UU-6 Serial No.: 23501 and up

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18.

Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch PPC lock solenoid valve Left work equipment PPC valve Right work equipment PPC valve Travel PPC valve Blade PPC valve Engine Hydraulic pump Emergency work equipment operating switch Offset PPC valve PPC lock cut relay

PC78US-6

Input/Output signals a. Controller power source b. Solenoid power source c. Solenoid valve drive signal Function • The PPC lock switch is linked with the safety lock lever. If the safety lock lever is set to the LOCK position, the PPC lock switch is turned OFF. • If the PPC lock switch is turned OFF, the current to the PPC lock solenoid valve is cut out and the work equipment does not move any more even if the work equipment control lever is operated.

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STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

INTERFERENCE PREVENTION SYSTEM PC78UU-6 •

•

•

•

•

•

•

Structure of the machine's work equipment can introduce interference of the bucket against the cab when you turn on the left offset operation or operation of the work equipment.This interference potentially occurs at the front side and right side of the canopy or the cab. The interference prevention system constantly monitors the bucket position in order to automatically stop movement of the work equipment and sound the alarm buzzer if the bucket approaches any of these interfering zones. Drawing dimension: A: 230 – 260 mm B: 150 – 200 mm This function ensures work safety and operating performance in the left offset area.

The potentiometers of boom (1), offset (2), and arm (3) sense the boom turning angle, offset turning angle, and arm turning angle. The controller calculates coordinates X, Y, and Z constantly from the signals of the potentiometers. If point A enters the zone where it is approaching the interference zone (speed reducing zone), the moving speed of the work equipment is lowered. If point A moves on and enters the interference zone, the work equipment is stopped automatically and the alarm buzzer is turned ON to prevent interference. If the controller or any potentiometer has abnormality, the controller cuts out the power for each EPC valve and solenoid valve and stops the work equipment. If you set the emergency work equipment operation switch to the "In emergency" position, however, you can do the all operations temporarily.

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PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

Overall operation diagram a The bucket position in the diagram is somewhat modified from that in actual operations to facilitate descriptions of the system function.

A. Interference B. Emergency stop/alarm point B1:50 mm B2:50 mm C. Stop/alarm point C1:200 mm C2:200 mm D. Reduction start point D1:1,500 mm D2: 700 mm E. Emergency stop zone F. Stop zone G. Reduction zone H. Safety zone

PC78US-6

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STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

1. Reduction function • Speed of the bucket is reduced when it passes through the safety zone A and enters the reduction zone B. The system ensures smooth reduction of the bucket without introducing the "boom up", "arm retract" and "offset left" speeds. • In order to reduce the speed, EPC valve reduces output pressure from PPC valve to the operation valve. 2. Stop/alarm function • If the bucket passes through the reduction zone B and enters the interference zone C its movement is automatically stopped and the alarm buzzer is turned on. a The EPC valves cut off output pressure from the PPC valve to the operation valve to stop bucket movement. a Resume bucket movement by driving the bucket out of the stop zone using the operation not currently disabled. 3. Emergency stop/alarm function • If the bucket does not stop at the predetermined stop point due to failures of the EPC valves, and enters the emergency stop zone, the system stops action of all actuator, and sounds the alarm buzzer. • Using the solenoid valve, the system cuts off the source pressure from the control pump to the PPC valve. Thus, every operation using the PPC circuit will be disabled. a When this function has been turned on, you need to resort to the cancel function for the recovery. See the "Cancel Function" in Section 4.

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A. Safety zone B. Reduction zone C. Interference zone Reduction operation

Boom RAISE Arm IN Offset left

Stop operation

Boom RAISE Arm IN Offset left

Alarm buzzer

Delayed sounding intervals (once every 0.8 seconds)

Stop operation

All actuator

Alarm buzzer

Quick sounding interval (once every 0.4 seconds)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

4. Cancel function • If the emergency stop function is turned on, or if the controller or any of the potentiometers fails, the controller will stop action of the all actuator by cutting off signal current to the solenoid and EPC valves. • This situation requires your immediate checkups. In case the machine must be moved to a safe place before starting the checkups, use the emergency work equipment operation switch S situated under the operator seat. Turning this switch on allows you to move the work equipment to any desired location. (1) Normal position (2) In emergency • As soon as the emergency work equipment operation switch S is turned on, "In emergency (2)", the alarm buzzer will start sounding will also start flashing to notify the operator that the cancel function has been turned on. a If the electric circuit of any EPC valve has abnormality (When user code "E41" of "Abnormality in solenoid system" is displayed on the monitor panel display), the cancel function is not turned ON. a When turning the emergency work equipment operation switch S to the "emergency (2)" position, be careful to operate the work equipment because the interference prevention function of the controller does not work. a The emergency work equipment operation switch S is an auto-return type. Namely, if you move your hand off the switch in the "In emergency (2)" position, it will automatically return to the "Normal (1)" position.

PC78US-6

ELECTRIC CONTROL SYSTEM

Stop cancel operation

All actuator

Alarm buzzer

Sounded for 7 seconds

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STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

5. Reset function 1) Input signal (potentiometer mount angle) reset function • If a potentiometer is mounted at an inappropriate angle in its replacement or replacement of work equipment, error in input signal can result due to an error in the mounting angle. This reset function allows you to correct the error through a single switch operation without measuring the output voltage level or resorting to fine adjustment of the potentiometer. • For the correction, enter the input reset signal while maintaining the boom up, arm retract and offset right at the stroke end. The computer will determine the difference between the angle A computed based upon actual output voltage from respective potentiometers and the specified angle B on the computer (mounting error). The difference will be stored in memory as the "compensation value C".

ELECTRIC CONTROL SYSTEM

•

For the correction, stop the bucket in the specified position, then enter the automatic left-and-right stop position reset signal. With this function, it will reference the actual output voltage from respective potentiometers, will calculate the difference (calculation error) between the computed value A and the standard value B and stores it in memory as the "compensation value C".

2) Automatic fore-and-aft stop position reset function • When an error has resulted in the automatic cab fore stop position from errors in measuring the work equipment size (used in the bucket position calculation) or computer calculation error, this function allows you to correct it in a single switch operation. • For the correction, stop the bucket in the specified position, then enter the automatic fore-and-aft stop position reset signal. With this function, it will reference the actual output voltage from respective potentiometers, will calculate the difference (calculation error) between the computed value A and the standard value B and stores it in memory as the "compensation value C". 3) Automatic left-and-right stop position reset function • When an error has resulted in the automatic side stop position of the cab from errors in measuring the work equipment size (used in the bucket position calculation) or computer calculation error, this function allows you to correct it in a single switch operation. • This function can also be used for correcting the stop position when an optional narrower or wider bucket is used.

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PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

4) Depth indication reset function • When an error has resulted in the depth indication from errors in measuring the work equipment size (used in the bucket position calculation) or computer calculation error, this function allows you to correct it in a single switch operation. • For the correction, place the bucket on the ground surface at points a and then b, then enter the depth indication reset signal when the bucket is at a as well as at b. This function will determine the difference (calculation error) between the actual depth A and the depth B calculated based upon the output voltage from respective potentiometers and stores it in memory as the "compensation value C". a A compensation value once stored will remain undeleted if you turn off the starter switch. a If the work equipment positioned significantly away from the specified position, the compensation value becomes 0 (zero). In this case, the position control is turned on without a compensation value. a For detailed procedures for resetting, refer to the "TESTING AND ADJUSTING" section.

PC78US-6

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STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

DEPTH MEASUREMENT SYSTEM •

This system facilitates your operations by displaying a current digging depth or depth of a target of measurement on the monitor panel. • Two depth indication approaches are available from the depth measurement system. One is a measurement from the ground level (G. L.) and the other is that from the datum plane. a When the starter switch is turned on, a measurement from the ground level is automatically turned on. 1. Depth-from-Ground-Level display function • The depth C of the measurement level B from the ground level (G.L.) is kept displayed on the monitor panel depth indicator during the operation.

1. 2. 3. 4. 5.

Display Depth set 0 indicator Height indicator Setup switch Selector switch

[Setup procedure] • Turn the starter switch on and this function will be automatically started. [Display method] • Depth under the ground level is displayed in 0.1 mm steps. a Fractions are rounded off at two decimal places. • A height above the ground level is preceded by the indication "UP". a You must stretch the bucket straight when setting the zero point in this display system. If the bucket is in any other position, discrepancy E can result from the displayed and actual depth. a If you select the Depth-from-Datum-Plane Display Function, this function will be cancelled.

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PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

2. Depth-from-Datum-Plane display function [Depth 0 set mode] • This function displays a depth from any datum plane you set on the monitor panel depth indicator as long as your operation is continued. a If you select this function, the Depth-fromGround-Level display Function is automatically cancelled. [Setup procedures] • Move the bucket to the datum plane A. • Press the selector switch to flash the depth set 0 indicator (The indicator flashes for 3 seconds). • While the indicator is flashing, press the setup switch. Check that the indicator lights up and "0.0" is displayed. a Set the bucket in the same position when the datum plane A is set and when the bucket is placed on the measurement level B. a If the bucket is not set in the same position, the indicated depth may be different from the actual depth. [Display method] • Depth below the datum plane A is indicated in 0.1 mm steps. a Fractions are rounded off at two decimal places. • A depth above the datum plane A will be preceded by the indication "UP". [Canceling procedures] • Press the setup switch again. • The indicator starts flashing and goes off after 3 seconds. a If you cancel this function, the "Depth-fromGround-Level Display Function" will be restored on the depth indicator. •

Explanatory notes on the depth measurement C = Yc - Ya D = Yc - Yb C : Depth from the ground level (G.L.) D : Depth from the datum plane. Ya : Depth from the boom foot to the ground level (constant) Yb : Depth from the boom foot to any datum plane selected Yc : Depth from the boom foot to the measurement level

PC78US-6

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STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

AUTOMATIC HEIGHT STOP SYSTEM •

•

Automatic height stop function is capable of stopping movement of the boom when it reaches the predetermined height during operation. These functions are helpful in ensuring work safety and efficiency when working in job sites where obstacles such as electric wires are present.

1. Height setup function [height mode] • You can stop movement of the boom during operation at any height A you have previously set. • You can limit the height of the work equipment by setting the limit on the boom lift height. • This function reduces speed of the boom prior to the forced stop to minimize resulting shocks or impacts. a Note that this function is not usable for limiting the bucket height.

1. 2. 3. 4. 5.

Display Depth set 0 indicator Height indicator Setup switch Selector switch

[Setup procedures] • Lift the boom up to the height where you want to set the limit. • Press the selector switch to flash the height indicator (The indicator flashes for 3 seconds). • While the indicator is flashing, press the setup switch. Check that the indicator lights up. [Operation] • Lower the boom. Then, if you raise the boom during work, the buzzer always sounds 2 times at the set position. • This stop is caused by reducing and then shutting down the output pressure from the PPC valve to the boom operation valve (UP side) at the EPC valve. A: Setup position B: Setup angle C: Operation possible zone D: Operation impossible zone [Canceling procedures] • Press the setup switch again. • The indicator starts flashing and goes off after 3 seconds.

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PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

BOOM END CUSHIONING FUNCTION • In the boom up move, this function reduces speed of the boom before it reaches the stroke end to lighten resulting impacts and, thus, to prevent spillage of dirt or dust as well as lighten load to the machine body and cylinder. [Operation] • A cushioning zone is provided before the boomup stroke end (approximately 45°). • This function reduces move speed of the boom in this zone by reducing output pressure from the boom PPC valve to the boom operation valve (UP move) at the EPC valve. • This arrangement helps reducing undesirable impacts at the stroke end. ARM END CUSHIONING FUNCTION • In the arm retract move, this function reduces speed of the arm before it reaches the stroke to lighten resulting impacts and, thus, to prevent spillage of dirt or dust as well as lighten load to the machine body and cylinder. [Operation] • A cushioning zone is provided before the arm retract stroke end (approximately 40°). • This function reduces move speed of the arm in this zone by reducing output pressure from the arm PPC valve to the arm operation valve (RETRACT move) at the EPC valve. • This arrangement helps reduce undesirable impacts at the stroke end.

PC78US-6

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STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SELF-DIAGNOSTIC FUNCTION 1. Error code display and alarm function • The system of this function consists of the controller and the electronic components such as the potentiometers that output input signals and the solenoid valves and EPC valves that receive output signals. The controller is constantly checking that those electronic component and itself are functioning normally. • If a problem occurs in any of these components, the controller carries out troubleshooting and displays the result as a "user code" or "service code" on the display unit (1) of the monitor panel and turns on the alarm buzzer to warn the operator of the trouble. a For details of the display and action to take, see TESTING AND ADJUSTING.

10-250 (10)

ELECTRIC CONTROL SYSTEM

2. Error code memory function • If a problem occurs in the leading system, it is detected by the self-diagnostic function and its error code is stored in memory. a For details of the display and resetting method, see TESTING AND ADJUSTING.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

SYSTEM COMPONENTS Fuel control dial PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up

1. Fuel control dial 2. Fuel control motor

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PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

PC78US-6 Serial No.: 6501 and up

1. 2. 3. 4. 5. 6.

Knob Dial Spring Ball Potentiometer Connector

Function • The potentiometer (5) is installed under the knob (1) below the monitor panel. When the knob is turned, the shaft of the potentiometer (5) rotates. • When the shaft rotates, the resistance value of the variable resistor in the potentiometer (5) changes and any throttle signal is sent to the controller.

PC78US-6

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STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

Fuel control motor PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up

1. Motor assembly 2. Cable 3. Connector

Input and output signals SWP-6P [CN-K27] Pin No.

10-254 (10)

Signal name

1

Motor acceleration signal

2

Power source

3

One-touch deceleration signal

4

Motor deceleration signal

Input/Output signal Input — Output Input

5

Acceleration signal

Output

6

Deceleration signal

Output

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

PC78US-6 Serial No.: 6501 and up

1. 2. 3. 4. 5. 6.

Cable Connector Potentiometer Pulley Gear unit Motor

PC78US-6

Input and output signals DEUTSCH-6P [CN-M48] Pin No.

Signal name

Input/Output signal

1

Potentiometer input

Input

2

Potentiometer output

Output

3

Potentiometer GND

—

4

NC

5

Motor (+)

Input

—

6

Motor (Ð)

Input

10-255 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

Controller PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500

Model selection table CN-M96, 37P PC78US-6

Q

PC78UU-6

Q

CN-M96, 27P

CN-M96, 7P

CN-M96, 16P

Q

Attachment selection table CN-M95, 17P Standard arm

Q Q

Long arm with Xcounterweight Sliding arm

CN-M96, 17P

Q

Long arm Standard arm with X-counterweight

CN-M95, 11P

Q Q

Q

Q

Q

Multi-changer arm

Q : GND : OPEN

10-256 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

Input/output signals DEUTSCH-24P [CN-M95] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12

Signal name NC Boom cylinder bottom pressure sensor Boom angle GND (Signal) 2-stage travel speed selection switch Arm IN PPC oil pressure switch NC Slide capacity NC GND signal Attachment 2 Boom RAISE oil pressure switch

I/O signal — Input Input — Input Input — Input — — Input Input

Pin No. 13 14 15 16 17 18 19 20 21 22 23 24

Signal name NC Offset angle NC NC Attachment 1 Travel PPC oil pressure switch Boom cylinder head pressure sensor Arm angle GND (Analog) Sensor power source (+5 V) NC Swing PPC oil pressure switch

I/O signal — Input — — Input Input Input Input — Output — Input

DEUTSCH-40P (1) [CN-M96] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Signal name NC Set Mode select 2 232C_RXD NC NC UU/US selection signal Electrical system Date NC NC CAN shield Mode selection 1 232C_TXD Back-up light signal Main monitor selection signal Attachment 3 Strobe Clock Slide arm limit switch

I/O signal — Input Input Input — — Input Output Output — — — Input Output Input Input Input Output Output Input

Pin No. 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Signal name

I/O signal

S-NET CAN0-L CAN1-L Prevention signal for writing in flash memory NC Reset 2 Mode selection 2 — GND pulse NC GND (S-NET) CAN0-H CAN1-H GND (232C) Cancel signal for arm angle alam Reset 1 Model selection 1 Clear GND (Pulse) Engine speed sensor (+)

Input/Output Input/Output Input/Output Input — Input Input — — — — Input/Output Input/Output — Input Input Input Input — Input

Signal name

I/O signal

GND (Controller) Solenoid power source GND (Solenoid) Key signal Governor motor relay (For acceleration) Boom RAISE EPC valve 2-stage travel speed selector solenoid valve NC Deceleration signal Emergency work equipment operation switch GND controller GND controller GND controller NC Governor motor relay (For deceleration) NC — PPC lock solenoid valve Auto-deceleration signal NC

— Input — Input Output Output Output — Input Input — — — — Output — — Output Input —

DEUTSCH-40P (2) [CN-M97] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Signal name Controller power Solenoid power GND (Solenoid) NC Arm IN EPC valve NC Swing holding brake solenoid valve One-touch deceleration pilot lamp One-touch deceleration switch Air conditioner signal Controller power Solenoid power GND (Solenoid) Key signal Offset left stop EPC valve TVC-EPC vlave Swing and travel alarm Governor motor relay (For drive) Acceleration signal Alarm actuation switch

PC78US-6

I/O signal Input Input — — Output — Output Output Input Input Input Input — Input Output Output Output Output Input Input

Pin No. 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

10-257 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

PC78US-6 Serial No.: 5501 – 6500 PC78UU-6 Serial No.: 23501 and up

Model selection table CN-M96, 37P PC78US-6

Q

PC78UU-6

Q

CN-M96, 27P

CN-M96, 7P

CN-M96, 16P

Q

Attachment selection table CN-M95, 17P Standard arm

Q Q

Long arm with Xcounterweight Sliding arm

CN-M96, 17P

Q

Long arm Standard arm with X-counterweight

CN-M95, 11P

Q Q

Q

Q

Q

Multi-changer arm

Q : GND : OPEN

10-258 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

Input/output signals DEUTSCH-24P [CN-M95] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12

Signal name NC Boom cylinder bottom pressure sensor Boom angle GND (Signal) 2-stage travel speed selection switch Arm IN PPC oil pressure switch NC Slide capacity NC GND signal Attachment 2 Boom RAISE oil pressure switch

I/O signal — Input Input — Input Input — Input — — Input Input

Pin No. 13 14 15 16 17 18 19 20 21 22 23 24

Signal name NC Offset angle NC NC Attachment 1 Travel PPC oil pressure switch Boom cylinder head pressure sensor Arm angle GND (Analog) Sensor power source (+5 V) NC Swing PPC oil pressure switch

I/O signal — Input — — Input Input Input Input — Output — Input

DEUTSCH-40P (1) [CN-M96] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Signal name NC Set Mode select 2 232C_RXD NC NC UU/US selection signal Electrical system Date NC NC CAN shield Mode selection 1 232C_TXD Back-up light signal Main monitor selection signal Attachment 3 Strobe Clock Slide arm limit switch

I/O signal — Input Input Input — — Input Output Output — — — Input Output Input Input Input Output Output Input

Pin No. 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Signal name

I/O signal

S-NET CAN0-L CAN1-L Prevention signal for writing in flash memory Signal for selecting Tire 2 Reset 2 Mode selection 2 — GND pulse NC GND (S-NET) CAN0-H CAN1-H GND (232C) Cancel signal for arm angle alam Reset 1 Model selection 1 Clear GND (Pulse) Engine speed sensor (+)

Input/Output Input/Output Input/Output Input Input Input Input — — — — Input/Output Input/Output — Input Input Input Input — Input

Signal name

I/O signal

GND (Controller) Solenoid power source GND (Solenoid) Key signal Governor motor relay (For acceleration) Boom RAISE EPC valve 2-stage travel speed selector solenoid valve NC Deceleration signal Emergency work equipment operation switch GND controller GND controller GND controller NC Governor motor relay (For deceleration) NC — PPC lock solenoid valve Auto-deceleration signal NC

— Input — Input Output Output Output — Input Input — — — — Output — — Output Input —

DEUTSCH-40P (2) [CN-M97] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Signal name Controller power Solenoid power GND (Solenoid) NC Arm IN EPC valve NC Swing holding brake solenoid valve One-touch deceleration pilot lamp One-touch deceleration switch Air conditioner signal Controller power Solenoid power GND (Solenoid) Key signal Offset left stop EPC valve TVC-EPC vlave Swing and travel alarm NC Acceleration signal Alarm actuation switch

PC78US-6

I/O signal Input Input — — Output — Output Output Input Input Input Input — Input Output Output Output — Input Input

Pin No. 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

10-259 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

PC78US-6 Serial No.: 6501 and up

DEUTSCH-40P [CN-M95] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Signal name

I/O signal

Controller power supply Key signal NC Boom angle sensor Overload alarm ON switch Engine speed sensor (+) Governor motor drive relay (For acceleration) NC TVC-EPC valve 2nd travel speed selection solenoid valve Controller power supply Key signal Fuel control dial Arm angle sensor Travel PPC oil pressure switch (Right, left, forward, reverse) NC Governor motor drive relay (For deceleration) S-NET Swing holding brake solenoid valve Engine STOP solenoid seizure prevention relay

Input Input — Input Input Input Output — Output Output Input Input Input Input

10-260 (10)

Input — Output Input/Output Output Output

Pin No. 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40

Signal name GND (Controller) Potentiometer power supply (+5 V) Governor motor FB potentiometer Pump pressure sensor Swing PPC oil pressure switch (Right, left) Arm IN PPC oil pressure switch Travel/Swing alarm drive relay CANO-H Rotary lamp relay & bucket DUMP prohibition solenoid Solenoid power supply GND (Controller) GND (Analog) Boom bottom pressure sensor One-touch deceleration switch Boom RAISE PPC oil pressure switch NC Air conditioner compressor signal CANO-L CANO-SH GND (Common to solenoids)

I/O signal — Output Input Input Input Input Output Input/Output Output Input Input Input Input Input Input — Input Input/Output — —

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

Potentiometer PC78UU-6

1. Shaft 2. Housing 3. Bearing

4. Brush 5. Resistor 6. Connector

Functions • A potentiometer is installed on each of the boom feet, arm foot and second boom top to detect the angle of the boom, arm and offset work equipment. • Using the resistance value of the variable resistor, potentiometers send angle data to the controller by converting the supply voltage (5V) into signal voltage according to the angle of the work equipment.

PC78US-6

10-261 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

Register

1. Register 2. Connector Specifications Model

System

Resistance (z)

PC78US-6

For TVC-EPC valve of hydraulic pump

30

PC78UU-6

For boom raise stop EPC valve Arm IN stop EPC valve Left offset stop EPC valve

5

Function • When the emergency pump drive switch is turned ON, this resistor is used to supply a proper current to EPC valve according to the condition of the work equipment. a Current does not flow under the normal condition.

10-262 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

PPC oil pressure switch

1. Plug 2. Switch 3. Connector Specifications Contact composition: N.O. contact Operation (ON) pressure:490 ± 98.1 kPa {5.0 ± 1.0 kg/cm2} Reset (OFF) pressure: 294 ± 49.0 kPa {3.0 ± 0.5 kg/cm2} Function • The control valve has 5 PPC oil pressure switches, which sense the operating condition of each actuator from the PPC pressure and send it to the controller.

PC78US-6

10-263 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SYSTEM COMPONENTS

Pump pressure sensor PC78US-6 Serial No.: 6501 and up

1. Plug 2. Sensor 3. Connector Function • Mounted on the inlet circuit of control valve, this sensor changes discharging pressure of pump into voltage, and send it to automatic travel speed change controller.

Engine speed sensor a See SENSOR.

TVC-EPC valve aSee HYDRAULIC PUMP.

PPC lock solenoid valve 2-stage travel speed selector solenoid valve Swing holding brake solenoid valve Boom raise stop solenoid valve PC78UU-6 Arm IN stop EPC valve PC78UU-6 Left offset stop solenoid valve PC78UU-6 a See EPC SOLENOID VALVE.

Monitor panel a See MONITOR SYSTEM

10-264 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

MONITOR SYSTEM

MONITOR SYSTEM

1. 2. 3. 4. 5.

Monitor panel Battery Controller Sensors and switches Wiper motor, windshield washer motor

Outline • The monitor system monitors the machine condition by the sensors installed to various parts of the machine and processes and displays it on the panel immediately to notify the operator of the condition of the machine.

Input and output signals a. Power source b. Switch signal c. Caution signal d. Sensor, switch signal e. Sensor, switch signal f. Drive output

PC78US-6

10-265 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

MONITOR SYSTEM

MONITOR PANEL PC78US-6

Outline • The monitor panel has the monitor display function, gauge display function, service meter function, electric system display function, and alarm buzzer. • The monitor panel has a CPU (Center Processing Unit) in it to display and output information. • The monitor switch unit consists of 3 flat sheet switches. Each time those switches are pressed, the displayed machine condition changes. The currently displayed condition is indicated by the LED at the top of the switches. • If there is any trouble in the monitor panel, controller, or wiring between monitor panel and controller, the monitor does not display information correctly. Input and output signals AMP070-12P [CN-P01] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12

Signal name Starting switch (Battery) Starting switch (Battery) Windshield washer motor output Starting switch (Terminal C) Wiper W contact GND GND VB+ (24 V) Wiper motor (+) Wiper motor (–) Alarm buzzer ON signal Wiper P contact

10-266 (10)

AMP040-20P [CN-P02] Input/ Output signal Input Input Output Input Input — — Input Output Output Input Input

Pin No.

Signal name

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Engine coolant temperature Fuel level Radiator water level NC Air cleaner clogged NC Engine oil pressure Engine oil level S-NET signal S-NET signal Charge level NC GND (Analog signal) NC Pull-up window limit switch Alarm buzzer cancel Swing lock Preheating Lamp switch GND (S-NET)

Input/ Output signal Input Input Input Input Input Input Input Input Input/Output Input/Output Input — — — Input Input Input Input Input —

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

MONITOR SYSTEM

PC78UU-6

Outline • The monitor panel has the monitor display function, gauge display function, service meter function, electric system display function, and alarm buzzer. • The monitor panel has a CPU (Center Processing Unit) in it to display and output information. • The monitor switch unit consists of 3 flat sheet switches. Each time those switches are pressed, the displayed machine condition changes. The currently displayed condition is indicated by the LED at the top of the switches. • If there is any trouble in the monitor panel, controller, or wiring between monitor panel and controller, the monitor does not display information correctly. Input and output signals AMP070-12P [CN-P01] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12

Signal name Starting switch (Battery) Starting switch (Battery) Windshield washer motor output Starting switch (Terminal C) Wiper W contact GND GND VB+ (24 V) Wiper motor (+) Wiper motor (–) Alarm buzzer ON signal Wiper P contact

PC78US-6

AMP040-20P [CN-P02] Input/ Output signal Input Input Output Input Input — — Input Output Output Input Input

Pin No.

Signal name

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Engine coolant temperature Fuel level Radiator water level NC Air cleaner clogged NC Engine oil pressure Engine oil level S-NET signal S-NET signal Charge level NC GND (Analog signal) NC Pull-up window limit switch Alarm buzzer cancel Swing lock Preheating Lamp switch GND (S-NET)

Input/ Output signal Input Input Input Input Input Input Input Input Input/Output Input/Output Input — — — Input Input Input Input Input —

10-267 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

MONITOR SYSTEM

METER DISPLAY UNIT

No. Display type 1

Service meter

[*1] 2

3a

Display item

Display

Gauge

3b

Monitor

4a

Gauge

Coolant temperature

Fuel level 4b

Monitor

5

Display range

Display method

0-99999.9 h

Time is measured while engine is running (alternator is generating) (Lamp always lights up even if starting switch is at OFF position.)

3 alphanumerics [*2] 0 – 9.9 m

If electric control system has trouble, 3 alphanumerics (user code, service code) is displayed. In depth 0 set mode, depth from datum plane is displayed. [*2] 0 – 9.9 m • Depth of bucket from ground level is displayed. • If bucket is above ground level, "UP" is displayed. • In depth set 0 mode, depth from datum plane is displayed.

See above drawing. Above set temperature (99°C) See above drawing. Below set level (30 liters)

Preheating

During preheating

One-touch deceleration

When one-touch decelerator operates

Charge level

When charging is defective (charge voltage < battery voltate)

Pilot 6

7 Caution 8

Engine oil pressurre

Segment of corresponding level and all segments below it light up. [Monitor lamp blinks when 8th level lights up (above 99°C). Monitor lamp blinks and alarm buzzer sounds when 9th level lights up.] Segment of corresponding level and all segments below it light up. [Monitor lamp blinks when 1st level lights up (below 30 liters).] Lamp lights up for about 30 seconds when starting switch is turned to HEAT position, then blinks (for about 10 seconds) to show that preheating is finished and then goes off.

Display color Remarks

Blue

LCD

Red

LED

Blue

LCD

Red

LED

Green

Lamp lights up when one-touch decelerator operates.

Lamp lights up when starting switch is turned to ON position and goes off after engine starts. Lamp is turned off when normal and on when abnormal. Below set pressure (If trouble occurs while engine is running, (49 kPa {0.5 kg/cm2}) buzzer sounds.)

Lamp

Red

*1: For the display method of the marked items, see ELECTRIC CONTROL SYSTEM. *2: This function is installed to only PC78UU-6.

10-268 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

MONITOR SYSTEM

MONITOR SWITCH UNIT PC78US-6

No. 1

2

3

4

Name

Function

Operation

Travel speed selector switch

Switch used to select 1 of 2 travel speeds When Lo lamp is ON: Low travel speed When Hi lamp is ON: High travel speed

Working mode selector switch

Switch used to set movement and power of work equipment When E lamp is OFF: Active mode (For heavy load work) When E lamp is ON: E mode (For work in which fuel consumption is more important)

Active (OFF) io E (Lamp OFF)

Wiper switch

Switch used to operate front glass wiper When ON lamp is ON: Wiper operates continuously. When INT lamp is ON: Wiper operates intermittently. When all lamps are OFF: Wiper is stopped.

OFF (Lamp OFF) o INT (Intermittent) o ON (Continuous)

Switch used to spout washing liquid over front glass

[When wiper is stopped] ON: Washing liquid spouts and wiper operates continuously. OFF:After switch is released, wiper operates by 2 cycles continuously and then stops. [When wiper is operating intermittently] ON: Washing liquid spouts and wiper operates continuously. OFF:After switch is released, wiper operates for 2 cycles continuously and then starts intermittent operation again.

Windshield washer switch

Lo io Hi

a The boldfaced letters in the operation column denote the position to which each switch is reset when the starting switch is turned to the "ON" position.

PC78US-6

10-269 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

MONITOR SYSTEM

PC78UU-6

No.

Name

Function

Operation

1

Travel speed selector switch

Switch used to select 1 of 2 travel speeds When Lo lamp is ON: Low travel speed When Hi lamp is ON: High travel speed

2

Working mode selector switch

Switch used to set movement and power of work equipment When E lamp is OFF: Active mode (For heavy load work) When E lamp is ON: E mode (For work in which fuel consumption is more important)

Wiper switch

Switch used to operate front glass wiper When ON lamp is ON: Wiper operates continuously. When INT lamp is ON: Wiper operates intermittently. When all lamps are OFF: Wiper is stopped.

OFF (Lamp OFF) o INT (Intermittent) o ON (Continuous)

Windshield washer switch

Switch used to spout washing liquid over front glass

[When wiper is stopped] ON: Washing liquid spouts and wiper operates continuously. OFF:After switch is released, wiper operates by 2 cycles continuously and then stops. [When wiper is operating intermittently] ON: Washing liquid spouts and wiper operates continuously. OFF:After switch is released, wiper operates for 2 cycles continuously and then starts intermittent operation again.

Mode selector switch

Depth set 0 mode and height mode are set/cleared with selector switch and set/clear switch.

3

4

5

Lo io Hi

Active (OFF) io E (Lamp OFF)

5a. Selector switch

Switch used to select depth set 0 mode or height mode

OFF (Lamp OFF) o Depth set 0 o Height

5b. Set/Clear switch

Switch used to set and clear mode

• Mode of flashing indicator is set. • Mode of lighting indicator is cleared.

a The boldfaced letters in the operation column denote the position to which each switch is reset when the starting switch is turned to the "ON" position.

10-270 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SENSORS

SENSORS • • •

The signals from the sensors are input directly to the panel or controller. The sensors are classified into 3 of contact type, resistance type, and electromagnetic type. Either of each sensor of contact type must be connected to the chassis ground. Type of display

Type of sensor

Sensing method

When normal

When abnormal

Caution

Engine oil pressure

Contact

OFF (Open)

ON (Closed)

Coolant temperature

Resistance

—

—

Fuel level

Resistance

—

—

Engine speed

Electromagnetic

—

—

Gauge –

ENGINE OIL PRESSURE SENSOR

1. Plug 2. Contact ring

3. Contact 4. Diaphragm

5. Spring 6. Terminal

Function • This sensor is installed to the engine cylinder block to sense oil pressure with diaphragm (4). If the oil pressure lowers below the set level, the switch is turned on and the signal is sent to the monitor panel.

COOLANT TEMPERATURE SENSOR

1. Connector

2. Plug

3. Thermistor

Function • This sensor is installed to the engine cylinder block. It senses changes of temperature by changes of the resistance of thermistor (3) and sends the change signals to the monitor panel.

PC78US-6

10-271 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SENSORS

FUEL LEVEL SENSOR PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up

1. Float 2. Arm

3. Connector 4. Variable resistor

Function • This sensor is installed to the fuel tank and its float (1) moves up and down according to the fuel level. Float (1) operates variable resistor (4) through arm (2) and sends the signals to the monitor panel.

10-272 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SENSORS

PC78US-6 Serial No.: 6501 and up

1. Float 2. Arm

3. Variable resistor 4. Connector

FUNCTION • The fuel level sensor is installed to the side of the fuel tank and its float moves up and down according to the fuel level in the tank. The movement of the float operates the variable resistor through the arm, and then signals are generated according to the change of the resistance.

PC78US-6

10-273 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SENSORS

ENGINE SPEED SENSOR

1. Wire 2. Magnet 3. Terminal

4. Housing 5. Connector

Function • This sensor is installed to the engine flywheel cover. It counts the number of teeth which pass in front of it and sends the signals to the controller. Reference: Number of teeth of ring gear: 110

10-274 (10)

PC78US-6

20 TESTING AND ADJUSTING STANDARD VALUE TABLE ..................................... 20- 2 Standard value table for engine ............................. 20- 2 Standard value table for chassis ............................. 20- 3 Standard value table for electrical parts ................. 20-12 TESTING AND ADJUSTING.................................. 20-101 TROUBLESHOOTING ........................................... 20-201

Note the following when making judgements using the standard value tables for testing, adjusting, or troubleshooting. 1. The standard value for a new machine given in the table is the value used when shipping the machine from the factory and is given for reference. It is used as a guideline for judging the progress of wear after the machine has been operated, and as a reference value when carrying out repairs. 2. The service limit value given in the tables is the estimated value for the shipped machine based on the results of various tests. It is used for reference together with the state of repair and the history of operation to judge if there is a failure. 3. These standard values are not the standards used in dealing with claims. WARNING! When carrying out testing, adjusting, or troubleshooting, park the machine on level ground, insert the safety pins, and use blocks to prevent the machine from moving. WARNING! When carrying out work together with other workers, always use signals and do not let unauthorized people near the machine. WARNING! When checking the water level, always wait for the water to cool down. If the radiator cap is removed when the water is still hot, the water will spurt out and cause burns. WARNING! Be carught in the fan, fan belt or other rotating parts.

PC78US-6

20-1 (1)

STANDARD VALUE TABLE FOR ENGINE

TESTING AND ADJUSTING

STANDARD VALUE TABLE FOR ENGINE PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500 PC78US-6: 4001 – 5500 PC78UU-6: 22832 – 23500

Machine Model Engine Item

4D95LE-2

Measurement Conditions

Standard Value for New Machine

Service Limit Value

2,020 ± 50

—

1,130 +50

—

1,850

—

Bosch Index

Max. 4.0 Max 1.0

6.0 2.0

mm

0.35 0.50

— —

Unit

High idling (When mounted on machine) Revolving speed

Low idling (When mounted on machine)

rpm

Rated revolving speed

0

Exhaust gas color

At sudden acceleration At high idling

Valve clearance (At normal temperature)

Air intake valve Exhaust valve

Compression pressure (SAE15W-40 oil)

Oil temperature: 40 – 60 °C (Engine speed)

MPa {kg/cm2} (rpm)

Min. 2.94 {Min. 30} 320 – 360

2.06 {21} —

Blow-by pressure (SAE30 oil)

(Water temperature operating range) At rated output

Pa {mmH2O}

Max. 490 {50} reference value

980 {100} reference value

0.34 – 0.54 {3.5 – 5.5}

0.25 {2.5}

0.29 – 0.49 {3.0 – 5.0}

0.21 {2.1}

(SAE30)

Min. 0.18 {Min. 1.8}

0.15 {1.5}

(SAE10W)

Min. 0.15 {Min. 1.5}

0.13 {1.3}

°C

90 – 110

120

° (Deg.)

10 ± 0.75

10 ± 0.75

6 – 10

6 – 10

6 – 10

6 – 10

(Water temperature operating range) (SAE30) At high idling (SAE10W)

Oil pressure

MPa {kg/cm2}

At low idling

Oil temperature

All revolution range (In oil pan)

Fuel injection timing

Before compression top dead center

Tension of fan belt

Deflection under finger pressure of approx. 58.8 N {6 kg}

mm

Tension of air compressor belt

20-2 (7)

Deflection under finger pressure of approx. 58.8 N {6 kg}

PC78US-6

STANDARD VALUE TABLE FOR ENGINE

TESTING AND ADJUSTING

PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up PC78US-6: 5501 and up PC78UU-6: 23501 and up

Machine Model Engine Item

S4D95LE-3

Measurement Conditions

Standard Value for New Machine

Service Limit Value

2,020 ± 50

—

1,130 +50

—

1,850

—

Bosch Index

Max. 3.5 Max. 1.0

6.0 2.0

mm

0.35 0.50

— —

Unit

High idling (When mounted on machine) Revolving speed

Low idling (When mounted on machine)

rpm

Rated revolving speed

0

Exhaust gas color

At sudden acceleration At high idling

Valve clearance (At normal temperature)

Air intake valve Exhaust valve

Compression pressure (SAE15W-40 oil)

Oil temperature: 40 – 60 °C (Engine speed)

MPa {kg/cm2} (rpm)

Min. 2.94 {Min. 30} 320 – 360

2.06 {21} —

Blow-by pressure (SAE30 oil)

(Water temperature operating range) At rated output

Pa {mmH2O}

Max. 490 {50} reference value

980 {100} reference value

0.34 – 0.54 {3.5 – 5.5}

0.25 {2.5}

0.29 – 0.49 {3.0 – 5.0}

0.21 {2.1}

(SAE30)

Min. 0.18 {Min. 1.8}

0.15 {1.5}

(SAE10W)

Min. 0.15 {Min. 1.5}

0.13 {1.3}

°C

90 – 110

120

° (Deg.)

5 ± 0.75

5 ± 0.75

6 – 10

6 – 10

6 – 10

6 – 10

(Water temperature operating range) (SAE30) At high idling (SAE10W)

Oil pressure

MPa {kg/cm2}

At low idling

Oil temperature

All revolution range (In oil pan)

Fuel injection timing

Before compression top dead center

Tension of fan belt

Deflection under finger pressure of approx. 58.8 N {6 kg}

mm

Tension of air compressor belt

PC78US-6

Deflection under finger pressure of approx. 58.8 N {6 kg}

20-2-1 (7)

TESTING AND ADJUSTING

STANDARD VALUE TABLE FOR CHASSIS

STANDARD VALUE TABLE FOR CHASSIS PC78US-6 PC78UU-6

Machine Model

Stroke of control lever

Engine speed

Category

Item

At relief of 1 pump

• • •

Hydraulic oil temperature: 45 ~ 55 °C Engine water temperature: Within operating range Relief of 1 pump....Arm DUMP relief

Unit

Standard Value for New Machine

Service Limit Value

rpm

Min. 1,800

Min. 1,800

Boom control lever

N → RAISE, LOWER

85 ± 10

Max. 95 Min. 75

Arm control lever

N → IN, OUT

85 ± 10

Max. 95 Min. 75

N → CURL, DUMP

85 ± 10

Max. 95 Min. 75

N → LEFT, RIGHT

85 ± 10

Max. 95 Min. 75

N → LEFT, RIGHT

21 ± 2

Max. 23 Min. 19

Blade control lever

N → RAISE, LOWER

53 ± 6

Max. 59 Min. 47

Travel control lever

N → FORWARD, REVERSE

115 ± 12

Max. 127 Min. 103

Play of control lever

Max. 10

Max. 15

Boom control lever

15.7 ± 3.9 {1.6 ± 0.4}

Max. 24.5 {Max. 2.5}

15.7 ± 3.9 {1.6 ± 0.4}

Max. 24.5 {Max. 2.5}

12.7 ± 2.9 {1.3 ± 0.3}

Max. 21.6 {Max. 2.2}

12.7 ± 2.9 {1.3 ± 0.3}

Max. 21.6 {Max. 2.2}

78.4 ± 19.6 {8.0 ± 2}

Max. 117.7 {Max. 12}

25.5 ± 6.9 {2.6 ± 0.7}

Max. 39.2 {Max. 4.0}

Lever

24.5 ± 5.9 {2.5 ± 0.6}

Max. 39.2 {Max. 4.0}

Pedal

74.5 ± 18.6 {7.6 ± 1.9}

Max. 107.6 {Max. 11}

Bucket control lever

•

Swing control lever

• •

Offset control pedal •

Arm control lever Operating effort of control lever

Measurement Conditions

•

Bucket control lever • Swing control lever Offset control pedal

• •

Center of lever grip End of pedal Read Max. value through stroke end Stop engine

mm

Measure operating effort of each control lever by installing push-pull scale to center of its grip. Measure operating effort of each control pedal by installing push-pull scale to its end. Read Max. value through stroke end. Stop engine.

Blade control lever

N {kg}

Travel control lever

PC78US-6

20-3 ➄

STANDARD VALUE TABLE FOR CHASSIS

TESTING AND ADJUSTING

PC78US-6 PC78UU-6

Machine Model

Standard Value for New Machine

Service Limit Value

Boom

26.5 ± 0.98 {270 ± 10}

26.5 ± 1.47 {270 ± 15}

Arm

26.5 ± 0.98 {270 ± 10}

26.5 ± 1.47 {270 ± 15}

Bucket

26.5 ± 0.98 {270 ± 10}

26.5 ± 1.47 {270 ± 15}

Offset

26.5 ± 0.98 {270 ± 10}

26.5 ± 1.47 {270 ± 15}

With blade

20.5 ± 0.98 {210 ± 10}

20.5 ± 1.47 {210 ± 15}

Without blade

23 ± 0.98 {235 ± 10}

23 ± 1.47 {235 ± 15}

12.74 + 01.96 {130 ± 10}

12.74 ± 1.47 {130 ± 15}

21.08 ± 0.98 {215 ± 10}

21.08 ± 1.47 {215 ± 15}

26.5 ± 0.98 {270 ± 10}

26.5 ± 1.47 {270 ± 15}

3.14 + 0.2 0

3.14 + 0.3 0

{32 + 02 }

{32 + 03 }

Max. 20

Max. 20

deg (mm)

40 ± 10 {297 ± 74}

Max. 60 {Max. 446}

sec

2.2 ± 0.3 {2.6 ± 0.3}

Max. 2.8 {Max. 3.2}

3.7 ± 0.3 {4.1 ± 0.3}

Max. 4.3 {Max. 4.7}

Category

Item

Oil pressure

Swing

Measurement Conditions

• •

Hydraulic oil temperature: 45 – 55 °C Relief pressure with engine at full throttle (Relieve only circuit to be measured)

Unit

MPa {kg/cm2} RAISE

Blade LOWER Travel

Control

Lowering of oil pressure

• •

Hydraulic oil temperature: 45 – 55 °C Difference between relief pressure at Max. engine speed and relief pressure at 1/2 of rated engine speed (Pressure at relief of 1 pump)

Position of work equipmentMax. Reach

Overrun of swing • • • Swing

•

Run engine a full throttle Hydraulic oil temperature: 45 – 55 °C Deviation of swing circle made when it stops after swinging 1 turn Value in { } is deviation of periphery of swing circle

90°

Time required to start swinging • • • •

20-4 (12)

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Time required to swing 90° and 180° from starting point Value in { } is measured under rated bucket load

180°

PC78US-6

TESTING AND ADJUSTING

STANDARD VALUE TABLE FOR CHASSIS

PC78US-6 PC78UU-6

Machine Model

Category

Item

Unit

Standard Value for New Machine

Service Limit Value

sec

30 ± 2

Max. 35

mm (deg)

0 (0)

0 (0)

Max. 3.5

Max. 7.0

Low speed

34 ± 3

41

High speed

25 ± 3 {23 ± 2}

30 {28}

Low speed

24 ± 2 {23 ± 2}

28 {20}

High speed

16 ± 2 {14.5 ± 2}

28 {18.5}

Measurement Conditions

Position of work equipment

Max. Reach

Time required to finish swinging • • •

Run engine at full throttle Hydraulic oil temperature: 45 ~ 55 °C Time required to swing 5 turns after swinging 1 turn

Swing

Position of work equipment: Extend to Max. reach with bucket under rated load or filled with dirt and sand (Rated load: 450 kg)

Hydraulic drift of swing

Leakage from swing motor

• • • • •

Run engine at full throttle Hydraulic oil temperature: 45 ~ 55 °C Swing upper structure to 45° on slope of 15° Make match marks on swing circle outer race and track frame Measure deviation of marks made in 15 minutes

• • •

Run engine at full throttle Hydraulic oil temperature: 45 ~ 55 °C Relieve swing circle

/min.

Position of work equipment

Travel speed (1) • • •

Travel

•

Run engine at full throttle Hydraulic oil temperature: 45 ~ 55 °C Raise either track and measure time required to move 5 turns after finishing 1 turn. { }: Rubber shoe specification

sec

Position of work equipment

Travel speed (2)

• • • •

PC78US-6

Run engine at full throttle Hydraulic oil temperature: 45 ~ 55 °C Measure time required to travel 20 m after runup of at least 10 m on flat surface { }: Rubber shoe specification

20-5 ➄

TESTING AND ADJUSTING

STANDARD VALUE TABLE FOR CHASSIS

PC78US-6 PC78UU-6

Machine Model

Category

Item

Measurement Conditions

Unit

Standard Value for New Machine

Service Limit Value

mm

Max. 300

330

cc/min.

Max. 10

Max. 50

mm

0

0

Max. 4.5

Max. 7.0

Position for measurement

Travel

Travel deviation

Leakage from swivel joint (Each port)

• • • •

Run engine at full throttle Hydraulic oil temperature: 45 ~ 55 °C Measure deviation made during travel of 20 m after runup of at least 10 m on flat surface Measure on firm and level place

★

Measure distance x

• •

Hydraulic oil temperature: 45 ~ 55 °C Apply relief pressure to port to be measured

Position for measurement

Hydraulic drift of travel

Leakage from travel motor

20-6 ➄

• • • •

Stop engine Hydraulic oil temperature: 45 ~ 55 °C Stop machine on slope of 30° with sprocket up Measure hydraulic drift of travel made in 5 minutes

• • •

Run engine at full throttle Hydraulic oil temperature: 45 ~ 55 °C Lock shoes and relieve travel circuit

/min.

PC78US-6

STANDARD VALUE TABLE FOR CHASSIS

TESTING AND ADJUSTING

PC78US-6 PC78UU-6

Machine Model

Category

Item

Whole work equipment (Hydraulic drift of bucket tooth tip)

Measurement Conditions

Unit

Hydraulic drift Work equipment

•

Measure extension and retraction of each cylinder and hydraulic drift of bucket tooth tip from above position Measure on level and flat surface Bucket: Apply rated load of 4,413 N {450 kg} Set lever in neutral Stop engine Hydraulic oil temperature: 45 – 55 °C Start measurement just after setting Measure hydraulic drift every 5 minutes and judge after 15 minutes

Bucket cylinder (Retraction of cylinder)

• • • • • • •

Blade (Hydraulic drift of blade tip

• • •

Stop engine Hydraulic oil temperature: 45 – 55 °C Measure hydraulic drift of blade tip from Max. height in 15 minutes

Leakage from cylinder (Each cylinder)

• •

Hydraulic oil temperature: 45 – 55 °C Apply relief pressure to cylinder to be measured

mm

cc/min.

Position for measurement Boom Bucket tooth on ground

Work equipment speed

Max. extension of cylinder

Max. 350

Max. 600

Max. 8

Max. 12

Max. 41

Max. 62

Max. 25

Max. 38

Max. 20

Max. 30

Max. 1.5

Max. 7.5

RAISE

US: 3.2 ± 0.3 UU: 3.5 ± 0.4

Max. 4 Max. 4.3

(To just before (To just before cushion) cushion)

LOWER • •

3.3 ± 0.3

Max. 3.9

3.2 ± 0.3

Max. 4.0

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C

Position for measurement sec Arm Max. retraction of cylinder

Max. extension of cylinder

PC78US-6

Service Limit Value

Position for measurement

Boom cylinder (Retraction of cylinder)

Arm cylinder (Extension of cylinder)

Standard Value for New Machine

• • •

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Offset to right so that clearance between right end of operator's cab and bucket will be 200 mm or wider (Only PC78UU-6).

IN

(To just before (To just before cushion) cushion)

OUT

(To just before (To just before cushion) cushion)

2.7 ± 0.3

Max. 3.3

20-7 (12)

STANDARD VALUE TABLE FOR CHASSIS

TESTING AND ADJUSTING

PC78US-6 PC78UU-6

Machine Model

Category

Item

Standard Value for New Machine

Service Limit Value

CURL

3.1 ± 0.4

Max. 3.9

DUMP

2.1 ± 0.3

Max. 2.9

Offset (L.H.)

4.3 ± 0.4

Max. 5.2

Offset (R.H.)

4.5 ± 0.4

Max. 5.3

1.3 ± 0.3

Max. 2.1

1.3 ± 0.3

Max. 2.1

Max. 2

Max. 3.9

Measurement Conditions

Unit

Position for measurement Bucket Max. retraction of cylinder

Max. extension of cylinder

• •

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C

Work equipment

Work equipment speed

Position for measurement Offset Max. retraction of cylinder

Max. extension of cylinder • •

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C

Position for measurement Blade Blade on ground

RAISE

Max. height of blade

LOWER • •

sec

Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C

Time lag

Position for measurement

Boom

• • •

20-8 (12)

Run engine at slow Hydraulic oil temperature: 45 – 55 °C Retract arm and bucket cylinder fully and lower boom from Max. height. Measure time from when bucket touches ground until when machine body rises.

PC78US-6

STANDARD VALUE TABLE FOR CHASSIS

TESTING AND ADJUSTING

PC78US-6 PC78UU-6

Machine Model Category

Item

Measurement Conditions

Unit

Standard Value for New Machine

Service Limit Value

0

Max. 1.0

0

Max. 1.0

Max. 1.0

Max. 2.0

See following pages

See following pages

Position for measurement

Arm

• • •

Run engine at slow Hydraulic oil temperature: 45 – 55 °C Set upside of boom level and retract bucket cylinder fully. Extend bucket cylinder and measure time from when arm stops on lower side until when arm starts moving again.

sec

Bucket

Work equipment

Time lag

Position for measurement

• • •

Run engine at slow Hydraulic oil temperature: 45 – 55 °C Set upside of boom level and retract bucket cylinder fully. Extend bucket cylinder and measure time from when arm stops on lower side until when arm starts moving again.

Position for measurement

Blade

Discharge of hydraulic pump

• • •

PC78US-6

Piston pump

Run engine at slow Hydraulic oil temperature: 45 – 55 °C Lower blade from Max. height and measure time from when blade touches ground until when machine body rises.

See following pages

/min.

20-9 (12)

STANDARD VALUE TABLE FOR CHASSIS

TESTING AND ADJUSTING

PC78US-6 (Without blade) PC78UU-6 Main pump discharge

Performance of hydraulic pump

Category

• •

Rated pump speed: 1,850 rpm Output current of TVC and EPC valves: 200 mA (With boom raised and arm in, in travel mode) Checkpoint

Discharge pressure of test pump (MPa {kg/cm2})

Average pressure (MPa {kg/cm2})

Standard discharge ( /min.)

Lower limit of criterion ( /min.)

Any

P1 (P)

P1 (P2)

See graph

See graph

a Avoid measuring near a bend of the graph since the error is large there. a When measuring without removing the pump from the machine, if the engine speed cannot be set to the specified level with the fuel control dial, calculate the pump discharge pressure at the specified speed from the actual engine speed and measured pump discharge.

20-10 (5)

PC78US-6

STANDARD VALUE TABLE FOR CHASSIS

TESTING AND ADJUSTING

PC78US-6 (With blade) PC78UU-6 Main pump discharge

Performance of hydraulic pump

Category

•

Rated pump speed: 1,850 rpm Checkpoint

Discharge pressure of test pump (MPa {kg/cm2})

Average pressure (MPa {kg/cm2})

Standard discharge ( /min.)

Lower limit of criterion ( /min.)

Any

P1 (P2)

P1 (P2)

See graph

See graph

Avoid measuring near a bend of the graph since the error is large there. When measuring without removing the pump from the machine, if the engine speed cannot be set to the specified level with the fuel control dial, calculate the pump discharge pressure at the specified speed from the actual engine speed and measured pump discharge.

PC78US-6

20-11 (7)

STANDARD VALUE TABLE FOR ELECTRIC PARTS

TESTING AND ADJUSTING

STANDARD VALUE TABLE FOR ELECTRIC PARTS PC78UU-6 Serial No.: 22832 and up PC78US-6 Serial No.: 4001 – 6500 Component Name

Sys tem

Connector No.

Inspection Method

Measurement Conditions

Criteria

Source voltage

M97

Measurement voltage

If the condition is within the range shown in the table below, it is normal. Between (1), (11) – chassis ground (*1) *1. Since power is constantly supplied, voltage is detected even if starting switch is turned OFF.

M97 M13

Measurement voltage

Between (2), (12) , (22) – chassis ground

PPC main pressure lock solenoid

20 – 30 V

20 – 30 V

If the condition is within the range shown in the table below, it is normal. Between M97 (38) – (13)

1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON.

20 – 28 V

1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON.

Offset left stop solenoid

Potentio powersource

M97

M95

Measurement of current

M97

Measurement of current

Arm IN EPC solenoid

M97

Measurement of voltage

Controller

Boom RAISE EPC solenoid

Measurement of current

If the condition is within the range shown in the table below, it is normal. Between (26) – (23) When safety lock lever is at FREE When safety lock lever is at LOCK

940 ± 50 mA

20 – 30 V M13 Between (1) – (2) Max. 0 V

If the condition is within the range shown in the table below, it is normal. Between (5) – (23)

940 ± 50 mA

1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON. 4) Exclude part near arm IN stroke end.

940 ± 50 mA

1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON. 4) Exclude part near offset stroke end.

If the condition is within the range shown in the table below, it is normal. Between (15) – (23)

If the condition is within the range shown in the table below, it is normal. Between (22) – (21)

1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON. 4) Exclude part near boom RAISE stroke end.

5 ± 0.5 V

1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON.

Model selection

20-12 (12)

M95 M96

Measurement of voltage

If the condition is within the range shown in the table below, it is normal. Model

PC78US-6

PC78UU-6

Between M96 (37) – M95 (10)

Max. 1 V

Max. 1 V

Between M96 (27) – M95 (10)

Min. 7 V

Min. 7 V

Between M96 (7) – M95 (10)

Max. 1 V

Min. 7 V

Between M96 (16) – M95 (10)

—

Max. 1 V

1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON.

PC78US-6

STANDARD VALUE TABLE FOR ELECTRIC PARTS

TESTING AND ADJUSTING

System

Component Name

Connector No.

Inspection Method

Measurement Conditions

Criteria

Attachment selection

M95 M96

Measurement of voltage

If the condition is within the range shown in the table below, it is normal Attachment

Standard arm

Long arm

Between M95 (37) – (10)

Max. 1 V

Min. 7 V

Between M95 (11) – (10)

Min. 7 V

Max. 1 V

Between M96 (17) – (10)

Min. 7 V

Min. 7 V

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON.

System clear signal

M97

Measurement of voltage

If the condition is within the range shown in the table below, it is normal When normal When cleared (Whenelectric system clear switch is ON)

Between – (30) – (31), (32), (33)

Max. 1V 20 – 30 V

Boom RAISE pressure switch

M95

Measurement of voltage

If the condition is within the range shown in the table below, it is normal Between M95 (12) – chassis ground

When boom is raised When in neutral

Max. 1V 5 ± 0.5 V

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON.

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON.

Swing, arm IN, travel pressure switch

M95

Measurement of voltage

Controller

If the condition is within the range shown in the table below, it is normal When machine swings When arm is moved IN When machine travels

When in neutral

Between (24) – chassis ground Between (6) – chassis ground Between (18) – chassis ground

Max. 1 V

5 ± 0.5 V

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON.

Boom angle potentiometer signal

M95

Measurement of voltage

If the condition is within the range shown in the table below, it is normal

Between (3) – (21)

PC78US-6

PC78UU-6

0.30 – 1.25V

0.30 – 1.13V

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON. 4) Raise boom to stroke end.

Arm angle potentiometer signal

PC78US-6

M95

Measurement of voltage

If the condition is within the range shown in the table below, it is normal

Between (20) – (21)

PC78US-6

PC78UU-6

STD

0.38 – 1.38V

0.30 – 1.22V

Long

0.48 – 1.48V

0.30 – 1.23V

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON. 4) Move arm in to stroke end.

20-13 (7)

STANDARD VALUE TABLE FOR ELECTRIC PARTS

TESTING AND ADJUSTING

System

Component Name

Connector No.

Inspection Method

Measurement Conditions

Criteria

M95

Controller

Offset angle potentiometer signal

Measurement of voltage

If the condition is within the range shown in the table below, it is normal Between (14) – (21)

3.20 – 4.20 V

Swing holding brake clear solenoid

M97

Measurement of resistance

If the condition is within the range shown in the table below, it is normal When swing holding brake clear switch is OFF (When normal) When swing holding brake clear switch is ON (When cleared)

20 – 30 V Between (7) ~ (13) Max. 1 V

Boom angle potentiometer

M29 (Male)

Measurement of resistance

If the condition is within the range shown in the table below, it is normal Between (C) – (B)

0.2 – 7 kz

Between (B) – (A)

0.2 – 7 kz

Between (C) – (A)

4 – 6 kz

Arm IN stop EPC solenoid

Left offset stop EPC solenoid

20-14 (7)

M11 (Male)

M12 (Male)

M10 (Male)

Measurement of resistance Measurement of resistance

Boom RAISE stop EPC valve

M71 (Male)

Measurement of resistance

Offset angle potentiometer

M72 (Male)

Measurement of resistance

Four systems

Arm angle potentiometer

Measurement of resistance

If the condition is within the range shown in the table below, it is normal Between (A) – (B)

0.2 – 7 kz

Between (B) – (C)

0.2 – 7 kz

Between (A) – (C)

4 – 6 kz

If the condition is within the range shown in the table below, it is normal Between (C) – (B)

0.2 – 7 kz

Between (B) – (A)

0.2 – 7 kz

Between (C) – (A)

4 – 6 kz

If the condition is within the range shown in the table below, it is normal Between M11 (male) (1) – (2) Between M11 (male) (1), (2) – chassis ground

5 – 25 z Min. 1 Mz

If the condition is within the range shown in the table below, it is normal Between M12 (male) (1) – (2) Between M12 (male) (1), (2) – chassis ground

5 – 25 z Min. 1 Mz

If the condition is within the range shown in the table below, it is normal Between M10 (male) (1) – (2) Between M10 (male) (1), (2) – chassis ground

5 – 25 z Min. 1 Mz

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON. 4) Move right offset to stroke end. 1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter. 4) Turn starting switch ON. 5) Swing or move arm in.

1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter.

1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter.

1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter.

1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter.

1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter.

1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter.

PC78US-6

STANDARD VALUE TABLE FOR ELECTRIC PARTS

TESTING AND ADJUSTING

Machine control

Swing holding brake reset solenoid

2nd travel speed selection solenoid

Inspection Method

M13 (Male)

M14 (Male)

M15 (Male)

Measurement of resistance

PPC main pressure lock solenoid

Connector No.

Measurement of resistance

Component Name

Measurement of resistance

System

Measurement Conditions

Criteria If the condition is within the range shown in the table below, it is normal. Between M13 (Male) (1) – (2)

35 – 80 z

Between M13 (Male) (1), (2) – chassis ground

Min. 1 Mz

If the condition is within the range shown in the table below, it is normal. Between M14 (Male) (1) – (2)

35 – 80 z

Between M14 (Male) (1), (2) – chassis ground

Min. 1 Mz

If the condition is within the range shown in the table below, it is normal. Between M15 (Male) (1) – (2)

35 – 80 z

Between M15 (Male) (1), (2) – chassis ground

Min. 1 Mz

1) Turn starting switch OFF. 2) Disconnect adapter. 3) Connect Tadapter.

1) Turn starting switch OFF. 2) Disconnect adapter. 3) Connect Tadapter.

1) Turn starting switch OFF. 2) Disconnect adapter. 3) Connect Tadapter.

If the monitor panel displays as shown in Tables 1 and 2, it is normal. Table 1 (Check and caution section).

Machine monitor system

Monitored Item (Input connector)

Engine oil pressure P02 (7)

Measurement Conditions

Preheater P02 (18)

PC78US-6

Sensor Input Signal

Light is ON.

Max. 1 V

Light is OFF.

20 – 30 V

Light is ON.

Max. 5 V

Light is OFF.

20 – 30 V

Light is ON.

20 – 30 V

Light is OFF.

Max. 1 V

Start engine.

Check and caution section Charge level P02 (11)

Display

1) Connect Tadapter

Start engine.

Stop Engine.

20-15 (7)

STANDARD VALUE TABLE FOR ELECTRIC PARTS

TESTING AND ADJUSTING

Component Name

System

Connector No.

Inspection Method

Criteria

Measurement Conditions

Table 2 (Gauge)

Item indicated by gauge

Display level resistance (kz) (Monitor panel input resistance)

Turn starting switch ON

Turn starting switch OFF

1) Turn starting switch OFF and insert dummy resistor or measure resistance of sensor. 2) Turn starting switch ON and check indication.

Min. – Max. Upper side

I Measurement of resistance of coolant temperature gauge P02 (1) – (13)

Position of indication

Machine monitor system

O

Lower side Gauge section

9

4.00 – 3.45

8

3.13 – 3.75

7

3.39 – 3.94

6

3.56 – 4.39

5

3.97 – 5.18

4

4.68 – 6.89

3

6.23 – 10.88

2

10.34 – 36.86

1

33.35 – 37.83

Blink at levels 8 and 9.

Item indicated by gauge

Display level resistance (z) (Monitor panel input resistance)

Turn starting switch ON

Turn starting switch OFF

1) Turn starting switch OFF and insert dummy resistor or measure resistance of sensor. 2) Turn starting switch ON and check indication.

Min. – Max. Upper side

I Measurement of resistance of fuel level gauge P02 (2) – (13)

Position of indication

O

Lower side

9

10 – 6.8

8

6.2 – 13.7

7

12.4 – 22.1

6

20.0 – 30.5

5

27.6 – 41.0

4

37.1 – 54.6

3

49.4 – 77.7

2

70.3 – 101.9

1

92.2 – 10

Level 1 blinks.

20-16 (7)

PC78US-6

TESTING AND ADJUSTING

Fuel level sensor

Alternator

PC78US-6

Check of continuity

Measurement Conditions

Criteria If the condition is within the range shown in the table below, it is normal.

Between terminal ~ chassis ground

Normal engine oil pressure

No continuity

Low engine oil pressure

Normal continuity

If the condition is within the range shown in the table below, it is normal.

If the condition is within the range shown in the table below, it is normal.

M9 (Male)

Between T4 (Terminal R) ~ chassis ground

M18 (Male)

Machine monitor system

Coolant temperature sensor

T6

Inspection Method

Measurement of resistance

Engine oil pressure sensor

Connector No.

Measurement of resistance

Component Name

Measurement of voltage

System

STANDARD VALUE TABLE FOR ELECTRIC PARTS

Between (1) ~ (2)

Between (1) ~ (2)

Normal temperature (25 °C)

Approx. 40 kΩ

105 °C

Approx. 3.3 kΩ

Full

2~5Ω

Empty

105 ~ 110 Ω

While engine is running (at 1/2 or more of full throttle) → 27.5 ~ 29.5 V If battery is deteriorated or temperature is low, voltage may not rise for a while after engine is started.

1) Start engine 2) Disconnect terminal

1) Turn starting switch OFF 2) Disconnect connector

1) Turn starting switch OFF 2) Disconnect connector

1) Start engine

20-17 ➄

STANDARD VALUE TABLE FOR ELECTRIC PARTS

TESTING AND ADJUSTING

PC78US-6 Serial No.: 6501 and up System

Component Name

Connector No.

Inspection Method

Measurement Conditions

Criteria

Boom RAISE pressure switch

M95

M95

Measurement of voltage

Potentio powersource

M95

Measurement of voltage

Source voltage

Measurement voltage

If the condition is within the range shown in the table below, it is normal Between (1), (11) – chassis ground (*1)

20 – 30 V

*1. Since power is constantly supplied, voltage is detected even if starting switch is turned OFF. Between (30) – chassis ground or monitoring [1036]

20 – 30 V

If the condition is within the range shown in the table below, it is normal Between (22) – (21)

5 ± 0.5 V

If the condition is within the range shown in the table below, it is normal When boom is raised

Between M95 (35) – chassis ground

Max. 1V

Or monitoring [1023] bit (6) lights up.

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON.

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON. 1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON.

If the condition is within the range shown in the table below, it is normal

Swing, arm IN, travel pressure switch

M95

Measurement of voltage

Controller

When machine swings When arm is moved IN When machine travels

Measurement of voltage

M95

Max. 1 V

Or monitoring [1023] When machine swings

Bit (4)

Bit lights up.

When arm is moved IN

Bit (5)

Bit lights up.

When machine travels

Bit (3)

Bit lights up.

Bits (3), (4), and (5)

Bit goes off.

When in neutral

Boom angle potentiometer signal

Between (25) – chassis ground Between (26) – chassis ground Between (15) – chassis ground

If the condition is within the range shown in the table below, it is normal PC78US-6 Between (4) – (32) or monitoring [1030]

0.30 – 1.25V

Arm angle potentiometer signal

20-18 (12)

M95

Measurement of voltage

If the condition is within the range shown in the table below, it is normal PC78US-6 Between (14) – (32) or monitoring [1032]

STD

0.38 – 1.38V

Long

0.48 – 1.48V

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON.

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON. 4) Raise boom to stroke end.

1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON. 4) Move arm in to stroke end.

PC78US-6

STANDARD VALUE TABLE FOR ELECTRIC PARTS

TESTING AND ADJUSTING

System

Component Name

Connector No.

Inspection Method

Measurement Conditions

Criteria If the condition is within the range shown in the table below, it is normal

Swing holding brake clear solenoid

M95

Measurement of resistance

Controller

When swing brake clear When swing brake is applied

Between (19) – (40)

20 – 30 V Max. 1 V

Or monitoring [1060] bit (1) When swing brake is reset

Bit lights up

When swing brake is applied

Bit goes off

PPC main pressurelock solenoi

M13 (Male)

Measurement of resistance

If the condition is within the range shown in the table below, it is normal Between M13 (Male) (1) – (2)

35 – 80 z

Between M13 (Male) (1), (2) – chassis ground

Min. 1 Mz

Swing holding brake reset solenoid

M14 (Male)

Measurement of resistance

Machine control

If the condition is within the range shown in the table below, it is normal Between M14 (Male) (1) – (2)

35 – 80 z

Between M14 (Male) (1), (2) – chassis ground

Min. 1 Mz

2nd travel speed selection solenoid

PC78US-6

M15 (Male)

Measurement of resistance

If the condition is within the range shown in the table below, it is normal Between M15 (Male) (1) – (2)

35 – 80 z

Between M15 (Male) (1), (2) – chassis ground

Min. 1 Mz

1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter. 4) Turn starting switch ON. 5) Swing or move arm in.

1) Turn starting switch OFF. 2) Disconnect adapter. 3) Connect Tadapter.

1) Turn starting switch OFF. 2) Disconnect adapter. 3) Connect Tadapter.

1) Turn starting switch OFF. 2) Disconnect adapter. 3) Connect Tadapter.

20-19 (12)

STANDARD VALUE TABLE FOR ELECTRIC PARTS

TESTING AND ADJUSTING

System

Component Name

Connector No.

Inspection Method

Measurement Conditions

Criteria

If the monitor panel displays as shown in Tables 1 and 2, it is normal. Table 1 (Check and caution section).

Machine monitor system

Monitored Item (Input connector)

Engine oil pressure P02 (7)

Charge level P02 (11)

(12)

Display

Sensor Input Signal

Light is ON.

Max. 1 V

Light is OFF.

20 – 30 V

Light is ON.

Max. 5 V

Light is OFF.

20 – 30 V

Light is ON.

20 – 30 V

Light is OFF.

Max. 1 V

Start engine.

Check and caution section

Preheater P02 (18)

20-20

Measurement Conditions

1) Connect Tadapter

Start engine.

Stop Engine.

PC78US-6

STANDARD VALUE TABLE FOR ELECTRIC PARTS

TESTING AND ADJUSTING

System

Component Name

Connector No.

Inspection Method

Criteria

Measurement Conditions

Table 2 (Gauge)

Item indicated by gauge

Display level resistance (kz) (Monitor panel input resistance)

Turn starting switch ON

Turn starting switch OFF

1) Turn starting switch OFF and insert dummy resistor or measure resistance of sensor. 2) Turn starting switch ON and check indication.

Min. – Max. Upper side

I Measurement of resistance of coolant temperature gauge P02 (1) – (13)

Position of indication

Machine monitor system

O

Lower side Gauge section

9

4.00 – 3.45

8

3.13 – 3.75

7

3.39 – 3.94

6

3.56 – 4.39

5

3.97 – 5.18

4

4.68 – 6.89

3

6.23 – 10.88

2

10.34 – 36.86

1

33.35 – 37.83

Blink at levels 8 and 9.

Item indicated by gauge

Display level resistance (z) (Monitor panel input resistance)

Turn starting switch ON

Turn starting switch OFF

1) Turn starting switch OFF and insert dummy resistor or measure resistance of sensor. 2) Turn starting switch ON and check indication.

Min. – Max. Upper side

I Measurement of resistance of fuel level gauge P02 (2) – (13)

Position of indication

O

Lower side

9

101 – 20.5

8

18.5 – 26.3

7

23.8 – 31.5

6

28.5 – 36.8

5

33.3 – 42.5

4

38.5 – 49.4

3

44.7 – 58.8

2

53.2 – 72.5

1

65.6 – 1111

Level 1 blinks.

PC78US-6

20-21 (12)

STANDARD VALUE TABLE FOR ELECTRIC PARTS

TESTING AND ADJUSTING

Fuel level sensor

Alternator

20-22 (12)

Check of continuity

Measurement Conditions

Criteria If the condition is within the range shown in the table below, it is normal.

Between terminal – chassis ground

Normal engine oil pressure

No continuity

Low engine oil pressure

Normal continuity

If the condition is within the range shown in the table below, it is normal.

If the condition is within the range shown in the table below, it is normal.

M9 (Male)

Between T4 (Terminal R) – chassis ground

M18 (Male)

Machine monitor system

Coolant temperature sensor

T6

Inspection Method

Measurement of resistance

Engine oil pressure sensor

Connector No.

Measurement of resistance

Component Name

Measurement of voltage

System

Between (1) – (2)

Between (1) – (2)

Normal temperature (25 °C)

Approx. 40 kz

105 °C

Approx. 3.3 kz

Full

Max. 20.5 z

Empty

Min. 65.6 z

While engine is running (at 1/2 or more of full throttle) o 27.5 – 29.5 V * If battery is deteriorated or temperature is low, voltage may not rise for a while after engine is started.

1) Start engine 2) Disconnect terminal

1) Turn starting switch OFF 2) Disconnect connector

1) Turn starting switch OFF 2) Disconnect connector

1) Start engine

PC78US-6

TESTING AND ADJUSTING List of devices for testing, adjusting, & troubleshooting .............................................................................. 20-102 Measuring engine speed............................................................................................................................. 20-103 Measuring exhaust gas color ...................................................................................................................... 20-104 Adjusting valve clearance ........................................................................................................................... 20-105 Measuring compression pressure ............................................................................................................... 20-106 Measuring blow-by pressure .................................................................................................................... 20-106-2 Testing and adjusting fuel injection timing................................................................................................... 20-108 Measuring engine oil pressure ..................................................................................................................20-111-1 Adjusting engine stop solenoid ....................................................................................................................20-112 Adjusting fuel control linkage .......................................................................................................................20-114 Adjusting engine speed sensor ................................................................................................................ 20-115-1 Testing and adjusting hydraulic pressure in work equipment, swing, and travel circuits..............................20-116 Measuring LS differential pressure and adjusting LS valve .........................................................................20-119 Adjusting PC valve ...................................................................................................................................... 20-121 Testing TVC-EPC solenoid output pressure ............................................................................................... 20-121 Measuring control circuit pressure .............................................................................................................. 20-122 Measuring PPC valve output pressure ....................................................................................................... 20-123 Testing solenoid valve output pressure ....................................................................................................... 20-124 Adjusting work equipment valve and swing PPC valve .............................................................................. 20-126 Testing travel deviation ............................................................................................................................... 20-127 Testing parts which can cause hydraulic drift of work equipment ............................................................... 20-129 Measuring oil leakage from swing and travel motors .................................................................................. 20-130 Releasing residual pressure from hydraulic circuit ..................................................................................... 20-131 Testing clearance of swing circle bearing ................................................................................................... 20-132 Testing and adjusting track shoe tension .................................................................................................... 20-133 Bleeding air from hydraulic circuit ............................................................................................................... 20-134 Procedure for adjusting installation of long arm .......................................................................................... 20-136 Testing and adjusting hood catch............................................................................................................. 20-136-1 Replacement procedure of potentiometers ................................................................................................. 20-137 Procedure for testing diode ......................................................................................................................... 20-138 Pm-Clinic service ........................................................................................................................................ 20-139

PC78US-6

20-101 (18)

LIST OF DEVICES FOR TESTING, ADJUSTING, & TROUBLESHOOTING

TESTING AND ADJUSTING

LIST OF DEVICES FOR TESTING, ADJUSTING, & TROUBLESHOOTING Items to Be Tested/Adjusted Engine speed

Symbol A

Water temperature and oil temperature

Part No.

Part Name

Remarks

1

799-205-1100

Tachometer KIT

Digital indication: 6.0 – 99999.9 rpm

2

6210-81-4111

Gear box

—

799-101-1500

Digital thermometer

-50 – 1,200 °C

799-101-5002

Hydraulic tester KIT

790-261-1203

B

Pressure gauge

2.5, 5.9, 39.2, 58.8 MPa {25, 60, 400, 600 kg/cm2}

Digital hydraulic tester

Pressure gauge

58.8 MPa {600 kg/cm2}

799-401-2320

Hydraulic gauge

Pressure gauge

1.0 MPa {10 kg/cm2}

799-101-5160

Nipple

PT1/8

799-101-5220

Nipple

10 mm P = 1.25

07002-11023

O-ring

—

799-401-2910

Nipple

(Both male and female) 9/16-18 UNF (Female: PT1/8)

02896-11008

O-ring

—

07043-00108

Plug

PT1/8 (Hexagon hole)

5

799-401-2701

Differential pressure gauge

—

1

795-502-1590

Compression gauge

0 – 6.9 MPa {0 – 70 kg/cm2} • Kit No.: 795-502-1205

2

795-502-1370

Adapter

—

1

2

Oil pressure

3

C

4

Compression pressure

D

Blow-by pressure

E

799-201-1504

Blow-by checker

0 – 4,900 Pa {0 – 500 mmH2O}

Valve clearance

F

Purchased

Filler gauge

—

1

799-201-9001

Handy smoke checker

2

Purchased

Smoke meter

Exhaust gas color

G

Bosch index: 0 – 9

Operating effort

H

Purchased

Push-pull scale

—

Stroke and hydraulic drift

I

Purchased

Scale

—

Work equipment speed

J

Purchased

Stopwatch

—

790-601-9320

Box

24-pin

799-601-9310

Plate

Applicable to 40-pole connector

799-601-8000

Adapter assembly

Including 21-pin box

1 2 Troubleshooting for wiring harnesses and sensors

K 3

Oil leakage

Fuel injection timing

20-102 (13)

For SWP12

799-601-7050

For SWP6

799-601-7520

Adapter

12 for 070

799-601-7360

Relay 5P

799-601-7370

Relay 6P

799-601-9200

Adapter kit

—

Commercially available

Measuring cylinder

—

2

795-102-2102

Spring pusher

—

3

Commercialy available

Dial guage

—

L

O

799-601-7310

PC78US-6

MEASURING ENGINE SPEED

TESTING AND ADJUSTING

MEASURING ENGINE SPEED a Measuring instruments for engine speed Symbol A

Part No.

Part name

1

799-205-1200

Tachometer KIT

2

6210-81-4111

Gear box

a The engine speed can be measured in monitoring mode [1010]. • Unit: 10 rpm

k When installing and removing the measuring instruments, take care not to touch a hot part of the engine.

1. Remove the fan guard. 2. Remove injection timing adjustment cover (1) for the fuel injection pump from the timing gear case and install gear box A2.

3. Install tachometer KIT A1 to gear box A2.

PC78US-6

4. Measure the engine speed under each condition. 1) Low idling speed i) Set the fuel control dial in the low idling (MIN) position. ii) Set the work equipment, swing, and travel levers in neutral and measure the engine speed. 2) High idling speed i) Turn the auto-decelerator OFF. ii) Set the fuel control dial in the high idling (MAX) position. iii) Set the work equipment, swing, and travel levers in neutral and measure the engine speed. 3) Engine speed when 1 pump is relieved i) Set the fuel control dial in the high idling (MAX) position. ii) Relieve the arm circuit by moving the arm IN and measure the engine speed. 5. After finishing measurement, remove the measuring instruments and return the removed parts.

20-103 (12)

MEASURING EXHAUST GAS COLOR

TESTING AND ADJUSTING

MEASURING EXHAUST GAS COLOR a Measuring instruments for exhaust gas color Symbol G

•

1 2

Part No.

Part name

790-201-9000

Handy smoke checker

Commercially available Smoke meter

When an air source and a power source are not available in the field, use handy smoke checker G1. When recording formal data, etc., use smoke meter G2. a Before measuring the exhaust gas color, raise the cooling water temperature to the operating range.

4) Loosen cap nut [5] of the suction pump and fit the filter paper. a Fit the filter paper securely so that the exhaust gas will not leak. 5) Turn ON the power switch of tool G2. 6) Raise the engine speed sharply and press accelerator pedal [3] of tool G2 simultaneously to have the filter paper absorb the exhaust gas. 7) Place the stained filter paper on the unused filter paper (at least 10 pieces) in the filter paper holder and read the indicated value.

When installing and removing the measuring instrument, take care not to touch a hot part. 1. Measuring with handy smoke checker G1 1) Install a piece of filter paper to tool G1. 2) Insert the exhaust gas suction pipe in the exhaust pipe, then raise the engine speed sharply and operate the handle of tool G1 simultaneously to have the filter paper absorb the exhaust gas. 3) Remove the filter paper and compare it with the attached scale.

2. Measuring with smoke meter G2 1) Insert probe [1] of G2 in the outlet of the exhaust pipe and tighten the clip to secure the probe to the exhaust pipe. 2) Connect probe hose [2], cable of accelerator pedal [3], and air hose [4] to tool G2. a Set the supplied air pressure below 1.47 MPa {15 kg/cm2}. 3) Connect the power cable to an outlet of AC 100 V. a When connecting the power cable, check that the power switch of tool G2 is turned OFF.

20-104 (12)

a The firing order of the engine is as follows • Firing order: 1 – 2 – 4 – 3 a The air intake valves and exhaust valves may be adjusted in the firing order by revolving the crankshaft forward by 180° (4 cylinders). a For the valve clearance, see TESTING AND ADJUSTING, Failure criteria table.

PC78US-6

ADJUSTING VALVE CLEARANCE

TESTING AND ADJUSTING

ADJUSTING VALVE CLEARANCE a Measuring instruments for valve clearance Symbol F

Part No.

Part name

Commercially available Feeler gauge

1. Open the engine hood and remove the cylinder head cover. 2. Rotate the crankshaft forward to bring the stamped "1.4TOP" line (a) of the crank pulley to pointer (2) and set the No. 1 cylinder to the compression top dead center. a Rotate the crankshaft with the crank pulley mounting bolt. a When the No. 1 cylinder is at the compression top dead center, the rocker arm of the No. 1 cylinder can be moved by the valve clearance with the hand. If the rocker arm cannot be moved, the No. 1 cylinder is not at the compression top dead center. In this case, rotate the crankshaft one more turn.

1) Insert feeler gauge F in clearance (b) between rocker arm (2) and valve stem (3) and adjust the clearance with adjustment screw (4). a With the feeler gauge inserted, turn the adjustment screw to a degree that you can move the filler gauge lightly. 2) While securing adjustment screw (4), tighten locknut (5). Locknut: 39.2 – 49 Nm {4 – 5 kgm} a After tightening the locknut, check the valve clearance again. a After adjusting all of the valves marked with q, go to the next procedure.

4. Rotate the crankshaft forward to bring the stamped "1.4TOP" line (a) of the crank pulley to pointer (1) and set the No. 4 cylinder to the compression top dead center.

3. While the No. 1 cylinder is at the compression top dead center, adjust the valve clearances marked with q in the valve arrangement drawing according to the following procedure.

5. While the No. 4 cylinder is at the compression top dead center, adjust the valve clearances marked with $ in the valve arrangement drawing. a Adjust the valve clearance according to step 4 above. 6. After finishing adjustment, return the removed parts. Cylinder head cover mounting bolt: 7.84 – 9.8 Nm {0.8 – 1.0 kgm}

PC78US-6

20-105 (13)

MEASURING COMPRESSION PRESSURE

TESTING AND ADJUSTING

MEASURING COMPRESSION PRESSURE a Measuring instruments for compression pressure Symbol D

Part No.

5. Set the multi-tachometer to the engine. a See Measuring engine speed.

Part name

1

795-502-1590

Compression gauge

2

795-502-1370

Adapter

When measuring the compression pressure, take care not to touch the exhaust manifold, etc. to burn yourself or the rotary parts such as the fan, fan belt, etc. to be caught in them. 1. Adjust the valve clearance accurately. For details, see Adjusting valve clearance. 2. Warm up the engine until the oil temperature is 40 – 60 °C. 3. Remove nozzle holder assembly (1) of the cylinder to be measured. 4. Install adapter D2 to the fitting part of the nozzle holder and connect pressure gauge D1. PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500

6. Disconnect wiring harnesses (2) from the terminals of the engine stop solenoid. Revolve the engine with the starting motor and measure the compression pressure and engine speed at this time. a Read the pressure gauge when its pointer is stabilized. a When measuring the compression pressure, measure the engine speed, too, and check that it is in the range of the measurement conditions. a After measuring the compression pressure, install nozzle holder assembly (1). Nozzle holder mounting bolt: 39.2 – 49 Nm {4 – 5 kgm} PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500

PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up

20-106 (12)

PC78US-6

TESTING AND ADJUSTING

MEASURING COMPRESSION PRESSURE

PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up

PC78US-6

20-106-1 (7)

MEASURING BLOW-BY PRESSURE

TESTING AND ADJUSTING

MEASURING BLOW-BY PRESSURE a Measuring instruments for blow-by pressure Symbol

Part No.

E

799-201-1504

Part name

3. Install cylinder head cover (1) and install blow-by pressure gauge E to the oil filler.

Blow-by checker

PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500 1. Remove cylinder head cover (1).

4. Run the engine at the rated output and measure the blow-by pressure. Take care not to touch the hot parts or rotating parts during measurement. 2. Install plug E to breather tube (2).

20-106-2 (12)

a The regular blow-by pressure is measured while the engine is running at the rated output. • In the field, an approximate value is obtained by relieving the hydraulic equipment. • If it is impossible to run the engine at the rated output or relief the hydraulic equipment, measure while the engine is running at high idling. The value obtained in this case is about 80% of the blow-by pressure at the rated output. a The blow-by pressure may vary largely with the engine condition. If the measured value is judged abnormal, check for increase of oil consumption, bad exhaust gas color, deterioration of oil, high deterioration speed of oil, etc. which are related to the abnormal blowby pressure. a After finishing measurement, be sure to remove plug E from the breather tube.

PC78US-6

TESTING AND ADJUSTING

PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up a Measure the blow-by pressure under the following condition. • Cooling water temperature: Within operating range • Hydraulic oil temperature: 40 – 60°C 1. Install the nozzle of blow-by checker E to blowby hose (2).

MEASURING BLOW-BY PRESSURE

a Normally, the blow-by pressure should be measured while the engine is operated at the rated output. In the field, however, an approximate value can be obtained by relieving the hydraulic circuit. a If it is impossible to run the engine at the rated output or relieve the hydraulic circuit, measure while the engine is running at high idling. The value obtained in this case is about 80% of the blow-by pressure at the rated output. a The blow-by pressure may vary largely with the engine condition. If the measured value is judged abnormal, check for increase of oil consumption, bad exhaust gas color, deterioration of oil, high deterioration speed of oil, etc. which are related to the abnormal blowby pressure.

2. Connect the nozzle to the gauge by the hose. 3. Set the working mode in the ACTIVE mode, run the engine at full throttle, and relieve the arm dump circuit. 4. When the gauge pointer is stabilized, measure the blow-by pressure. Do not touch a hot part or a rotary part during measurement.

PC78US-6

20-107 (7)

TESTING AND ADJUSTING

TESTING AND ADJUSTING FUEL INJECTION TIMING

TESTING AND ADJUSTING FUEL INJECTION TIMING a Adjusting instruments for fuel injection timing Symbol Part No. Part name 2 795-102-2102 Spring pusher O 3 Commercially available Dial gauge

Adjustment by use of match marks a Apply this method usually. (Then installing the fuel injection pump to the original engine without repairing it, when checking only the injection timing, etc.) 1. Bring cylinder No. 1 to the compression top dead center. 1) Turn the crankshaft forward and match 1.4Top line (a) on the crank pulley to pointer (1).

2) Check that cylinder No. 1 is at the compression top dead center by the following method. If the following condition is not obtained, turn the crankshaft one more turn. a If the fuel injection pump is removed: Check that mark C is seen at the tooth tip of the idler gear (2). a If the fuel injection pump is installed to the engine: Remove the head cover and check that (both air intake valve and exhaust valve of cylinder No. 1 have the valve clearance).

20-108 (13)

2. Remove front cover (3) of the fuel injection pump. 3. Install the fuel injection pump holder and drive gear as one unit to the engine. 4. Insert the timing check pin 4.0 – 4.5 mm in diameter and 80 mm in length on hole a of the front gear cover and match it to the hole of the drive gear. a Check that the timing check pin enters straight and the hole of the fuel injection pump holder is aligned with the mounting hole of the front gear cover (in which the mounting bolt will be inserted). a If the holes are deviated from each other, remove the fuel injection pump and check its engagement with the drive gear.

5. Remove the timing check pin and tighten each bolt.

PC78US-6

TESTING AND ADJUSTING

Adjustment by delivery valve method (When installing a repaired or replaced fuel injection pump, when checking after disassembling or replacing the gear train)

TESTING AND ADJUSTING FUEL INJECTION TIMING

4. Using spring pusher O2, compress the valve spring and remove valve cotter (5). 5. Loosen spring pusher O2 and remove spring seat (6) and valve spring (7).

1. Remove the cylinder head cover. 2. Bring cylinder No. 1 to the compression top dead center. 1) Turn the crankshaft forward and match injection timing line (a) on the crank pulley to pointer (1). 2) Check that both air intake valve and exhaust valve of cylinder No. 1 have the valve clearance. a If either or both of the valves do not have the valve clearance, turn the crankshaft one more turn. 6. Turn the stem of air intake valve (8) with the fingers while it is in contact with the top of piston (9) to fit it securely.

3. Remove snap ring (3) from the front end of the rocker shaft, then remove air intake rocker arm (4) of cylinder No. 1.

PC78US-6

20-109 (13)

TESTING AND ADJUSTING FUEL INJECTION TIMING

TESTING AND ADJUSTING

7. Apply dial gauge O3 to the valve stem end and turn the crankshaft forward or in reverse to set the dial gauge to 0 when its pointer starts turning in reverse. 8. Turn the crankshaft about 45 degrees in reverse from the compression top dead center of cylinder No. 1. 9. Turn the crankshaft forward so that the dial gauge indicates standard dimension b. a This dimension corresponds to the set angle of the fuel injection timing. Fuel injection timing and standard dimension b Serial No. PC78US-6

4001 – 5500

5501 and up

PC78UU-6

22832 – 23500

23501 and up

BTDC °(Deg)

10 ± 0.75

5 ± 0.75

1.17 ± 0.17

0.3 ± 0.08

b

mm

10. Disconnect fuel injection pipe (10) of cylinder No. 1. 11. Remove delivery valve holder (11), and remove delivery valve (12) and spring (13) from its inside. Then, install delivery valve holder (11) again.

20-110 (13)

12. Set the fuel injection lever to the FULL position. 13. Loosen the nut at the oblong hole of the injection pump mounting flange, then loosen the injection pump mounting bolts (14).

14. Turning the injection pump outward and operating the priming pump, move the injection pump toward the cylinder block little by little and stop when the fuel stops flowing out of the delivery valve holder. a If the injection pump is slanted out, the injection timing is delayed. If the former is slanted toward the cylinder block, the latter is advanced. 15. Tighten injection pump mounting bolts (14) alternately. 16. Tighten the nut at the oblong hole of the injection pump mounting flange.

PC78US-6

TESTING AND ADJUSTING FUEL INJECTION TIMING

TESTING AND ADJUSTING

17. Turn the crankshaft forward and check that the pointer of the dial gauge is in the standard range shown in the following table when cylinder No. 1 is at the top dead center (when the pointer of the dial gauge starts moving in reverse). a If the pointer of the dial gauge is out of this range, repeat the above steps from 7. Serial No. PC78US-6

4001 – 5500

5501 and up

PC78UU-6

22832 – 23500

23501 and up

0 ± 0.22

0 ± 0.08

Dimension when cylinder is at top dead center (mm)

18. Remove the delivery valve holder (11) and install delivery valve (12) and spring (13) to it, then install delivery valve holder (14) again. a Replace the o-ring and copper gasket of the delivery valve. Tighten the delivery valve 3 times to secure it. (If it is not tightened sufficiently, the gasket may be broken.) Delivery valve holder: 39.2 – 44.1 Nm {4 – 4.5 kgm} 19. Connect fuel injection pipe (3). Sleeve nut: 19.6 – 24.5 Nm {2 – 2.5 kgm} 20. Install valve spring (7) and valve seat (6). 21. Compress the valve spring with spring pusher O2 and install valve cotter (5). 22. Install air intake rocker arm (4) of cylinder No. 1, then install snap ring (3). a Install the snap ring securely. 23. Install the cylinder head cover. Cylinder head cover mounting bolt: 7.84 – 9.8 Nm {0.8 – 1.0 kgm}

PC78US-6

20-111 (13)

MEASURING ENGINE OIL PRESSURE

TESTING AND ADJUSTING

MEASURING ENGINE OIL PRESSURE a Measuring instruments for engine oil pressure Symbol C

Part No.

Part Name

1

799-101-5002

Hydraulic tester KIT

2

799-401-2320

Hydraulic gauge

PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500

a Measure the engine oil pressure under he following condition. • Cooling water temperature: Within operating range 1. Remove oil pressure pickup plug (1) (PT 1/8) from the engine block under the alternator. PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500 PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up

PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up 3. Run the engine at low idling and high idling and measure the engine oil pressure at each speed.

2. Install oil pressure measuring nipple C3 and connect oil pressure gauge C2 (0.98 MPa {10 kg/cm2}).

20-111-1 (12)

PC78US-6

ADJUSTING ENGINE STOP SOLENOID

TESTING AND ADJUSTING

ADJUSTING ENGINE STOP SOLENOID 1. Install ball joint (2) to solenoid (1) and tighten locknut (3). a a: Approx. 1mm (thread)

2. Install rod (4) and rod end (5) to ball joint (2) temporarily. a Screwing depth b of rod in ball joint: Approx. 12.5 mm a Screwing depth c of rod end in rod: Approx. 10.0 mm

20-112 (7)

3. Supply power to solenoid (1) to turn it on. a If stop lever (6) and rod end (5) of the fuel injection pump are connected before the solenoid is turned on, the solenoid cannot pull sufficiently (the operating current flows continuously) and the coil will burn. Accordingly, do not connect them at this time.

4. Check that solenoid (1) is turned on, then connect rod end (5) to stop lever (6) and adjust the length of rod (4) so that the stop lever will touch the lever end on the service side. a In the case of PC78UU-6, serial No. 23501 or up, or PC78US-6, serial No. 5501 or up, if solenoid (1) is connected to the power source without using the machine wiring, do not keep the PULL terminal cable connected. (If the PULL terminal cable is kept connected, the operating current flows continuously and the coil will burn.)

PC78US-6

TESTING AND ADJUSTING

a Stop lever (6) touches the lever end on the service side (inside the fuel injection pump). a Play: 0 mm

ADJUSTING ENGINE STOP SOLENOID

5. Tighten nut (7) of the joint of stop lever (6) and rod end (5) and insert the cotter pin. a Install the rod end with grease hole (8) up. Rod end: Grease (G2-LI)

6. Lengthen rod (4) to give play to the stop lever end on the service side. a Play d: 1.0 – 2.0 mm (loosen rod by 1/2 – 1 turn.)

a When adjusting the length of rod (4), do not apply force so strongly that stop lever (6) will be pulled up more than the lever end. a Adjust the length of the rod as shown below.

7. Tighten locknut (8). a At this time, take care that rod (4) will not turn together with locknut (9). Do not twist stop lever (6) forcibly. 8. Start and stop the engine 2 – 3 times and check that solenoid (6) operates smoothly to stop the engine.

PC78US-6

20-113 (12)

ADJUSTING FUEL CONTROL LINKAGE

TESTING AND ADJUSTING

ADJUSTING FUEL CONTROL LINKAGE 1. Adjusting control linkage 1) If any part was replaced, connect the cable to the fuel injection pump governor lever securely. a Connect the cable to the hole at the end of the injection pump governor lever. 2) Turn the starting switch to the ON position and set the fuel control dial to the FULL position. a For PC78US-6, Serial No. 6501 and up, refer to TROUBLESHOOTING, Display and special functions of monitor panel, and perform this procedure after entering in [03] (Adjusting governor lever) mode. 3) Bring fuel injection pump governor lever (1) in contact with stopper (2) on the FULL side. 4) Under this condition, pull cable (3) with force of about 98 N {about 10 kg} and tighten nuts (4) and (5) temporarily. a Tighten the nuts while pulling the cable to eliminate play. 5) Return nut (4) by 2 turns and tighten nut (5) by 2 turns retighten them. 6) Start the engine and check that it runs at the specified speed.

PC78US-6 Serial No.: 6501 and up

PC78US-6 Serial No.: 4001 and up PC78UU-6 Serial No.: 22832 and up 1.PC78US-6 Serial No.: 5501 – 6500 PC78UU-6 Serial No.: 23501 and up

20-114 (12)

PC78US-6

TESTING AND ADJUSTING

2. Adjusting control linkage finely PC78US-6 Serial No.: 4001 –6500 PC78UU-6 Serial No.: 22832 and up If the control linkage cannot be adjusted by the method in 1. above, adjust it finely with the turnbuckle above the cable. • When the engine speed (high idling speed) is below the specified level 1) Turn the starting switch to the ON position and set the fuel control dial to the FULL position. 2) Loosen nut (6) (right-hand screw) and nut (7) (left-hand screw). 3) Turn bolt (8) counterclockwise, seeing from the governor lever side, to eliminate the clearance between injection pump governor lever (1) and full stopper (2). 4) Tighten nuts (6) and (7).

ADJUSTING FUEL CONTROL LINKAGE

4) Tighten nuts (6) and (7). Nut: 8.8 – 10.8 Nm {0.9 – 1.1 kgm} a At this time, check that clearance A and B between bolt (8) and nuts (6) and (7) are 5 ± 3.5 mm (1.5 – 8.5 mm). a At this time, check that the rubber boot (10) of the cable is not twisted. 5) Start the engine and check that it runs at the specified speed.

Nut: 8.8 – 10.8 Nm {0.9 – 1.1 kgm}

5) • 1)

2) 3)

a At this time, check that clearance A and B between bolt (8) and nuts (6) and (7) are 5 ± 3.5 mm (1.5 – 8.5 mm) respectively. a At this time, check that the rubber boot (10) of the cable is not twisted. Start the engine and check that it runs at the specified speed. When the engine speed (low idling speed) is above the specified speed. Turn the starting switch to the ON position and set the fuel control dial to the deceleration (SLOW) position. Loosen nut (6) (right-hand screw) and nut (7) (left-hand screw). Turn bolt (8) counterclockwise, seeing from the governor lever side, to lengthen the cable and eliminate the clearance between injection pump governor lever (1) and low idling stopper (9).

PC78US-6

20-115 (12)

TESTING AND ADJUSTING

ADJUSTING ENGINE SPEED SENSOR

ADJUSTING ENGINE SPEED SENSOR a Adjust the engine speed sensor for the pump controller according to the following procedure. a The engine G speed and engine Ne speed sensor for the engine controller cannot be adjusted. 1. Screw in sensor (1) until its tip touches the tooth tip of flywheel ring gear (2). a Before installing the sensor check that its tip is free from steel chips and flaws. Threads: Hydraulic sealant 2. Return sensor (1) by 1/2 – 2/3 turns. a A clearance of 0.75 – 1.00 mm is made between the sensor tip and gear tooth tip. 3. Secure sensor (1) with nut (3). Nut: 69 – 74 Nm {7.0 – 7.5 kgm}

20-115-1 (7)

PC78US-6

TESTING AND ADJUSTING HYDRAULIC PRESSURE IN WORK EQUIPMENT, SWING, AND TRAVEL CIRCUITS

TESTING AND ADJUSTING

TESTING AND ADJUSTING HYDRAULIC PRESSURE IN WORK EQUIPMENT, SWING, AND TRAVEL CIRCUITS a Hydraulic oil temperature for measurement: 45 – 55 °C Lower the work equipment to the ground and stop the engine. Then, loosen the hydraulic oil filler cap slowly to release the internal pressure of the hydraulic tank. Set the safety valve lock lever to the LOCK position. a Testing and adjusting instruments for oil pressure in work equipment, swing, and travel circuits Symbol 1 C 3

Part No.

Part name

799-101-5002

Hydraulic tester KIT

790-261-1203

Digital hydraulic tester

799-101-5160

Nipple

799-101-5220

Nipple

07002-11023

O-ring

Measuring hydraulic pressure in boom arm, bucket, travel, and swing circuits • Machine model: PC78US-6 Measuring hydraulic pressure in boom arm, bucket, offset, and travel circuits • Machine model: PC78UU-6 1. Measuring 1) Installing pressure gauge i) Open the top cover of the valve and remove the side cover. ii) Remove pressure pickup plug (1) or (2) (10 mm, P = 1.25) and install nipple C3, then connect oil pressure gauge C1 (58.8 MPa {600 kg/cm2} a Use plug (1) to measure the hydraulic pressure in boom, arm, and bucket circuits and use plug (2) to measure the hydraulic pressure in the swing and travel circuits.

20-116 (12)

2) Measuring unload pressure Measure the hydraulic pressure while the engine is running at full throttle and the control lever is in neutral. 3) Measuring pump relief pressure Measure the hydraulic pressure when each actuator is relieved while the engine is running at full throttle.

PC78US-6

TESTING AND ADJUSTING

TESTING AND ADJUSTING HYDRAULIC PRESSURE IN WORK EQUIPMENT, SWING, AND TRAVEL CIRCUITS

Measuring hydraulic pressure in swing and blade circuits • Machine model: PC78UU-6 1. Measuring pump relief pressure 1) Remove the top cover of the valve. 2) Remove pressure pickup plug (3) (10 mm, P = 1.25) and install nipple C3, then connect oil pressure gauge (58.8 MPa {600 kg/cm2}). a See the photo.

3) Measure the hydraulic pressure when swing or blade lower actuator is relieved while the engine is running at full throttle. 2. Adjusting Adjusting main relief valve for boom, arm, bucket, offset swing, and travel circuits. Machine model: PC78US-6

k Do not turn end cap (6) counterclockwise more than one revolution or end cap (6) could fly off. 1) Loosen locknut (5) on main relief valve (4) and adjust pressure by turning end cap (6). a As the end cap is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of end cap: 12.5 MPa {128 kg/cm2} Locknut: 39 – 49 Nm {4 – 5 kgm} End cap: 39 – 49 Nm {4 – 5 kgm}

PC78US-6

20-117 (18)

TESTING AND ADJUSTING

TESTING AND ADJUSTING HYDRAULIC PRESSURE IN WORK EQUIPMENT, SWING, AND TRAVEL CIRCUITS

Adjusting main relief valve for swing and blade (LOWER) circuits

k Do not turn end cap (9) counterclockwise more than one revolution or end cap (9) could fly off. 1) Loosen locknut (8) on main relief valve (7) and adjust pressure by turning end cap (9). a As the end cap is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of end cap: 12.5 MPa {128 kg/cm2}. Locknut: 39 – 49 Nm {4 – 5 kgm} End cap: 39 – 49 Nm {4 – 5 kgm}

20-118 (18)

Adjusting main relief valve for blade (RAISE) circuits (UU and US of blade specification)

k Do not turn end cap (12) counterclockwise more than one revolution or end cap (12) could fly off. 1) Loosen locknut (11) on main relief valve (10) and adjust pressure by turning end cap (12). a As the end cap is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of end cap: 19.6 MPa {200 kg/cm2}. Locknut: 39 – 49 Nm {4 – 5 kgm} End cap: 39 – 49 Nm {4 – 5 kgm}

PC78US-6

TESTING AND ADJUSTING

MEASURING LS DIFFERENTIAL PRESSURE AND ADJUSTING LS VALVE

MEASURING LS DIFFERENTIAL PRESSURE AND ADJUSTING LS VALVE a Measuring instruments for LS valve Symbol

Part No. 799-101-5160

3

Part name Nipple (PT 1/8)

799-101-5220

Nipple (10 x 1.25 mm)

07002-11023

O-ring

799-401-2910

Nipple (9/16-18UNF)

4

02896-11008

O-ring

07043-00108

Plug (PT 1/8)

5

799-401-2701

Differential pressure gauge

C

1. Measuring LS differential pressure 1) Measuring with main relief differential pressure gauge i) Remove pump pressure pickup plug (1) (on the high pressure side) and disconnect LS pressure hose (2). Install nipple C3 to the high pressure side and nipple C4 to the LS pressure side. ii) Connect differential pressure gauge C5. a Connect the high pressure side of the differential pressure gauge to the main relief pressure side and connect the low pressure side to the LS pressure side. iii) Measure the LS differential pressure under the condition in Table 1. Table 1 Fuel Control Dial

Operation

Differential Pressure {kg/cm2}

FULL

Set lever in neutral

2.5 – 4.4 {25 – 45}

FULL

Curl bucket (With lever at FULL position)

2.11 ± 0.1 {21.5 ± 1}

PC78US-6

20-119 (12)

TESTING AND ADJUSTING

MEASURING LS DIFFERENTIAL PRESSURE AND ADJUSTING LS VALVE

2) Measuring with oil pressure gauge a Measure with the same gauge. i) Remove pump pressure pickup plug (1) (on the high pressure side) and disconnect LS pressure hose (2) (on the low pressure side) and install adapter C3. ii) Connect pressure gauge C1 (39.2 MPa {400 kg/cm2}). a Use a pressure gauge having unit divisions of 1.0 MPa {10 kg/cm2}. (If a pressure gauge of 39.2 MPa {400 kg/cm2} is not available, one of 58.8 MPa {600 kg/cm2} will do.) iii) Measure the pump discharge pressure under the condition in Table 1. a Read the pointer correctly, facing the gauge. iv) Measure the LS pressure under the condition in Table 1. a Read the pointer correctly, facing the gauge. LS differential pressure = (Pump discharge pressure) – (LS pressure)

20-120 (12)

Adjusting 1. Adjusting LS valve a If the differential pressure is abnormal, adjust the LS valve according to the following procedure. a Before loosening the locknut, be sure to make match marks. 1) Loosen locknut (3) and adjust with adjustment screw (4). a As the adjustment screw is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of adjustment screw: 1.27 MPa {13 kg/ cm2}. 2) After adjusting, tighten locknut (3). Locknut: 29.4 – 39.2 Nm {3 – 4 kgm} a After adjusting, measure the LS differential pressure, referring to Measuring described above. a When loosening or tightening the locknut, secure adjustment screw (4) with a spanner so that it will not be dragged.

PC78US-6

TESTING AND ADJUSTING

ADJUSTING PC VALVE a When the load is increased, the engine speed may lower or the engine speed may be normal and working speed may be lower. If this trouble occurs and the pump discharge pressure and LS differential pressure are normal, adjust the pump PC valve according to the following procedure. a Before loosening locknut, be sure to make match marks. 1. Loosen locknut (1) and adjust with adjustment screw (2). a Since the PC valve is of eccentric type, in which direction the adjustment screw should be turned to increase the absorption torque is unknown. Accordingly, monitor the engine speed when turning the adjustment screw. 2. After adjusting, tighten locknut (1).

ADJUSTING PC VALVE, TESTING TVC-EPC SOLENOID OUTPUT PRESSURE

TESTING TVC-EPC SOLENOID OUTPUT PRESSURE Measuring a Hydraulic oil temperature for measurement: 45 ~ 55 °C 1) Remove pump pressure pickup plug (1) (10 mm, P = 1.25) and install nipple C3 of the oil pressure gauge kit and connect oil pressure gauge kit and connect oil pressure gauge C1 (5.9 MPa {60 kg/cm2}).

BWP10640

Locknut: 29.4 ~ 39.2 Nm {3 ~ 4 kgm}

BWP10639 2) Start the engine and measure the oil pressure under the following condition. Table 1 Measurement Condition PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500

PC78US-6

Engine Speed

Measurement Condition

Measured Pressure MPa {kg/cm2}

Monitor Output Current

FULL

Neutral

0.54 – 0.84 {5.5 – 8.5}

410 mA

FULL

Float one side and run idle

0 – 0.2 {0 – 2}

100 mA

SLOW

Neutral

2.74 – 3.53 {28 – 36}

900 mA

20-121 (13)

TESTING TVC-EPC SOLENOID OUTPUT PRESSURE

TESTING AND ADJUSTING

PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up Engine Speed

Measurement Condition

Measured Pressure MPa {kg/cm2}

Monitor Output Current

FULL

Neutral

0.93 – 1.23 {9.5 – 12.5}

510 mA

FULL

Float one side and run idle

0.05 – 0.25 {0.5 – 2.5}

200 mA

SLOW

Neutral

2.74 – 3.53 {28 – 36}

900 mA

20-121-1 (13)

PC78US-6

TESTING AND ADJUSTING

MEASURING CONTROL CIRCUIT PRESSURE

MEASURING CONTROL CIRCUIT PRESSURE Measuring a Hydraulic oil temperature for measurement: 45 – 55 °C

k WARNING! Lower the work equipment to the ground and stop the engine. Then, loosen the hydraulic oil filler cap slowly to release the internal pressure of the hydraulic tank. Set the safety valve lock lever to the LOCK position.

3) Connect nipple C3 and install oil pressure gauge C1 (5.8 MPa {60 kg/cm2}).

1) Remove the front cover front guard plate of the valve. 2) Remove pressure pickup plug (1) (10 mm, P = 1.25) from the top of the solenoid valve block. Machine model: PC78US-6 4) Start and run the engine at full throttle and measure the circuit pressure.

Machine model: PC78UU-6

Adjusting • If the control circuit pressure is abnormal, adjust the control relief valve according to the following procedure. 1) Loosen locknut (2) of relief valve (1) and adjust with adjustment screw (3). a As the adjustment screw is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of adjustment screw: 0.32 MPa {3.3 kg/cm2}. Locknut: 20 – 29 Nm {2 – 3 kgm} a After adjusting, check the set pressure according to the procedure in 1.

20-122 (5)

PC78US-6

TESTING AND ADJUSTING

MEASURING PPC VALVE OUTPUT PRESSURE

MEASURING PPC VALVE OUTPUT PRESSURE a Hydraulic oil temperature for measurement: 45 – 55 °C 1. Measuring PPC valve output pressure 1) Disconnect hose (1) of the circuit to be measured.

a Measuring points a. b. c. d. e. f. g. h. i.

Blade RAISE Blade LOWER RIGHT swing LEFT swing LEFT REVERSE travel LEFT FORWARD travel RIGHT REVERSE travel RIGHT FORWARD travel RIGHT offset

J. k. l. m. n. o. p. q. r.

LEFT offset Boom RAISE Boom LOWER Arm OUT Arm IN Bucket DUMP Bucket CURL Service Service

Machine Model: PC78UU-6 STD

2) Install adapter C4 between hose (1) and elbow. 3) Install oil pressure gauge C1 (5.9 MPa {60 kg/cm2}) to adapter C3. 4) Run the engine at full throttle and operate the control lever of the circuit to be measured and measure oil pressure. Machine Model: PC78US-6 (Blade specification)

a If the output on the control valve side is low, measure the input pressure of the PPC valve. Of the input pressure of the PPC valve is normal, the PPC valve is defective.

PC78US-6

Machine Model: PC78US-6 (Blade specification + Service valve)

20-123 (12)

TESTING SOLENOID VALVE OUTPUT PRESSURE

TESTING AND ADJUSTING

TESTING SOLENOID VALVE OUTPUT PRESSURE Measuring a Hydraulic oil temperature for measurement: 45 – 55 °C 1. Measuring output pressure of automatic stop and work equipment control EPC solenoid valve Machine model: PC78UU-6 1) Disconnect EPC solenoid valve output hose (1) and install oil pressure gauge C1 (5.9 MPa {60 kg/cm2}), using nipples C3 and C4 in the oil pressure gauge kit. a The EPC solenoid valve is installed in the 6-spool solenoid valve assembly under the floor plate.

2. Measuring output pressure of ON-OFF solenoid valve. 1) Disconnect ON-OFF solenoid valve output hose (3) and install oil pressure gauge C1 (5.9 MPa {60 kg/cm2}), using nipple C3 in the oil pressure gauge kit. 2) Measure the output pressure of the solenoid valve under the condition in Table 2. a The ON-OFF solenoid valve. • Installed in the 3-spool soleoid valve assembly at the front under the floor plate PC78US-6. • Installed in the 6-spool soleoid valve assembly at the front under the floor plate PC78UU-6.

2) Measure the output pressure under the condition in Table 1.

Table 1 Solenoid Name

Measurement Condition During arm in operation

1

Arm IN stop EPC Stops automatically in automatic stop range

2

Boom RAISE stop EPC

During boom RAISE operation Stops automatically in automatic stop range Relieving by right offset (Pressure is raised)

3

Oil pressure MPa {kg/cm2}

Remarks

3.14 ± 0.49 {32 ± 5}

—

0

—

3.14 ± 0.49 {32 ± 5}

—

0

—

3.14 ± 0.49 {32 ± 5}

—

0

—

Left offset stop Stopping automatically in automatic stop range(Pressure is not raised)

20-124 (12)

PC78US-6

TESTING AND ADJUSTING

TESTING SOLENOID VALVE OUTPUT PRESSURE

Table 2 Solenoid Name

1

2

3

PPC oil pressuressure lock

Swing holding brake

Travel speed selector

Operating Condition

Operation of solenoid

Oil pressure MPa {kg/cm2}

Set safety lock lever in FREE position.

Oil pressure is applied to PPC valve circuit.

ON

3.14 ± 0.29 {32 ± 3}

Set safety lock lever in LOCK position.

Oil pressure is not applied to PPC valve circuit.

OFF

0

Operate swing or arm-in lever.

Brake is released.

ON

3.14 ± 0.49 {32 ± 5}

Set swing or arm-in lever in neutral (5 sec after Brake is applied. setting in neutral)

OFF

0

Set travel speed selector switch in Hi.

Travel speed is increased.

ON

3.14 ± 0.49 {32 ± 5}

Set travel speed selector switch in Lo.

Travel speed is decreased.

OFF

0

Measurement Condition

Remarks

Note: Operation of solenoid valve is as follows; When ON : Power is applied (Hydraulic oil is generated). When OFF: Power is not applied (Hydraulic oil is 0).

PC78US-6

20-125 (5)

TESTING AND ADJUSTING

ADJUSTING WORK EQUIPMENT VALVE AND SWING PPC VALVE

ADJUSTING WORK EQUIPMENT VALVE AND SWING PPC VALVE a If the work equipment control lever or swing control lever has excessive play, adjust it according to the following procedure.

PC78US-6 Serial No.: 6501 and up

Lower the work equipment to the ground and stop the engine. Then, loosen the hydraulic oil filler cap slowly to release the internal pressure of the hydraulic tank. Set the safety valve lock lever to the LOCK position. 1. Remove the PPC valve. 2. Remove boot (1). 3. Loosen locknut (2) and screw in disc (3) until it touches the heads of 4 pistons (4). a At this time, do not move the pistons. 4. Fix disc (3) and tighten locknut (2) to the specified torque. 3 Locknut: 98 – 127 Nm {10 – 13 kgm}

5. Install boot (1). a The clearance between disc (3) and piston (4) is eliminated by the above adjustment. PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up

20-126 (12)

PC78US-6

TESTING AND ADJUSTING

TESTING TRAVEL DEVIATION

TESTING TRAVEL DEVIATION 1. Measuring when traveling 1) Set the machine in the travel posture. ★ For the travel posture, extend the bucket and arm cylinder rods fully, and hold the boom angle at 45°. 2) Travel for 10 m, then measure deviation a when traveling for the next 20 m. ★ Measure with the engine at full throttle. ★ Install a hydraulic pressure gauge and measure the pump discharge pressure a the same time.

PC78US-6

20-127 b

TESTING AND ADJUSTING

Adjusting ★ Travel deviation can be corrected by draining a part of the oil discharged from the pump which discharges more oil with the adjustment plugs. If the travel deviation is corrected by this method, however, the travel speed, work equipment speed in the compound operation, and relief pressure lower since the pump discharge is reduced. ★ The following is the method of correcting deviation applied when the machine deviates to the right (left) in both travel directions. ★ Travel deviation can be corrected by the following method only when it is 200 mm or less.

TESTING TRAVEL DEVIATION

2. Insert hexagonal wrench (1) (Width across flats: 4 mm) in adjustment plug (1) or (2). ★ Insert the hexagonal wrench securely. 3. Loosen locknut (3), leaving the hexagonal wrench inserted. ★ Before adjusting, mark the position of the locknut with paint. ★ Loosen the locknut, securing the hexagonal wrench. • Loosening angle of locknut: Approx. 90 ~ 180°

WARNING! If the adjustment plug is loosened more than the adjustment limit, high pressure oil spurts out. Take care extremely. WARNING! Lower the work equipment to the ground and stop the engine. Then, loosen the hydraulic oil filler cap slowly to release the internal pressure of the hydraulic tank. 1. Check the position of each adjustment plug of the main pump. • When the machine deviates to the right: Loosen adjustment plug (1). • When the machine deviates to the left: Loosen adjustment plug (2). ★ Loosen only either plug. Do not loosen both plugs at the same time.

4. Correct the travel deviation by loosening adjustment plug (1) or (2). • Quantity of correction of travel deviation per turn of adjustment plug: 150 mm (For reference) ★ When the machine is shipped, the adjustment plugs are tightened fully. Adjust the correction angle by the loosening angle of the adjustment plugs. ★ If the adjustment plug is dragged when the locknut is loosened, tighten it again. ★ The adjustable range of each adjustment plug is 2 turns / 720 degrees from the tightened position. 5. Tighten locknut (3). Locknut: 2.94 ~ 4.9 Nm {0.3 ~ 0.5 kgm} 6. Check for travel deviation again. If the machine still deviates, adjust again according to the above procedure. ★ Do not loosen the adjustment plugs more than the adjustable range (2 turns / 720 degrees).

20-128 b

PC78US-6

TESTING AND ADJUSTING

TESTING PARTS WHICH CAN CAUSE HYDRAULIC DRIFT OF WORK EQUIPMENT

TESTING PARTS WHICH CAN CAUSE HYDRAULIC DRIFT OF WORK EQUIPMENT a Hydraulic oil temperature for measurement: 45 – 55 °C 1. Work equipment cylinder a If the hydraulic drift of the work equipment exceeds the standard value, measure the leakage in the cylinder according to the following procedure to see if the cause of the hydraulic drift is on the cylinder side or control valve side. • If the leakage is less than the standard value, the cause is on the control valve side. • If the leakage is above the standard value, the cause is on the cylinder side. 1) Extend the rod of the cylinder to be measured and stop the engine. 2) Disconnect hoses (1) – (4) on the head side and block the pipes on the machine side with plugs. 1. Boom cylinder head hose 2. Arm cylinder head hose 3. Bucket cylinder head hose 4. Offset cylinder head hose

Machine Model: PC78UU-6

Machine Model: PC78US-6

Take care not to disconnect the bottom hoses.

3) Run the engine at full throttle and apply relief pressure to the cylinder bottom.

Machine Model: PC78UU-6

4) After 30 seconds, measure the oil leakage in 1 minute.

PC78US-6

20-129 (12)

TESTING AND ADJUSTING

MEASURING OIL LEAKAGE FROM SWING AND TRAVEL MOTORS

MEASURING OIL LEAKAGE FROM SWING AND TRAVEL MOTORS a Measuring instrument for oil leakage Symbol L

Part No.

Part name

Commercially available Measuring cylinder

a Hydraulic oil temperature for measurement: 45 – 55 °C 1. Swing motor 1) Disconnect drain hose (1) of the swing motor (on the hydraulic tank side). a Plug the hydraulic tank. 2) Stick the bucket into the ground to lock the swing mechanism. 3) Run the engine at full throttle and relieve the swing circuit. 4) After 30 seconds, measure the oil leakage in 1 minute. a After measuring 1 time, swing 180° and measure again.

20-130 (12)

2. Travel motor 1) Disconnect drain hose (3) of the travel motor and plug the hose. 2) Put a block in the grouser of the track shoe or between the sprocket and the frame to lock the track shoe. 3) Run the engine at full throttle and relieve the travel circuit. Since a wrong operation of a lever can cause an accident, make signs and confirm the operations security. 4) After 30 seconds, measure the oil leakage in 1 minute. a Measure the oil leakage several times, moving the motor little by little (shifting the valve plate and piston from the cylinder).

PC78US-6

TESTING AND ADJUSTING

RELEASING RESIDUAL PRESSURE FROM HYDRAULIC CIRCUIT

RELEASING RESIDUAL PRESSURE FROM HYDRAULIC CIRCUIT ★ Since an accumulator is not installed, the residual pressure in the piping between the control valve and each hydraulic cylinder or swing motor cannot be released even if the control levers are operated. Accordingly, when removing the above piping, observe the following points. 1) Run the engine at low speed and lower the work equipment to the ground, taking care not to relieve the cylinder at the stroke end, then stop the engine. ★ If the hydraulic cylinder is relieved at the stroke end before the engine is stopped, do not perform the following work for 5 ~ 10 minutes. 2) Loosen pressure release plug (4) of the control valve gradually to release the residual pressure from the circuit.

PC78US-6

20-131 b

TESTING AND ADJUSTING

TESTING CLEARANCE OF SWING CIRCLE BEARING

TESTING CLEARANCE OF SWING CIRCLE BEARING Method of testing clearance of swing circle bearing on machine 1. Fix dial gauge with magnet (1) to the swing circle outer ring (2) (or inner ring) (3) and apply the probe to the end face of the inner ring (or outer ring). Set the dial gauge to the front or rear part.

4. Set the arm at about right angles to the ground and lower the boom until the front part of the undercarriage floats. At this time, the front part of the upper structure rises and the rear part lowers. 5. Read the dial gauge. The indicated value is the clearance of the swing circle bearing. WARNING! Do not put your hand or foot under the undercarriage during measurement.

2. Extend the work equipment to the maximum reach and set the bucket tip to the height of the underside of the revolving frame. At this time, the front part of the upper structure lowers and the rear part rises. 3. Set the dial gauge to the zero point. 6. Set the machine in the position explained in 2 above again and check that the dial gauge indicates zero. If the dial gauge does not indicate zero, repeat Steps 2 ~ 5.

20-132 b

PC78US-6

TESTING AND ADJUSTING TRACK SHOE TENSION

TESTING AND ADJUSTING

TESTING AND ADJUSTING TRACK SHOE TENSION Testing 1. Run the engine at low idling and move the machine forward by the length of the track on the ground and stop slowly. 2. Place square wood bar (3) over idler (1) and carrier roller (2). 3. Measure the maximum distance between the top of the track and the underside of the wood bar. • If the standard slack a is in the following range, the shoe tension is normal. Specification

Standard Slack a

Road liner, steel shoe

10 – 30 mm

Rubber shoe

1 – 3 mm

Adjusting a If the track shoe tension is abnormal, adjust it according to the following procedure. 1. When tension is too high. 1) Loosen valve (1) to discharge grease. Since the high pressure grease may spurt out, do not loosen the valve more than 1 turn. a If the grease is not discharged sufficiently, move the machine slowly forward and in reverse. 2) To check that the track shoe tension is normal, run the engine at low idling and move the machine forward by the length of track on ground and stop slowly. 3) Test the track shoe tension again. If it is still not normal, adjust it again. 2. When tension is low 1) Supply grease through grease fitting (2). a If the track shoe tension is not tensed well, move the machine slowly forward and in reverse. 2 Grease fitting: Grease (G2-LI)

2) To check that the track shoe tension is normal, run the engine at low idling and move the machine forward by the length of track on ground and stop slowly. 3) Test the track shoe tension again. If it is still not normal, adjust it again.

PC78US-6

20-133 (12)

BLEEDING AIR FROM HYDRAULIC CIRCUIT

TESTING AND ADJUSTING

BLEEDING AIR FROM HYDRAULIC CIRCUIT Contents of work and procedures for bleeding air Air bleeding item

Procedure for Bleeding Air 1

—

2

3

4

5

6

7

8

Bleeding air from pump

Starting engine

Bleeding air from circuit between pump and hydraulic tank

Bleeding air from LS circuit

Bleeding air from cylinders

Bleeding air from swing motor

Bleeding air from travel motor

Bleeding air from swing PPC circuit

Starting operation

Q

Q

Q

Q

Q

Contents of work • Replacing hydraulic oil • Cleaning strainer

Q Note)

Q

Q

• Replacing return filter element • Replacing or repairing pump • Removing suction pipe

Q Note)

Q

Q

• Replacing or repairing control valve

Q

• Replacing cylinder • Removing cylinder piping

Q

• Replacing swing motor • Removing swing motor piping

Q

• Replacing travel motor and swivel • Removing travel motor and swivel

Q

• Replacing or removing swing PPC circuit parts (Swing PPC valve, piping, pressure switch, etc.)

Q

Q Q

Q

Q

Q

Q

Q Q

Q

Q Q

Q

Q Q

Q Q

Q

Note: Bleed air from the swing motor and travel motor only after the oil in the motor case is drained. 1. Bleeding air from pump a If the pump is operated without filling pump case with hydraulic oil, it is heated abnormally and may be broken soon. Accordingly, bleed all air from the pump before operating the pump. 1) Loosen air bleeder (1) installed to the drain port and check that oil oozes out. 2) After bleeding air, tighten the air bleeder. 3 Bleeder: 7.8 – 9.8 Nm {0.8 – 1.0 kgm}

20-134 (12)

2. Bleeding air between pump and hydraulic tanks. a If the pump is operated without bleeding air from the circuit between the pump and hydraulic tank, it is heated abnormally and may be broken soon. Accordingly, bleed all air. 1) Run the engine at medium speed (approx. 1,650 rpm) 2) Operate the work equipment slowly for about 5 minutes to bleed air. 3. Bleeding air from LS circuit a Bleed air only after the hoses of the pump, valve, and LS circuit are replaced. a If air is not bled from the LS circuit, the work equipment may malfunction. 1) Loosen air bleeder (2) installed to the LS port of the pump. 2) Run the engine at low idling for 2 minutes. 3) Operate the bucket (dump and curl bucket to the stroke ends) for about 2 minutes. 4) After bleeding air, tighten air bleeder (2).

PC78US-6

TESTING AND ADJUSTING

BLEEDING AIR FROM HYDRAULIC CIRCUIT

4. Bleeding air from hydraulic cylinder a If the engine speed is heightened or the cylinder is moved to the stroke end at first, the air in the cylinder will damage the piston packing, etc. 1) Run the engine at medium speed (approx. 1,650 rpm) and move each cylinder to about 100 mm before each stroke end 4 – 5 times. a Never relieve the oil. 2) Move each cylinder to each stroke end 3 – 4 times. 3) Move each cylinder to each stroke end 4 – 5 more times to bleed air. 5. Bleeding air from swing motor a Bleed air from the swing motor only after the oil is drained from the swing motor case. a If the swing motor is operated without bleeding air from it, its bearings may be broken. 1) Run the engine at low idling and loosen drain hose (3). If oil oozes out, tighten the drain hose. a Do not swing the machine while bleeding air. 2) Keep the engine speed at low idling and swing evenly at least 2 turns in each direction.

7. Bleeding air from swing PPC circuit 1) Stick the bucket into the ground to lock the swing mechanism. 2) Run the engine at low idling. 3) Loosen air bleeders (4) and (5) of the control valve. 4) Move the swing control lever through the full stroke repeatedly to check that all air is bled through bleeders (4) and (5). 5) Tighten bleeders (4) and (5). Bleeder: 7.8 – 9.8 Nm {0.8 – 1.0 kgm}

6. Bleeding air from travel motor a Bleed air from the travel motor only after the oil is drained from the travel motor case. 1) Run the engine at low idling and loosen drain hose (3). If oil oozes out, tighten the drain hose. 2) Keep the engine speed at low idling and swing 90° and float the track a little with the work equipment, then run idle for 2 minutes. 3) Perform Step 2 above for each side.

PC78US-6

20-135 (12)

PROCEDURE FOR ADJUSTING INSTALLATION OF LONG ARM

TESTING AND ADJUSTING

PROCEDURE FOR ADJUSTING INSTALLATION OF LONG ARM •

When replacing the work equipment with the long arm, observe the following procedure. a If a breaker, clamshell bucket, wide bucket, long arm other than Komatsu genuine long arm, etc. is installed, the interference prevention mechanism does not work. take car,

2. Reset the input and output signals without fail. a For details, see TROUBLESHOOTING.

PC78US-6 Serial No.: 4001 and up PC78UU-6 Serial No.: 22832 and up 1. Replace attachment selection wiring harness (1) with one for the replaced attachment. Table 1 Attachment selection wiring harness Specification

Attachment selection connector

Model Arm

Additional weight

Part No.

Color

PC78US-6 Serial No.: 6501 and up

Standard

Installed/ Not installed

20U-06-42260

Black

•

20U-06-42260 (20U-06-42280 is also usable)

Black

20U-06-42280

Green

Not installed

20U-06-42260

Black Black

Installed

20U-06-42260 (20U-06-42290 is also usable) 20U-06-42290

White

20U-06-42280

Green

20U-06-42280

Green

20U-06-42310

Blue

20U-06-42280 (20U-06-42310 is also usable)

Green

PC78US Long

Installed/ Not installed

Standard

PC78UU

Refer to TROUBLESHOOTING, Special functions of monitor panel, [18] (Setting arm crane specification) and [19] (Setting model and attachment), set the necessary items by operating the monitor panel.

Not installed Long Installed

20-136 (12)

PC78US-6

TESTING AND ADJUSTING

TESTING AND ADJUSTING HOOD CATCH

TESTING AND ADJUSTING HOOD CATCH Testing Press key lock (1) of the hood, hold knob (2), and raise the hood in the opening direction to check for "play".

2. Adjustment of stopper (3) height (at the center) Remove the rubber cover of hood knob (2) and adjust the projection of stopper (3) until the stopper touches bracket (6) through the hole (9) of the hood knob.

Adjusting a If there is "play", adjust it according to the following procedure. 1. Open the hood, loosen nut (4) of hood stopper (3), and reduce projection "a" of stopper (3).

PC78US-6

20-136-1 (18)

TESTING AND ADJUSTING

TESTING AND ADJUSTING HOOD CATCH

3. Adjustment of hook (5) installation in fore-aft direction of the machine Loosen mounting bolt (7) of bracket (6), move the bracket, and tighten the mounting bolt again. Clearance b: 0 mm (target value) Clearance c: 0 ± 1 mm (target value) a Close the hood and repeat the above procedure until "play" has been eliminated. At this time, ensure that the effort required to operate the hood key lock is not increased. (If lock bar (8) of the bracket is pressed strongly against key lock hook (5), the effort required to operate the key lock is increased preventing smooth hood opening and closing operation.) a Key lock operating effort: Max. 49.0 N {5 kg}

4. Open and close the hood several times to ensure that "play" has been eliminated, and return the rubber cover of knob (2).

20-136-2 (18)

PC78US-6

TESTING AND ADJUSTING

REPLACEMENT PROCEDURE OF POTENTIOMETERS

REPLACEMENT PROCEDURE OF POTENTIOMETERS PC78UU-6 a It is impossible to replace only the potentiometers. Accordingly, if the potentiometers need to be replaced, replace the case assemblies. If the case assemblies need to be used again, fix levers (3), (6), and (10) to the potentiometer bodies before removing them. 1. Remove potentiometer assemblies (1), (4), and (8) from the work equipment. a Do not swing a removed potentiometer assembly around its lever or turn the lever unnecessarily. • Boom potentiometer (1) • Arm potentiometer (4) • Offset potentiometer (8) 2. Install potentiometer assemblies (1), (4), and (8). 3. Be sure to reset input and output signals. a For details, see TROUBLESHOOTING, Resetting procedure. a It is possible to connect arm potentiometer rod (7) even if lever (6) of the potentiometer assembly is in the opposite position, so be particularly careful when rod (7) has been disconnected. a If it is connected in the opposite position, error code [E40] will be displayed when the starting switch is turned ON, and the buzzer will sound. a If this happens, turn the starting switch OFF and connect the rod (7) correctly. a When rod (7) is installed to lever (6), it may be broken by the tightening force of the mounting bolt. To prevent this, hold lever (6) with a spanner, etc. when tightening the mounting bolt.

PC78US-6

20-137 (13)

PROCEDURE FOR TESTING DIODE

TESTING AND ADJUSTING

PROCEDURE FOR TESTING DIODE a Check an assembled-type diode (8 pins) and single diode (2 pins) in the following manner.

a The conductive direction of each diode is marked on its surface as shown below.

1. When using digital type circuit tester 1) Switch the testing mode to diode range and confirm the indicated value. a Voltage of the battery inside is displayed with conventional circuit testers. 2) Put the red probe (+) of the test lead to the anode (P) and the black probe (–) to the cathode (N) of diode, and confirm the displayed value. 3) Determine if a specific diode is good or no good with the indicated value. • No change in the indicated value: No continuity (defective). • Change in the indicated value: Continuity established (normal) (Note) a A silicon diode shows a value between 460 and 600.

20-138 (12)

2. When using analog type circuit tester 1) Switch the testing mode to resistance range. 2) Check the needle swing in case of the following connections. i) Put the red probe (+) of the test lead to the anode (P) and the black probe (–) to the cathode (N) of diode. ii) Put the red probe (+) of the test lead to the cathode (N) and the black probe (–) to the anode (P) of diode. 3) Determine if a specific diode is good or no good by the way the needle swings. • If the needle does not swing in Case i), but swings in Case ii): Normal (but the breadth of swing (i.e. resistance value) will differ depending on a circuit tester type or a selected measurement range) • If the needle swings in either case of i) and ii): Defective (short-circuited internally) • If the needle does not swing in any case of i) and ii): Defective (short-circuited internally)

PC78US-6

Pm-CLINIC SERVICE

TESTING AND ADJUSTING

Pm-CLINIC SERVICE Model

Serial No.

Engine serial No.

Service meter

T PC78UU-6 T PC78US-6

h

Implemented on /

User's name

Operator's name

Inspector

/

t Equipment Main work equipment T Standard T Standard T Standard T Standard

Boom: Arm: Bucket: Blade:

T( T( T( T(

Optional work equipment ) ) ) )

T Arm crane T Breaker T( T(

) )

Shoe T City pad shoe T Road liner T Triple shoe T Rubber shoe T(

)

t Oil and coolant level check Must check item T Engine coolant T Engine oil T Hydraulic oil

As required T Damper case oil T Machinery case oil T Final drive case oil

T( T( T(

) ) )

t Operation place Ambient temperature T T

Elevation °C °F

m

t Operator's comment

t Result of visual check

t Failure code history Code No.

Symptom (Refer to SHOP MANUAL page 20-248)

Indication elapsed time h h h h h h h h h

PC78US-6

20-139 (15)

Pm-CLINIC SERVICE

TESTING AND ADJUSTING

Check sheet (1/3) Model

Serial No.

Service meter

T PC78UU-6 T PC78US-6

User's name

Implemented on /

h

Inspector

/

1. Engine No.

1

2

3

Check item

Engine speed

Engine oil pressure

Blow-by pressure

20-140 (15)

At high idle At low idle

Checking condition

Unit

Standard value for new machine

• Hydraulic oil temp.: 45 – 55°C • Coolant temp.: At operating range • Hydraulic pump relief (Arm IN relief)

rpm

Min.1,800

0.34 – 0.54 • Coolant temp.: {3.5 – 5.5} At operating range MPa • Engine oil: SAE30 2 {kg/cm } Min.0.18 {Min.1.8} • Coolant temp.: At operating range Pa • Engine speed: {mmH2O} 1,850rpm (Rated speed) • Engine oil: SAE30

Max.490 {Max.50}

Service limit value

Min.1,800

Judgment Measured value Good Bad

Min.0.25 {Min.2.5} Min.0.13 {Min1.3} Max.980 {Max.100}

PC78US-6

Pm-CLINIC SERVICE

TESTING AND ADJUSTING

Check sheet (2/3) 2. Work equipment speed No.

1

2

3

4

5

Check item

Checking condition

Service limit value

2.9 – 3.5 (PC78UU)

Max. 4.0 (PC78UU)

3.1 – 3.9 (PC78US)

Max. 4.3 (PC78US)

• Hydraulic oil temp.: 45 – 55°C • Engine speed: High idle • Bucket tooth on ground o Max. extension of cylinder (To just before cushion)

sec.

Arm IN (*1)

• Hydraulic oil temp.: 45 – 55°C • Engine speed: High idle • Max.retraction of cylinder o Max. extension of cylinder (To just before cushion)

sec.

2.9 – 3.5

Max. 4.0

Arm OUT (*1)

• Hydraulic oil temp.: 45 – 55°C • Engine speed: High idle • Max.extension of cylinder o Max. retraction of cylinder (To just before cushion)

sec.

2.4 – 3.0

Max. 3.3

Bucket CURL

• Hydraulic oil temp.: 45 – 55°C • Engine speed: High idle • Max.retraction of cylinder o Max. extension of cylinder

sec.

2.7 – 3.5

Max. 3.9

Swing (5 turns)

• Hydraulic oil temp.: 45 – 55°C • Engine speed: High idle • Time required to swing 5 turns after swinging 1 turn • Work equipment extended fully

sec.

28 – 32

Max. 35

31 – 37

Max. 41

Travel (5 idle turns)

• Hydraulic oil temp.: 45 – 55°C • Engine speed: High idle • Raise either track and measure time required to move 5 turns after finishing 1 turn. • ( ): Rubber shoe spec.

22 – 28 (21 – 25)

Max. 30 (Max. 28)

Boom RAISE

Low 6

Unit

Standard value for new machine

High

Judgment Measured value Good Bad

sec.

*1: Offset to right so that clearance between right end of operator's cab and bucket will be 200mm or wider. (Only PC78UU-6)

PC78US-6

20-141 (15)

Pm-CLINIC SERVICE

TESTING AND ADJUSTING

Check sheet (3/3) 3. Oil pressure No.

1

2

Check item

• Hydraulic oil temp.: MPa 3.14 – 3.34 3.14 – 3.44 45 – 55°C {32 – 35} {kg/cm2} {32 – 34} • Engine speed: High idle

Main relief pressure

• Hydraulic oil temp.: 45 – 55°C MPa 25.5 – 27.5 25.0 – 27.9 • Engine speed: High idle {kg/cm2} {260 – 280} {255 – 285} • Operation: Arm dump relief

LS differential pressure

4

Swing safety valve relief pressure

With blade Without blade

• Hydraulic oil temp.: 45 – 55°C MPa • Engine speed: High idle {kg/cm2} • Operation: Swing lock switch ON

All levers • Hydraulic oil temp.: in neutral 45 – 55°C • Engine speed: High idle Float one • Operation: Refer left line side track and run idle

All levers in neutral Float one side track and run idle

(15)

22.1 – 24.0 21.6 – 24.5 {225 – 245} {220 – 250}

0.54 – 0.83 0.54 – 0.83 {5.5 – 8.5} {5.5 – 8.5} 0 – 0.2 {0 – 2}

0 – 0.2 {0 – 2}

2.74 – 3.53 2.74 – 3.53 {28 – 36} {28 – 36}

MPa 2} {kg/cm • Hydraulic oil temp.: 0.93 – 1.23 0.93 – 1.23 45 – 55°C {9.5 – 12.5} {9.5 – 12.5} • Engine speed: High idle • Operation: Refer left line 0.05 – 0.25 0.05 – 0.25 {0.5 – 2.5} {0.5 – 2.5}

<Machine model> PC78UU: • Hydraulic oil temp.: 23501 and up All levers 45 – 55°C PC78US: in neutral • Engine speed: Low idle 5501 and up • Operation: Refer left line

20-142

19.6 – 21.48 19.1 – 22.1 {200 – 220} {195 – 225}

• Hydraulic oil temp.: 45 – 55°C MPa 25.5 – 27.5 25.0 – 27.9 • Engine speed: High idle {kg/cm2} {260 – 280} {255 – 285} • Operation: Track shoe fixed

<Machine model> PC78UU: • Hydraulic oil temp.: 22001 – 23500 All levers 45 – 55°C PC78US: in neutral • Engine speed: Low idle 4001 – 5500 • Operation: Refer left line TVC-EPC solenoid output pressure

Judgment Measured value Good Bad

All levers • Hydraulic oil temp.: 2.5 – 4.4 2.5 – 4.4 in neutral 45 – 55°C {25 – 45} {25 – 45} • Engine speed: High idle MPa Bucket • Operation: Refer left line {kg/cm2} CURL 2.01 – 2.21 2.01 – 2.21 (Lever at {20.5 – 22.5} {20.5 – 22.5} FULL)

Travel safety valve relief pressure

TVC-EPC solenoid output pressure

6

Unit

Service limit value

Control pressure

3

5

Checking condition

Standard value for new machine

2.74 – 3.53 2.74 – 3.53 {28 – 36} {28 – 36}

PC78US-6

TROUBLESHOOTING Points to remember when troubleshooting.................................................................................................. 20-202 Sequence of events in troubleshooting ....................................................................................................... 20-203 Precautions when carrying out maintenance .............................................................................................. 20-204 Checks before troubleshooting ................................................................................................................... 20-212 CONNECTOR TYPES AND MOUNTING LOCATIONS (PC78US-6 Serial No.: 4001 – 5500) ................. 20-214 Connector arrangement diagram (PC78US-6 Serial No.: 4001 – 5500)................................................. 20-215-1 CONNECTOR TYPES AND MOUNTING LOCATIONS (PC78US-6 Serial No.: 5501 – 6500) ................. 20-217 CONNECTOR ARRANGEMENT DIAGRAM (PC78US-6 Serial No.: 5501 – 6500)............................... 20-218-2 CONNECTOR TYPES AND MOUNTING LOCATIONS (PC78US-6 Serial No.: 6501 and up) .............. 20-218-5 CONNECTOR ARRANGEMENT DIAGRAM (PC78UU-6 Serial No.: 6501 and up)............................... 20-218-8 CONNECTOR TYPES AND MOUNTING LOCATIONS (PC78UU-6 Serial No.: 22832 – 23500) ............. 20-219 CONNECTOR ARRANGEMENT DIAGRAM (PC78UU-6 Serial No.: 22832 – 23500)........................... 20-219-3 CONNECTOR TYPES AND MOUNTING LOCATIONS (PC78UU-6 Serial No.: 23501 and up) ............ 20-219-6 CONNECTOR ARRANGEMENT DIAGRAM (PC78UU-6 Serial No.: 23501 and up)............................. 20-219-9 Connection table for connector pin numbers .............................................................................................. 20-220 Explanation of functions of electric system control mechanism .................................................................. 20-244 Display and special functions of monitor panel ........................................................................................... 20-246 TVC valve current adjustment table ......................................................................................................... 20-255-4 How to read flow of troubleshooting......................................................................................................... 20-255-6 Contents and procedure of troubleshooting ................................................................................................ 20-260 Troubleshooting for communication system (N mode)................................................................................ 20-301 Troubleshooting for controller (governor control system) (E mode)............................................................ 20-325 Troubleshooting for controller (pump control system) (C mode)................................................................. 20-351 Troubleshooting for controller (input signal system) (F mode).................................................................... 20-401 Troubleshooting for hydraulic and mechanical systems (H mode) ............................................................. 20-425 Troubleshooting for machine monitor system (M mode) ............................................................................. 20-501

PC78US-6

20-201 (13)

TROUBLESHOOTING

POINTS TO REMEMBER WHEN TROUBLESHOOTING

POINTS TO REMEMBER WHEN TROUBLESHOOTING Stop the machine in a level place, and check that the safety pin, blocks, and parking brake are securely fitted. When carrying out the operation with two or more workers, keep strictly to the agreed signals, and do not allow any unauthorized person to come near. If the radiator cap is removed when the engine is hot, hot coolant may spurt out and cause burns, so wait for the engine to cool down before starting troubleshooting. Be extremely careful not to touch any hot parts or to get caught in any rotating parts. When disconnecting wiring, always disconnect the negative (–) terminal of the battery first. When removing the plug or cap from a location which is under pressure from oil, water or air, always release the internal pressure first. When installing measuring equipment, be sure to connect it properly. The aim of troubleshooting is to pinpoint the basic cause of the failure, to carry out repairs swiftly, and to prevent reoccurrence of the failure. When carrying out troubleshooting, an important point is to understand the structure and function of the machine. However, a short cut to effective troubleshooting is to ask the operator various questions to form some idea of possible causes of the failure that would produce the reported symptoms. 1. When carrying out troubleshooting, do not hurry to disassemble the components. If components are disassembled immediately after a failure occurs: • Parts that have no connection with the failure or other unnecessary parts will be disassembled. • It will become impossible to find the cause of the failure. It will also cause a waste of man hours, parts, or oil and grease. At the same time, it will also lose the confidence of the user or operator. For this reason, when carrying out troubleshooting, it is necessary to carry out thorough prior investigation and to carry out troubleshooting in accordance with the fixed procedure. 2. Points to ask the user or operator. 1) Have any other problems occurred apart from the problem that has been reported? 2) Was there anything strange about the machine before the failure occurred? 3) Did the failure occur suddenly, or were there problems with the machine condition before this? 4) Under what conditions did the failure occur? 5) Had any repairs been carried out before the failure? When were these repairs carried out? 6) Has the same kind of failure occurred before?

4) Check the stroke of the control valve spool. 5) Other maintenance items can be checked externally, so check any item that is considered to be necessary. 4. Confirming the failure. Confirm the extent of the failure yourself, and judge whether to handle it as a real failure or as a problem with the method of operation, etc. a When operating the machine to re-enact the troubleshooting symptoms, do not carry out any investigation or measurement that may make the problem worse. 5. Troubleshooting Use the results of the investigation and inspection in Steps 2 – 4 to narrow down the causes of the failure, then use the troubleshooting flowchart to locate the position of the failure exactly. a The basic procedure for troubleshooting is as follows. 1) Start from the simple points. 2) Start from the most likely points. 3) Investigate other related parts or information. 6. Measures to remove root cause of failure. Even if the failure is repaired, if the root cause of the failure is not repaired, the same failure will occur again. To prevent this, always investigate why the problem occurred. Then, remove the root cause.

3. Check before troubleshooting. 1) Check the oil level. 2) Check for any external leakage of oil from the piping or hydraulic equipment. 3) Check the travel of the control levers.

20-202 (12)

PC78US-6

TROUBLESHOOTING

SEQUENCE OF EVENTS IN TROUBLESHOOTING

SEQUENCE OF EVENTS IN TROUBLESHOOTING

PC78US-6

20-203 (2)

TROUBLESHOOTING

PRECAUTIONS WHEN CARRYING OUT MAINTENANCE

PRECAUTIONS WHEN CARRYING OUT MAINTENANCE To maintain the performance of the machine over a long period, and to prevent failures or other troubles before they occur, correct operation, maintenance and inspection, troubleshooting, and repairs must be carried out. This section deals particularly with correct repair procedures for mechatronics and is aimed at improving the quality of repairs. For this purpose, it gives sections on 'Handling electric equipment' and 'Handling hydraulic equipment' (particularly hydraulic oil). 1. PRECAUTIONS WHEN HANDLING ELECTRIC EQUIPMENT 1) Handling wiring harnesses and connectors Wiring harnesses consist of wiring connecting one component to another component, connectors used for connecting and disconnecting one wire from another wire, and protector or tubes used for protecting the wiring. Compared with other electrical components fitted in boxes or cases, wiring harnesses are more likely to be affected by the direct effects of rain, water, heat, or vibration. Furthermore, during inspection and repair operations they are frequently removed and installed again, so they are likely to suffer deformation or damage. For this reason, it is necessary to be extremely careful when handling wiring harnesses. •

Main failures occurring in wiring harness (1) Faulty contact of connectors (faulty contact between male and female). Problems with faulty contact are likely to occur because the male connector is not properly inserted into the female connector, or because one or both of the connectors is deformed or the position is not correctly aligned, or because there is corrosion or oxidation of the contact surfaces. (2) Defective compression or soldering of connectors The pins of the male and female connectors are in contact at the compressed terminal or soldered portion, but there is excessive force on the wiring, and the plating peels to cause improper connection or breakage.

20-204 (12)

PC78US-6

TROUBLESHOOTING

PRECAUTIONS WHEN CARRYING OUT MAINTENANCE

(3) Disconnections in wiring If the wiring is held and tugged and the connectors are pulled apart, or components are lifted with a crane with the wiring still connected, or a heavy object hits the wiring, the crimping compression of the connectors to the wire may be loosened, or the soldering may be damaged, or the wiring may be broken. (4) High pressure water entering a connector The connector is designed to make it difficult for water to enter (drip-proof structure), but if high-pressure water is sprayed directly on the connector, water may enter the connector depending on the direction of the water jet. The connector is designed to prevent water from entering, but if water does enter, it is difficult for it to be drained. Therefore, if water should get into the connector, the pins will be short-circuited by the water, so if any water gets in, immediately dry the connector or take other appropriate action before passing electricity through it. (5) Oil, grease or dirt stuck to connector If oil or grease are stuck to the connector and an oil film is formed on the mating surface between the male and female pins, the oil will not let the electricity pass, and this will cause a defective contact. If there is oil or grease or dirt stuck to the connector, wipe it off with a dry cloth or blow dry with air, and spray it with a contact restorer. a When wiping the mating portion of the connector, be careful not to use excessive force or deform the pins. a If there is water or oil present, it will increase the contamination of the points, so clean with air until all water and oil has been removed.

PC78US-6

20-205 (12)

TROUBLESHOOTING

PRECAUTIONS WHEN CARRYING OUT MAINTENANCE

2) Removing, installing, and drying connectors and wiring harnesses • Disconnecting connectors (1) Hold the connectors when disconnecting. When disconnecting the connectors, hold the connectors and not the wires. For connectors held by a screw, loosen the screw fully, then hold the male and female connectors in each hand and pull apart. For connectors which have a lock stopper, press down the stopper with your thumb and pull the connectors apart. a Never try to pull apart with one hand. (2) When removing the connectors from the clips, pull the connector in a parallel direction to the clip. a If the connector is twisted to the left and right or up and down, the housing may break.

(3) Action to take after removing connectors. After removing any connector, cover it with a vinyl bag to prevent any dust, dirt, oil, or water from getting in the connector portion. a If the machine is left for a long time, it is particularly easy for improper contact to occur, so always cover the connector.

20-206 (12)

PC78US-6

TROUBLESHOOTING

•

PRECAUTIONS WHEN CARRYING OUT MAINTENANCE

Connecting connectors (1) Check the connector visually. i) Check that there is no oil, dirt, or water stuck to the connector pins (mating portion). ii) Check that there is no deformation, defective contact, corrosion, or damage to the connector pins. iii) Check that there is no damage or breakage to the outside of the connector. a If there is any oil, water, or dirt stuck to the connector, wipe it off with a dry cloth. If any water has got inside the connector, warm the inside of the wiring with a dryer, but be careful not to make it too hot as this will cause short circuits. a If there is any damage or breakage, replace the connector. (2) Fix the connector securely. Align the position of the connector correctly, then insert it securely. For connectors with lock stopper, push in the connector until the stopper clicks into position. (3) Correct any protrusion of the boot and any misalignment of the wiring harness. For connectors fitted with boots, correct any protrusion or the boot. In addition, if the wiring harness is misaligned, or the clamp is out of position, adjust it to its correct position. a If the connector cannot be corrected easily, remove the clamp and adjust the position. (4) If the connector clamp has been removed, be sure to return it to its original position. Check also that there are no loose clamps.

•

Connecting connectors (DT type connector) Since the DT 8-pole and 12-pole DT type connectors have 2 latches respectively, push them in until they click 2 times. 1. Male connector, 2. Female connector • Normal locking state (Horizontal): a, b, d • Incomplete locking state (Diagonal): c

PC78US-6

20-207 (12)

TROUBLESHOOTING

•

PRECAUTIONS WHEN CARRYING OUT MAINTENANCE

Drying wiring harness If there is any oil or dirt on the wiring harness, wipe it off with a dry cloth. Avoid washing it in water or using steam. If the connector must be washed in water, do not use high pressure water or steam directly on the wiring harness. If water gets directly on the connector, do as follows: (1) Disconnect the connector and wipe off the water with a dry cloth. a If the connector is blown dry with air, there is the risk that oil in the air may cause a faulty contact, so avoid blowing with air. (2) Dry the inside of the connector with a dryer. If water gets inside the connector, use a dryer to dry the connector. a Hot air from the dryer can be used, but be careful not to make the connector or related parts too hot, as this will cause deformation or damage to the connector.

(3) Carry out a continuity test on the connector. After drying, leave the wiring harness disconnected and carry out a continuity test to check for any short circuits between pins caused by water. a After completely drying the connector, spray it with contact restorer and reassemble.

20-208 (12)

PC78US-6

TROUBLESHOOTING

PRECAUTIONS WHEN CARRYING OUT MAINTENANCE

3) Handling control box (1) The control box contains a microcomputer and electronic control circuits. This controls all of the electronic circuits on the machine, so be extremely careful when handling the control box. (2) Do not open the cover of the control box unless necessary.

(3) Do not place objects on top of the control box. (4) Cover the control connectors with tape or a vinyl bag. (5) Never touch the connector contacts with your hand. (6) Do not leave the control box in a place where it is exposed to rain.

(7) Do not place the control box on oil, water, or soil, or in any hot place, even for a short time. (Place it on a suitable dry stand) (8) Precautions when carrying out arc welding When carrying out arc welding on the body, disconnect all wiring harness connectors connected to the control box. Fit an arc welding ground close to the welding point.

2. Points to remember when troubleshooting electric circuits 1) Always turn the power OFF before disconnecting or connecting connectors. 2) Before carrying out troubleshooting, check that all the related connectors are properly inserted. a Disconnect and connect the related connectors several times to check. 3) Always connect any disconnected connectors before going on to the next step. a If the power is turned ON with the connectors still disconnected, unnecessary abnormality displays will be generated. 4) When carrying out troubleshooting of circuits (measuring the voltage, resistance, continuity, or current), move the related wiring and connectors several times and check that there is no change in the reading of the tester. a If there is any change, there is probably defective contact in the circuit.

PC78US-6

20-209 (12)

TROUBLESHOOTING

PRECAUTIONS WHEN CARRYING OUT MAINTENANCE

3. Points to remember when handling hydraulic equipment With the increase in pressure and precision of hydraulic equipment, the most common cause of failure is dirt (foreign material) in the hydraulic circuit. When adding hydraulic oil, or when disassembling or assembling hydraulic equipment, it is necessary to be particularly careful. 1) Be careful of the operating environment Avoid adding hydraulic oil, replacing filters, or repairing the machine in rain or high winds, or places where there is a lot of dust. 2) Disassembly and maintenance work in the field If disassembly or maintenance work is carried out on hydraulic equipment in the field, there is danger of dust entering the equipment. It is also difficult to confirm the performance after repairs, so it is desirable to use unit exchange. Disassembly and maintenance of hydraulic equipment should be carried out in a specially prepared dust proof workshop, and the performance should be confirmed with special test equipment.

3) Sealing openings After any piping or equipment is removed, the openings should be sealed with caps, tape, or vinyl bags to prevent any dirt or dust from entering. Never leave any openings opened or blocked with a rag, this could cause particles or dirt to get into the system. Drain all oil into a container and not unto the ground and be sure to follow the proper environmental regulation for any disposal of oil.

4) Do not let any dirt, or dust get in during refilling operations. Be careful not to let any dirt or dust get in when refilling with hydraulic oil. Always keep the oil filler and the area around it clean, and also use clean pumps and oil containers. If an oil cleaning device is used, it is possible to filter out the dirt that has collected during storage, so this is an even more effective method.

20-210 (2)

PC78US-6

TROUBLESHOOTING

PRECAUTIONS WHEN CARRYING OUT MAINTENANCE

5) Change hydraulic oil when the temperature is high. When hydraulic oil or other oil is warm, it flows easily. In addition, the sludge can also be drained out easily from the circuit together with the oil, so it is best to change the oil when it is still warm. When changing the oil, as much as possible of the old hydraulic oil must be drained out. (Do not drain the oil from the hydraulic tank; but drain the oil from the filter and from the drain plug in the circuit.) If any old oil is left, the contaminants and sludge in it will mix with the new oil and will shorten the life of the hydraulic oil. 6) Flushing operations After disassembling and assembling the equipment, or changing the oil, use flushing oil to remove the contaminants, sludge, and old oil from the hydraulic circuit. Normally, flushing is carried out twice: primary flushing is carried out with flushing oil, and secondary flushing is carried out with the specified hydraulic oil.

7) Cleaning operations After repairing the hydraulic equipment (pump, control valve, etc.) or when running the machine, carry out oil cleaning to remove the sludge or contaminants in the hydraulic oil circuit. The oil cleaning equipment is used to remove the ultra fine (about 3µ) particles that the filter built into the hydraulic equipment cannot remove, so it is an extremely effective device.

PC78US-6

20-211 c

TROUBLESHOOTING

CHECKS BEFORE TROUBLESHOOTING

CHECKS BEFORE TROUBLESHOOTING

Lubricating oil, coolant

Item 1. 2. 3. 4. 5. 6. 7. 8.

Check fuel level, type of fuel Check for impurities in fuel Check hydraulic oil level Check hydraulic oil strainer Check swing machinery oil level Check engine oil level, type of engine oil Check coolant level Check dust indicator for clogging

Electrical equipment

Hydraulic, Electrical mechanical equipment equipment

9. Check hydraulic oil filter 1.

Add fuel Clean, drain Add oil Clean, drain Add oil Add oil Add coolant Clean or replace

—

Replace

Action

Check for looseness, corrosion of battery terminal, wiring

—

Tighten or replace

2. Check for looseness, corrosion of alternator terminal, wiring

—

Tighten or replace

3. Check for looseness, corrosion of starting motor terminal, wiring

—

Tighten or replace

1.

—

Repair

2. Check for oil leakage

—

Repair

3. Carry out air bleeding

—

Bleed air

20 - 30 V — — —

Replace Add or replace Replace Repair

—

Disconnect connector and dry

— After running for several minutes: 27.5 ~ 29.5 V

Replace

—

—

Check for abnormal noise, smell

1. 2. 3. 4. 5.

Check battery voltage (Engine stopped) Check battery electrolyte level Check for discolored, burnt, exposed wiring Check for missing wiring clamps, hanging wire Check for water leaking on wiring (Pay particular attention to water leaking on connectors or terminals) 6. Check for blown, corroded fuses 7.

Check alternator voltage (Engine running at 1/2 throttle or above)

8. Sound of actuation of battery relay (When starting switch is turned ON, OFF)

20-212 b

Judgement Value — — — — — — — —

Replace

PC78US-6

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

CONNECTOR TYPES AND MOUNTING LOCATIONS PC78US-6 Serial No.: 4001 – 5500 a The addresses in the address column are used in the connector arrangement drawing (3-dimensional drawing). Connector No.

Type of Connector

No. of Pins

Location

Address

Connector No.

Type of Connector

No. of Pins

D4

SWP

2

Diode (Engine stop solenoid)

H-1

K33

SHINAGAWA

5

Decelerator relay

N-8

D5

SWP

2

Diode (Starting switch BR o Battery relay BR)

G-1

K34

SHINAGAWA

5

Motor drive relay

O-8

D6

SWP

2

Diode (Alternator R o Battery relay BR)

G-1

K42

SUMITOMO

16

Floor intermediate connector

P-8

D11

SWP

2

Diode (TVC solenoid)

R-5

K45

M

1

Radio ground

Q-3

D12

SWP

2

Diode (TVC solenoid)

R-4

K51

AMP090

20

Intermediate connector (Starting switch, light switch)

M-7

D13

SWP

2

Diode (Swing holding brake solenoid)

R-4

K52

M

3

Light switch

N-8

D22

SWP

2

Diode (Air conditioner compressor)

H-1

K53

M

2

Buzzer cancel switch

O-8

Fuse box

R-3

K54

M

3

Rotary lamp switch

P-8

FB1

Address

Location

K1

S1

12

Intermediate connector (Monitor panel)

N-7

M1

L

2

Intermediate connector (Power supply, ground)

M-4

K2

S

16

Intermediate connector (Monitor panel)

M-7

M2

X

2

Intermediate connector (Power supply, glow plug)

M-3

K3

DT

2

2nd travel speed selection solenoid valve

O-2

M3

DT

8

Intermediate connector (Fuel level sensor, hydraulic switch)

M-3

K11

SWP

12

Auto A/C unit

N-1

M4

DT

8

Intermediate connector (Washer, travel/swing alarm)

M-4

K12

M

2

Resister

Q-8

M5

DT

8

Intermediate connector (TVC, power supply, starting switch)

M-3

K17

X

2

Optional power supply

P-2

M6

DT

8

Intermediate connector (Pressure switch, air conditioner sensor)

M-3

K18

AMP090

2

Decelerator switch

Q-2

M7

DT

8

Intermediate connector

M-3

K19

PA

9

Radio

R-3

M9

DT

2

Intermediate connector (Fuel sensor)

I-2

K20

M

8

Cab inlet

R-6

M13

DT

2

PPC hydraulic lock

M-2

K21

S

8

Cab inlet

R-6

M14

DT

2

Swing holding brake

N-2

K22

DT

2

Attachment selector wire

P-8

M15

DT

2

Travel speed selector

M-2

K23

Relay

5

Starting motor cut relay (PPC lock)

R-7

M16

DT

2

Engine speed sensor

J-3

K26

AMP090

2

Horn switch

M-7

M17

X

1

Glow plug

K-8

K27

SWP

6

Fuel governor control motor

N-7

M18

DT

2

Engine water temperature

L-8

K28

M

3

PPC hydraulic lock switch

P-2

M19

X

1

Air conditioner compressor

L-7

K32

SHINAGAWA

5

Accelerator relay

O-8

M20

DT

2

TVC solenoid

K-8

20-214 (12)

PC78US-6

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

Connector No.

Type of Connector

No. of Pins

Address

Connector No.

Type of Connector

No. of Pins

M21

X

2

Pressure switch (Boom RAISE)

G-9

T5

Terminal

1

Alternator B

L-5

M22

X

2

Pressure switch (Swing)

I-9

T6

Terminal

1

Engine oil pressure switch

L-3

M23

X

2

Pressure switch (Swing)

G-9

T7

Terminal

1

Engine stop solenoid (+)

K-8

M24

X

2

Pressure switch (Arm IN)

H-9

T8

Terminal

1

Engine stop solenoid (-)

K-9

M25

X

2

Pressure switch (Travel)

I-9

T9

Terminal

1

Battery relay E

A-4

M26

L

2

Fusible link

C-8

T10

Terminal

1

Battery relay BR

A-3

M27

L

2

Fusible link

B-7

T11

Terminal

1

Battery relay M

A-6

M28

SWP

6

Intermediate connector (Working lamp)

J-9

T12

Terminal

1

Battery relay B

A-5

M30

X

2

Safety relay (S, R)

K-3

T31

Terminal

1

Safety relay B

K-3

M31

KES

2

Windshield washer

C-8

T32

Terminal

1

Safety relay C

J-3

M32

DT

2

Travel/Swing alarm (Optional)

J-2

T33

Terminal

1

Starting motor B

L-7

M33

DT

2

Air conditioner outside temperature sensor (Optional)

L-4

T34

Terminal

1

Starting motor C

L-6

M75

DT

2

Working lamp

D-9

W04

M

6

Wiper motor

M-5

M80

AMP040

2

Horn

M-2

W19

2

Cigarette lighter

M-5

M95

DT

24

Controller

R-8

B

Terminal

1

Starting switch terminal B

M-9

M96

DT

40

Controller

R-8

BR

Terminal

1

Starting switch terminal BR

M-8

M97

DT

40

Controller

Q-8

ACC

Terminal

1

Starting switch terminal ACC

M-8

M99

DT

2

Arm ground angle alarm cancel selector

Q-8

C

Terminal

1

Starting switch terminal C

M-9

M100

SHINAGAWA

5

Rotary lamp drive relay

R-7

R1

Terminal

1

Starting switch terminal R1

N-8

P01

AMP040

12

Monitor panel

M-6

R2

Terminal

1

Starting switch terminal R2

N-8

P02

AMP040

20

Monitor panel

M-6

P15

AMP040

2

Sunlight sensor (Optional)

M-6

T1

Terminal

1

Revolving frame ground

I-2

T2

Terminal

1

Revolving frame ground

H-1

T3

Terminal

1

Revolving frame ground

H-1

T4

Terminal

1

Alternator R

L-5

PC78US-6

Location

Address

Location

20-215 (7)

TROUBLESHOOTING

CONNECTOR ARRANGEMENT DIAGRAM

CONNECTOR ARRANGEMENT DIAGRAM PC78US-6 Serial No.: 4001 – 5500

20-215-1 (7)

PC78US-6

TROUBLESHOOTING

PC78US-6

CONNECTOR ARRANGEMENT DIAGRAM

20-215-2 (7)

TROUBLESHOOTING

20-216 (7)

CONNECTOR ARRANGEMENT DIAGRAM

PC78US-6

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

CONNECTOR TYPES AND MOUNTING LOCATIONS PC78US-6 Serial No.: 5501 – 6500 a The addresses in the address column are used in the connector arrangement drawing (3-dimensional drawing). Connector No.

Type of Connector

No. of Pins

Address

Connector No.

Type of Connector

No. of Pins

D4

SWP

2

Diode (Engine stop solenoid HOLD)

H-1

K28

M

3

PPC hydraulic lock switch

P-2

D5

SWP

2

Diode (Starting switch BR o Battery relay BR)

G-1

K32

SHINAGAWA

5

Accelerator relay

O-8

D6

SWP

2

Diode (Alternator R o Battery relay BR)

G-1

K33

SHINAGAWA

5

Decelerator relay

N-8

D11

SWP

2

Diode (TVC solenoid)

R-5

K34

SHINAGAWA

5

Motor drive relay

O-8

D12

SWP

2

Diode (TVC solenoid)

R-4

K42

SUMITOMO

16

Floor intermediate connector

P-8

D13

SWP

2

Diode (Swing holding brake solenoid)

R-4

K45

M

1

Radio ground

Q-3

D22

SWP

2

Diode (Air conditioner compressor)

H-1

K51

AMP090

20

Intermediate connector (Starting switch, light switch)

M-7

D25

SWP

2

Diode (Engine stop solenoid pull)

G-1

K52

M

3

Light switch

N-8

D26

SWP

2

Diode (Engine stop solenoid relay, coil)

H-9

K53

M

2

Buzzer cancel switch

O-8

Fuse box

R-3

K54

M

3

Rotary lamp switch

P-8

FB1

Location

Address

Location

K1

S1

12

Intermediate connector (Monitor panel)

M-7

M1

L

2

Intermediate connector (Power supply, ground)

M-4

K2

S

16

Intermediate connector (Monitor panel)

N-7

M2

X

2

Intermediate connector (Power supply, glow plug)

M-3

K3

DT

2

2nd travel speed selection solenoid valve

O-2

M3

DT

8

Intermediate connector (Fuel level sensor, hydraulic switch)

M-4

K11

SWP

12

Auto A/C unit

N-2

M4

DT

8

Intermediate connector (Washer, travel/swing alarm)

M-4

K12

M

2

Resister

Q-8

M5

DT

8

Intermediate connector (TVC, power supply, starting switch)

M-3

K17

X

2

Optional power supply

P-2

M6

DT

8

Intermediate connector (Pressure switch, air conditioner sensor)

M-3

K18

AMP090

2

Decelerator switch

Q-2

M9

DT

2

Intermediate connector (Fuel sensor)

I-2

K19

PA

9

Radio

R-3

M13

DT

2

PPC hydraulic lock

M-2

K20

M

8

Cab inlet

R-6

M14

DT

2

Swing holding brake

N-2

K21

S

8

Cab inlet

R-6

M15

DT

2

Travel speed selector

M-2

K22

DT

2

Attachment selector wire

P-8

M16

DT

2

Engine speed sensor

J-3

K23

Relay

5

Starting motor cut relay (PPC lock)

R-7

M17

X

1

Glow plug

K-8

K26

AMP090

2

Horn switch

M-7

M18

DT

2

Engine water temperature

L-8

K27

SWP

6

Fuel governor control motor

N-7

M19

X

1

Air conditioner compressor

L-7

PC78US-6

20-217 (12)

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

Connector No.

Type of Connector

No. of Pins

Address

Connector No.

Type of Connector

No. of Pins

M20

DT

2

TVC solenoid

K-8

T1

Terminal

1

Revolving frame ground

I-2

M21

X

2

Pressure switch (Boom RAISE)

G-9

T2

Terminal

1

Revolving frame ground

H-1

M22

X

2

Pressure switch (Swing)

I-9

T3

Terminal

1

Revolving frame ground

H-1

M23

X

2

Pressure switch (Swing)

G-9

T4

Terminal

1

Alternator R

L-6

M24

X

2

Pressure switch (Arm IN)

H-9

T5

Terminal

1

Alternator B

L-6

M25

X

2

Pressure switch (Travel)

I-9

T6

Terminal

1

Engine oil pressure switch

L-5

M26

L

2

Fusible link

C-8

HOLD

Terminal

1

Engine stop solenoid (HOLD)

L-2

M27

L

2

Fusible link

B-7

GND

Terminal

1

Engine stop solenoid (GND)

L-2

M28

DT

2

Intermediate connector (Working lamp)

J-9

T9

Terminal

1

Battery relay E

A-4

M30

X

2

Safety relay (S, R)

J-3

T10

Terminal

1

Battery relay BR

A-3

M31

KES

2

Windshield washer

C-8

T11

Terminal

1

Battery relay M

A-6

M32

DT

2

Travel/Swing alarm (Optional)

J-2

T12

Terminal

1

Battery relay B

A-5

M33

DT

2

Air conditioner outside temperature sensor (Optional)

L-5

T16

Terminal

1

Engine stop solenoid relay (Contact 1)

K-3

M35

L

2

Intermediate connector (Starting motor C)

K-1

T17

Terminal

1

Engine stop solenoid relay (Contact 2)

K-3

M36

DT

2

Engine stop solenoid relay (Coil)

J-2

T31

Terminal

1

Safety relay B

K-3

M75

DT

2

Working lamp

D-9

T32

Terminal

1

Safety relay C

L-5

M80

AMP040

2

Horn

M-2

T33

Terminal

1

Starting motor B

L-7

M95

DT

24

Controller

R-8

T34

Terminal

1

Starting motor C

L-6

M96

DT

40

Controller

R-8

W04

M

6

Wiper motor

M-5

M97

DT

40

Controller

Q-8

W19

2

Cigarette lighter

M-5

M99

DT

2

Arm ground angle alarm cancel selector

Q-8

B

Terminal

1

Starting switch terminal B

M-9

M100

SHINAGAWA

5

Rotary lamp drive relay

R-7

BR

Terminal

1

Starting switch terminal BR

M-8

P01

AMP040

12

Monitor panel

M-6

ACC

Terminal

1

Starting switch terminal ACC

M-8

P02

AMP040

20

Monitor panel

M-6

C

Terminal

1

Starting switch terminal C

M-9

P15

AMP040

2

Sunlight sensor (Optional)

M-6

R1

Terminal

1

Starting switch terminal R1

N-8

PULL

Terminal

1

Engine stop solenoid relay (PULL)

L-3

R2

Terminal

1

Starting switch terminal R2

N-8

20-218 (12)

Location

Address

Location

PC78US-6

TROUBLESHOOTING

CONNECTOR ARRANGEMENT DIAGRAM

CONNECTOR ARRANGEMENT DIAGRAM PC78US-6 Serial No.: 5501 – 6500

20-218-2 (12)

PC78US-6

TROUBLESHOOTING

PC78US-6

CONNECTOR ARRANGEMENT DIAGRAM

20-218-3 (7)

TROUBLESHOOTING

20-218-4 (7)

CONNECTOR ARRANGEMENT DIAGRAM

PC78US-6

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

CONNECTOR TYPES AND MOUNTING LOCATIONS PC78US-6 Serial No.: 6501 and up a The addresses in the address column are used in the connector arrangement drawing (3-dimensional drawing). Connector No.

Type of Connector

No. of Pins

Address

Connector No.

Type of Connector

No. of Pins

ACC

Terminal

1

Starting switch terminal ACC

M-9

K42

SUMITOMO

16

Floor intermediate connector

O-8

B

Terminal

1

Starting switch terminal B

M-9

K45

M

1

Radio ground

Q-3

BR

Terminal

1

Starting switch terminal BR

M-8

K51

AMP090

20

Intermediate connector (Starting switch and light switch)

M-7

C

Terminal

1

Starting switch terminal C

M-9

K52

M

3

Light switch

N-8

D4

SWP

8

Diode (Assembled-type diode)

K-2

K53

M

2

Buzzer cancel switch

O-8

D5

SWP

2

Diode (Starting switch BR o Battery relay BR)

R-7

K54

M

3

Rotary lamp switch

O-8

D6

SWP

2

Diode (Alternator R o Battery relay BR)

R-5

K55

M

3

Fuel control dial

N-7

F02

YAZAKI 1

2

Rotary lamp junction (If equipped)

I-9

M1

L

2

Intermediate connector (Power supply)

J-2

F03

DT

2

Rotary lamp (If equipped)

I-9

M2

X

2

Intermediate connector (Glow plug, ground)

J-2

FB1

—

—

Fuse box

R-4

M3

SWP

16

Intermediate connector

K-1

GND

Terminal

1

Engine stop solenoid (GND)

L-9

M7

DT

8

For connecting arm crane

H-1

HOLD

Terminal

1

Engine stop solenoid (HOLD)

L-9

M9

X

2

Fuel sensor

G-1

J1

SUMITOMO 2

20

Junction connector

R-7

M13

DT

2

PPC oil pressure lock

M-2

J2

SUMITOMO 2

20

Junction connector

R-7

M13

M

2

Speaker (Right)

I-9

K1

S

12

Intermediate connector (Monitor panel)

M-7

M14

DT

2

Swing holding brake

N-2

K2

S

16

Intermediate connector (Monitor panel)

N-7

M15

DT

2

Travel speed selection

N-2

K11

SWP

12

Air conditioner unit

R-4

M16

DT

2

Engine speed sensor

J-3

K12

M

2

Resistor

Q-8

M17

X

1

Glow plug

J-8

K17

X

2

Optional power supply

P-2

M18

DT

2

Engine coolant temperature

K-7

K18

AMP090

2

Decelerator switch

Q-3

M19

X

1

Air conditioner compressor

J-8

K19

PA

9

Radio

R-3

M20

DT

2

TVC solenoid

K-7

K20

M

8

Cab inlet

R-6

M21

X

2

Pressure switch (Boom RAISE)

G-9

K21

S

8

Cab inlet

R-6

M22

X

2

Pressure switch (Swing)

J-2

K23

Relay

5

Starting motor cutout relay (PPC lock)

N-7

M23

X

2

Pressure switch (Swing)

I-2

K26

AMP090

2

Horn switch

M-6

M24

X

2

Pressure switch (Arm IN)

G-9

K28

M

3

PPC oil pressure lock switch

Q-2

M25

X

2

Pressure switch (Travel)

J-3

K32

SHINAGAWA

5

Accelerator relay

N-2

M26

L

2

Fusible link

R-5

K33

SHINAGAWA

5

Decelerator relay

N-1

M27

L

2

Fusible link

R-5

PC78US-6

Location

Address

Location

20-218-5 (12)

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

Connector No.

Type of Connector

No. of Pins

Address

Connector No.

Type of Connector

No. of Pins

M28

DT-T

2

Intermediate connector (Working lamp)

J-2

T9

Terminal

1

Battery relay E

K-5

M30

X

2

Safety relay (S, R)

L-2

T10

Terminal

10

Battery relay BR

K-5

M31

KES

2

Windshield washer

E-9

T11

Terminal

1

Battery relay M

K-5

M32

DT

2

Travel/Swing alarm (If equipped)

K-2

T11

Terminal

1

Cab ground

K-6

M35

L

2

Intermediate connector (Starting motor C)

K-9

T12

Terminal

1

Battery relay B

K-5

M36

DT

2

Engine stop solenoid relay (Coil)

K-3

T16

Terminal

1

Engine stop solenoid relay (Contact 1)

L-4

M40

YAZAKI 1

2

Cab headlamp

H-9

T17

Terminal

1

Engine stop solenoid relay (Contact 2)

K-2

M41

YAZAKI 1

2

Additional cab headlamp (If equipped)

G-9

T31

Terminal

1

Safety relay B

L-3

M71

M

2

Room light

J-8

T32

Terminal

1

Safety relay C

L-3

M73

M

2

Speaker (Left)

J-8

T33

Terminal

1

Starting motor B

K-7

M75

DT-T

2

Working lamp

F-9

T34

Terminal

1

Starting motor C

K-7

M80

AMP090

2

Horn

M-3

V2

DT

12

Intermediate connector

Q-8

M87

S

12

Air conditioner junction

M-7

V3

SHINAGAWA

5

Starting motor cutout relay

R-7

M88

YAZAKI 2

10

Air conditioner foot area air outlet servo

M-4

W03

X

2

Window limit switch

I-9

M95

DRC26

40

Controller

R-8

W04

M

6

Wiper motor

M-5

M100

SHINAGAWA

5

Rotary lamp drive relay (If equipped)

R-8

W19

Terminal

2

Cigarette lighter

M-4

P01

AMP040

12

Monitor panel

M-6

P02

AMP040

20

Monitor panel

M-5

P15

AMP040

2

Daylight sensor (If equipped)

M-6

PULL

Terminal

1

Engine stop solenoid (PULL)

L-9

R1

Terminal

1

Starting switch terminal R1

N-9

R2

Terminal

1

Starting switch terminal R2

N-8

S2

SWP

6

Fuel governor control motor

P-2

S3

DT

3

Main pump pressure sensor

I-2

S4

SHINAGAWA

5

Travel/Swing alarm relay (If equipped)

P-2

T1

Terminal

1

Revolving frame ground

J-1

T2

Terminal

1

Revolving frame ground

J-1

T3

Terminal

1

Revolving frame ground

J-1

T4

Terminal

1

Alternator R

K-7

T5

Terminal

1

Alternator B

K-6

T6

Terminal

1

Engine oil pressure switch

K-5

20-218-6 (12)

Location

Address

Location

PC78US-6

TROUBLESHOOTING

CONNECTOR ARRANGEMENT DIAGRAM

CONNECTOR ARRANGEMENT DIAGRAM PC78US-6 Serial No.: 6501 and up

20-218-8 (17)

PC78US-6

TROUBLESHOOTING

PC78US-6

CONNECTOR ARRANGEMENT DIAGRAM

20-218-9 (12)

TROUBLESHOOTING

20-218-10 (12)

CONNECTOR ARRANGEMENT DIAGRAM

PC78US-6

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

CONNECTOR TYPES AND MOUNTING LOCATIONS PC78UU-6 Serial No.: 22832 – 23500 a The addresses in the address column are used in the connector arrangement drawing (3-dimensional drawing). Connector No.

Type of Connector

No. of Pins

Address

Connector No.

Type of Connector

No. of Pins

Location

Address

D4

SWP

2

Diode (Engine stop solenoid)

H-1

K23

Relay

5

Starting motor cut relay (PPC lock)

R-7

D5

SWP

2

Diode (Starting switch BR o Battery relay BR)

G-1

K26

AMP090

2

Horn switch

M-7

D6

SWP

2

Diode (Alternator R o Battery relay BR)

G-1

K27

SWP

6

Fuel governor control motor

M-7

D11

SWP

2

Diode (TVC solenoid)

R-7

K28

M

3

PPC hydraulic lock switch

P-2

D12

SWP

2

Diode (TVC solenoid)

R-5

K32

SHINAGAWA

5

Accelerator relay

O-8

D13

SWP

2

Diode (PPC main pressure lock solenoid)

Q-8

K33

SHINAGAWA

5

Decelerator relay

N-7

D14

SWP

2

Diode (PPC main pressure lock solenoid)

R-4

K34

SHINAGAWA

5

Motor drive relay

N-8

D15

SWP

2

Diode (Boom raise stop solenoid)

R-3

K42

SUMITOMO

16

Floor intermediate connector

O-8

D16

SWP

2

Diode (Boom raise stop solenoid)

R-3

K45

M

1

Radio ground

Q-3

D17

SWP

2

Diode (Swing parking brake solenoid)

R-8

K51

AMP090

20

Intermediate connector

M-7

D18

SWP

2

Diode (Arm IN stop solenoid)

Q-8

K52

M

3

Light switch

N-8

D19

SWP

2

Diode (Arm IN stop solenoid)

R-5

K53

M

2

Buzzer cancel switch

O-8

D20

SWP

2

Diode (Left offset stop solenoid)

R-5

K54

M

3

Rotary lamp switch

P-8

D21

SWP

2

Diode (Left offset stop solenoid)

R-4

K55

SHINAGAWA

5

PPC lock cut relay

Q-8

D22

SWP

2

Diode (Air conditioner compressor)

H-1

M1

L

2

Intermediate connector (Power supply, ground)

M-4

Fuse box

R-3

M2

X

2

Intermediate connector (Power supply, glow plug)

M-3

FB1

Location

K1

S

12

Intermediate connector (Monitor panel)

N-7

M3

DT

8

Intermediate connector (Fuel level sensor, hydraulic switch)

M-4

K2

S

16

Intermediate connector (Monitor panel)

M-7

M4

DT

8

Intermediate connector (Washer, rotation sensor)

M-4

K3

DT

2

Travel speed pedal

P-2

M5

DT

8

Intermediate connector (TVC, power supply, battery relay)

M-3

K11

SWP

12

Auto A/C unit

P-2

M6

DT

8

Intermediate connector (Pressure switch)

M-3

K12

M

2

Resister

P-8

M7

DT

8

Intermediate connector (Potentiometer, sensor)

M-3

K13

M

2

Resister

P-8

M9

DT

2

Intermediate connector (Fuel sensor)

I-2

K17

X

2

Optional power supply

Q-3

M10

DT

2

Left offset stop EPC valve

N-2

K18

AMP 090

2

Decelerator switch

Q-2

M11

DT

2

Boom stop EPC valve

O-2

K19

PA

9

Radio

Q-3

M12

DT

2

Arm IN stop EPC valve

O-2

K20

M

8

Cab inlet

R-6

M13

DT

2

PPC hydraulic rock

M-2

K21

S

8

Cab inlet

R-6

M14

DT

2

Swing holding brake

N-2

K22

DT

2

Attachment selector wire

P-8

M15

DT

2

Travel speed selector

N-2

PC78US-6

20-219 (12)

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

Connector No.

Type of Connector

No. of Pins

Address

Connector No.

Type of Connector

No. of Pins

M16

DT

2

Engine speed sensor

J-3

T1

Terminal

1

Revolving frame ground

I-2

M17

X

1

Glow plug

K-8

T2

Terminal

1

Revolving frame ground

H-1

M18

DT

2

Engine water temperature

L-8

T3

Terminal

1

Revolving frame ground

H-1

M19

X

1

Air conditioner compressor

L-7

T4

Terminal

1

Alternator R

L-5

M20

DT

2

TVC solenoid

K-8

T5

Terminal

1

Alternator B

L-5

M21

X

2

Pressure switch (Boom RAISE)

H-9

T6

Terminal

1

Engine oil pressure switch

L-4

M22

X

2

Pressure switch (Swing)

I-9

T7

Terminal

1

Engine stop solenoid (+)

K-9

M23

X

2

Pressure switch (Swing)

H-9

T8

Terminal

1

Engine stop solenoid (-)

J-9

M24

X

2

Pressure switch (Arm IN)

I-9

T9

Terminal

1

Battery relay E

A-4

M25

X

2

Pressure switch (Travel)

I-9

T10

Terminal

1

Battery relay BR

A-3

M26

L

2

Fusible link

C-8

T11

Terminal

1

Battery relay M

A-6

M27

L

2

Fusible link

B-7

T12

Terminal

1

Battery relay B

A-5

M28

SWP

6

Intermediate connector (Working lamp)

J-9

T21

Terminal

1

System cancel switch

M-6

M29

DT

3

Boom angle potentiometer

J-9

T22

Terminal

1

System cancel switch

O-2

M30

X

2

Sefety relay (S, R)

K-3

T31

Terminal

1

Safety relay B

K-3

M31

KES

2

Windshield washer

C-8

T32

Terminal

1

Safety relay C

K-3

M32

DT

2

Travel/Swing alarm

J-2

T33

Terminal

1

Starting motor B

L-7

M33

DT

2

Air conditioner outside temperature sensor (Optional)

L-4

T34

Terminal

1

Starting motor C

L-6

M71

DT

3

Offset angle potentiometer

G-9

W04

M

6

Wiper motor

M-6

M72

DT

3

Arm angle potentiometer

A-7

W19

2

Cigarette lighter

M-4

M73

DT

2

Working lamp

D-9

B

Terminal

1

Starting switch terminal B

M-9

M74

DT

2

Working lamp

G-9

BR

Terminal

1

Starting switch terminal BR

M-8

M80

AMP040

2

Horn

M-2

ACC

Terminal

1

Starting switch terminal ACC

M-8

M95

DT

24

Controller

R-8

C

Terminal

1

Starting switch terminal C

M-9

M96

DT

40

Controller

R-8

R1

Terminal

1

Starting switch terminal R1

N-8

M97

DT

40

Controller

Q-8

R2

Terminal

1

Starting switch terminal R2

N-8

M99

DT

2

Arm ground angle alarm cancel selector

P-8

M100

SHINAGAWA

5

Rotary lamp drive relay

R-7

P01

AMP040

12

Monitor panel

M-6

P02

AMP040

20

Monitor panel

M-5

P15

AMP040

2

Sunlight sensor (Optional)

M-6

20-219-1 (12)

Location

Address

Location

PC78US-6

TROUBLESHOOTING

CONNECTOR ARRANGEMENT DIAGRAM

CONNECTOR ARRANGEMENT DIAGRAM PC78UU-6 Serial No.: 22832 – 23500

20-219-3 (12)

PC78US-6

TROUBLESHOOTING

PC78US-6

CONNECTOR ARRANGEMENT DIAGRAM

20-219-4 (12)

TROUBLESHOOTING

20-219-5 (12)

CONNECTOR ARRANGEMENT DIAGRAM

PC78US-6

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

CONNECTOR TYPES AND MOUNTING LOCATIONS PC78UU-6 Serial No.: 23501 and up a The addresses in the address column are used in the connector arrangement drawing (3-dimensional drawing). Connector No.

Type of Connector

No. of Pins

Address

Connector No.

Type of Connector

No. of Pins

D4

SWP

2

Diode (Engine stop solenoid HOLD)

H-1

K21

S

8

Cab inlet

R-6

D5

SWP

2

Diode (Starting switch BR o Battery relay BR)

G-1

K22

DT

2

Attachment selector wire

P-8

D6

SWP

2

Diode (Alternator R o Battery relay BR)

G-1

K23

Relay

5

Starting motor cut relay (PPC lock)

R-7

D11

SWP

2

Diode (TVC solenoid)

R-7

K26

AMP090

2

Horn switch

M-7

D12

SWP

2

Diode (TVC solenoid)

R-5

K27

SWP

6

Fuel governor control motor

N-7

D13

SWP

2

Diode (PPC main pressure lock solenoid)

Q-8

K28

M

3

PPC hydraulic lock switch

P-2

D14

SWP

2

Diode (PPC main pressure lock solenoid)

R-4

K32

SHINAGAWA

5

Accelerator relay

O-8

D15

SWP

2

Diode (Boom raise stop solenoid)

R-3

K33

SHINAGAWA

5

Decelerator relay

N-7

D16

SWP

2

Diode (Boom raise stop solenoid)

R-3

K34

SHINAGAWA

5

Motor drive relay

N-8

D17

SWP

2

Diode (Swing parking brake solenoid)

R-8

K42

SUMITOMO

16

Floor intermediate connector

O-8

D18

SWP

2

Diode (Arm IN stop solenoid)

Q-8

K45

M

1

Radio ground

Q-3

D19

SWP

2

Diode (Arm IN stop solenoid)

R-5

K51

AMP090

20

Intermediate connector

M-7

D20

SWP

2

Diode (Left offset stop solenoid)

R-5

K52

M

3

Light switch

N-8

D21

SWP

2

Diode (Left offset stop solenoid)

R-4

K53

M

2

Buzzer cancel switvh

O-8

D22

SWP

2

Diode (Air conditioner compressor)

H-1

K54

M

3

Rotary lamp switch

O-8

D25

SWP

2

Diode (Engine stop solenoid pull)

G-1

K55

SHINAGAWA

5

PPC lock cut relay

Q-8

D26

SWP

2

Diode (Engine stop solenoid relay, coil)

H-9

M1

L

2

Intermediate connector (Power supply, ground)

M-4

Fuse box

R-3

M2

X

2

Intermediate connector (Power supply, glow plug)

M-3

FB1

Location

Address

Location

K1

S

12

Intermediate connector (Monitor panel)

M-7

M3

DT

8

Intermediate connector (Fuel level sensor, hydraulic switch)

M-4

K2

S

16

Intermediate connector (Monitor panel)

N-7

M4

DT

8

Intermediate connector (Washer, rotation sensor)

M-4

K3

DT

2

Travel speed pedal

P-2

M5

DT

8

Intermediate connector (TVC, power supply, battery relay)

M-3

K11

SWP

12

Auto A/C unit

P-2

M6

DT

8

Intermediate connector (Pressure switch)

M-3

K12

M

2

Resister

P-8

M7

DT

8

Intermediate connector (Potentiometer, sensor)

M-3

K13

M

2

Resister

P-8

M9

DT

2

Intermediate connector (Fuel sensor)

I-2

K17

X

2

Optional power supply

Q-3

M10

DT

2

Left offset stop EPC valve

N-2

K18

AMP 090

2

Decelerator switch

Q-2

M11

DT

2

Boom stop EPC valve

O-2

K19

PA

9

Radio

Q-3

M12

DT

2

Arm IN stop EPC valve

O-2

K20

M

8

Cab inlet

R-6

M13

DT

2

PPC hydraulic rock

M-2

PC78US-6

20-219-6 (12)

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

Connector No.

Type of Connector

No. of Pins

Address

Connector No.

Type of Connector

No. of Pins

M14

DT

2

Swing holding brake

N-2

P01

AMP040

12

Monitor panel

M-6

M15

DT

2

Travel speed selector

N-2

P02

AMP040

20

Monitor panel

M-5

M16

DT

2

Engine speed sensor

J-3

P15

AMP040

2

Sunlight sensor (Optional)

M-6

M17

X

1

Glow plug

K-8

PULL

Terminal

1

Engine stop solenoid relay (PULL)

L-3

M18

DT

2

Engine water temperature

L-8

T1

Terminal

1

Revolving frame ground

I-2

M19

X

1

Air conditioner compressor

L-7

T2

Terminal

1

Revolving frame ground

H-1

M20

DT

2

TVC solenoid

K-8

T3

Terminal

1

Revolving frame ground

H-1

M21

X

2

Pressure switch (Boom RAISE)

H-9

T4

Terminal

1

Alternator R

L-6

M22

X

2

Pressure switch (Swing)

I-9

T5

Terminal

1

Alternator B

L-6

M23

X

2

Pressure switch (Swing)

H-9

T6

Terminal

1

Engine oil pressure switch

L-5

M24

X

2

Pressure switch (Arm IN)

I-9

HOLD

Terminal

1

Engine stop solenoid (HOLD)

L-2

M25

X

2

Pressure switch (Travel)

I-9

GND

Terminal

1

Engine stop solenoid (GHD)

L-2

M26

L

2

Fusible link

C-8

T9

Terminal

1

Battery relay E

A-4

M27

L

2

Fusible link

B-7

T10

Terminal

1

Battery relay BR

A-3

M28

SWP

6

Intermediate connector (Working lamp)

J-9

T11

Terminal

1

Battery relay M

A-6

M29

DT

3

Boom angle potentiometer

J-9

T12

Terminal

1

Battery relay B

A-5

M30

X

2

Sefety relay (S, R)

J-3

T16

Terminal

1

Engine stop solenoid relay (Contact 1)

K-3

M31

KES

2

Windshield washer

C-8

T17

Terminal

1

Engine stop solenoid relay (Contact 2)

K-3

M32

DT

2

Travel/Swing alarm

J-2

T21

Terminal

1

System cancel switch

M-6

M33

DT

2

Air conditioner outside temperature sensor (Optional)

L-5

T22

Terminal

1

System cancel switch

O-2

M35

L

2

Intermediate connector (Starting motor C)

K-1

T31

Terminal

1

Safety relay B

K-3

M36

DT

2

Engine stop solenoid relay (Coil)

J-2

T32

Terminal

1

Safety relay C

L-5

M71

DT

3

Offset angle potentiometer

G-9

T33

Terminal

1

Starting motor B

L-7

M72

DT

3

Arm angle potentiometer

A-7

T34

Terminal

1

Starting motor C

L-6

M73

DT

2

Working lamp

D-9

W04

M

6

Wiper motor

M-6

M74

DT

2

Working lamp

G-9

W19

2

Cigarette lighter

M-4

M80

AMP040

2

Horn

M-2

B

Terminal

1

Starting switch terminal B

M-9

M95

DT

24

Controller

R-8

BR

Terminal

1

Starting switch terminal BR

M-8

M96

DT

40

Controller

R-8

ACC

Terminal

1

Starting switch terminal ACC

M-8

M97

DT

40

Controller

Q-8

C

Terminal

1

Starting switch terminal C

M-9

M99

DT

2

Arm ground angle alarm cancel selector

P-8

R1

Terminal

1

Starting switch terminal R1

N-8

M100

SHINAGAWA

5

Rotary lamp drive relay

R-7

R2

Terminal

1

Starting switch terminal R2

N-8

20-219-7 (12)

Location

Address

Location

PC78US-6

TROUBLESHOOTING

CONNECTOR ARRANGEMENT DIAGRAM

CONNECTOR ARRANGEMENT DIAGRAM PC78UU-6 Serial No.: 23501 and up

20-219-9 (12)

PC78US-6

TROUBLESHOOTING

PC78US-6

CONNECTOR ARRANGEMENT DIAGRAM

20-219-10 (12)

TROUBLESHOOTING

20-219-11 (12)

CONNECTOR ARRANGEMENT DIAGRAM

PC78US-6

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

TROUBLESHOOTING

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS a The terms male and female refer to the pins while the terms male housing and female housing refer to the mating portion of the housing. X-Type Connector

Number of Pins

Male (Female Housing)

Female (Male Housing)

T-adapter Part Number

1

Part Number: 08055-00181

Part Number: 08055-00191

799-601-7010

BWP04702 2

799-601-7020

Part Number: 08055-00282

Part Number: 08055-00292

BWP04703 3

BWP04704

Part Number: 08055-00381

BWP04705

4

Part Number: 08055-00481

799-601-7030

Part Number: 08055-00391

BWP04706

799-601-7040

Part Number: 08055-00491

—

Terminal part number: 79A-222-3370 • Wire size: 0.85 • Grommet: black • Quantity: 20 pieces

Terminal part number: 79A-222-3390 • Wire size: 0.85 • Grommet: black • Quantity: 20 pieces

—

—

Terminal part number: 79A-222-3380 • Wire size: 2.0 • Grommet: red • Quantity: 20 pieces

Terminal part number: 79A-222-3410 • Wire size: 2.0 • Grommet: red • Quantity: 20 pieces

—

20-220 (1)

PC78US-6

TROUBLESHOOTING

Number of Pins

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

SWP-Type Connector Male (Female Housing)

BWP04707

Female (Male Housing)

BWP04708

6

799-601-7050

Part Number: 08055-10681

8

BWP04709

Part Number: 08055-10881

BWP04711 12

Part Number: 08055-11281

BWP04713

Part Number: 08055-10691

BWP04710 799-601-7060

Part Number: 08055-10891

BWP04712

799-601-7310

Part Number: 08055-11291

BWP04714

14

799-601-7070

Part Number: 08055-11481

PC78US-6

T-adapter Part Number

Part Number: 08055-11491

20-221 b

TROUBLESHOOTING

Number of Pins

16

—

—

20-222 b

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

SWP-Type Connector Male (Female Housing)

BWP04715

Part Number: 08055-11681 Terminal part number: • Wire size: 0.85 • Grommet: black • Quantity: 20 pieces Terminal part number: • Wire size: 1.25 • Grommet: red • Quantity: 20 pieces

Female (Male Housing)

BWP04716

Part Number: 08055-11691 Terminal part number: • Wire size: 0.85 • Grommet: black • Quantity: 20 pieces Terminal part number: • Wire size: 1.25 • Grommet: red • Quantity: 20 pieces

T-adapter Part Number

799-601-7320

—

—

PC78US-6

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

TROUBLESHOOTING

M-Type Connector

Number of Pins

Male (Female Housing)

Female (Male Housing)

T-adapter Part Number

1

Part Number: 08056-00171

Part Number: 08056-00181

799-601-7080

2

BWP04717

Part Number: 08056-00271

3

BWP04719

Part Number: 08056-00371

4

BWP04721

Part Number: 08056-00471

6

BWP04723

Part Number: 08056-00671

8

BWP04725

Part Number: 08056-00871

PC78US-6

BWP04718 799-601-7090

Part Number: 08056-00281

BWP04720

799-601-7110

Part Number: 08056-00381

BWP04722

799-601-7120

Part Number: 08056-00481

BWP04724

799-601-7130

Part Number: 08056-00681

BWP04726

799-601-7340

Part Number: 08056-00881

20-223 (12)

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

TROUBLESHOOTING

Number of Pins

8

S-Type Connector Male (Female Housing)

BWP04727

Part Number: 08056-10871

10 (White)

BWP04729

Part Number: 08056-11071

12 (White)

BWP04731

Part Number: 08056-11271

16 (White)

BWP04733

Part Number: 08056-11671

20-224 (1)

Female (Male Housing)

T-adapter Part Number

BWP04728 799-601-7140

Part Number: 08056-10881

BWP04730

799-601-7150

Part Number: 08056-11081

BWP04732

799-601-7350

Part Number: 08056-11281

BWP04734

799-601-7330

Part Number: 08056-11681

PC78US-6

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

TROUBLESHOOTING

Number of Pins

10 (Blue)

S-Type Connector Male (Female Housing)

BWP04735

—

12 (Blue)

BWP04737

Part Number: 08056-11272

16 (Blue)

BWP04739

Part Number: 08056-11672

PC78US-6

Female (Male Housing)

T-adapter Part Number

BWP04736 —

—

BWP04738

799-601-7160

Part Number: 08056-11282

BWP04740

799-601-7170

Part Number: 08056-11682

20-225 (1)

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

TROUBLESHOOTING

Number of Pins

MIC-Type Connector Male (Female Housing)

Female (Male Housing)

T-adapter Part Number

7

Body Part Number: 79A-222-2640 (Quantity: 5 pieces)

Body Part Number: 79A-222-2630 (Quantity: 5 pieces)

—

11

Body Part Number: 79A-222-2680 (Quantity: 5 pieces)

Body Part Number: 79A-222-2670 (Quantity: 5 pieces)

—

5

BWP04741

Body Part Number: 79A-222-2620 (Quantity: 5 pieces)

9

BWP04743

Body Part Number: 79A-222-2660 (Quantity: 5 pieces)

13

BWP04745

Body Part Number: 79A-222-2710 (Quantity: 2 pieces)

20-226 (12)

BWP04742 799-601-2710

Body Part Number: 79A-222-2610 (Quantity: 5 pieces)

BWP04744

799-601-2950

Body Part Number: 79A-222-2650 (Quantity: 5 pieces)

BWP04746

799-601-2720

Body Part Number: 79A-222-2690 (Quantity: 2 pieces)

PC78US-6

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

TROUBLESHOOTING

Number of Pins

17

MIC-Type Connector Male (Female Housing)

BWP04747

Body Part Number: 79A-222-2730 (Quantity: 2 pieces)

21

PC78US-6

BWP04749

Female (Male Housing)

T-adapter Part Number

BWP04748 799-601-2730

Body Part Number: 79A-222-2720 (Quantity: 2 pieces)

BWP04750

Body Part Number: 79A-222-2750 (Quantity: 2 pieces)

Body Part Number: 79A-222-2740 (Quantity: 2 pieces)

Body Part Number: 79A-222-2770 (Quantity: 50 pieces)

Body Part Number: 79A-222-2760 (Quantity: 50 pieces)

799-601-2740

—

20-227 (1)

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

TROUBLESHOOTING

Number of Pins

8

AMP040-Type Connector Male (Female Housing)

BWP04751

—

12

20

799-601-7180

Housing Part Number: 79A-222-3430 (Quantity: 5 pieces)

BWP047544

BWP04756

799-601-7210

Housing Part Number: 79A-222-3450 (Quantity: 5 pieces)

BWP04757

—

799-601-7190

Housing Part Number: 79A-222-3440 (Quantity: 5 pieces)

BWP04755

—

T-adapter Part Number

BWP04752

BWP04753

—

16

Female (Male Housing)

BWP04758

799-601-7220

Housing Part Number: 79A-222-3460 (Quantity: 5 pieces)

a Terminal Part Number: 79A-222-3470 (For all numbers of pins).

20-228 (12)

PC78US-6

TROUBLESHOOTING

Number of Pins

10

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

AMP070-Type Connector Male (Female Housing)

BWP04759

—

12

BWP04761

—

14

BWP04763

—

18

BWP04765

—

20

BWP04767

—

PC78US-6

Female (Male Housing)

T-adapter Part Number

BWP04760 799-601-7510

Part Number: 08195-10210

BWP04762

799-601-7520

Part Number: 08195-12210

BWP04764

799-601-7530

Part Number: 08195-14210

BWP04766

799-601-7540

Part Number: 08195-18210

BWP04768

799-601-7550

Part Number: 08195-20210

20-229 b

TROUBLESHOOTING

Number of Pins

2

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

L-Type Connector Male (Female Housing)

BWP04769

Female (Male Housing)

BWP04770

—

Number of Pins

9

—

—

Female (Male Housing)

T-adapter Part Number

PA-Type Connector Male (Female Housing)

BWP04771

BWP04772

—

Number of Pins

10

b

— BENDIX MS-Type Connector

Male (Female Housing)

BWP04773

—

20-230

T-adapter Part Number

Female (Male Housing)

T-adapter Part Number

BWP04774 799-601-3460

—

PC78US-6

TROUBLESHOOTING

Number of Pins

2

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

KES1 Automobile-Type Connector Male (Female Housing)

BWP04775

Part Number: 08027-10210 (Natural color) 08027-10220 (Black)

3

BWP04777

Part Number: 08027-10310

4

BWP04779

Part Number: 08027-10410 (Natural color) 08027-10420 (Black)

6

BWP04781

Part Number: 08027-10610 (Natural color) 08027-10620 (Black)

PC78US-6

Female (Male Housing)

T-adapter Part Number

BWP04776 —

Part Number: 08027-10260 (Natural color) 08027-10270 (Black)

BWP04778

—

Part Number: 08027-10360

BWP04780

—

Part Number: 08027-10460 (Natural color) 08027-10470 (Black)

BWP04782

—

Part Number: 08027-10660 (Natural color) 08027-10670 (Black)

20-231 b

TROUBLESHOOTING

Number of Pins

8

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

KES1 Automobile-Type Connector Male (Female Housing)

BWP04783

Part Number: 08027-10810 (Natural color) 08027-10820 (Black)

20-232 b

Female (Male Housing)

T-adapter Part Number

BWP04784 —

Part Number: 08027-10860 (Natural color) 08027-10870 (Black)

PC78US-6

TROUBLESHOOTING

Number of Pins

5

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

Socket-Type Connector for Relay Male (Female Housing)

BWP04785

—

6

BWP04787

—

PC78US-6

Female (Male Housing)

T-adapter Part Number

BWP04786 799-601-7360

—

BWP04788 799-601-7370

—

20-233 b

TROUBLESHOOTING

Number of Pins

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

F-Type Connector Male (Female Housing)

BWP04785

Female (Male Housing)

BWP04786

4

—

—

20-234 b

T-adapter Part Number

—

PC78US-6

TROUBLESHOOTING

Type (Shell Size Code)

18-8 (1)

18-14 (2)

PC78US-6

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS The pin number is also marked on the connector (Electric wire insertion end). HD30 Series Connector Body (Plug)

Body (Receptacle)

Pin (Male Terminal)

Pin (Female Terminal)

Part Number: 08191-11201, 08191-11202, 08191-11205, 08191-11206 Pin (Female Terminal)

Part Number: 08191-14101, 08191-14102, 08191-14105, 08191-14106 Pin (Male Terminal)

Part Number: 08191-12201, 08191-12202, 08191-12205, 08191-12206 Pin (Male Terminal)

Part Number: 08191-13101, 08191-13102, 08191-13105, 08191-13106 Pin (Female Terminal)

Part Number: 08191-21201, 08191-12202, 08191-21205, 08191-12206 Pin (Female Terminal)

Part Number: 08191-24101, 08191-24102, 08191-24105, 08191-24106 Pin (Male Terminal)

Part Number: 08191-22201, 08191-22202 08191-22205, 08191-22206

Part Number: 08191-23101, 08191-23102, 08191-23105, 08191-23106

T-adapter Part Number

799-601-9210

799-601-9220

20-235 b

TROUBLESHOOTING

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS The pin number is also marked on the connector (Electric wire insertion end).

Type (Shell Size Code)

18-20 (3)

18-21 (4)

20-236 b

HD30 Series Connector Body (Plug)

Body (Receptacle)

Pin (Male Terminal)

Pin (Female Terminal)

Part Number: 08191-31201, 08191-31202

Part Number: 08191-34101, 08191-34102

Pin (Female Terminal)

Pin (Male Terminal)

Part Number: 08191-32201, 08191-32202

Part Number: 08191-33101, 08191-33102

Pin (Male Terminal)

Pin (Female Terminal)

Part Number: 08191-41201, 08191-42202

Part Number: 08191-44101, 08191-44102

Pin (Female Terminal)

Pin (Male Terminal)

Part Number: 08191-42201, 08191-42202

Part Number: 08191-43101, 08191-43102

T-adapter Part Number

799-601-9230

799-601-9240

PC78US-6

TROUBLESHOOTING

Type (Shell Size Code)

24-9 (5)

24-16 (6)

PC78US-6

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS The pin number is also marked on the connector (Electric wire insertion end). HD30 Series Connector Body (Plug)

Body (Receptacle)

Pin (Male Terminal)

Pin (Female Terminal)

Part Number: 08191-51201, 08191-51202 Pin (Female Terminal)

Part Number: 08191-54101, 08191-54102 Pin (Male Terminal)

Part Number: 08191-52201, 08191-52202 Pin (Male Terminal)

Part Number: 08191-53101, 08191-53102 Pin (Female Terminal)

Part Number: 08191-61201, 08191-62202, 08191-61205, 08191-62206 Pin (Female Terminal)

Part Number: 08191-64101, 08191-64102, 08191-64105, 08191-64106 Pin (Male Terminal)

Part Number: 08191-62201, 08191-62202, 08191-62205, 08191-62206

Part Number: 08191-63101, 08191-63102, 08191-63105, 08191-63106

T-adapter Part Number

799-601-9250

799-601-9260

20-237 b

TROUBLESHOOTING

Type (Shell Size Code)

24-21 (7)

24-22 (8)

20-238 b

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS The pin number is also marked on the connector (Electric wire insertion end). HD30 Series Connector Body (Plug)

Body (Receptacle)

Pin (Male Terminal)

Pin (Female Terminal)

Part Number: 08191-71201, 08191-71202, 08191-71205, 08191-71206 Pin (Female Terminal)

Part Number: 08191-74101, 08191-74102, 08191-74105, 08191-74106 Pin (Male Terminal)

Part Number: 08191-72201, 08191-72202, 08191-72205, 08191-72206 Pin (Male Terminal)

Part Number: 08191-73101, 08191-73102, 08191-73105, 08191-73106 Pin (Female Terminal)

Part Number: 08191-81201, 08191-81202, 08191-81203, 08191-81204, 08191-81205, 08191-81206 Pin (Female Terminal)

Part Number: 08191-84101, 08191-84102, 08191-84103, 08191-84104, 08191-84105, 08191-84106 Pin (Male Terminal)

Part Number: 08191-82201, 08191-82202, 08191-82203, 08191-82204, 08191-82205, 08191-82206

Part Number: 08191-83101, 08191-83102, 08191-83103, 08191-83104, 08191-83105, 08191-83106

T-adapter Part Number

799-601-9270

799-601-9280

PC78US-6

TROUBLESHOOTING

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS The pin number is also marked on the connector (Electric wire insertion end).

Type (Shell Size Code)

24-31 (9)

PC78US-6

HD30 Series Connector Body (Plug)

Body (Receptacle)

Pin (Male Terminal)

Pin (Female Terminal)

Part Number: 08191-91203, 08191-91204, 08191-91205, 08191-91206

Part Number: 08191-94103, 08191-94104, 08191-94105,08191-94106

Pin (Female Terminal)

Pin (Male Terminal)

Part Number: 08191-92203, 08191-92204, 08191-92205, 08191-92206

Part Number: 08191-93103, 08191-93104, 08191-93105, 08191-93106

T-adapter Part Number

799-601-9290

20-239 b

TROUBLESHOOTING

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS The pin number is also marked on the connector (Electric wire insertion end).

No. of Pins

DT Series Connector Body (Plug)

Body (Receptacle)

2

799-601-9020

Part Number: 08192-12200 (Normal type) 08192-22200 (Fine wire type)

Part Number: 08192-12100 (Normal type) 08192-22100 (Fine wire type)

3

799-601-9030

Part Number: 08192-13200 (Normal type) 08192-23200 (Fine wire type)

Part Number: 08192-13100 (Normal type) 08192-23100 (Fine wire type)

4

799-601-9040

Part Number: 08192-14200 (Normal type) 08192-24200 (Fine wire type)

Part Number: 08192-14100 (Normal type) 08192-24100 (Fine wire type)

6

799-601-9050

Part Number: 08192-16200 (Normal type) 08192-26200 (Fine wire type)

20-240 b

T-adapter Part Number

Part Number: 08192-16100 (Normal type) 08192-26100 (Fine wire type)

PC78US-6

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

TROUBLESHOOTING

No. of Pins

DT Series Connector Body (Plug)

Body (Receptacle)

8GR:799-601-9060 8B:799-601-9070 8G:799-601-9080 8BR:799-601-9090

8

Part Number: 08192-1820T (Normal type) 08192-2820T (Fine wire type)

Part Number: 08192-1810T (Normal type) 08192-2810T (Fine wire type)

12GR:799-601-9110 12B:799-601-9120 12G:799-601-9130 12BR:799-601-9140

12

Part Number: 08192-1920T (Normal type) 08192-2920T (Fine wire type)

PC78US-6

T-adapter Part Number

Part Number: 08192-1910T (Normal type) 08192-2910T (Fine wire type)

20-241 (12)

CONNECTION TABLE FOR CONNECTOR PIN NUMBERS

TROUBLESHOOTING

The pin number is also marked on the connector (Electric wire insertion end). No. of Pins

DTM Series Connector Body (Plug)

Body (Receptacle)

2

T-adapter Part Number

799-601-9010

Part Number: 08192-02200

Part Number: 08192-02100 The pin number is also marked on the connector (Electric wire insertion end).

No. of Pins

DTHD Series Connector Body (Plug)

Body (Receptacle)

Part Number: 08192-31200 (Contact size #12) 08192-41200 (Contact size #8) 08192-51200 (Contact size #4)

Part Number: 08192-31100 (Contact size #12) 08192-41100 (Contact size #8) 08192-51100 (Contact size #4)

T-adapter Part Number

1

20-242 (12)

PC78US-6

TROUBLESHOOTING

EXPLANATION OF FUNCTIONS OF ELECTRIC SYSTEM CONTROL MECHANISM

EXPLANATION OF FUNCTIONS OF ELECTRIC SYSTEM CONTROL MECHANISM Machine model: PC78US-6 The control mechanism of the electric system consists of the monitor panel, governor, and pump controller. Those components receive signals necessary to them. The governor and pump controller output or input the necessary signal according to the signals selected by the monitor panel to control the absorption torque, engine output, etc.

Network information 1) 2) 3) 4) 5)

Working mode (Standard, E) information One-touch slow-down (ON/OFF) signal Travel Hi/Lo signal Coolant temperature (Water temperature) information Service code (Failure code) information

20-244 (12)

(Monitor panel o Controller) (Monitor panel i Controller) (Monitor panel i Controller) (Monitor panel o Controller) (Controller o Monitor panel)

PC78US-6

TROUBLESHOOTING

PC78US-6

EXPLANATION OF FUNCTIONS OF ELECTRIC SYSTEM CONTROL MECHANISM

20-245 (12)

TROUBLESHOOTING

EXPLANATION OF FUNCTIONS OF ELECTRIC SYSTEM CONTROL MECHANISM

Machine model: PC78UU-6 The control mechanism of the electric system consists of the monitor panel, governor, and pump controller. Those components receive signals necessary to them. The governor and pump controller output or input the necessary signal according to the signals selected by the monitor panel to control the absorption torque, engine output, etc.

Network information 1) Working mode (Standard, E) information 2) One-touch slow-down (ON/OFF) signal 3) Travel Hi/Lo signal 4) Coolant temperature (Water temperature) information 5) Service code (Failure code) information 6) Automatic control information (Only PC78UU)

20-245-1 ➄

(Monitor panel ! Controller) (Monitor panel  Controller) (Monitor panel  Controller) (Monitor panel ! Controller) (Controller ! Monitor panel) (Monitor panel ! Controller)

PC78US-6

TROUBLESHOOTING

PC78US-6

EXPLANATION OF FUNCTIONS OF ELECTRIC SYSTEM CONTROL MECHANISM

20-245-2 ➄

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL 1. Diagnostic function of lamps, gauges, and buzzer If the starting switch is turned ON, all the lamps and gauges light up for about 3 seconds and the buzzer sounds for about 1 second to check the monitor panel, then the monitor panel displays normally (A lamp which does not light up at this time is broken). 2. Function of displaying "user code" All trouble information items of the controller are sent to the monitor panel. An emergent information item among them is displayed as a "user code" automatically on the display (1) of the monitor panel to urge the operator to take proper actions. ★ The lamps other than display (1), service meter unit (2), and lighting parts (solid parts in the following illustration) are turned OFF.

1) Display of User Code (1) Display (2) Service meter unit (3) Mode selector switch (UP) (4) Mode selector switch (DOWN) (5) Set switch (6) Travel speed selector switch (7) Working mode selector switch (8) Buzzer cancel switch Note) Since the switches "3, 4, and 5" are not indicated on the panel of model US, operate the same parts as the panel of model UU.

Example)User code "E02" is displayed.

2) User Codes List

E02

TVC-EPC system

E03

Swing holding brake system

E05

Governor control system

E40

Angle sensor input system

E41

EPC solenoid and PPC basic pressure lock solenoid output system

20-246 ➄

Abnormal system

  

User Code

Only PC78UU-6

PC78US-6

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

3. Function of displaying "service code" All trouble information items of the controller are sent to the monitor panel. All of the information items which must display "user codes" and those which do not need display "user codes" are saved as "service codes" in the monitor panel. If the following operation is executed, the service code is displayed on the display of the monitor panel and the letter "E" to indicate that the trouble is happening currently and the lapse time (service meter reading) are displayed on the service meter unit. 1) Method of displaying and deleting service code i) The service code is displayed by the following procedure: (1) Push and hold the "Buzzer cancel switch (8)" and "Working mode selector switch (7)" for 2.5 seconds. (2) Push the "Buzzer cancel switch (8)" and "Mode selector switch (UP) (3)" [or Mode selector switch (DOWN) (4)] and set "01" tothe 2nd and 3rd columns from the left on service meter unit (2).

(1) Display (2) Service meter unit (3) Mode selector switch (UP) (4) Mode selector switch (DOWN)

(5) Set switch (6) Travel speed switch (7) Working mode selector switch (8) Buzzer cancel switch

(3) Push the "Set switch (5)".

Since the switches "3, 4, and 5" are not indicated on the panel of model US, operate the same parts as the panel of model UU. Example 1)"01" is displayed on service meter unit (2).

Example 2)"E213" happened 6 hours ago. a If "E213" is still happening, the letter "E" is displayed in the 2nd column of service meter unit (2). If "E213" has been repaired, "E" is not displayed. a The lapse time is displayed in the 3 columns from the right of service meter unit (2).

PC78US-6

20-247 (1)

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

Example 3)If any service code is not saved, "-" is displayed in every column of display (1) and service meter unit (2). ii) To see the next displayed service code, push the "Buzzer cancel switch (8)" and "Mode selector switch (UP)" (3). iii) To see the previous displayed service code, push the "Buzzer cancel switch (8)" and "Mode selector switch (DOWN) (4)".

iv) To stop display of the service code, push the "Buzzer cancel switch (8)" and "Working mode selector switch (7)". v) To delete the saved service codes, press the "Buzzer cancel switch (8)" and turn OFF the "starting switch" simultaneously, then turn ON the "starting switch" again and push and hold the "Buzzer cancel switch (8)" for 5 seconds. a If the number of service codes exceeds 20, they are deleted one by one from the oldest one.

2) Service codes list Error Code

Abnormal System

User Code

E101

Error history data are abnormal

—

E108

Engine coolant temperature is 105°C

— —

E112

Short circuit in forward system of wiper motor drive

E113

Short circuit in reverse system of wiper motor drive

—

E114

Short circuit in windshield washer drive system

—

E115

Wiper does not start wiping in 10 seconds

—

E116

Wiper is not retracted in 10 seconds

E203

Short circuit or grounding fault in swing holding brake solenoid system

E206

Short circuit or grounding fault in 2nd travel speed selection solenoid system

—

E213

Disconnection in swing holding brake solenoid system

—

E216

Disconnection in 2nd travel speed selection solenoid system

—

E224

Defective pump pressure sensor system

—

E227

Short circuit or grounding fault in engine speed sensor system

—

E232

Short circuit or grounding fault in TVC-EPC Solenoid system

E02

E233

Disconnection in TVC-EPC Solenoid system

E02

E258

Grounding fault on power source side of all angle sensors

—

— E03

E304 (*3)

Short circuit or grounding fault in engine stop solenoid relay system

—

E306 (*4)

Defective governor feedback potentiometer

—

E308 (*4)

Defective fuel control dial system

E314 (*3)

Disconnection in engine stop solenoid relay system

E321 (*2)

Grounding fault in governor control motor drive relay system

E05

E323

Grounding fault in governor control accelerator relays system

E05

E325

Grounding fault in governor control decelerator relays system

E05

E328

Abnormality in governor control motor stal

E05

E401 (*1)

Disconnection on boom angle sensor (-) side

E40

E402 (*1)

Grounding fault or disconnection on boom angle sensor signal side or disconnection on (+) side

E40

E403 (*1)

Defective correction of boom angle sensor

—

E404 (*1)

Disconnection on arm angle sensor (-) side

E40

E405 (*1)

Grounding fault or disconnection on arm angle sensor signal side or disconnection on (+) side

E40

E406 (*1)

Defective correction of arm angle sensor

E407 (*1)

Disconnection on offset left angle sensor (-) side

E40

E408 (*1)

Grounding fault or disconnection on offset left angle sensor signal side or disconnection on (+) side

E40

E05 —

—

E411 (*1)

Defective correction of offset left angle sensor

E421 (*1)

Short circuit or grounding fault in boom raise EPC system

E41

E422 (*1)

Disconnection in boom raise EPC system

E41

E423 (*1)

Short circuit or grounding fault in arm-in EPC system

E41

E424 (*1)

Disconnection in arm-in EPC system

E41

E425 (*1)

Short circuit or grounding fault in offset left EPC system

E41

E426 (*1)

Disconnection in offset left EPC system

E41

20-248 (12)

—

PC78US-6

TROUBLESHOOTING

Error Code E431 (*1) E435

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

Abnormal System Short circuit or grounding fault in PPC basic pressure lock solenoid system Emergency stop

User Code E41 —

E441 (*1)

Defective correction of interference prevention (Front)

—

E442 (*1)

Defective correction of interference prevention (Side)

—

E443 (*1)

Defective correction of depth display

—

E501

Machine model not set

—

E502

Defective machine model selection signal

—

*1. *2. *3. *4.

PC78UU only Serial No.: PC78US: 4001 – 5500, PC78UU: 22832 – 23500 Serial No.: PC78US: 5501 and up, PC78UU: 23501 and up Serial No.: PC78US: 6501 and up

PC78US-6

20-248-1 (12)

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

4. Function of displaying "monitoring code" The input signals from the sensors to each component and the output signals to drive the solenoids can be checked in real time with the monitoring codes. If the following operation is executed, the monitoring code No. is displayed in the 3rd column through the 5th column from the left on service meter unit (2) of the monitor panel and the monitoring information is displayed on display (1). 1) Method of displaying monitoring code i) The monitoring code is displayed by the following procedure: (1) Push and hold the "Buzzer cancel switch (8)" and "Working switch (7)" for 2.5 seconds. (2) Push the "Buzzer cancel switch (8)" and "Mode selector switch (UP) (3)" [or Mode selector switch (DOWN) (4)] and set "02" to the 2nd and 3rd columns from the left on display (2). (3) Push the "Set switch (5)". Since the switches "3, 4, and 5" are not indicated on the panel of model US, operate the same parts as the panel of model UU.

(1) Display (2) Service meter unit (3) Mode selector switch (UP) (4) Mode selector switch (DOWN)

(5) Set switch (6) Travel speed switch (7) Working mode selector switch (8) Buzzer cancel switch

Example 1)A numerical monitoring code (Engine speed: 2,050 rpm) is displayed.

Example 2)A bit pattern monitoring code 1020 (ON/OFF input state (1)) is displayed.

PC78US-6

20-249 (1)

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

ii)

To see the next displayed monitoring code, push the "Buzzer cancel switch (8)" and "Mode selector switch (UP) (3)". iii) To see the previous displayed monitoring code, push the "Buzzer cancel switch (8)" and "Mode selector switch (DOWN) (4)". iv) To stop display of the monitoring code, push and hold the "Buzzer cancel switch (8)" and "Working mode selector switch (5)" for 2.5 seconds. 2) Monitoring codes list a For details of a code marked with "(6 bit)" in the Unit column, see the bit patterns table. Code No. 0001 0008 0041 0042 0043 0045 0046 0047 0048 0049 0200 1000

1001 1010 1020 1021 1022 1023 1024 1025 1026 1030 1031 1032 1033 1040 1050 1051 1052 1053 1060

20-250 (7)

Item

Unit

Monitor model code — S-NET connection state (6bit) Water temperature sensor voltage 10 mA Fuel level sensor voltage 10 mA Charge voltage 100 mA Sensor input 1 (6bit) Sensor input 2 (6bit) Output state (6bit) Wiper state (6bit) Spare Software version No. (Monitor) Software version No. If 1.0 is displayed, version No. of controller is 1.0. (Controller) 00: Standard arm 01: Long arm Attachment selection 02: Slide arm 03: Multi-changer Engine speed 10 rpm ON/OFF input 1 (6bit) ON/OFF input 2 (6bit) ON/OFF input 3 (6bit) ON/OFF input 4 (6bit) ON/OFF input/output (6bit) ON/OFF input/output (6bit) ON/OFF input/output (6bit) Work equipment angle V sensor voltage (Boom) Work equipment angle If 2.4 is displayed, input voltage is 2.4 V. V sensor voltage (Offset) Work equipment angle V sensor voltage (Arm) Work equipment potentiometer slide V Boom bottom pressure If 2.4 is displayed, pressure is 2.4 MPa. MPa EPC output current 10 mA (TVC) EPC output current 10 mA (Boom RAISE) If 55 is displayed, current is 55 mA. If current is 1 A, however, FF is displayed. EPC output current 10 mA (Arm IN) EPC output current 10 mA (Off-set LEFT) ON/OFF output (6bit)

Component Name Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller

Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller Controller

PC78US-6

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

TROUBLESHOOTING

3) Bit patterns list (Bits of corresponding Nos. light up) a [1] – [6] on digital display unit (1) are bit Nos. a The monitoring code No. (4 digits) is displayed in the 2nd column through 5th column from the left on service meter display unit (2).

Code No.

Item

0008

S-NET connection state

0045

Sensor input 1

0046

Sensor input 2

0047

State of output

0048

State of wiper

0049

Spare

1020

ON/OFF input 1 a For detail of model selection, see Table 1. a For detail of ATT selection, see Table 2.

1021

ON/OFF input 2

Bit

ID2 is connected. ID3 is connected. ID4 is connected. ID5 is connected. ID6 is connected. ID7 is connected. Starting switch is at "ON" Starting switch is at "START" Starting switch is at "PREHEAT" Light switch is at "ON" Constant bit Engine oil pressure (When low) Charge level is low (Engine is stopped) Buzzer output Washer output (Washer switch is turned ON) Wiper output 1 Wiper output 2 Wiper output 3 Wiper output 4 Buzzer cancel switch Window limit switch (ON) W contact (Wiper is operated) P contact (Wiper is operated)

(1) (2) (3) (4) (5) (6) (3) (4)

ATT selection 2 (GND is connected) (*1) ATT selection 1 (GND is connected) (*1) Model selection 1 (GND is connected) (*1) ATT selection 3 (GND is connected) (*1) UU/US selection (GND is connected) (*1) Model selection 2 (GND is connected) (*1) Compressor signal — a Tier 2 selection signal (When power source is connected) (*1) 2nd travel speed selection switch (Panel) Working mode selector switch Backup light (*1) SET/CLEAR switch Mode selector (E) switch Mode selector (R) switch

(5)

1022

PC78US-6

ON/OFF input 3

Details (State When Bit Lights Up)

(1) (2) (3) (4) (5) (6) (1) (2) (3) (4) (2) (3) (6) (1) (2) (3) (4) (5) (6) (2) (3) (4) (5)

(1) (2) (3) (4) (5) (6)

20-251 (12)

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

TROUBLESHOOTING

Code No.

1023

Item

ON/OFF input 4

1024

ON/OFF input/output

1025

ON/OFF input/output

Bit (3) (4) (5)

Details (State When Bit Lights Up) Travel pressure switch Swing pressure switch Arm IN pressure switch

(6) (1) (2) (3) (4) (5) (6) (1) (2) (3) (6)

Boom RAISE pressure switch Deceleration signal (*1) Acceleration signal (*1) Motor drive power supply (*1) Auto deceleration signal (*1) Motor relay (–) Motor relay (+) — Display selector switch (Monitor) Arm ground angle alarm cancel switch (*1) Bucket dump prohibition solenoid + Rotary lamp Deceleration switch (*1), Overload alarm switch (When alarm is effective) (*2) Alarm cancel Emergency work equipment operation switch (*1) 2nd travel speed selection switch (Pedal) (*1) Slide arm limit switch (*1) Swing holding brake switch (Brake is released) PPC main pressure lock (Main pressure lock is reset) (*1) 2nd travel speed is selected (Machine travels at 2nd gear speed) Travel/Swing alarm (Alarm is output)

(1) (2) 1026

ON/OFF input/output

(3) (4) (5) (1) (2)

1060

ON/OFF input/output (4) (5)

*1. PC78US-6 Serial No.: 4001 – 6500, PC78UU-6 Seral No.: 22832 and up *2. PC78US-6 Serial No.: 6501 and up

20-252 (12)

PC78US-6

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

TROUBLESHOOTING

Table 1 Model selection table Model Selection 1

Model Selection 2

UU/US Selection Signal

Tier 2 Signal

PC78US-6 (*1)

GND

OPEN

GND

OPEN

PC78US-6 (*2)

GND

OPEN

GND

Connection of power source

PC78UU-6 (*1)

GND

OPEN

OPEN

OPEN

PC78UU-6 (*2)

GND

OPEN

OPEN

Connection of power source

*1. PC78US-6 Serial No.: 4001 – 5500, PC78UU-6 Seral No.: 22832 – 23500 *2. PC78US-6 Serial No.: 5501 – 6500, PC78UU-6 Seral No.: 23501 and up Table 2 Connection table of attachment selection wires a The bits of GND are displayed during normal operation. Attachment

Attachment Selection (1)

Attachment Selection (2)

Attachment Selection (3)

GND

OPEN

OPEN

Standard specification Standard arm Long arm

OPEN

GND

OPEN

Slide arm

GND

GND

OPEN

OPEN

OPEN

OPEN

Multi-changer

PC78US-6

20-252-1 (13)

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

TROUBLESHOOTING

Procedure for correcting angle sensor, preventing interference, setting depth display to 0, adjusting engine governor, setting arm crane specification, and setting work equipment. Back mode (When SP monitor is used) Table 2 Method of selecting back mode and ordinary display 02

PC78US-6

Q

Q

PC78UU-6

Q

Q

Buzzer cancel Working mode selection

Q

Q

Q

Q

Mode Code (Note 2)

B a

Back Mode 06 10 11 18 19 These modes are set to 2 levels (Note 5) EmerSetting Setting Setting Error Adjusting Adjusting CorrectSetting gency prevendisarm Error Next Previ- Memory Adjusting service ing work Trouble Memory Monitor- engine service tion of played crane Item ous Item Deletion meter governor potenti- interfer- depth to specifica- equiping (Note 3) Display lever ometer ment (Note 4) (Note 4) ence D tion 01

03

Q

—

—

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

Q

(Note9) (Note6)

Q

Q

(Note6) (Note9)

Q

—

—

Q

Q

(Note7)

—

—

Q

Q

(Note8)

Q

Q

Q

Q

Q

Q 3 (Note10)

1

b

Travel selection

Q

(Note10)

c

SET/CLEAR

Q

(Note10)

d

Model selection (E)

e

Model selection (R) Wiper selection Washer Continuous operation time (SEC)

Note Note Note Note Note

1) 2) 3) 4) 5) *

Note 6) Note 7) Note 8) Note 9) Note 10)

2 4

Q

(Note10)

Q

2.5

5 (Note1)

Limited to 5 seconds after the power is turned ON. Displayed on the service meter unit. A flag from the controller is a trigger. Used to save monitoring error. Select with Buzzer cancel + Working mode selection. Select next or previous items with Buzzer cancel + E/R. Enter each mode with the SET/CLEAR switch. Unnecessary entry to this mode can cause a trouble, however. When adjusting SMR, enter this mode by a different method. Do not this mode for model US. Serial No.: 5501 and up Serial No.: 23501 and up Serial No.: 6501 and up Press switches 1 – 4 in order.

PC78US-6

20-253 (12)

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

"03" Adjusting engine governor lever PC78US-6 Serial No.: 6501 and up 1) In this mode, set the decelerator motor cable in the engine high idling position (where it becomes shortest). 2) Use this mode to set the engine governor lever fully. (When the starting switch is turned ON, if the system is not set in this mode, the governor motor may not operate.) 3) If a short circuit or a grounding fault occurs in the circuit of the governor control system, the cable may move out of the normal control range. At this time, even if the cause of the trouble is removed, the governor motor cannot be controlled. If this occurs, operate the panel switch in this mode to return the cable into the normal control range and restore the governor motor control. No.

1

2

3

Operation 1) Turn the starting switch ON and set the fuel control dial to the FULL position. a At this time, turn the automatic decelerator (onetouch decelerator) OFF (reset it). 2) Hold buzzer cancel switch (B) and working mode selector switch (a) for 2.5 seconds. 3) Set the code in the service meter section to "03". (B) + (d): Next code (B) + (e): Previous code 4) Press switch (c). a Under this condition, the deceleration motor cable is in the engine high idling position (It becomes shortest). Use this function for only above purpose 3). (Do not use this function usually.) Be sure to remove the cause of the trouble before using this function. 5)-1. When engine speed does not rise from low idling Press switch (d) several times and operate the fuel control dial to check that the governor control is restored. 5)-2. When engine speed does not lower from high idling Press switch (e) several times and operate the fuel control dial to check that the governor control is restored. To finish the decelerator motor adjustment, perform the operation in 1-(2), and the monitor panel displays normally.

a Since US does not have displays of c, d, and e, operate the same parts with UU.

Display The display section displays "GOV" and the service meter display section displays "GSET".

UU monitor panel

B: Buzzer cancel switch is installed to top of right console.

20-253-1 (13)

PC78US-6

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

"06" Correcting angle sensor (Only UU) The stroke end is saved for initial setting of each cylinder (portion where the angle sensor is installed). No.

1

Operation 1) Turn the starting switch ON or run the engine, and then hold alarm buzzer cancel switch (B) and working mode selector switch (a) for 2.5 seconds. 2) Set the code of the service meter section to "06". (B) + (d): Next code (B) + (e): Previous code 3) Press switch (c).

Display The display section displays "S-1".

Set the machine in "posture 1" and press switch (c). (Posture 1) • 1st boom: RAISE end • Offset boom: RIGHT end (Only UU) • Arm: IN end

After switch (c) is pressed, the display section displays "ooo", and then it displays "S-2". When normal

2

If the system is not reset normally, "---" is displayed.

Set the machine in "posture 2" and press switch (c). (Posture 2) • Offset boom: LEFT end (Only UU) • Arm: DUMP end • Do not lower bucket to ground.

After switch (c) is pressed, the display section displays "ooo", and then it displays "---". When normal

(Completion of setting)

3

If the system is not reset normally, "---" flashes.

4

When abnormal

When abnormal (Flashing)

To finish monitoring, perform the operation of 1-1), and the monitor panel returns to the ordinary display state.

a If the system is not reset normally, check the service code with the error history display function to find out the defective potentiometer. a If the system is not reset normally, the data before writing are deleted and the initial data are applied. Accordingly, be sure to reset again. a Since US does not have displays of c, d, and e, operate the same parts with UU.

UU monitor panel

B: Buzzer cancel switch is installed to top of right console. PC78US-6

20-253-2 (13)

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

"10" Setting of prevention of interference (Only UU) Setting of front and side stop positions and emergency stop position No.

1

2

Operation 1) Turn the starting switch ON or start the engine, then push and hold warning buzzer cancel switch (B) and working mode selector switch (a) for 2.5 seconds. 2) Set the code on service meter unit to "10". (B) + (d): Next code (B) + (e): Previous code 3) Push switch (c). Set the bucket to the front automatic stop position and push switch (c).

Display "F-1" is displayed on the display.

After switch (c) is pushed, "ooo" is displayed on the display, then "S-1" is displayed.

(Setting of front stop position)

When normal

If the data are not reset normally, "---" is displayed.

When abnormal

Set the bucket to the side automatic stop position and push switch (c).

After switch (c) is pushed, "ooo" is displayed on the display, then "---" is dislayed.

Setting of front stop position

(Setting of side stop position) When normal

3 If the data are not reset normally, "---" is displayed.

(Setting is completed)

When abnormal

4

To stop monitoring, perform the operation in 1-1), and the monitor panel displays the normal items. Monitor Panel of Model UU

a If the data are not reset normally, check the service code with the function of displaying the failure history to find out the defective potentiometer. a If the data are not reset normally, the data before writing are deleted and the initial data are saved. Be sure to reset again. B: The buzzer cancel switch is installed above the right console.

20-254 (5)

PC78US-6

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

"11" Setting of displayed depth to 0 (Only UU) Correction of dispersion of displayed depth No.

1

Operation 1) Turn the starting switch ON or start the engine, then push and hold warning buzzer cancel switch (B) and working mode selector switch (a) for 2.5 seconds. 2) Set the code on service meter unit to "11". (B) + (d): Next code (B) + (e): Previous code 3) Push switch (c).

Display "d-1" is displayed on the display.

Set the machine to the working position in (Position 3) and push switch (c).

After switch (c) is pushed, "ooo" is displayed on the display, then "d-2" is displayed.

(Position 3) • Move bucket in (Lower bucket to ground with its top vertical.)

When normal

2

If the data are not reset normally, "---" is displayed. When abnormal Set the machine to the working position in (Position 4) and push switch (c).

After switch (c) is pushed, "ooo" is displayed on the display, then "---" is displayed.

(Position 4) • Move arm out (Lower bucket to ground with its top vertical.)

When normal

(Setting is completed)

3 When abnormal If the data are not reset normally, "---" is displayed.

4

To stop monitoring, perform the operation in 1-1), and the monitor panel displays the normal items. Monitor Panel of Model UU

a If the data are not reset normally, check the service code with the function of displaying the failure history to find out the defective potentiometer. a If the data are not reset normally, the data before writing are deleted and the initial data are saved. Be sure to reset again. B: The buzzer cancel switch is installed above the right console.

PC78US-6

20-255 (5)

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

"19" Setting work equipment PC78US-6 Serial No.: 6501 and up a Since the attachments for the above machines are selected with the monitor panel, an attachment selector connector is not installed. a Set the specification of the work equipment (The machine with the standard arm specification does not need to be set). No.

1

Operation 1) Hold alarm buzzer cancel switch (B) and switch (a) for 2.5 seconds. 2) Set the code of the service meter section to "19". (B) + (d): Next code (B) + (e): Previous code 3) Press switch (c).

Display The display section displays "10" and the service meter section displays "19SET". (If 19SET has been set, the display section displays the current set value.)

1) Set the value of the display section to a desired value.

Example) When long arm is selected

Set value Arm Remarks 0 Standard arm Controller default 1 Long arm (B) + (d): Next code (B) + (e): Previous code 2) Press switch (c).

After switch (c) is pressed, the display section displays "ooo", and then it displays "---".

2

3

To finish selection of model, perform the operation of 1-1), and the monitor panel returns to the ordinary display state. After finishing setting 19SET, be sure to turn the starting switch OFF once. This setting becomes effective only after the starting switch is turned OFF.

a Since US does not have displays of c, d, and e, operate the same parts with UU.

UU monitor panel

B: Buzzer cancel switch is installed to top of right console.

20-255-1 (13)

PC78US-6

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

TROUBLESHOOTING

Service adjustment This service adjustment is set for adjustment of dispersion of components and parts and for replay to requests of each user. Perform this adjustment for the following phenomena and users' requests. a Basically, the following items do not need to be adjusted, since they are adjusted when delivered. a This service adjustment is not effective when a component or a part is broken. 1) Service adjustment items table The phenomena of the machine which need service adjustment, procedure for changing the set values, and precautions are listed. a Usually, each adjustment value is set to the initial value. Service adjustment item

Adjustment code/set value

Phenomenon of machine/Users' request

Procedure for changing set value

Engine speed lowers largely during work.

Change set value to decrease pump absorption torque.

Adjust to degree that work equipment cycle time is not lengthened.

Work equipment speed is low.

Change set value to increase pump absorption torque.

Adjust to degree that engine speed is not lowered largely.

Precautions

Adjustment of PC-EPC valve current

204

Travel/Swing alarm output (If travel alarm is installed)

210

Set for each user who wants to sound alarm during swinging.

Set to 211.

Alarm sounds when machine travels or swings.

Change of emergency stop position (Front of cab)

220

When bucket is in interference range of cab, emergency stop system does not operate.

Increase set value.

Since stop position becomes closer to emergency stop position, adjust stop position, too.

Change of emergency stop position (Side of cab)

230

When bucket is in interference range of cab, emergency stop system does not operate.

Increase set value.

Since stop position becomes closer to emergency stop position, adjust stop position, too.

Decrease EPC pressure.

• Adjust to degree that boom RAISE speed is not lowered. • Boom stops to prevent interference even when engine speed is low.

Increase EPC pressure.

• Adjust to degree that function of boom RAISE end cushion is not lowered. • Adjust to degree that large shock is not made when boom stops to prevent interference.

Decrease EPC pressure.

• Adjust to degree that arm IN speed is not lowered. • Arm stops to prevent interference even when engine speed is low.

• When arm IN end cushion works, work equipment speed is low. • When arm stops to prevent interference, work equipment speed is low.

Increase EPC pressure.

• Adjust to degree that function of arm IN end cushion is not lowered. • Adjust to degree that large shock is not made when arm stops to prevent interference.

Low idling speed is extremely high.

Decrease set value.

Adjustment of boom RAISE EPC valve current

Adjustment of arm RAISE EPC valve current

Adjustment of governor cable stroke (Low idling) (*1)

• Boom RAISE end cushion does not work normally. • Large shock is made when boom stops to prevent interference. 243

• When boom RAISE end cushion works, work equipment speed is low. • When boom stops to prevent interference, work equipment speed is low. • Arm IN end cushion does not work normally. • Large shock is made when arm stops to prevent interference.

253

324

Adjustment of governor cable stroke (Arm crane mode) (*1)

334

Adjustment of governor cable stroke (E mode) (*1)

344

Initialization of set values (Only contents of service adjustment)

400

Low idling speed is extremely low (Adjustment is not necessary usually since cable touches stopper).

Increase set value.

High idling speed is extremely high in arm crane mode.

Decrease set value.

High idling speed is extremely low in arm crane mode.

Increase set value.

High idling speed is extremely high in E mode.

Decrease set value.

High idling speed is extremely low in E mode.

Increase set value.

Adjust low idling speed to 1,130 – 1,180 rpm.

Adjust high idling speed to 1,400 – 1,600 rpm in arm crane mode.

Adjust high idling speed to 1,750 – 1,950 rpm in arm crane mode.

If 401 is selected, all service adjustment items are set to initial values.

*1. PC78US-6 Serial No.: 6501 and up

PC78US-6

20-255-2 (12)

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

How to improve exhaust gas color at high altitude • Adjust the TVC current in this mode to reduce the pump absorption torque and improve the exhaust gas color at high altitude. a The work equipment speed, travel speed, and swing speed are lowered by the following operation. a The following operation is not necessary for the normal work. No.

1

2

3

4

5

Operation 1) Turn the starting switch ON or run the engine and hold buzzer cancel switch (B), travel speed shifting switch (b), and switch (c) for 2.5 seconds. 2) Adjustment code (3) is displayed (flashed) at the left 2 positions and set value (4) is displayed (lighted) at the right 1 position on display unit (1). "5-5E7" (S-SET) is displayed on service meter unit (2).

Adjustment code "20" flashes. Set the adjustment code with switch (c). • The flashing adjustment code lights up. • The lighting set value flashes. Increase or decrease the set value with switches (d) or (e) and set it with switch (c). • (d): Code is increased. • (e): Code is decreased. • The lighting adjustment code flashes again. • The flashing set value lights up again. a For details of the adjustment code and set value, see the TVC valve current adjustment table. To finish adjustment of the TVC valve current, perform Step 1-1), and the monitor panel returns to the normal display state. a The set value is saved when the monitor panel returns to the normal display state. Caution: If the mode is reset forcibly by turning the starting switch OFF, the set value is not changed.

Display

Change of setting is completed.

[ 1] Flashing: Code/Set value can be changed. [ 2] Lighting: Code is selected/set.

To initialize the set value of the TVC valve current adjustment mode, set the adjustment code and the set value to "40" and "1" respectively with switches (d) and (e), and then finish the adjustment mode.

Note) If switch (d) or (e) is pressed at Step 2, the adjustment code changes. Accordingly, do not press those switches.

UU monitor panel

B: The buzzer cancel switch is installed to the right console.

20-255-3 (12)

PC78US-6

TVC VALVE CURRENT ADJUSTMENT TABLE

TROUBLESHOOTING

TVC VALVE CURRENT ADJUSTMENT TABLE Adjustment code (Left 2 positions of display unit)

20

PC78US-6

Set value (Right 1 position of display unit)

Initial value

Contents

0

Increase pump absorption torque by +2.0 kgm (-100 mA).

1

Increase pump absorption torque by +1.5 kgm (-75 mA).

2

Increase pump absorption torque by +1.0 kgm (-50 mA).

3

Increase pump absorption torque by +0.5 kgm (-25 mA).

4

Q

Exhaust gas color

Bad

Initial value

5

Decrease pump absorption torque by -0.5 kgm (+25 mA)

6

Decrease pump absorption torque by -1.0 kgm (+50 mA)

7

Decrease pump absorption torque by -1.5 kgm (+75 mA)

8

Decrease pump absorption torque by -2.0 kgm (+100 mA)

Good

20-255-4 (12)

HOW TO READ JUDGMENT TABLE

TROUBLESHOOTING

HOW TO READ JUDGMENT TABLE This judgment table is a tool to see if a trouble of the machine is caused by the electrical system or the hydraulic and mechanical system and go to a proper troubleshooting code (E-QQ, C-QQ, F-QQ, H-QQ, M-QQ, or CR-QQ). In the judgment table, you can judge which troubleshooting code to take by the displayed user code and service code. a If a trouble (warning) is displayed on the monitor panel, directly go to the troubleshooting code (M-QQ) displayed on the machine monitor. (See the troubleshooting of the machine monitor system.) 1. How to read controller (governor control system) and engine judgment table • If a service code is displayed on the monitor panel, go to the troubleshooting code (E-QQ) at the bottom line of the judgment table. (The mark of "q" is put in the place where the trouble mode and service code are matched to each other.) • When there is a trouble while no service codes are displayed on the monitor panel, go to the troubleshooting code (E-QQ or S-QQ) at the right end which is matched to the trouble mode in the judgment table. <Example> When trouble mode of "Engine does not start" is displayed [Procedure] See if a servomotor is displayed on the monitor panel.

[Judgment] 1) When a service code is displayed on the monitor panel --- Carry out troubleshooting for "E3-QQ" of the controller (governor control) system. 2) When "the engine does not start" while a service code is not displayed on the monitor panel.

• Check revolution of starting motor.

PC78US-6

When starting motor revolves ....................... Go to troubleshooting "S-2" of mechanical system. Go to troubleshooting "E-8" of electrical When starting motor does not revolve.......... system.

20-255-6 (12)

HOW TO READ JUDGMENT TABLE

TROUBLESHOOTING

2. How to read controller (pump control system) and hydraulic equipment judgment table • If a service code is displayed on the monitor panel, go to the troubleshooting code (C-QQ) at the bottom line of the judgment table. (The mark of "q" is put in the place where the trouble mode and service code are matched to each other.) • When there is a trouble while no service codes are displayed on the monitor panel, check that an input signal matched to the trouble mode in the judgment table (the input signal at the point marked with Q) is displayed, and then; • If the input signal is displayed normally, go to the troubleshooting code (H-QQ or C-QQ) at the right end of the judgment table. • If the input signal is not displayed, go to the troubleshooting code (F-QQ) at the bottom line of the judgment table. <Example> When trouble mode of "Machine does not swing" is displayed [Procedure] See if a servomotor is displayed on the monitor panel.

[Judgment] 1) When a service code is displayed on the monitor panel ......... Carry out troubleshooting for "C-QQ" of the controller (governor control) system. 2) When "the machine does not swing" while a service code is not displayed on the monitor panel

• Check input signal of controller (in monitoring mode).

20-255-7 (12)

When there is signal........................

Go to troubleshooting "H-34" or "C-38) of mechanical system.

When there is not signal..................

Go to troubleshooting "F-QQ" of controller input signal system (F mode of corresponding system).

PC78US-6

HOW TO READ FLOW OF TROUBLESHOOTING

TROUBLESHOOTING

HOW TO READ FLOW OF TROUBLESHOOTING 1. Classification of diagnosis code Nos. Diagnosis Code No.

Objective System of Diagnosis

Service Code

N-QQ

Communication system

E-QQ

Electric system of controller (Governor control system)

321, 323, 325, 328

C-QQ

Electric system of controller (Pump control system)

232, 233

F-QQ

Controller (Input signal system)

501, 502, 258, 401, 402, 404, 405, 407, 408

H-QQ

Hydraulic and mechanical systems

M-QQ

Monitor panel

— E1-QQ system

2. How to read troubleshooting (method) for each failure mode 1) Title column In the title column of the troubleshooting, the troubleshooting code, service code, and failure mode (trouble) are entered. 2) Classification of cases If the troubleshooting method for a failure mode (a trouble) varies with the machine model, component, phenomenon, the failure mode (the trouble) is classified further (This work is called classification of cases), execute an applicable one. (See (2) in the example.) If the cases are not classified, start troubleshooting from the first of the failure mode. 3) How to carry out troubleshooting • Perform checking or measurement in the first step . Then, select either branch of YES and NO and go to the next step . (Note: The "No." at the right shoulder of each is the reference No. It is not the No. of the step.) • If the branch of YES or NO is connected directly to the Cause column, take the remedy shown in the Remedy column. (See (3) in the example.) • Under the , the method of inspection, measurement, judgment, etc. are shown. If the result is matched to the criterion, question, etc., take the branch of YES. If not, take the branch of NO. • Under the , preparation work for inspection and measurement and criterion are also shown. If your neglect the preparation work or take a wrong method of operation or handling, you may have a wrong judgment or may damage the devices. Accordingly, read well before starting inspection and measurement, then carry out the work in the correct order. 4) General precautions The general precautions for troubleshooting of each failure mode (trouble) are marked with a under the title (See (4) in the example). The precautions marked with a are not shown in the . Be sure to take them when performing the inspections in the . 5) Diagnostic tools For the diagnostic tools necessary for troubleshooting, see TESTING AND ADJUSTING, Diagnostic tools list. Prepare them before starting the work.

20-256 (12)

PC78US-6

HOW TO READ FLOW OF TROUBLESHOOTING

TROUBLESHOOTING

6) Locations and connector pin Nos. Before starting the work, check the Nos., inspection points, types, and locations of the wiring connectors which appear in the flow of the troubleshooting for each failure mode (trouble) with the table of locations and Nos. of connector pins. <Example> (1) M-1 [E101] (Error history data are abnormal) is displayed (2) a HThis error is displayed when the connector P01, connector K1, fuse 18, connector M6, connector M2, battery relay terminal B, or battery terminal in the monitor panel power supply system is disconnected or connected for troubleshooting. This phenomenon does not indicate an error. (When the power supply circuit of the monitor panel is cut out while the starting switch is at the OFF position.) a If the service code is displayed again after the resetting operation is performed, carry out the troubleshooting according to the following procedure. Cause

Remedy

1 • Perform "resetting operation", then operate machine usually and observe its condition for a while (See Note 1).

After "resetting operation" is performed, is service code displayed again?

NO

Normal

—

NO

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between battery – battery relay B - M27 (1), (2) – P01 (Female) (8)

Repair or replace

Defective monitor panel

Replace

YES

2 • Turn starting switch OFF. • 20 – 30 V

Is voltage between P01 (8) – chassis ground normal? YES

PC78US-6

20-259 (12)

CONTENTS AND PROCEDURE OF TROUBLESHOOTING

TROUBLESHOOTING

CONTENTS AND PROCEDURE OF TROUBLESHOOTING If a trouble occurs, carry out troubleshooting according to the judgment table, controller (governor control system), and controller (pump control system). For the detailed contents and procedure of the troubleshooting, however, see the following flow. Before starting the troubleshooting, ask the operator about the trouble as long as possible and check the following items in advance. (1) Connecting condition of the controller (Check with monitoring code 0001), (2) Breakage of the fuses, (3) Battery voltage, (4) Generating (charge input) voltage (Monitoring code 0043 "H-34").

YES

1 Is user code displayed on monitor panel?

E02

(PC-EPC system)

E03

(Swing holding brake and 2nd travel speed selection solenoid systems)

E05

(Governor motor system)

}

o Go to 2

E200 group: Troubleshooting for pump controller (Pump control system) (C-mode)

YES E300 group: Troubleshooting for pump controller (Governor control system) (E-mode)

}

Carry out troubleshooting in corresponding mode.

2 NO

Is service code displayed on monitor panel? • Operate and check service code.

YES

Carry out troubleshooting by engine (in S-mode).

5 Engine system

4 YES 3 NO

Is input/output signal of controller normal? • Check by monitoring code.

Is trouble in engine system or hydraulic (Mechanical) system? • Adjust hydraulic pressure, then judge by engine speed. • Is work equipment always heavy and does engine speed lower under heavy load?

Is electric system of engine with no failure code normal? • Flow of part of judgment table where no troubles are indicated. NO

Hydraulic Mechanical System NO

Carry out troubleshooting by electric system of engine (in E-mode). (Flow of part where there is no indication) (E-7 – E-9)

(Carry out troubleshooting in Hmode).

Troubleshoot by input signal system (F-mode).

a Judge the details by judgment table for controllers (governor control system) (pump control system). * For the No. and contents of monitoring, see the monitoring codes table.

20-260 (12)

PC78US-6

TROUBLESHOOTING OF COMMUNICATION SYSTEM (N MODE)

N-1 Defective communication ................................................................................................................... 20-302

a When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the service code "E" is not displayed, the condition has returned to normal. a If the starting switch was turned OFF after the trouble occurred, turn the starting switch ON and check that the service code displays "E" at the head. (If "E" is not displayed, the condition has returned to normal.) a Before carrying out troubleshooting, check that all the related connectors are properly inserted. a Always connect and disconnected connectors before going on to the next step. PC78US-6

20-301 (1)

N-1

TROUBLESHOOTING

N-1 Defective communication PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up Cause

Remedy

1 NO

Is operation of monitor display switch normal?

YES Condition is normal

—

Defective controller

Replace

Disconnection or defective contact in wiring harness between P02 (Female) (9), (10) – M96 (Female) (21)

Repair or replace

Defective monitor panel

Replace

2 • Turn starting switch ON • Min. 0.75 V • Disconnect M96 and measure voltage on wiring harness side

Is voltage between M96 (Female) (21) – chassis ground normal?

NO

YES

3 Is resistance between P02 (Female) (9), (10) – M96 (Female) (21) normal?

NO

YES

a If the communication becomes defective, the following troubles occur. • The working mode cannot be changed. • The travel speed cannot be changed with the panel switches. • The monitor lamp does not light up when the one-touch slow-down mechanism is turned on. • Normal figures are not displayed on the display and service meter unit. • A mode cannot be selected. N-1 Electrical circuit diagram of each system

20-302 (12)

PC78US-6

N-1

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up Cause

Remedy

1 NO

Is operation of monitor display switch normal?

YES Condition is normal

—

Defective controller

Replace

Disconnection or defective contact in wiring harness between P02 (Female) (9), (10) – M95 (Female) (18)

Repair or replace

Defective monitor panel

Replace

2 • Turn starting switch ON • Min. 0.75 V • Disconnect M96 and measure voltage on wiring harness side

Is voltage between M95 (Female) (18) – chassis ground normal?

NO

YES

3 Is resistance between P02 (Female) (9), (10) – M95 (Female) (18) normal?

NO

YES

a If the communication becomes defective, the following troubles occur. • The working mode cannot be changed. • The travel speed cannot be changed with the panel switches. • The monitor lamp does not light up when the one-touch slow-down mechanism is turned on. • Normal figures are not displayed on the display and service meter unit. • A mode cannot be selected. N-1 Electrical circuit diagram of each system

PC78US-6

20-303 (12)

TROUBLESHOOTING FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) (E MODE)

Precautions for troubleshooting for controller (governor control system).................................................... 20-326 Action taken by controller when trouble occurs and problems on machine ............................................... 20-328 Judgment table for controller (governor control system) and engine .......................................................... 20-330 E- 1 Controller power supply is defective (LED of controller is turned off) ................................................ 20-332 E- 2 [E321] (Short circuit in motor drive relay) is displayed....................................................................... 20-333 E- 3 [E323] (Short circuit in accelerator relay system) is displayed........................................................... 20-334 E- 4 [E325] (Short circuit in decelerator relay system) is displayed ....................................................... 20-334-3 E- 5 [E328] (Stall of motor) is displayed .................................................................................................... 20-336 E- 6 [E227] (Trouble in engine speed sensor) is displayed ....................................................................... 20-338 E- 7 [E306] Trouble in governor motor feedback potentiometer is displayed......................................... 20-338-2 E- 8 [E308] Trouble in fuel control dial system is displayed ................................................................... 20-338-3 E- 9 One-touch slow-down mechanism does not work ............................................................................. 20-339 E-10 Engine does not start ......................................................................................................................... 20-340 a) [E304] Short circuit in engine stop solenoid relay system is displayed......................................... 20-340 b) [E314] Disconnection in engine stop solenoid relay system is displayed ..................................... 20-340 c) Engine stop solenoid system ........................................................................................................ 20-341 d) Starting system ............................................................................................................................. 20-344 E-11 Engine does not stop ...................................................................................................................... 20-349-2

PC78US-6

20-325 (12)

TROUBLESHOOTING

PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (GOVERNOR CONTROL SYSTEM)

PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) 1. Precautions to be taken when trouble is repaired by itself 1) When a trouble is repaired by itself. 2) When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the service code is not displayed or the monitor displays normally, the same trouble will occur again probably. Accordingly, follow up the condition of the machine sufficiently. 3) After finishing troubleshooting, be sure to delete the saved service code. 2. Handling of function of saving service code When displaying a saved service code for troubleshooting, "take the notes of the all displayed items and delete those items", then reproduce the trouble and start the troubleshooting according to the service code displayed at this time. (Troubles caused by wrong operation, disconnection of a connector, etc. may be saved in the memory. In this case, you can avoid unnecessary work by performing the above operation.)

20-326 (12)

PC78US-6

TROUBLESHOOTING

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up User Code

Service Code E321 (*1)

E05

Short circuit in motor drive relay system

Contents of Trouble 1) Short circuit in wiring harness between M97 pin 18 – K34 pin 1. 2) Short circuit in relay K34.

E323

Short circuit in accelerator relay system

1) Short circuit in wiring harness between M97 pin 25 – K32 pin 1. 2) Short circuit in relay K32.

E325

Short circuit in decelerator relay system

1) Short circuit in wiring harness between M97 pin 35 – K33 pin 1. 2) Short circuit in relay K33.

E328

—

Troubled System

E304 E314 (*2)

Stall of motor (When burn preventive function of motor operates)

1) 2) 3) 4)

Short circuit of M97 pin 19 with power source. Short circuit of M97 pin 29 with power source. Short circuit of M97 pin 39 with power source. Trouble in motor.

1) Short circuit or disconnection in wiring harness between M97 (4) – M36 (1). 2) Disconnection in wiring harness between M36 (2) – chassis ground. Disconnection engine stop solenoid relay system 3) Trouble in M36 relay. Short circuit in engine stop solenoid relay system

*1.: PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500 *2.: PC78US-6 Serial No.: 5501 – 6500 PC78UU-6 Serial No.: 23501 and up When the motor is normal, its condition can be monitored as shown below.

• • • • •

•

When fuel control dial is operated (Slow o Full) Displayed code [1024] : (2), (3), (4), (6), light up and motor operates, then (2), (3), (4), (6) go off and motor stops (Only (4) keeps lighting up). When fuel control dial is operated (Full o Slow) Displayed code [1024] : While only (4) is lighting up, (1), (3), (5) light up and motor operates, then all lamps go off and motor stops. In E-mode (When fuel control dial is at FULL Displayed code [1024] : While only (4) is lighting up, (3), (5) light up and position) motor operates, then (2) lights up and (3), (5) go off and motor stops (Only (2) and (4) keep lighting up). When E-mode is changed to standard motor Displayed code [1024] : While only (2), (4) are lighting up, (3), (6) light up and (When fuel control dial is at FULL position) motor operates, then (2), (3), (6) go off and motor stops (Only (4) keeps lighting up). Displayed code [1024] : While only (4) is lighting up, (3), (5) light up and When one-touch slow-down mechanism is motor operates, then (2) lights up and (3), (4), (5) go turned on (When fuel control dial is at FULL off and motor stops (Only (2) keeps lighting up). position) Displayed code [1026] : When one-touch slow-down switch is turned on, (1) lights up (This is same as in resetting operation). Displayed code [1024] : While only (2) is lighting up, (3), (6) light up and When one-touch slow-down mechanism is motor operates, then (4) lights up and (2), (3), (6) go turned off (When fuel control dial is at FULL off and motor stops (Only (4) keeps lighting up). position)

20-328 (16)

PC78US-6

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

TROUBLESHOOTING

Action taken by controller when trouble occurs Between M97 pin 18 – chassis ground: Min. 1 Mz K34 pin 1 If trouble is detected, motor Resistance between K34 relay pin 1 – pin 2: 290 z ± 10% drive relay output, accelerator relay output, and decelerator Resistance between K34 relay pin 1, 2 – pin: 3, 5, 6 relay output are stopped. : Min. 1 Mz Between M97 pin 25 – chassis ground: Min.: 1 Mz K32 pin 1 Resistance between K32 relay pin 1 – pin 2: 290 z ± 10% Resistance between K32 relay pin 1, 2 – pin 3, 5, 6 : Min. 1 Mz Between M97 pin 35 – chassis ground: Min. 1 Mz K33 pin 1 Resistance between K33 relay pin 1 – pin 2: 290 z ± 10% Resistance between K33 relay pin 1, 2 – pin 3, 5, 6 : Min. 1 Mz Motor starts and stops from slow to full and from full to slow If accelerator, decelerator, or in 2 seconds. one-touch slow-down mechanism works for more than 10 seconds, motor drive relay output, accelerator relay output, and decelerator relay output are stopped. Normal condition

Relay M97 (female)

M36 (male)

Resistance

(4) – Chassis ground

(1) – (2)

68 z ± 10%

Stop solenoid output is stopped.

Problems on machine 1. Fuel control dial cannot be operated (For acceleration and deceleration). 2. One-touch slow-down mechanism cannot be operated. 3. When working mode is changed, engine speed does not change.

•

When signal system is troubled Motor operates but stalls soon. Then, it does not operated even if dial is moved. • When motor is troubled Motor stalls from the first, then it does not operate even if dial is moved. 1. Stop solenoid cannot be pulled (Engine cannot be started).

Engine governor control system

*1.: PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500

PC78US-6

20-329 (12)

TROUBLESHOOTING

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

PC78US-6 Serial No.: 6501 and up User Code

Service Code

Troubled System

E323

Short circuit in accelerator relay system

E325

Short circuit in decelerator relay system

Contents of Trouble 1) Short circuit in wiring harness between M95 pin 7 – K32 pin 2. 2) Short circuit in relay K32. 1) Short circuit in wiring harness between M95 pin 17 – K33 pin 2. 2) Short circuit in relay K33.

E05

E328

—

E304 E314

—

E306

E05

E308

20-329-1 (12)

Stall of motor (When burn preventive function of motor operates)

1) Short circuit of S2 pin 15 – pin 6 with power source. 2) Trouble in motor. 3) Short circuit in relay K32, K33.

1) Short circuit or disconnection in wiring harness between M95 (20) – M36 (1). 2) Disconnection in wiring harness between M36 (2) – chassis ground. Disconnection engine stop solenoid relay system 3) Trouble in M36 relay. Short circuit in engine stop solenoid relay system

1) Short circuit in wiring harness between M95 (23) – (22) Short circuit in wiring harness between M95 (23) – (32) 2) Disconnection in wiring harness between M95 (22) – S2 (1) Disconnection in wiring harness between M95 (23) – S2 (2) Trouble in governor motor feedback potentiomeDisconnection in wiring harness between ter M95 (32) – S2 (3) 3) Short circuit in wiring harness between S2 (male) (2) – (1) Short circuit in wiring harness between S2 (male) (2) – (3) Short circuit in wiring harness between S2 (male) (1) – (3) 4) Defective potentiometer 1) Short circuit in wiring harness between M95 (13) – (22) Short circuit in wiring harness between M95 (13) – (32) 2) Disconnection in wiring harness between M95 (22) K55 (1) Disconnection in wiring harness between M95 (13) – K55 (2) Disconnection in wiring harness between Fuel control dial system M95 (32) – K55 (3) 3) Short circuit in wiring harness between K55 (male) (2) – (1) Short circuit in wiring harness between K55 (male) (2) – (3) Short circuit in wiring harness between K55 (male) (1) – (3) 4) Defective potentiometer

PC78US-6

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

TROUBLESHOOTING

Action taken by controller Problems on machine when trouble occurs If trouble is detected, accelera- 1. Fuel control dial cannot be operBetween M95 pin 7 – chassis ground: Min.: 1 Mz ated (For acceleration and decelResistance between K32 relay pin 1 – pin 2: 290 z ± 10% tor relay output, and deceleraeration). tor relay output are stopped. Resistance between K32 relay pin 1, 2 – pin 3, 5, 6 2. One-touch slow-down mecha: Min. 1 Mz nism cannot be operated. Between M95 pin 17 – chassis ground: Min. 1 Mz 3. When working mode is changed, Resistance between K33 relay pin 1 – pin 2: 290 z ± 10% engine speed does not change. Resistance between K33 relay pin 1, 2 – pin 3, 5, 6 : Min. 1 Mz • When signal system is troubled Motor starts and stops from slow to full and from full to slow If accelerator, decelerator, or Motor operates but stalls soon. in 2 seconds. one-touch slow-down mechaThen, it does not operated even if nism works for more than 10 dial is moved. seconds, motor drive relay out• When motor is troubled put, accelerator relay output, Motor stalls from the first, then it and decelerator relay output does not operate even if dial is are stopped. moved. Relay Stop solenoid output is 1. Stop solenoid cannot be pulled stopped. (Engine cannot be started). Normal condition

M95 (female)

M36 (male)

Resistance

(20) – Chassis ground

(1) – (2)

68 z ± 10%

M95 (female)

S2 (male)

Resistance

Relay (23) – (22)

(2) – (1)

0.25 – 5 kz

(23) – (32)

(2) – (3)

0.25 – 5 kz

—

(1) – (2)

4 – 6 kz

—

Min. 1 Mz

Between each pin – chassis ground

* Exclude the GND line, however.

Relay M95 (female)

R55 (male)

Resistance

(13) – (22)

(2) – (1)

0.25 – 5 kz

(13) – (32)

(2) – (3)

0.25 – 5 kz

—

(1) – (3)

4 – 6 kz

—

Min. 1 Mz

Between each pin – chassis ground

PC78US-6

Calculates motor position from 1. Engine speed control accuracy voltage just before occurrence may lower. of trouble, then controls with it. For example, 1) Engine speed does not rise to maximum level (It keeps a little lower). 2) Engine speed is not set to low idling (It keeps a little higher). 3) Auto-decelerator or automatic warm-up system is defective. 4) Engine may not stop. a Governor motor moves in direction to stop engine but may not to full stop position. 5) Engine may hunt.

Calculates motor position from 1. Engine cannot be set in partial operation mode from full operavoltage just before occurrence tion mode. of trouble, then controls with it. 2. Engine cannot be set in full operation mode from partial operation mode. 3. Engine may hunt. 4. Output is insufficient (Maximum engine speed is insufficient).

20-329-2 (12)

TROUBLESHOOTING

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

When the motor is normal, its condition can be monitored as shown below.

•

•

•

•

•

•

When fuel control dial is operated (Slow o Full) Displayed code [1024] : (2), (3), (4), (6), light up and motor operates, then (2), (3), (4), (6) go off and motor stops (Only (4) keeps lighting up). When fuel control dial is operated (Full o Slow) Displayed code [1024] : While only (4) is lighting up, (1), (3), (5) light up and motor operates, then all lamps go off and motor stops. In E-mode (When fuel control dial is at FULL Displayed code [1024] : While only (4) is lighting up, (3), (5) light up and position) motor operates, then (2) lights up and (3), (5) go off and motor stops (Only (2) and (4) keep lighting up). When E-mode is changed to standard motor Displayed code [1024] : While only (2), (4) are lighting up, (3), (6) light up and (When fuel control dial is at FULL position) motor operates, then (2), (3), (6) go off and motor stops (Only (4) keeps lighting up). When one-touch slow-down mechanism is Displayed code [1024] : While only (4) is lighting up, (3), (5) light up and turned on (When fuel control dial is at FULL motor operates, then (2) lights up and (3), (4), (5) go position) off and motor stops (Only (2) keeps lighting up). Displayed code [1026] : When one-touch slow-down switch is turned on, (1) lights up (This is same as in resetting operation). Displayed code [1024] : While only (2) is lighting up, (3), (6) light up and When one-touch slow-down mechanism is motor operates, then (4) lights up and (2), (3), (6) go turned off (When fuel control dial is at FULL off and motor stops (Only (4) keeps lighting up). position)

Engine governor control system

20-329-3 (13)

PC78US-6

TROUBLESHOOTING

JUDGMENT TABLE FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) AND ENGINE

JUDGMENT TABLE FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) AND ENGINE PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up Controller and Engine

User Code

E05

Service Code

Monitoring Code

—

321 323 325 328 304 314 227

1024

1

Engine does not start easily

2

Engine does not start

3

Engine speed does not rise sharply (Does not follow up accelerator pedal)

4

Engine stops

5

Engine hunts (hunting)

6

Engine output (Power) is low

7

Exhaust gas color is bad (Imperfect combustion)

8

Much oil is consumed (or exhaust gas color is bad)

9

Oil becomes dirty soon

10

Much fuel is consumed

11

Coolant contains oil or blows back or its level lowers

12

Oil pressure caution lamp lights up

13

Oil level rises

14

Coolant temperature rises too high (Overheating)

15

Abnormal sound is heard

16

Many vibrations are made

17

Engine speed does not follow up throttle valve

q

q

q

q

q

(*1) (*1) (*1)

18

One-touch slow-down mechanism does not work

q

q

q

q

q

(*1) (*1) (*1)

19

When working mode is changed, engine speed does not change

q

q

q

q

q

q (*1) (*1) (*1)

20

Engine does not stop

q

Diagnosis code displayed when service code is displayed Diagnosis code displayed when trouble is detected by monitoring or with machine monitor

q

Motor drive relay output (*2)

Auto deceleration signal

Deceleration signal

Trouble in engine speed sensor system

Short circuit in engine stop solenoid relay (*3) Disconnection in engine stop solenoid relay (*3)

Stall of motor

Short circuit in decelerator relay system

Short circuit in accelerator relay system

Short circuit in motor drive relay system (*2)

Trouble in controller power supply

Self-diagnosis Display

Acceleration signal

Items Checked/ Inspected by monitoring

q

E-1 E-2 E-3 E-4 E-5 E-8 E-8 E-6

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

q: Items corresponding to service codes. Q: Items checked by monitoring or with machine monitor. *1. : Items checked by monitoring.

20-330 (13)

PC78US-6

JUDGMENT TABLE FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) AND ENGINE

TROUBLESHOOTING

Monitoring Code

Acceleration Signal

1024

1026 1010 0041

Is value in red range?

Diagnosis code displayed when service code is not displayed

95 Series Min. 105 °C

Min. 102 °C

Engine water temperature voltage

Engine speed

One-touch slow-down signal

Decelerator relay output

Accelerator relay output

Items Items checked/inspected by inspected monitoring with machine monitor

108 (S-1) E-8 (S-2) (S-3) (S-4) (S-5) (S-6) (S-7) (S-8) (S-9) (S-10) (S-11) (S-12) (S-13)

Q

Q

(S-14) (S-15) (S-16)

(*1)

(*1)

(*1)

(*1)

(*1)

(*1)

E-5 E-7

(*1)

E-5, E-6

(*1)

E-9 —

—

—

—

—

—

—

—

—

—

—

—

M-15 M-15

*2.: PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500 *3.: PC78US-6 Serial No.: 5501 – 6500 PC78UU-6 Serial No.: 23501 and up PC78US-6

20-331 (13)

TROUBLESHOOTING

JUDGMENT TABLE FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) AND ENGINE

PC78US-6 Serial No.: 6501 and up

User Code

E05

Service Code

— E05

—

Auto deceleration signal

Deceleration signal

Trouble in fuel control dial

Trouble in governor motor feedback potentiometer

Trouble in engine speed sensor system

Short circuit in engine stop solenoid relay Disconnection in engine stop solenoid relay

Stall of motor

Short circuit in decelerator relay system

Short circuit in accelerator relay system

Trouble in controller power supply

Self-diagnosis Display

Acceleration signal

Items Checked/ Inspected by monitoring

Controller and Engine

Monitoring Code

323 325 328 304 314 227 306 308

1024

1

Engine does not start easily

2

Engine does not start

3

Engine speed does not rise sharply (Does not follow up accelerator pedal)

4

Engine stops

q

q

5

Engine hunts (hunting)

q

q

6

Engine output (Power) is low

7

Exhaust gas color is bad (Imperfect combustion)

8

Much oil is consumed (or exhaust gas color is bad)

9

Oil becomes dirty soon

10

Much fuel is consumed

11

Coolant contains oil or blows back or its level lowers

12

Oil pressure caution lamp lights up

13

Oil level rises

14

Coolant temperature rises too high (Overheating)

15

Abnormal sound is heard

16

Many vibrations are made

17

Engine speed does not follow up throttle valve

q

q

q

q

q

q (*1) (*1) (*1)

18

One-touch slow-down mechanism does not work

q

q

q

q

q

(*1) (*1) (*1)

19

When working mode is changed, engine speed does not change

q

q

q

q

q

(*1) (*1) (*1)

20

Engine does not stop

q

Diagnosis code displayed when service code is displayed Diagnosis code displayed when trouble is detected by monitoring or with machine monitor

q

q

q

E-1 E-3 E-4 E-5 E-8 E-8 E-6 —

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

—

q: Items corresponding to service codes. Q: Items checked by monitoring or with machine monitor. *1 : Items checked by monitoring.

20-331-1 (13)

PC78US-6

JUDGMENT TABLE FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) AND ENGINE

Monitoring Code 1024

Acceleration Signal

Is value in red range?

Items inspected with machine monitor

Diagnosis code displayed when service code is not displayed

95 Series Min. 105 °C

Governor motor feedback potentiometer input

Fuel control dial voltage input

Engine water temperature voltage

Engine speed

One-touch slow-down signal

Decelerator relay output

Accelerator relay output

Items checked/inspected by monitoring

Min. 102 °C

TROUBLESHOOTING

Monitoring

1026 1010 0041 1034 1035

108 (S-1) E-8 (S-2) (S-3)

(*1)

(*1)

(S-4)

(*1)

(*1)

(S-5) (S-6) (S-7) (S-8) (S-9) (S-10) (S-11) (S-12) (S-13)

Q

Q

(S-14) (S-15) (S-16)

(*1)

(*1)

(*1)

(*1)

(*1)

(*1)

(*1) (*1) (*1)

(*1)

E-5

(*1)

E-7

(*1)

E-5, E-6 E-9

—

—

—

—

—

—

—

—

—

—

PC78US-6

—

—

M-15 M-15

20-331-2 (12)

E-1

TROUBLESHOOTING

E-1 Controller power supply is defective (LED of controller is turned off) PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Check that fuse 20 is not broken. a Carry out the following troubleshooting when the starting motor revolves normally (If the starting motor does not revolve, see E-8, 19). Cause

Remedy

1 • Turn starting switch ON • 20 – 30 V

Is voltage between M97 (Female) (1), (11) – (21), (31), (32), (33), chassis ground normal?

NO

YES Defective controller

Replace

Disconnection or defective contact in wiring harness between fuse 20 – battery relay terminal B

Repair or replace

Disconnection or defective contact in wiring harness between fuse 20 – M97 (Female) (1), (11)

Repair or replace

2 • Turn starting switch ON • 20 – 30 V

Is voltage between fuse 20 and chassis ground normal?

YES

NO

E-1 Electrical circuit diagram of each system

20-332 (12)

PC78US-6

E-1

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a Check that fuse 20 is not broken. a Carry out the following troubleshooting when the starting motor revolves normally (If the starting motor does not revolve, see E-8, 19). Cause

Remedy

1 • Turn starting switch ON • 20 – 30 V

Is voltage between M95 (Female) (1), (11) – (21), (31) chassis ground normal?

NO

YES Defective controller

Replace

Disconnection or defective contact in wiring harness between fuse 20 – battery relay terminal B

Repair or replace

Disconnection or defective contact in wiring harness between fuse 20 – M95 (Female) (1), (11)

Repair or replace

2 • Turn starting switch ON • 20 – 30 V

Is voltage between fuse 20 and chassis ground normal?

YES

NO

E-1 Electrical circuit diagram of each system

PC78US-6

20-332-1 (12)

E-2

TROUBLESHOOTING

E-2 [E321] (Short circuit in motor drive relay) is displayed PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500 Cause

Remedy

1 • Turn starting switch ON • Operate dial

Is voltage between M97 (Female) (18) – (23) normal?

NO

YES Defective controller

Replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (18) – K34 (Female) (1)

Repair or replace

Defective Relay

Repair or replace

2

• Disconnect M97 and K34 • Min. 1 Mz

Is resistance between M97 (Female) (18) and chassis ground normal?

NO

YES

If the wiring harness between M97 (18) and K34 (1) is shorted to the coil actually, the controller output is cut out. Accordingly, if [E321] is displayed, the controller is defective. E-2 Electrical circuit diagram of each system

PC78US-6

20-333 (7)

E-3

TROUBLESHOOTING

E-3 [E323] (Short circuit in accelerator relay system) is displayed PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500 Cause

Remedy

1 • Turn starting switch ON • Operate dial

Is voltage between M97 (Female) (25) – (23) normal?

NO

YES Defective controller

Replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (25) – K32 (Female) (1)

Repair or replace

Defective Relay

Repair or replace

2 • Disconnect M97 and K32 • Min. 1 Mz

Is resistance between M97 (Female) (25) and chassis ground normal?

NO

YES

If the wiring harness between M97 (25) – K32 (1) is shorted to the coil actually, the controller output is cut out. Accordingly, if [E323] is displayed, the controller is defective.

E-3 Electrical circuit diagram of each system

20-334 (12)

PC78US-6

E-3

TROUBLESHOOTING

PC78US-6 Serial No.: 5501 – 6500 PC78UU-6 Serial No.: 23501 and up Cause

Remedy

1 • Turn starting switch ON • Operate dial

Is voltage between M97 (Female) (25) – (23) normal?

NO

YES Defective controller

Replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (25) – K32 (Female) (1)

Repair or replace

Defective Relay

Repair or replace

2 • Disconnect M97 and K32 • Min. 1 Mz

Is resistance between M97 (Female) (25) and chassis ground normal?

NO

YES

If the wiring harness between M97 (25) – K32 (1) is shorted to the coil actually, the controller output is cut out. Accordingly, if [E323] is displayed, the controller is defective.

E-3 Electrical circuit diagram of each system

PC78US-6

20-334-1 (12)

E-3

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up Cause

Remedy

1 • Disconnect M95 and K32 • Turn starting switch ON

Is voltage between M95 (female) (7) and chassis ground normal?

NO

YES Contact of wiring harness between M95 (female) (7) – K32 (female) (2) with (+) wiring harness

Repair or replace

Defective controller

Replace

Defective accelerator relay (K32)

Replace

2 • Disconnect K32

• 290 z ±10%

Is resistance between K32 (male) (1) and (2) normal?

NO

YES

E-3 Electrical circuit diagram of each system

20-334-2 (12)

PC78US-6

E-4

TROUBLESHOOTING

E-4 [E325] (Short circuit in decelerator relay system) is displayed PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500 Cause

Remedy

1 • Turn starting switch ON • Operate dial (to lower)

Is voltage between M97 (Female) (35) – (23) normal?

NO

YES Defective controller

Replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (35) – K33 (Female) (1)

Repair or replace

Defective Relay

Repair or replace

2 • Disconnect M97 and K33 • Min. 1 Mz

Is resistance between M97 (Female) (35) – chassis ground normal?

NO

YES

If the wiring harness between M97 (35) – K33 (1) is shorted to the coil actually, the controller output is cut out. Accordingly, if [E325] is displayed, the controller is defective. E-4 Electrical circuit diagram of each system

PC78US-6

20-334-3 (12)

E-4

TROUBLESHOOTING

PC78US-6 Serial No.: 5501 – 6500 PC78UU-6 Serial No.: 23501 and up Cause

Remedy

1 • Turn starting switch ON • Operate dial (to lower)

Is voltage between M97 (Female) (35) – (23) normal?

NO

YES Defective controller

Replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (35) – K33 (Female) (1)

Repair or replace

Defective Relay

Repair or replace

2 • Disconnect M97 and K33 • Min. 1 Mz

Is resistance between M97 (Female) (35) – chassis ground normal?

NO

YES

If the wiring harness between M97 (35) – K33 (1) is shorted to the coil actually, the controller output is cut out. Accordingly, if [E325] is displayed, the controller is defective. E-4 Electrical circuit diagram of each system

PC78US-6

20-335 (12)

E-4

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up Cause

Remedy

1 • Disconnect M95 and K33. • Turn starting switch ON.

Is voltage between M95 (female) (17) and chassis ground normal?

NO

YES Contact of wiring harness between M95 (female) (17) – K33 (female) (2) with (+) wiring harness

Repair or replace

Defective controller

Replace

Defective decelerator relay (K33)

Repair or replace

2 • Disconnect K33.

• 290 z ± 10%

Is resistance between K33 (male) (1) and (2) normal?

NO

YES

E-4 Electrical circuit diagram of each system

20-335-1 (12)

PC78US-6

E-5

TROUBLESHOOTING

E-5 [E328] (Stall of motor) is displayed PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500

a Stall of the motor ias displayed when the motor does not follow up the operation of the dial in 10 seconds. In this period, the input signal and relay output are checked by monitoring. Cause

Remedy

1 For state of bit, see Action taken by controller when trouble occurs and problems on machine.

NO

Is monitored value normal?

YES

• Turn starting switch ON • Max. 4 A when normal When dial is raised (1) side: (+), (4) side: (-) When dial is lowered (1) side: (-), (4) side: (+)

2 Is current between K27 (Female) (1) (Motor (+) and (4) (Motor (-) normal?

NO

YES

• Resistance between (1) ~ (2) of each relay: 290 z ± 10% • Operation of each relay (when starting switch is ON) When in neutral, (3) – (6) are connected. When dial is raised, K34 and K32 (3), (5) are connected. When dial is lowered, K34 and K33 (3), (5) are connected.

Defective motor (Drive system)

Replace motor

Defective relay

Replace

Disconnection or defective contact in wiring harness between K27 (Female) (1), (4) – K32 (Female) (3), K33 (Female) (3)

Repair or replace

NO

Disconnection or defective contact in wiring harness between M97 (Female) (19), (29), (39) – K27 (Female) (5), (6), (3)

Repair or replace

NO

Defective motor (Signal system)

Replace

Defective controller

Replace

3 Do relay of K32, K33, – K34 operate normally?

NO

YES

4 • Disconnect M97 and K27. • Resistance between pins: Max. 1 z • Resistance between pin and chassis and ground: Min. 1 Mz

• Is resistance between M97 (Female) (19) – K27 (Female) (5), between M97 (29) – K27 (Female) (6), between M97 (Female) (39) – K27 (Female) (3) normal? Is resistance between each wiring harness and chassis ground normal? YES

5 • Turn starting switch ON • When dial is raised Between K97 (19), (39) – (23): 24 V • When dial is lowered (slowed) Between M97 (29) – (23): 24 V

When dial is operated, is each input signal normal?

YES

20-336 (7)

PC78US-6

E-5

TROUBLESHOOTING

E-5 Electrical circuit diagram of each system

PC78US-6

20-336-1 (7)

E-5

TROUBLESHOOTING

PC78US-6 Serial No.: 5501 – 6500 PC78UU-6 Serial No.: 23501 and up a Stall of the motor is displayed when the motor does not follow up the operation of the dial in 10 seconds. In this period, the input signal and relay output are checked by monitoring. Cause

Remedy

1 For state of bit, see Action taken by controller when trouble occurs and problems on machine.

NO

Is monitored value normal?

YES

• Turn starting switch ON • Max. 4 A when normal When dial is raised (1) side: (+), (4) side: (-) When dial is lowered (1) side: (-), (4) side: (+)

2 Is current between K27 (Female) (1) (Motor (+) and (4) (Motor (-) normal?

NO

YES

• Resistance between (1) ~ (2) of each relay: 290 z ± 10% • Operation of each relay (when starting switch is ON) When in neutral, (3) – (6) are connected. When dial is raised, K32 (3), (5) are connected. When dial is lowered, K33 (3), (5) are connected.

Defective motor (Drive system)

Replace motor

Defective relay

Replace

Disconnection or defective contact in wiring harness between K27 (Female) (1), (4) – K32 (Female) (3), K33 (Female) (3)

Repair or replace

NO

Disconnection or defective contact in wiring harness between M97 (Female) (19), (29), (39) – K27 (Female) (5), (6), (3)

Repair or replace

NO

Defective motor (Signal system)

Replace

Defective controller

Replace

3 NO

Do relay of K32, K33 operate normally?

YES

4 • Disconnect M97 and K27. • Resistance between pins: Max. 1 z • Resistance between pin and chassis and ground: Min. 1 Mz

• Is resistance between M97 (Female) (19) – K27 (Female) (5), between M97 (29) – K27 (Female) (6), between M97 (Female) (39) – K27 (Female) (3) normal? Is resistance between each wiring harness and chassis ground normal? YES

5 • Turn starting switch ON • When dial is raised Between K97 (19), (39) – (23): 24 V • When dial is lowered (slowed) Between M97 (29) – (23): 24 V

When dial is operated, is each input signal normal?

YES

20-336-2 (12)

PC78US-6

TROUBLESHOOTING

E-5

Electrical circuit diagram of each system

PC78US-6

20-337 (7)

E-5

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a Trouble in the motor stall system is displayed when the motor does not follow up in 10 seconds after the dial is operated. In the meantime, check that the input signal and relay output are normal with the monitoring function. Cause

• Turn starting switch ON. • Max. 4 A when normal. When dial is heightened, measure between (5) (+) and (6) (–). When dial is lowered, measure between (5) (–) and (6) (+).

Remedy

1 Is current between S2 (female) (5) (motor (+)) and (6) (motor (–)) normal?

NO

YES

• Disconnect K32 and K33. • Resistance between K32 and K33 (male) (1), (2): 290 z ± 10% • Operation of each relay (when starting switch is ON): When in neutral, R08 and R09 (3), (6) are connected. When dial is heightened, R09 (3) and (5) are connected. When dial is lowered, R08 (3) and (5) are connected.

Defective motor (drive system)

Replace motor

Defective relay

Replace

Defective wiring harness Breakage of fuse (9)

Repair or replace

2

Do relays K32 and K33 operate normally?

NO

YES

E-5 Electrical circuit diagram of each system

20-337-1 (12)

PC78US-6

E-6

TROUBLESHOOTING

E-6 [E227] (Trouble in engine speed sensor) is displayed PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up Cause

Remedy

1 • When starting switch is OFF: 0 • When engine speed is +5

slow: 113 0 • When engine speed is at full throttle: 202 ± 5

NO

Is monitored engine speed normal?

YES Defective controller

Replace

NO

Defective engine speed sensor

Repair or replace

NO

Disconnection or defective contact in wiring harness between M96 (Female) (39) – M16 (Female) (1), (2)

Repair or replace

Defective installation of engine speed sensor

Test/Adjust

2 • Disconnect M16 • 500 – 1,000 z

Is resistance between M16 (Male) (1) – (2) normal?

YES 3 • Disconnect M16 • 500 – 1,000 z

Is resistance between M96 (Female) (39) – (40) normal?

YES

E-6 Electrical circuit diagram of each system

20-338 (12)

PC78US-6

E-6

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up Cause

Remedy

1 • When starting switch is OFF: 0 • When engine speed is +5

slow: 113 0 • When engine speed is at full throttle: 202 ± 5

NO

Is monitored engine speed normal?

YES Defective controller

Replace

Defective engine speed sensor

Repair or replace

Disconnection or defective contact in wiring harness between M95 (Female) (6), (32) – M16 (Female) (1), (2)

Repair or replace

Defective installation of engine speed sensor

Test/Adjust

2 • Disconnect M16 • 500 – 1,000 z

Is resistance between M16 (Male) (1) – (2) normal?

NO

YES 3 • Disconnect M16 • 500 – 1,000 z

Is resistance between M95 (Female) (6) – (32) normal?

NO

YES

E-6 Electrical circuit diagram of each system

PC78US-6

20-338-1 (12)

E-7

TROUBLESHOOTING

E-7 [E306] Trouble in governor motor feedback potentiometer is displayed PC78US-6 Serial No.: 6501 and up a Check that the input value is normal in the monitoring mode. Cause

• Reset auto-decelerator. • Feedback potentiometer voltage: • When fuel control dial at FULL: 4.5 – 4.7 V • When fuel control dial at SLOW: 2.7 – 3.2 V

Remedy

1 Is feedback potentiometer voltage of monitoring 1035 normal?

NO

YES

• Disconnect S2 • S2 (male) Between (1) – (2): 0.36 – 3.9 kz Between (2) – (3): 1.4 – 5.5 kz Between (1) – (3): 5 ± 1 kz • Between S2 (male) (1), (2), (3) – chassis ground: Min. 1 Mz

Defective controller

Replace

Defective decelerator motor

Replace

Defective wiring harness

Repair or replace

2 Is resistance between S2 (male) (1), (2), – (3) normal?

NO

YES

E-7 Electrical circuit diagram of each system

20-338-2 (12)

PC78US-6

E-8

TROUBLESHOOTING

E-8 [E308] Trouble in fuel control dial system is displayed PC78US-6 Serial No.: 6501 and up a Check that the input value is normal in the monitoring mode. Cause

Remedy

1 • Fuel control dial voltage: • When fuel control dial at FULL: 0.7 V – 4.3 V • When fuel control dial at SLOW: 0.7 V – 4.3 V

Is fuel control dial voltage of monitoring 1034 normal?

NO

YES

• Disconnect K55. • K55 (male) Between (1) – (2): 0.25 – 5 kz Between (2) – (3): 0.25 – 5 kz Between (1) – (3): 4 – 6 kz • Between K55 (male) (1), (2), (3) – chassis ground: Min. 1 Mz

Defective controller

Replace

Defective fuel control dial

Replace

Defective wiring harness

Repair or replace

2 Is resistance between K55 (male) (1), (2), – (3) normal?

NO

YES

E-8 Electrical circuit diagram of each system

PC78US-6

20-338-3 (12)

E-9

TROUBLESHOOTING

E-9 One-touch slow-down mechanism does not work PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up Cause

Remedy

1 NO

Does deceleration monitor light up normally?

YES See troubleshooting in E-5

—

NO

Defective one-touch decelerator switch

Replace lever assembly

NO

Disconnection or defective contact in wiring harness between K18 (Female) (1) – fuse (11) or breakage of fuse (11)

Repair or replace

Disconnection or defective contact in wiring harness between K18 (Female) (2) – M97 (Female) (9)

Repair or replace

2 • Disconnect K18 • When switch is ON: Max. 1z When switch is OFF: Min. 1 Mz

Is resistance between K18 (Male) (1) – (2) normal?

YES 3 • Disconnect K18 • Turn starting switch ON • 20 – 30 V

Is voltage between K18 (Male) (1) – chassis ground normal?

YES

E-9 Electrical circuit diagram of each system

PC78US-6

20-339 (12)

E-9

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up Cause

Remedy

1 NO

Does deceleration monitor light up normally?

YES See troubleshooting in E-5

—

Defective one-touch decelerator switch

Replace lever assembly

Disconnection or defective contact in wiring harness between K18 (Female) (1) – T2

Repair or replace

Disconnection or defective contact in wiring harness between K18 (Female) (2) – M95 (Female) (34)

Repair or replace

2 • Disconnect K18 • When switch is ON: Max. 1z When switch is OFF: Min. 1 Mz

Is resistance between K18 (Male) (1) – (2) normal?

NO

YES 3 • Disconnect K18 • Max. 1z

Is resistance between K18 (Male) (1) – chassis ground normal?

NO

YES

E-9 Electrical circuit diagram of each system

20-339-1 (12)

PC78US-6

E-10

TROUBLESHOOTING

E-10 Engine does not start a a a a a) b)

The signals from battery relay terminal M on the monitor screen, etc. must be normal. Carry out the following troubleshooting when the starting motor does not revolve. Before carrying out the troubleshooting, check that fuses 12, 14, 15, and 20 are normal. Lock the PPC hydraulic lock switch. (Raise the work equipment lever stand.) [E304] Short circuit in engine stop solenoid relay system is displayed [E314] Disconnection in engine stop solenoid relay system is displayed PC78US-6 Serial No.: 5501 – 6500 PC78UU-6 Serial No.: 23501 and up Cause

Remedy

1 • Disconnect M97. • Resistance between M97 (female) (4) – chassis ground: 68 z ± 10%

Is resistance between M97 (female) (4) – chassis ground normal?

NO

YES

• Disconnect M36. • Resistance between M36 (male) (1) – (2): 68 z ± 10% • Resistance between M36 (male) (1), (2) – chassis ground: Min. 1 Mz

Defective controller

Replace

NO

Defective stop solenoid relay

Replace

NO

Defective wiring harness (Grounding fault)

Repair or replace

Defective diode D26

Replace

2 Is resistance between stop solenoid relay M36 (male) (1) – (2) and between each pin and chassis ground normal? YES 3

• Disconnect D26 (with M36 disconnected). • Resistance between M97 (female) (4) – chassis ground: Min. 1 Mz

Is resistance between M97 (female) (4) – chassis ground normal?

YES

E-10 a), b) Electrical circuit diagram of each system

20-340 (12)

PC78US-6

E-10

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up Cause

Remedy

1 • Disconnect M95. • Resistance between M95 (female) (20) – chassis ground: 68 z ± 10%

Is resistance between M95 (female) (20) – chassis ground normal?

NO

YES

• Disconnect M36. • Resistance between M36 (male) (1) – (2): 68 z ± 10% • Resistance between M36 (male) (1), (2) – chassis ground: Min. 1 Mz

Defective controller

Replace

NO

Defective stop solenoid relay

Replace

NO

Defective wiring harness (Grounding fault)

Repair or replace

Defective diode D4

Replace

2 Is resistance between stop solenoid relay M36 (male) (1) – (2) and between each pin and chassis ground normal? YES 3

• Disconnect D4 (with M36 disconnected). • Resistance between M95 (female) (20) – chassis ground: Min. 1 Mz

Is resistance between M95 (female) (20) – chassis ground normal?

YES

E-10 a), b) Electrical circuit diagram of each system

PC78US-6

20-340-1 (12)

E-10

TROUBLESHOOTING

c) Engine stop solenoid system PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500 a Check that fuse 15 is normal. Cause

Remedy

1 a See TESTING AND ADJUSTING

When engine stop solenoid linkage is adjusted, does engine start?

NO

YES Defective adjustment of linkage

Adjust

Disconnection or defective contact in wiring harness between engine stop solenoid terminal T8 – chassis ground

Repair or replace

Defective engine stop solenoid

Replace

Disconnection or defective contact in wiring harness between outlet of fuse (15) – M3 (3) – solenoid terminal T7

Repair or replace

Defective starting switch (Between B – ACC)

Replace

Disconnection or defective contact in wiring harness between starting switch terminal ACC – inlet of fuse (15)

Repair or replace

2 • 20 – 29 V • Turn starting switch ON

Is voltage between engine stop solenoid terminal T7 – chassis ground normal?

NO

YES 3 • Max. 1 z • Turn starting switch OFF • Disconnect T8

Is resistance between engine stop solenoid terminal T8 – chassis ground normal?

NO

YES

4 • 20 – 29 V • Turn starting switch ON

Is voltage between outlet of fuse (15) – chassis ground normal?

NO

YES

5 • 20 – 29 V • Turn starting switch ON

Is voltage between starting switch terminal ACC – chassis ground normal?

YES

NO

E-10 c) Electrical circuit diagram of each system

PC78US-6

20-341 (12)

E-10

TROUBLESHOOTING

PC78US-6 Serial No.: 5501 – 6500 PC78UU-6 Serial No.: 23501 and up a Check that fuse 15 is normal. a Check that service codes [E304] and [E314] are not recorded in the history. Cause

Remedy

1 a See TESTING AND ADJUSTING

When engine stop solenoid linkage is adjusted, does engine start?

NO

YES Defective adjustment of linkage

Adjust

NO

Disconnection or defective contact in wiring harness between engine stop solenoid terminal GND – chassis ground

Repair or replace

NO

Disconnection or defective contact in wiring harness between engine stop solenoid PULL terminal – fusible link M26 (male) (2)

Repair or replace

Defective engine stop solenoid

Replace

Disconnection or defective contact in wiring harness between outlet of fuse (15) – M3 (3) – solenoid terminal T7

Repair or replace

Defective starting switch (Between B – ACC)

Replace

Disconnection or defective contact in wiring harness between starting switch terminal ACC – inlet of fuse (15)

Repair or replace

2 • 20 – 29 V • Turn starting switch ON

Is voltage between engine stop solenoid terminal – chassis ground normal?

NO

YES 3 • Max. 1 z • Turn starting switch OFF • Disconnect GND terminal

Is resistance between engine stop solenoid terminal GND – chassis ground normal?

YES 4 • 20 – 29 V • Disconnect PULL terminal. • For only 3 seconds after starting switch is turned ON.

Is voltage between engine stop solenoid PULL terminal and chassis ground normal?

YES

5 • 20 – 29 V • Turn starting switch ON

Is voltage between outlet of fuse (15) – chassis ground normal?

NO

YES

6 • 20 – 29 V • Turn starting switch ON

Is voltage between starting switch terminal ACC – chassis ground normal?

YES

20-342 (12)

NO

PC78US-6

TROUBLESHOOTING

E-10

E-10 c) Electrical circuit diagram of each system

PC78US-6

20-343 (12)

E-10

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a Check that fuse 15 is normal. a Check that service codes [E304] and [E314] are not recorded in the history. Cause

Remedy

1 a See TESTING AND ADJUSTING

When engine stop solenoid linkage is adjusted, does engine start?

NO

YES Defective adjustment of linkage

Adjust

NO

Disconnection or defective contact in wiring harness between engine stop solenoid terminal GND – chassis ground

Repair or replace

NO

Disconnection or defective contact in wiring harness between engine stop solenoid PULL terminal – fusible link M26 (male) (2)

Repair or replace

Defective engine stop solenoid

Replace

Disconnection or defective contact in wiring harness between outlet of fuse (15) – M3 (5) – solenoid terminal HOLD

Repair or replace

Defective starting switch (Between B – ACC)

Replace

Disconnection or defective contact in wiring harness between starting switch terminal ACC – inlet of fuse (15)

Repair or replace

2 • 20 – 29 V • Turn starting switch ON

Is voltage between engine stop solenoid terminal – chassis ground normal?

NO

YES 3 • Max. 1 z • Turn starting switch OFF • Disconnect GND terminal

Is resistance between engine stop solenoid terminal GND – chassis ground normal?

YES 4 • 20 – 29 V • Disconnect PULL terminal. • For only 3 seconds after starting switch is turned ON.

Is voltage between engine stop solenoid PULL terminal and chassis ground normal?

YES

5 • 20 – 29 V • Turn starting switch ON

Is voltage between outlet of fuse (15) – chassis ground normal?

NO

YES

6 • 20 – 29 V • Turn starting switch ON

Is voltage between starting switch terminal ACC – chassis ground normal?

YES

20-343-1 (12)

NO

PC78US-6

TROUBLESHOOTING

E-10

E-10 c) Electrical circuit diagram of each system

PC78US-6

20-343-2 (12)

E-10

TROUBLESHOOTING

d) Starting System Cause

Remedy

1 • Min. 24 V • Specific gravity: Min. 1.26

NO

Are battery voltage and specific gravity of battery fluid normal?

Insufficient battery capacity

Charge or replace

YES 2 NO

When starting switch is turned OFF, does battery relay make sound?

• Turn starting switch OFF

YES

3 NO

Is engaging sound of starting motor pinion heard?

YES 4

• Turn starting switch ON • 20 – 29 V

Is voltage between starting motor terminal B – chassis ground normal?

NO

Defective contact in wiring harness between battery (+) terminal – battery relay terminal B – battery relay terminal M – starting motor terminal B (including battery relay)

Repair or replace

YES Defective starting motor (Body)

Repair or Replace

Defective starting switch (Between terminals B and C)

Replace

Defective starting motor (Electromagnetic switch)

Repair or replace

Disconnection or defective contact in wiring harness between starting motor safety relay terminal C – starting motor terminal C

Repair or replace

Defective alternator

Repair or replace

Defective starting motor safety relay

Replace

5 • Turn starting switch to START position. • 20 – 29 V

NO

Is voltage between starting switch terminal C and chassis ground normal? YES 6 Is voltage between safety relay terminal S – chassis ground normal?

a Conditions are same as 5

NO

YES

7 Is voltage between starting motor terminal C – chassis ground normal?

a Conditions are same as 5

NO

YES

8 Is voltage between safety relay terminal C – chassis ground normal?

a Conditions are same as 5

NO

YES

9 • Turn starting switch ON • Max. 13 V

Is voltage between safety relay terminal R – chassis ground normal?

NO

YES To page 20-347 To page 20-345

20-344 (12)

PC78US-6

E-10

TROUBLESHOOTING

From page 20-344, 6 Cause

Remedy

10 • 20 – 29 V • Turn starting switch to START.

Is voltage between V2 (8) – chassis ground normal?

NO

Disconnection or defective contact in wiring harness between safety relay terminal S – M30 (1) – M5 (4) – V2 (Female) (8)

YES

Repair or replace

11 • 20 – 29 V • Turn starting switch to START

Is voltage between V2 (7) – chassis ground normal?

NO

YES

Disconnection or defective contact in wiring harness between V2 (Male) (7) – (8)

12 • 20 – 29 V • Turn starting switch to START

NO

Is voltage between K23 (3) – chassis ground normal? YES

Disconnection or defective contact in wiring harness between K23 (Female) (3) – V3 (Female) (3)

Repair or replace

Disconnection or defective contact in wiring harness between K23 (Female) (5) – K51 (6) – starting switch terminal C

Repair or replace

Disconnection or defective contact in wiring harness between K23 (Female) (2) – M1 (2) – chassis ground

Repair or replace

Defective K23 relay

Replace

Disconnection or defective contact in wiring harness between K28 (Male) (3) – K23 (Female) (1) – chassis ground

Repair or replace

13 • 20 – 29 V • Turn starting switch to START

NO

Is voltage between K23 (5) – chassis ground normal? YES 14

• 20 – 29 V • Turn starting switch ON • Lock PPC lock switch

NO

Is voltage between K23 (1) – chassis ground normal? YES 15

• Max. 1 z • Turn starting switch ON • Disconnect K23

Is resistance between K23 (Female) (2) – chassis ground normal?

NO

YES

16 • 20 – 29 V • Turn starting switch ON • Lock PPC lock lever

Is voltage between k28 (3) – chassis ground normal? YES

NO

To page 20-346

PC78US-6

20-345 (12)

E-10

TROUBLESHOOTING

PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500 From page 20-345, 16

Cause

Remedy

17 • 20 – 29 V • Turn starting switch ON

NO

Is voltage between K28 (1) – chassis ground normal? YES

Disconnection or defective contact in wiring harness between K28 (Male) (1) – fuse (12)

Repair or replace

Disconnection or defective contact in wiring harness between K28 (Female) (3) – K23 (Female) (1)

Repair or replace

PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up From page 20-345, 16

Cause

Remedy

17 • 20 – 29 V • Turn starting switch ON

Is voltage between K28 (1) – chassis ground normal? YES

20-346 (12)

NO

Disconnection or defective contact in wiring harness between K28 (Male) (1) – fuse (14)

Repair or replace

Disconnection or defective contact in wiring harness between K28 (Female) (3) – K23 (Female) (1)

Repair or replace

PC78US-6

E-10

TROUBLESHOOTING

From page 20-344, 2 Cause

18 • Connect (-) pin of tester to (-) terminal of battery • 20 – 29 V

NO

Is voltage at starting switch terminal B normal?

Remedy

Disconnection or defective contact in wiring harness between battery (+) terminal – M27 (1), (2) – M2 (1) – fuse (20) – K51 (1) – starting switch terminal B (including fusible link)

Replace

Defective starting switch (between terminal B – BR)

Replace

Disconnection or defective contact in wiring harness between starting switch terminal BR – K51 (3) – D5 (2), (1) – battery relay terminal BR (including diode)

Replace

Defective contact in wiring harness between battery relay terminal E - revolving frame ground terminal

Repair or replace

Defective battery relay

Replace

YES 19

• Disconnect terminal B • Turn starting switch to START

NO

Is there continuity between starting switch terminals B – BR?

YES 20 • Set tester in diode range and apply (+) to starting switch and (-) to battery relay • Disconnect both starting switch and battery relay

NO

Is there continuity between starting switch terminal BR – battery relay terminal BR?

YES 21

• Turn starting switch OFF

Is there continuity between chassis ground and battery relay terminal B?

NO

YES

PC78US-6

20-347 (12)

TROUBLESHOOTING

E-10

E-10 d) Electrical circuit diagram of each system PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500

20-348 (12)

PC78US-6

TROUBLESHOOTING

E-10

E-10 d) Electrical circuit diagram of each system PC78US-6 Serial No.: 5501 – 6500 PC78UU-6 Serial No.: 23501 and up

PC78US-6

20-349 (12)

TROUBLESHOOTING

E-10

E-10 d) Electrical circuit diagram of each system PC78US-6 Serial No.: 6501 and up

20-349-1 (12)

PC78US-6

E-11

TROUBLESHOOTING

E-11 Engine does not stop PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22832 – 23500 Cause

Remedy

1 NO

When engine stop solenoid linkage is adjusted, does engine stop?

YES Defective adjustment of linkage

Adjust

Contact of (+) wiring harness with wiring harness between starting switch terminal ACC – fuse (15) – M3 (3) – solenoid terminal T7

Replace or repair

Defective engine stop solenoid

Replace

2 • •

Max. 1 V Turn starting switch OFF

Is voltage between engine stop solenoid terminal T7 and chassis ground normal?

NO

YES

E-11 Electrical circuit diagram of each system

PC78US-6

20-349-2 (12)

E-11

TROUBLESHOOTING

PC78US-6 Serial No.: 5501 – 6500 PC78UU-6 Serial No.: 23501 and up Cause

Remedy

1 NO

When engine stop solenoid linkage is adjusted, does engine stop?

YES Defective adjustment of linkage

Adjust

Contact of (+) wiring harness with wiring harness between starting switch terminal ACC – fuse (15) – M3 (3) – solenoid terminal HOLD

Replace or repair

Defective engine stop solenoid

Replace

2 • •

Max. 1 V Turn starting switch OFF

Is voltage between engine stop solenoid terminal HOLD and chassis ground normal?

NO

YES

E-11 Electrical circuit diagram of each system

20-349-3 (12)

PC78US-6

E-11

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up Cause

Remedy

1 NO

When engine stop solenoid linkage is adjusted, does engine stop?

YES Defective adjustment of linkage

Adjust

Contact of (+) wiring harness with wiring harness between starting switch terminal ACC – fuse (15) – M3 (5) – solenoid terminal HOLD

Replace or repair

Defective engine stop solenoid

Replace

2 • •

Max. 1 V Turn starting switch OFF

Is voltage between engine stop solenoid terminal HOLD and chassis ground normal?

NO

YES

E-11 Electrical circuit diagram of each system

PC78US-6

20-349-4 (12)

TROUBLESHOOTING FOR CONTROLLER PUMP CONTROL SYSTEM (C MODE)

Precautions for troubleshooting for controller (pump control system). . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-352 Action taken by controller when trouble occurs and problems on machine . . . . . . . . . . . . . . . . . . . . . . . . 20-354 Judgement table for controller (pump control system) and hydraulic equipment . . . . . . . . . . . . . . . . . . . . 20-356 Electric circuit diagram of C Mode system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-358 C- 1 [E232] Trouble in TVC-EPC solenoid system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-359 C- 2 [E233] Trouble in TVC-EPC solenoid system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-359 C- 3 [E203] Trouble in swing holding brake solenoid system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-360 C- 4 [E213] Trouble in swing holding brake solenoid system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-360 C- 5 [E206] Trouble in 2nd travel speed selection solenoid system . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-361 C- 6 [E216] Trouble in 2nd travel speed selection solenoid system . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-361 C- 7 [E403] Trouble in boom angle sensor correction (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . 20-362 C- 8 [E406] Trouble in arm angle sensor correction (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . 20-362 C- 9 [E411] Trouble in offset boom angle sensor correction (Only PC78UU-6). . . . . . . . . . . . . . . . . . . . 20-362 C-10 [E441] Trouble in interference prevention (front) correction (Only PC78UU-6) . . . . . . . . . . . . . . . . 20-364 C-11 [E442] Trouble in interference prevention (side) correction (Only PC78UU-6) . . . . . . . . . . . . . . . . 20-364 C-12 [E443] Trouble in depth indication correction (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-365 C-13 [E258] Short circuit in 5V system of sensor power supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-366 C-14 [E224] Trouble in pump pressure sensor is displayed (PC78US-6: 6501 and up) . . . . . . . . . . . 20-366-3 C-15 [E401] Trouble in boom angle sensor system (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . 20-367 C-16 [E402] Trouble in boom angle sensor system (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . 20-367 C-17 [E404] Trouble in arm angle sensor system (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-368 C-18 [E405] Trouble in arm angle sensor system (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-368 C-19 [E407] Trouble in offset angle sensor system (Only PC78UU-6). . . . . . . . . . . . . . . . . . . . . . . . . . . 20-369 C-20 [E408] Trouble in offset angle sensor system (Only PC78UU-6). . . . . . . . . . . . . . . . . . . . . . . . . . . 20-369 C-21 [E421] Short circuit in boom raise EPC system is displayed (Only PC78UU-6) . . . . . . . . . . . . . . . 20-370 C-22 [E422] Disconnection in boom raise EPC system is displayed (Only PC78UU-6). . . . . . . . . . . . . . 20-371 C-23 [E423] Short circuit or grounding fault in arm-in EPC system is displayed (Only PC78UU-6). . . . . 20-372 C-24 [E424] Disconnection in arm-in EPC system is displayed (Only PC78UU-6) . . . . . . . . . . . . . . . . . 20-373 C-25 [E425] Short circuit or grounding fault in offset left EPC system is displayed (Only PC78UU-6). . . . . . 20-374 C-26 [E426] Disconnection in offset left EPC system is displayed (Only PC78UU-6) . . . . . . . . . . . . . . . 20-375 C-27 [E431] Short circuit or grounding fault in PPC basic pressure lock solenoid system is displayed (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-376 C-28 Boom does not stop automatically at normal position but interferes when it is raised (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-377 C-29 Arm does not stop automatically at normal position but interferes when it is moved in (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-378 C-30 Offset does not stop automatically at normal position but interferes when it is moved to left (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-379 C-31 Work equipment stops far or near (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-380 C-32 Buzzer sounds for 7 seconds while emergency work equipment operation switch is not turned ON (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-381 C-33 Boom raise end cushion does not work at all or normally (Only PC78UU-6) . . . . . . . . . . . . . . . . . . 20-382 C-34 Arm-in end cushion does not work at all or normally (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . 20-383 C-35 Offset end cushion does not work at all or normally (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . 20-384 C-36 Work equipment stops after or before set height (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . 20-385 C-37 When depth display is reset, 0.0 m is not indicated at GL (Only PC78UU-6). . . . . . . . . . . . . . . . . . 20-386 C-38 Work equipment still moves after work equipment lock lever is set to LOCK . . . . . . . . . . . . . . . . . . 20-387 C-39 Machine does not swing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-388 C-40 Travel speed does not rise (PC78US-6: 4001 – 6500, PC78UU-6: 22832 and up) . . . . . . . . . . . . . 20-389 C-41 Gear speed does not change automatically (PC78US-6: 6501 and up) . . . . . . . . . . . . . . . . . . . . 20-389-1 C-42 Trouble in controller power supply system (LED of controller is turned OFF) . . . . . . . . . . . . . . . 20-389-1

PC78US-6

20-351 (12)

TROUBLESHOOTING

PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (PUMP CONTROL SYSTEM)

PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (PUMP CONTROL SYSTEM) 1. Precautions to be taken when trouble is repaired by itself 1) When a trouble is repaired by itself or 2) When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the Tadapter is removed and the connector is returned, if the service code is not displayed or the monitor displays normally, the same trouble will occur again probably. Accordingly, follow up the condition of the machine sufficiently. 3) After finishing troubleshooting, be sure to delete the saved service code. 2. Handling of function of saving service code When displaying a saved service code for troubleshooting, "take the notes of the all displayed items and delete those items", then reproduce the trouble and start the troubleshooting according to the service code displayed at this time. (Troubles caused by wrong operation, disconnection of a connector, etc. May be saved in the memory. In this case, you can avoid unnecessary work by performing the above operation.)

20-352 ➀

PC78US-6

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

TROUBLESHOOTING

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up Application US

Q

Q

Q

Q

—

—

UU

Q

Q

Q

Q

Q

Q

User Code

Service Code

Troubled System

Contents of Trouble

E232

Short circuit in TVC-EPC solenoid system (When emergency pump drive switch is turned ON)

1. Short circuit in wiring harness between M97 pin 16 – M20 pin 1 2. Short circuit in EPC solenoid 3. Wrong operation of switch

E233

Disconnection in TVC-EPC solenoid system

1. Disconnection in wiring harness between M97 pin 16 – M20 pin 1 2. Disconnection in EPC solenoid 3. Disconnection in wiring harness between M20 pin 2 – M97 pin 23

E203

Short circuit in swing holding brake solenoid system

1. Short circuit in wiring harness between M97 pin 7 – M14 pin 2 2. Short circuit in solenoid

E213

1. Disconnection in wiring harness Disconnection in swing holding brake solebetween M97 pin 7 – M14 pin 2 noid system 2. Disconnection in solenoid 3. Disconnection in wiring harness (When emergency swing holding brake reset switch is turned ON) between M14 pin 1 – M97 pin 3 4. Wrong operation of switch

E206

Short circuit in 2nd travel speed selection solenoid system

E216

1. Disconnection in wiring harness between M97 pin 27 – M15 pin 2 Disconnection in 2nd travel speed selection 2. Disconnection in solenoid solenoid system 3. Disconnection in wiring harness between M15 pin 1 – M97 pin 3

E227

Trouble in engine speed sensor

1. Disconnection in wiring harness between M96 pin 40 – M16 pin 1 2. Disconnection in sensor 3. Disconnection in wiring harness between M16 pin 2 – M96 pin 39

E403

Trouble in boom angle sensor correction

E02

E03

—

—

—

1. Short circuit in wiring harness between M97 pin 27 – M15 pin 2 2. Short circuit in solenoid

1. Input voltage is abnormal when angle sensor is corrected (Out of range) When voltage error is out of ± 0.5 V Voltage must be 0.3 – 4.7 V, however

E406

Trouble in arm angle sensor correction

E411

Trouble in offset boom angle sensor correction

E441

Trouble in interference prevention (Front) correction

1. Out of front interference prevention correction range When quantity of longitudinal adjustment exceeds ± 300 mm

E442

Trouble in interference prevention (Side) correction

1. Out of side interference prevention correction range When quantity of lateral adjustment exceeds ± 300 mm 1. Out of depth indication correction range When quantity of vertical adjustment exceeds ± 500 mm

—

—

Q

—

E443

Trouble in depth indication correction

—

Q

—

E258

Short circuit in 5 V system of sensor power 1. Short circuit in wiring harness between M95 pin 22 – M29 pin C, M71 pin C, supply M72 pin A

20-354 (12)

PC78US-6

TROUBLESHOOTING

Normal Condition

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

Action Taken by Controller When Trouble Occurs

Problems on Machine

Between M97 pin 16 – chassis ground: Min. 1 Mz Between M20 pin 1 – solenoid body: Min. 1 Mz Resistance of M20 EPC solenoid (With Current does not flow in TVC-EPC solenoid. When trouble is detected, TVC-EPC solenoid Accordingly, if load is large, engine speed switch directed down): 3 – 15 W output is stopped. may lower to stall. Resistance between M97 pin 16 – M20 pin 1: Max. 1 Mz Resistance of M20 EPC solenoid: 3 – 15 z Resistance between M20 pin 2 – M97 pin 23: Max. 1 z Between M97 pin 7 – chassis ground: Min. 1 Mz Between M14 pin 2 – solenoid body: Min. 1 Mz Resistance of M14 solenoid: 35 – 80 z

When trouble is detected, swing holding Resistance between M97 pin 7 – M14 pin 2: brake reset solenoid output is stopped. Max. 1 z Resistance of M14 solenoid: 35 – 80 z Resistance between M14 pin 1 – M97 pin 3 (With switch directed down): Max. 1 z

Since motor brake is not released, machine does not swing.

Between M97 pin 27 – chassis ground: Min. 1 Mz Between M15 pin 2 – solenoid body: Min. 1 Mz Resistance of M15 solenoid: 35 – 80 z When trouble is detected, 2nd travel speed Resistance between M97 pin 27 – M15 pin selection solenoid output is stopped. 2: Max. 1 Mz Resistance of M15 solenoid: 35 – 80 z Resistance between M15 pin 1 – M97 pin 3: Max. 1 z

When speed selector switch pedal is operated, travel speed does not change. (It is kept at 1st gear.)

Resistance between M96 pin 40 – M16 pin 1: Max. 1 z Resistance of M16 sensor: 500 – 1,000 z Resistance between M16 pin 2 – M96 pin 39: Max. 1 z

Since constant current (600 mA) is output to TVC-EPC solenoid, work equipment speed and travel speed are low. If engine speed is low, engine may stall.

When trouble is detected, constant current flows in TVC-EPC solenoid (600 mA). Working mode cannot be changed. Engine governor control is limited to operation of fuel control dial.

Boom RAISE end cushion does not work. Stop position for interference prevention is wrong. Displayed depth is wrong.

Boom angle sensor voltage for monitoring At boom RAISE end: 0.6 V Arm angle sensor voltage for monitoring Standard arm Long arm At IN end: 0.7 V 0.7 V At OUT end: 4.1 V 3.7 V

When potentiometer is corrected, "———" is displayed and initial values are selected. If machine is operated without normal correction, it is controlled with initial values.

Offset end cushion does not work. Stop position for interference prevention is wrong. Displayed depth is wrong.

Offset angle sensor voltage for monitoring At RIGHT end: 1.3 V At LEFT end: 3.7 V When interference prevention is corrected, "000" is displayed, then "S-1" (Side correction) is displayed. When interference prevention is corrected, "000" is displayed, then "– – –" (Finish of correction) is displayed. In depth display correction position (1), "000" is displayed, then "d-1" is displayed. In depth display correction position (2), "000" is displayed, then "– – –" (Finish of correction) is displayed.

When interference prevention is corrected, "– – –" is displayed and initial values are Stop position for interference prevention is selected. wrong. If machine is operated without normal correction, it is controlled with initial values.

When interference prevention is corrected, "– – –" is displayed and initial values are selected. Displayed depth is wrong. If machine is operated without normal correction, it is controlled with initial values.

Resistance between M95 pin 22, M29 pin C, Boom RAISE, arm IN, and offset LEFT EPC M71 pin C, M72 pin A – chassis ground: Min. outputs are stopped. 1 Mz

PC78US-6

Arm IN end cushion does not work. Stop position for interference prevention is wrong. Displayed depth is wrong.

Boom RAISE, arm IN, and offset LEFT operations cannot be executed. (They can be executed if emergency work equipment operation switch is turned ON, however.)

20-355 (12)

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCUR AND PROBLEMS ON MACHINE

TROUBLESHOOTING

Application US

UU

!

—

!

—

!

—

!

—

20-355-1 ➄

User Code

Service Code

Disconnection on GND side of boom angle 1. Short circuit in wiring harness sensor between M95 pin 21 ~ M29 pin A

E402

1. Disconnection in wiring harness between M95 pin 22 ~ M29 pin C 2. Short circuit in wiring harness Disconnection on power supply side of between M95 pin 3 ~ M29 pin B boom angle sensor/Short circuit or discon3. Disconnection in wiring harness nection of signal line between M95 pin 3 ~ M29 pin B 4. Defective M29 angle sensor (Internal short circuit)

E404

Disconnection on GND side of arm angle sensor

1. Disconnection in wiring harness between M95 pin 21 ~ M72 pin C

E405

Disconnection on power supply side of arm angle sensor/Short circuit or disconnection of signal line

1. Disconnection in wiring harness between M95 pin 22 ~ M72 pin A 2. Short circuit in wiring harness between M95 pin 20 ~ M72 pin B 3. Disconnection in wiring harness between M95 pin 20 ~ M72 pin B 4. Defective M72 angle sensor (Internal short circuit)

E407

Disconnection on GND side of offset boom 1. Disconnection in wiring harness angle sensor between M95 pin 21 ~ M71 pin A

E408

1. Disconnection in wiring harness between M95 pin 22 ~ M71 pin C 2. Short circuit in wiring harness Disconnection on power supply side of between M95 pin 14 ~ M71 pin B offset boom angle sensor/Short circuit or 3. Disconnection in wiring harness disconnection of signal line between M95 pin 14 ~ M71 pin B 4. Defective M71 angle sensor (Internal short circuit)

E421

Short circuit in boom RAISE EPC solenoid system

1. Short circuit in wiring harness between M97 pin 26 ~ M11 pin 2 2. Short circuit in EPC solenoid

E422

Disconnection in boom RAISE EPC solenoid system

1. Disconnection in wiring harness between M97 pin 26 ~ M11 pin 2 2. Disconnection in EPC solenoid 3. Disconnection in wiring harness between M11 pin 1 ~ M97 pin 23

E423

Short circuit in arm IN EPC solenoid system

1. Short circuit in wiring harness between M97 pin 5 ~ M12 pin 2 2. Short circuit in EPC solenoid

E424

1. Disconnection in wiring harness between M97 pin 5 ~ M12 pin 2 Disconnection in arm IN EPC solenoid sys2. Disconnection in EPC solenoid tem 3. Disconnection in wiring harness between M12 pin 1 ~ M97 pin 23

E425

Short circuit in offset LEFT EPC solenoid system

E426

1. Disconnection in wiring harness between M97 pin 15 ~ M10 pin 2 Disconnection in offset LEFT EPC solenoid 2. Disconnection in EPC solenoid system 3. Disconnection in wiring harness between M10 pin 1 ~ M97 pin 23

E431

Short circuit in PPC main pressure solenoid system

E435

1. Boom RAISE, arm IN, and offset LEFT EPC solenoids are kept open because of dirt (In emergency stop range of When emergency stop is applied (Interference prevention) bucket) 2. Water is in connectors in boom, arm, or offset angle sensors

E40

—

Contents of Trouble

E401

E40

E41

Troubled System

1. Short circuit in wiring harness between M97 pin 15 ~ M10 pin 2 2. Short circuit in EPC solenoid

1. Short circuit in wiring harness between M97 pin 38 ~ M13 pin 2 2. Short circuit in EPC solenoid

PC78US-6

TROUBLESHOOTING

Normal Condition

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCUR AND PROBLEMS ON MACHINE

Action Taken by Controller When Trouble Occurs

Problems on Machine

Resistance between M95 pin 21 ~ M29 pin A: Max. 1 MΩ Between M95 pin 22 ~ M29 pin C: Max. 1 Ω Resistance between M95 pin 3, M29 pin B ~ chassis ground: Min. 1 MΩ Resistance between M95 pin 3 ~ M29 pin B: Boom RAISE, arm IN, and offset LEFT EPC outputs are stopped. Max. 1 Ω Resistance between M29 angle sensor pin A ~ pin C: 3 ~ 7 kΩ Resistance between M29 angle sensor pin A, C ~ pin B (Which changes as shaft is turned): 0 ~ 7 kΩ

Boom RAISE, arm IN, and offset LEFT operations cannot be executed. (They can be executed if emergency work equipment operation switch is turned ON, however.)

Resistance between M95 pin 21 ~ M72 pin C: Max. 1 Ω Resistance between M95 pin 21 ~ M29 pin A: Max. 1 Ω Resistance between M95 pin 20, M72 pin B ~ chassis ground: Min. 1 MΩ Resistance between M95 pin 20 ~ M72 pin B: Max. 1 Ω Resistance between M72 angle sensor pin A ~ pin C: 3 ~ 7 kΩ Resistance between M72 angle sensor pin A, C ~ pin B (Which changes as shaft is turned): 0 ~ 7 kΩ Resistance between M95 pin 21 ~ M71 pin A: Max. 1 Ω Resistance between M95 pin 22 ~ M71 pin C: Max. 1 Ω Resistance between M95 pin 14, M71 pin B ~ chassis ground: Min. 1 MΩ Resistance between M95 pin 14 ~ M71 pin B: Max. 1 Ω Resistance between M71 angle sensor pin A ~ pin C: 3 ~ 7 kΩ Resistance between M71 angle sensor pin A, C ~ pin B : 0 ~ 7 kΩ (Which changes as shaft is turned) Resistance between M97 pin 26, M11 pin 2 ~ chassis ground: Min. 1 MΩ Resistance of M11 EPC solenoid: 5 ~ 25 Ω Resistance between M97 pin 26 ~ M11 pin 2: Boom RAISE EPC solenoid output is stopped. Max. 1 Ω Resistance of M11 EPC solenoid: 3 ~ 15 Ω Resistance between M11 pin 1 ~ M97 pin 23: Max. 1 Ω

Boom cannot be raised.

Resistance between M97 pin 5, M12 pin 2 ~ chassis ground: Min. 1 MΩ Resistance of M12 EPC solenoid: 5 ~ 25 Ω Resistance between M97 pin 5 ~ M12 pin 2: Arm IN EPC solenoid output is stopped. Max. 1 Ω Resistance of M11 EPC solenoid: 3 ~ 15 Ω Resistance between M12 pin 1 ~ M97 pin 23: Max. 1 Ω

Arm cannot be moved IN.

Resistance between M97 pin 15, M10 pin 2 ~ chassis ground: Min. 1 MΩ Resistance of M10 EPC solenoid: 5 ~ 25 Ω Resistance between M97 pin 15 ~ M10 pin 2: Offset LEFT EPC solenoid output is stopped. Offset cannot be moved to LEFT. Max. 1 Ω Resistance of M10 EPC solenoid: 3 ~ 15 Ω Resistance between M10 pin 1 ~ M97 pin 23: Max. 1 Ω Resistance between M97 pin 38, M13 pin 2 ~ PPC main pressure solenoid output is chassis ground: Min. 1 MΩ stopped. Resistance of M15 solenoid: 35 ~ 80 Ω

Machine cannot operate equipment, travel, or swing.

Voltage of potentiometer at each cylinder end (Monitoring) Boom RAISE: 0.6 V ~ (LOWER) 4.3 V PPC main pressure solenoid output is Standard arm IN: 0.7 V ~ OUT 4.1 V stopped. Long arm: 0.7 V ~ 3.7 V Offset LEFT: 1.3 V ~ RIGHT 3.7 V

Machine cannot operate equipment, travel, or swing. (It can, however, if emergency work equipment operation switch is turned ON.)

PC78US-6

20-355-2 ➄

TROUBLESHOOTING

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

PC78US-6 Serial No.: 6501 and up User Code

Service Code

Troubled System

Contents of Trouble

Short circuit in TVC-EPC solenoid system (When emergency pump drive switch is turned ON)

1. Short circuit in wiring harness between M95 pin 9 – M20 pin 1 2. Short circuit in EPC solenoid 3. Wrong operation of switch

E233

Disconnection in TVC-EPC solenoid system

1. Disconnection in wiring harness between M95 pin 9 – M20 pin 1 2. Disconnection in EPC solenoid 3. Disconnection in wiring harness between M20 pin 2 – M95 pin 40

E203

Short circuit in swing holding brake solenoid system

1. Short circuit in wiring harness between M95 pin 19 – M14 pin 2 2. Short circuit in solenoid

E213

Disconnection in swing holding brake solenoid system (When emergency swing holding brake reset switch is turned ON)

1. Disconnection in wiring harness between M95 pin 19 – M14 pin 2 2. Disconnection in solenoid 3. Disconnection in wiring harness between M14 pin 1 – M95 pin 40 4. Wrong operation of switch

E206

Short circuit in 2nd travel speed selection solenoid system

1. Short circuit in wiring harness between M95 pin 10 – M15 pin 2 2. Short circuit in solenoid

E216

1. Disconnection in wiring harness between M95 pin 10 – M15 pin 2 Disconnection in 2nd travel speed selection solenoid 2. Disconnection in solenoid system 3. Disconnection in wiring harness between M15 pin 1 – M95 pin 40

E232 E02

E03

—

—

E224

Trouble in pump pressure sensor

1. Disconnection, defective contact, short circuit, or grounding fault in pressure sensor 2. Disconnection, defective contact, or short circuit in wiring harness between controller M95 pin 22 – pressure sensor S3 pin B (power supply side) or between M95 pin (32) – S3 pin A (negative side) 3. Disconnection, defective contact, or short circuit in wiring harness between controller M95 pin 24 – pressure sensor S3 pin C (SIG side) 4. Defective controller

—

E227

Trouble in engine speed sensor

1. Disconnection in wiring harness between M95 pin 6 – M16 pin 1 2. Disconnection in sensor 3. Disconnection in wiring harness between M16 pin 2 – M95 pin 32

—

E258

Short circuit in 5 V system of sensor power supply

1. Between M95 pin 22 – S2 pin 1, S3 pin B, or K55 pin 1

20-355-3 (12)

PC78US-6

TROUBLESHOOTING

Normal Condition

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

Action Taken by Controller When Trouble Occurs

Problems on Machine

Between M95 pin 9 – chassis ground: Min. 1 Mz Between M20 pin 1 – solenoid body: Min. 1 Mz No current flows in TVC-EPC solenoid. Resistance of M20 EPC solenoid (when When abnormality is detected, controller switch is directed down): 3 – 15 z stops outputting signal to TVC-EPC solenoid. Accordingly, if load is large, engine speed lowers extremely and engine may stalls. Between M95 pin 9 – M20 pin 1: Min. 1 Mz Resistance of M20 EPC solenoid: 3 – 15 z Resistance between M20 pin 2 – M95 pin 40: Max. 1 z Between M95 pin 19 – chassis ground: Min. 1 Mz Between M14 pin 2 – solenoid body: Min. 1 Mz When abnormality is detected, controller Resistance of M14 solenoid: 35 – 80 z Since motor brake is not released, machine stops outputting signal to swing holding brake does not swing. reset solenoid. Resistance between M95 pin 19 – M14 pin 2: Max. 1 z Resistance of M14 solenoid: 35 – 80 z Resistance between M14 pin 1 – M95 pin 40 (when switch is directed down): Max. 1 z Between M95 pin 10 – chassis ground: Min. 1 Mz Between M15 pin 2 – solenoid body: Min. 1 Mz When abnormality is detected, controller Resistance of M15 solenoid: 35 – 80 z stops outputting signal to 2nd travel speed Resistance between M95 pin 10 – M15 pin selection solenoid. 2: Max. 1 z Resistance of M15 solenoid: 35 – 80 z Resistance between M15 pin 1 – M95 pin 40: Max. 1 z

When speed selector switch or pedal is operated, travel speed is not changed (but kept at 1st).

• Between M96 pin 22 – pin 32: 4.5 – 5.5 V • Between M95 pin 24 – S3 pin C: 0.5 – 4.5 V Controller assumes pump pressure to be 0 • Between M95 pin 24 – pin 32, between Pa {0 kg/cm2} for operation. pin 24 – chassis ground: Min. 1 Mz (Disconnect M95 and S3.)

Gear speed does not change automatically.

Resistance between M95 pin 6 – M16 pin 1: Max. 1 z Resistance of M16 sensor: 500 – 1,000 z Resistance between M16 pin 2 – M95 pin 32: Max. 1 z

When abnormality is detected, controller outputs constant current (600 mA) to TVC-EPC solenoid. Working mode cannot be changed. Engine governor can be controlled with only fuel control dial.

Resistance between M95 pin 22, S2 pin 1, S3 pin B, K55 pin 1 – chassis ground: Min. 1 Mz

• Controller assumes pump pressure to be 0 Pa {0 kg/cm2} for operation. • Controller recognizes that boom is at rais- Gear speed does not change automatically. ing stroke end. • Controller recognizes that arm is at dumping stroke end.

PC78US-6

Since constant current (600 mA) is output to TVC-EPC solenoid, work equipment speed and travel speed are low. When engine speed is low, engine may stall.

20-355-4 (12)

JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT

TROUBLESHOOTING

JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up

Machine Model

Work equipment, travel, swing, blade

—

PC78US-6

—

Q

Q Q

Q Q

Q Q

Q Q

Q Q

Q Q

Q Q

Short circuit in 5 V system of sensor power supply

—

Defective correction of depth display

—

Defective correction of interference prevention (Side)

Defective correction of offset boom angle sensor

—

Defective correction of interference prevention (Front)

Defective correction of arm angle sensor

—

Defective correction of boom angle sensor

Disconnection in 2nd travel speed selection solenoid system

Short circuit in 2nd travel speed selection solenoid system

Disconnection in swing holding brake solenoid system

Short circuit in swing holding brake solenoid system

E03

232 233 203 213 206 216 227 403 406 411

PC78UU-6

Machine cannot move work equipment, travel, or move blade.

Disconnection in TVC-EPC solenoid system

E02

Service Code

Trouble in engine speed sensor system

User Code

Failure Mode

Short circuit in TVC-EPC solenoid system

Self-diagnosis Display By Controller

Trouble in controller power supply system

Part Which May Cause Trouble

—

—

—

—

441

442

443

258

—

—

—

—

—

—

—

Q

Q

Q

Q

Q

Q

Q

q q

Machine cannot raise boom, move arm in, or move offset to left. Speed or power of 2 or more systems of work equipment, travel, swing, and blade is low.

q

q

q

Engine speed lowers extremely or engine stalls.

q

q

q

q

q

2 or more systems of work equipment, travel, swing, and blade do not move. Boom Speed or power is low.

Arm Offset (Only UU)

Work equipment

Boom Does not move.

Arm Offset (Only UU)

Travel

Travel speed or power is low.

q

Travel speed does not change.

q

Swing speed or power is low. Swing

q q

Machine does not swing. Hydraulic drift is large. Boom RAISE does not stop automatically at correct position.

Interference prevention

q q

Stops just before interference prevention

q

Interferes

Stops just before interferArm IN does not stop automat- ence prevention ically at correct position. Interferes LEFT Offset does not stop automatically at correct position.

q q

q

Stops just before interference prevention

q

Interferes

Work equipment stops far or too near.

q

q q

Buzzer sounds for 7 seconds while emergency work equipment operation switch is not turned ON.

q

Boom RAISE end cushion does not work well or at all. Electronic cushion

Arm IN end cushion does not work well or at all.

q

Offset end cushion does not work at all.

q

Mode selection Work equipment exceeds or stops before set height. Depth display

q

When depth display is reset, 0.0 M is not displayed at ground level.

After work equipment lock lever is set to LOCK, work equipment still moves Diagnosis code displayed when service code is displayed

E-1 C-1 C-2 C-3 C-4 C-5 C-6 E-6 C-7 C-8 C-9 C-10 C-11 C-12 C-13

Diagnosis code displayed when trouble is detected by monitoring

—

20-356 (12)

—

—

—

—

—

—

—

—

—

—

—

—

—

—

PC78US-6

—

—

Q Q Q Q Q Q Q Q Q Q Q Q Q Q — — — Q — — — Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q Q —

— —

— —

—

PC78US-6 —

— —

q q

—

E40

q q

q q

q q

q q q q

q q

q q E41

401 402 404 405 407 408 421 422 423 424 425 426 431 435 1023

—

1021 1026 1060

CC- C- CC- C- C- C- C- C- C- Nor 14 C-15 16 17 18 C-19 20 21 22 23 24 25 26 mal — — — — — — — — — — — —

: Items that can only be checked by monitoring

—

—

—

—

—

—

—

—

— — — — — — — — F-3 F-4 F-2 F-1 F-7 F-5 F-6 — — — — — F-8 —

—

—

—

—

—

—

—

—

Offset LEFT EPC current output

Arm IN EPC current output

Boom RAISE EPC current output

TVC-EPC current output

Offset boom sensor voltage input

Arm angle sensor voltage input

Boom angle sensor voltage input

Engine speed input

Emergency work equipment operation switch input (3)

ATT selection

Model selection and UU/US selection cod

2nd travel speed selection (4)

Self-diagnosis Display By Controller

Swing holding brake (1)

Hydraulic Switch

PPC main pressure (2)

Travel speed selector pedal switch input (4)

Deceleration switch signal input (1)

Air compressor signal input (3)

Swing (4)

Travel (3)

Arm LOWER (5)

Boom RAISE (6)

When emergency stop is applied (Interference prevention)

Disconnection in PPC main pressure solenoid system

Disconnection in offset boom LEFT EPC solenoid system

Short circuit in offset boom LEFT EPC solenoid system

Disconnection in arm IN EPC solenoid system

Short circuit in arm IN EPC solenoid system

Disconnection in boom RAISE EPC solenoid system

Short circuit in boom RAISE EPC solenoid system

Disconnection on power supply side of offset boom angle sensor/Short circuit or disconnection of signal line

Disconnection on power supply side of arm angle sensor/Short circuit or disconnection of signal line Disconnection on GND side of offset boom angle sensor

Disconnection on GND side of arm angle sensor

Disconnection on power supply side of boom angle sensor/Short circuit or disconnection of signal line

Disconnection on GND side of boom angle sensor

TROUBLESHOOTING JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT

State of Solenoid

Items Checked By Monitoring

q q q q q q Diagnosis code displayed when trouble is not detected by monitoring

Monitoring Code

— — — — — — — — 1020 1026 1010 1030 1032 1031 1050 1051 1052 1053

q q C-14 – C-20

C-26

H-1

q q H-3

H-2

H-7

q q H-10

H-8

H-12

H-11

q q H-14

C-39,H-28

H-26

C-38,H-34 H-33

H-39

q

C-27 —

q

—

q

C-28

—

C-29

C-30

Q

C-31

C-32

q q

C-33

C-34

C-35

q

C-36

C-37

q : Items corresponding to service codes

20-357

(12)

JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up Items Checked By Monitoring

Part Which May Cause Trouble Self-diagnosis Display By Controller

Machine Model

PC78US-6

Machine cannot move work equipment, travel, or move blade. Work equipment, travel, swing, blade

—

Q

Q

Q

Q

Q

Q

Q

Q

—

Air compressor signal input (3)

Monitoring Code

232 233 203 213 206 216 224 227 258 —

Swing (4)

—

Travel (3)

—

Arm LOWER (5)

—

Boom RAISE (6)

Short circuit in 5 V system of sensor power supply

E03

Trouble in engine speed sensor system

Disconnection in 2nd travel speed selection solenoid system

Short circuit in 2nd travel speed selection solenoid system

Disconnection in swing holding brake solenoid system

Short circuit in swing holding brake solenoid system

Disconnection in TVC-EPC solenoid system

E02

Service Code

Trouble in pump pressure sensor system

User Code

Failure Mode

Short circuit in TVC-EPC solenoid system

Trouble in controller power supply system

Hydraulic Switch

1021

1023

Q

Q

Q

Q

Q

—

—

—

—

q q

Machine cannot raise boom, move arm in, or move offset to left. Speed or power of 2 or more systems of work equipment, travel, swing, and blade is low.

q

q

q

Engine speed lowers extremely or engine stalls.

q

q

q

q

q

2 or more systems of work equipment, travel, swing, and blade do not move. Speed or power is low. Work equipment Does not move. Travel

Boom Arm Boom Arm

Travel speed or power is low.

q

Travel speed does not change.

q

q

Swing speed or power is low. Swing

q q

Machine does not swing. Hydraulic drift is large.

Interference prevention

q q

Buzzer sounds for 7 seconds while emergency work equipment operation switch is not turned ON.

Mode selection Work equipment exceeds or stops before set height. Depth display

When depth display is reset, 0.0 M is not displayed at ground level.

After work equipment lock lever is set to LOCK, work equipment still moves Diagnosis code displayed when service code is displayed

E-1 C-1 C-2 C-3 C-4 C-5 C-6

E-6 C-13 —

Diagnosis code displayed when trouble is detected by monitoring

—

—

—

—

—

—

—

—

—

F-3 F-4 F-2 F-1 F-7

q : IIndicates an item corresponding to a service code.

20-357-1 (12)

PC78US-6

JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT

TROUBLESHOOTING

Items Checked By Monitoring

Diagnosis code displayed when trouble is not detected by monitoring

Pump pressure

Governor feedback potentiometer voltage input

Fuel control dial voltage input

TVC-EPC current output

Arm angle sensor voltage input

Boom angle sensor voltage input

Engine speed input

Emergency work equipment operation switch input (3)

2nd travel speed selection (4)

Swing holding brake (1)

PPC main pressure (2)

Deceleration switch signal input (1)

State of Solenoid

Monitoring Code 1026

Q

1060

Q

Q

1026 1010 1030 1032 1050 1034 1035 1042

Q

Q

Q

—

—

Q

Q

Q

Q C-26 C-14 – C-20 H-1 H-2 H-3 H-7 H-8 H-11 H-12 H-26

w

C-39,H-28 H-33 C-38,H-34 H-39

Q

C-31 C-35 C-36 C-37

—

—

—

—

—

—

—

—

—

F-5

—

—

—

F-8

—

—

—

—

Q : Indicates an item to be checked by monitoring or with the machine monitor. w : It does not correspond for serial No. 6501 and up. : Indicates an item to be checked by only monitoring.

PC78US-6

20-357-2 (12)

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM PC78UU-6 Serial No.: 22832 – 23500

20-358 (7)

PC78US-6

TROUBLESHOOTING

PC78US-6

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

20-358-1 (5)

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

PC78UU-6 Serial No.: 23501 and up

20-358-2 (7)

PC78US-6

TROUBLESHOOTING

PC78US-6

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

20-358-3 (7)

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

PC78US-6 Serial No.: 4001 – 5500

20-358-4 (7)

PC78US-6

TROUBLESHOOTING

PC78US-6

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

20-358-5 (7)

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

PC78US-6 Serial No.: 5501 – 6500

20-358-6 (12)

PC78US-6

TROUBLESHOOTING

PC78US-6

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

20-358-7 (7)

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

PC78US-6 Serial No.: 6501 and up

20-358-8 (12)

PC78US-6

TROUBLESHOOTING

PC78US-6

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

20-358-9 (12)

C-1, C-2

TROUBLESHOOTING

C-1 [E232], C-2 [E233] Trouble in TVC-EPC solenoid system PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Since this error is displayed when the emergency pump drive switch is turned ON (RAISE), check that this switch is turned OFF (LOWER). Cause

Remedy

1 • Disconnect M20 • 3 – 15 z • Resistance between solenoid and chassis ground: Min. 1 Mz

Is resistance of EPC solenoid normal and is EPC solenoid insulated from chassis?

NO

Defective TVC-EPC solenoid (Internal short circuit, disconnection)

Replace

Disconnection or defective contact in wiring harness between M97 (Female) (16), (23) – M20 (Female) (1), (2)

Repair or replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (16) – M20 (Female) (1)

Repair or replace

Defective controller

Replace

YES

2 • Disconnect M97 • Resistance: 3 – 15 z

NO

Is resistance between M97 (Female) (16) – (23) normal? YES

3 • Disconnect M97 • Resistance: Min. 1 Mz

Is resistance between M97 (Female) (16) – chassis ground normal?

NO

YES

C-1, C-2 Electrical circuit diagram of each system

PC78US-6

20-359 (12)

TROUBLESHOOTING

C-1, C-2

PC78US-6 Serial No.: 6501 and up a Since this error is displayed when the emergency pump drive switch is turned ON (RAISE), check that this switch is turned OFF (LOWER). Cause

Remedy

1 • Disconnect M20 • 3 – 15 z • Resistance between solenoid and chassis ground: Min. 1 Mz

Is resistance of EPC solenoid normal and is EPC solenoid insulated from chassis?

NO

Defective TVC-EPC solenoid (Internal short circuit, disconnection)

Replace

Disconnection or defective contact in wiring harness between M95 (Female) (9), (40) – M20 (Female) (1), (2)

Repair or replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M95 (Female) (9) – M20 (Female) (1)

Repair or replace

Defective controller

Replace

YES

2 • Disconnect M95 • Resistance: 3 – 15 z

NO

Is resistance between M95 (Female) (9) – (40) normal? YES

3 • Disconnect M95 • Resistance: Min. 1 Mz

Is resistance between M95 (Female) (16) – chassis ground normal?

NO

YES

C-1, C-2 Electrical circuit diagram of each system

20-359-1 (12)

PC78US-6

TROUBLESHOOTING

C-3, C-4

C-3 [E203], C-4 [E213] Trouble in swing holding brake solenoid system PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Since this error is displayed when the emergency swing holding brake release switch is turned ON (RAISE), check that this switch is turned OFF (LOWER). Cause

Remedy

1 • Disconnect M14 • 35 – 80 z • Resistance between solenoid and chassis ground: Min. 1 Mz

Is resistance of solenoid normal and is solenoid insulated from chassis?

NO

Defective swing holding brake solenoid (Internal short circuit, disconnection)

Replace

Disconnection or defective contact in wiring harness between M97 (Female) (7), (3) – M14 (Female) (2), (1)

Repair or replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (7) – M14 (Female) (2)

Repair or replace

Defective controller

Replace

YES

2 • Disconnect M97 • Resistance: 35 – 80 z

NO

Is resistance between M97 (Female) (7) – (3) normal? YES

3 • Disconnect M97 • Resistance: Min. 1 Mz

Is resistance between M97 (Female) (7) – chassis ground normal?

NO

YES

C-3, C-4 Electrical circuit diagram of each system

20-360 (12)

PC78US-6

C-3, C-4

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a Since this error is displayed when the emergency swing holding brake release switch is turned ON (RAISE), check that this switch is turned OFF (LOWER). Cause

Remedy

1 • Disconnect M14 • 35 – 80 z • Resistance between solenoid and chassis ground: Min. 1 Mz

Is resistance of solenoid normal and is solenoid insulated from chassis?

NO

Defective swing holding brake solenoid (Internal short circuit, disconnection)

Replace

Disconnection or defective contact in wiring harness between M95 (Female) (19), (40) – M14 (Female) (2), (1)

Repair or replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M95 (Female) (19) – M14 (Female) (2)

Repair or replace

Defective controller

Replace

YES

2 • Disconnect M95 • Resistance: 35 – 80 z

NO

Is resistance between M95 (Female) (19) – (40) normal? YES

3 • Disconnect M95 • Resistance: Min. 1 Mz

Is resistance between M95 (Female) (19) – chassis ground normal?

NO

YES

C-3, C-4 Electrical circuit diagram of each system

PC78US-6

20-360-1 (12)

C-5, C-6

TROUBLESHOOTING

C-5 [E206], C-6 [E216] Trouble in 2nd travel speed selection solenoid system PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up Cause

Remedy

1 • Disconnect M15 • 35 – 80 z • Resistance between solenoid – chassis ground: Min. 1 Mz

Is resistance of solenoid normal and is solenoid insulated from chassis?

NO

Defective 2nd travel speed selection solenoid (Internal short circuit, disconnection)

Replace

Disconnection or defective contact in wiring harness between M97 (Female) (27), (3) – M15 (Female) (2), (1)

Repair or replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (27) – M15 (Female) (2)

Repair or replace

Defective controller

Replace

YES

2 • Disconnect M97 • Resistance: 35 – 80 z

NO

Is resistance between M97 (Female) (27) – (3) normal? YES

3 • Disconnect M97 • Resistance: Min. 1 Mz

Is resistance between M97 (Female) (27) – chassis ground normal?

NO

YES

C-5, C-6 Electrical circuit diagram of each system

PC78US-6

20-361 (12)

TROUBLESHOOTING

C-5, C-6

PC78US-6 Serial No.: 6501 and up Cause

Remedy

1 • Disconnect M15 • 35 – 80 z • Resistance between solenoid – chassis ground: Min. 1 Mz

Is resistance of solenoid normal and is solenoid insulated from chassis?

NO

Defective 2nd travel speed selection solenoid (Internal short circuit, disconnection)

Replace

Disconnection or defective contact in wiring harness between M95 (Female) (10), (40) – M15 (Female) (2), (1)

Repair or replace

Short circuit with chassis ground or negative (-) wire in wiring harness between M95 (Female) (10) – M15 (Female) (2)

Repair or replace

Defective controller

Replace

YES

2 • Disconnect M95 • Resistance: 35 – 80 z

NO

Is resistance between M95 (Female) (10) – (40) normal? YES

3 • Disconnect M95 • Resistance: Min. 1 Mz

Is resistance between M95 (Female) (10) – chassis ground normal?

NO

YES

C-5, C-6 Electrical circuit diagram of each system

20-361-1 (12)

PC78US-6

TROUBLESHOOTING

C-7, C-8, C-9

C-7 [E403] Trouble in boom angle sensor correction C-8 [E406] Trouble in arm angle sensor correction C-9 [E411] Trouble in offset boom angle sensor correction (Only PC78UU-6) a Check by monitoring that model selection, UU/US selection code, and ATT selection code are normal. a Check that the angle sensor are installed normally.

Cause

Remedy

1 • Reset data again according to potentiometer correction procedure in back mode

Is error turned off after data are reset again?

NO

YES Defective correction (Wrong resetting)

—

Defective controller

Replace

Defective angle sensor having abnormal resistance

Replace

Disconnection or defective contact in wiring harness of circuit having abnormal resistance (Between M95 – M29, M71, M72) (See circuit diagram)

Repair or replace

2 Is monitored voltage of angle sensor at each cylinder end normal?

• See Table 1

NO

YES

3

M29, M71, M72 • Between (A) – (C): 3 – 7 kz • Between (A), (C) – (B): 0 – 7 kz (Resistance changes as shaft is turned)

Is resistance of each angle sensor normal?

NO

YES

Table 1

Voltage (V) Position

Boom RAISE end

Monitoring Code

Standard Arm

Long Arm

1030

0.3 – 1.1

0.3 – 1.1

0.8 – 1.8

0.8 – 1.8

3.2 – 4.2

3.2 – 4.2

0.3 – 1.2

0.3 – 1.2

3.6 – 4.6

3.2 – 4.2

Offset LEFT end 1031 Offset RIGHT end Arm IN end 1032 Arm DUMP end

20-362 (5)

PC78US-6

TROUBLESHOOTING

C-7, C-8, C-9

C-7, C-8, C-9 Electrical circuit diagram of each system

PC78US-6

20-363 ➄

TROUBLESHOOTING

C-10 C-11

, C-11

C-10, C-11

[E441] Trouble in interference prevention (front) correction [E442] Trouble in interference prevention (side) correction (Only PC78UU-6)

★ Check by monitoring that model selection, UU/US selection code, and ATT selection code are normal. ★ Check that the angle sensors are installed normally. Cause

Remedy

1 • Correct potentiometer and set interference prevention in back mode

NO

Is error turned off after data are reset again?

YES Defective correction (Wrong resetting)

—

Defective correction (Over-quantity of adjustment)

Re-set in adjustment range

Defective Controller

Replace

Defective angle sensor having abnormal resistance.

Replace

Disconnection or defective contact in wiring harness of circuit having abnormal resistance (Between M95 ~ M29, M71, M72) (See circuit diagram)

Repair or replace

2 • Quantity of longitudinal adjustment: ± 300 mm • Quantity of lateral adjustment: ± 300 mm

Is quantity of adjustment in standard range?

NO

YES 3

Same as values of C-7 ~ C-9

NO

Is monitored voltage of angle sensor at each cylinder end normal? YES

4 M29, M71, M72 • Between (A) ~ (C): 3 ~ 7kΩ • Between (A), (C) ~ (B): 0 ~ 7kΩ (Resistance changes as shaft is turned.)

Is resistance of each angle sensor normal?

YES

NO

C-10, C-11 Electrical circuit diagram of each system

20-364 ➄

PC78US-6

TROUBLESHOOTING

C-12

C-12

[E443] Trouble in depth indication correction (Only PC78UU-6)

★ Check by monitoring that model selection, UU/US selection code, and ATT selection code are normal. ★ Check that the angle sensors are installed normally. Cause

Remedy

1 • Correct potentiometer and depth display in back mode.

NO

Is error turned off after data are reset again?

YES Defective correction (Wrong resetting)

—

Defective correction (Over-quantity of adjustment)

Re-set in adjustment range

Defective Controller

Replace

Defective angle sensor having abnormal resistance.

Replace

Disconnection or defective contact in wiring harness of circuit having abnormal resistance (Between M95 ~ M29, M71, M72) (See circuit diagram)

Repair or replace

2

• Quantity of vertical adjustment: ± 500 mm

Is quantity of adjustment in standard range?

NO

YES 3

Same as values of C-7 ~ C-9

NO

Is monitored voltage of angle sensor at each cylinder end normal? YES

4 M29, M71, M72 • Between (A) ~ (C): 3 ~ 7kΩ • Between (A), (C) ~ (B): 0 ~ 7kΩ (Resistance changes as shaft is turned.)

Is resistance of each angle sensor normal?

YES

NO

C-12 Electrical circuit diagram of each system

PC78US-6

20-365 ➄

TROUBLESHOOTING

C-13

C-13 [E258] Short circuit in 5V system of sensor power supply (Only PC78UU-6) a If E258 is displayed, E40 is displayed, too. Carry out the troubleshooting for E40 (C-14 – C-19), too. Cause

Remedy

1 • Disconnect M95 • Min. 1Mz

Is resistance between M95 (Female) (22) chassis ground normal?

Short circuit with chassis ground in wiring harness between M95 (Female) (22) – M29, M71 (Female) (A), M72 (Female) (C) (Short circuit of sensor power supply with chassis ground.)

Repair or replace

NO

Short circuit with chassis ground or negative (-) wire in wiring harness between M95 (Female) (21) – M29, M71 (Female) (A), M72 (Female) (C)

Repair or replace

NO

Defective angle sensor having abnormal resistance (Internal short circuit)

Replace

Defective controller

Replace

NO

YES

2 • Disconnect M95, M72, M71, and M29. • Min. 1Mz

Is resistance between M95 (Female) (22) – (21)normal? YES

3 • Between (A) – (C): 3 – 7 kz • Between (A), (C) – (B): 0 – 7 kz (Resistance changes as shaft is turned)

Is resistance of each angle sensor normal? YES

C-13 Electrical circuit diagram of each system

20-366 (12)

PC78US-6

C-13

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a If E258 is displayed, E40 is also displayed.

Cause

Remedy

1 • Disconnect M95. • Min. 1 Mz

Is resistance between M95 (female) (22) and chassis ground normal?

NO

Grounding fault in wiring harness between M95 (female) (22) – chassis ground (Grounding fault in sensor power supply)

Repair or replace

NO

Defective fuel control dial potentiometer (Internal short circuit)

Replace

NO

Defective pump pressure sensor (Internal short circuit)

Replace

NO

Defective governor motor feedback potentiometer (Internal short circuit)

Replace

Defective controller

Replace

YES

2 • Operate fuel control dial. • 0.7 – 4.3 V

Is voltage of fuel control dial normal? (Monitoring code 1034) YES

3 • Turn starting switch ON: 0 {0} • When relieved: 26.5 ± 1.0 MPa {270 ± 10 kg/cm2}

Is monitoring value of pump pressure sensor normal? (Monitoring code 1042) YES

4 • Start engine. • Operate fuel control dial. • 2.7 – 4.7 V

Is voltage of governor feedback potentiometer normal? (Monitoring code 1035) YES

PC78US-6

20-366-1 (12)

TROUBLESHOOTING

C-13

C-13 Electrical circuit diagram of each system

20-366-2 (12)

PC78US-6

C-14

TROUBLESHOOTING

C-14 [E224] Trouble in pump pressure sensor is displayed PC78US-6 Serial No.: 6501 and up Cause

Remedy

1 • Turn starting switch ON: 0 {0] • Relief pressure: 26.5 ± 1.0 MPa {270 ± 10 kg/cm2}

Is monitored pump pressure normal? (Monitoring code 1040)

NO

Defective controller

Replace

NO

Grounding fault in wiring harness between M95 – S3

Repair or replace

NO

Short circuit in wiring harness between M95 – S3

Repair or replace

Disconnect in wiring harness between M95– S3

Repair or replace

Defective pump pressure sensor

Replace

YES

2 • Disconnect S3. • Disconnect M95. • Min. 1 Mz

Is resistance between S3 (female) (C) and chassis ground and between S3 (female) (B) and chassis ground normal? YES

3 • Disconnect S3. • Disconnect M95. • Min. 1 Mz

Is resistance between S3 (female) (C) and (B) and between S3 (female) (C) and (4) normal? YES

4 • Disconnect S3. • Disconnect M95. • Max. 1 z

Is resistance between M95 (female) (24) and S3 (female) (C), between M95 (female) (22) and S3 (female) (B), and between M95 (female) (25) and S3 (female) (A) normal?

NO

YES

C-14 Electrical circuit diagram of each system

PC78US-6

20-366-3 (12)

C-15, C-16

TROUBLESHOOTING

C-15 [E401], C-16 [E402] Trouble in boom angle sensor system (Only PC78UU-6) Cause

Remedy

1 • 0.3 – 4.7 V (Monitoring code 1030)

Is monitored voltage of boom angle sensor normal?

NO

YES Defective controller

Replace

Defective boom angle sensor (Disconnection, short circuit with chassis ground)

Replace

• Disconnection or defective contact in wiring harness between M95 (Female) (22), (3) – M29 (Female) (A), (B), (C) • Short circuit with chassis ground or negative (-) wire in wiring harness between M95 (Female) (3) – M29 (Female) (B)

Repair or replace

2 • Between (A) – (C): 3 – 7 kz • Between (A), (C) – (B): 0 – 7 kz (Resistance changes as shaft is turned.)

Is resistance of M29 angle sensor normal?

NO

YES

If the wiring harness between M95(3) – M29 (B) is shorted actually, the controller output is cut out. Accordingly, if [E402] is displayed, the controller is defective.

C-15, C-16 Electrical circuit diagram of each system

PC78US-6

20-367 (12)

TROUBLESHOOTING

C-17, C-18

C-17 [E404], C-18 [E405] Trouble in arm angle sensor system (Only PC78UU-6) Cause

Remedy

1 • 0.3 – 4.7 V (Monitoring code 1032)

Is monitored voltage of arm angle sensor normal?

NO

YES Defective controller

Replace

Defective arm angle sensor (Disconnection, short circuit with chassis ground)

Replace

• Disconnection or defective contact in wiring harness between M95 (Female) (21), (20), (22) – M72 (Female) (C), (B), (A) • Short circuit with chassis ground or negative (-) wire in wiring harness between M95 (Female)(20) – M72 (Female) (B)

Repair or replace

2 • Between (A) – (C): 3 – 7 kz • Between (A), (C) – (B): 0 – 7 kz (Resistance changes as shaft is turned.)

Is resistance of M72 angle sensor normal?

NO

YES

a If the wiring harness between M95 (20) – M72 (B) is shorted actually, the controller output is cut out. Accordingly, if [E405] is displayed, the controller is defective.

C-17, C-18 Electrical circuit diagram of each system

20-368 (12)

PC78US-6

C-19, C-20

TROUBLESHOOTING

C-19 [E407], C-20 [E408] Trouble in offset angle sensor system (Only PC78UU-6) Cause

Remedy

1 • 0.3 – 4.7 V (Monitoring code 1031)

Is monitored voltage of offset boom angle sensor normal?

NO

YES Defective controller

Replace

Defective offset angle sensor (Disconnection, short circuit with chassis ground)

Replace

• Disconnection or defective contact in wiring harness between M95 (Female) (22), (14), (21) – M71 (Female) (A), (B), (C) • Short circuit with chassis ground or negative (-) wire in wiring harness between M95 (Female) (14) – M71 (Female) (B)

Repair or replace

2 • Between (A) – (C): 3 – 7 kz • Between (A), (C) – (B): 0 – 7 kz (Resistance changes as shaft is turned.)

Is resistance of M71 angle sensor normal?

NO

YES

a If the wiring harness between M95 (14) – M71 (B) is shorted actually, the controller output is cut out. Accordingly, if [E408] is displayed, the controller is defective.

C-19, C-20 Electrical circuit diagram of each system

PC78US-6

20-369 (12)

TROUBLESHOOTING

C-21

C-21 [E421] Short circuit in boom raise EPC system is displayed (Only PC78UU-6) Cause

Remedy

1 • Turn starting switch OFF. • Disconnect M11.

Is resistance between M11 (male) (1) and (2) and between (2) and chassis ground as shown in Table 1?

NO

Defective boom raise EPC solenoid (Internal disconnection)

Replace

NO

Disconnection in wiring harness between D15 (female) (1) – M11 (2), M97 (23) – M11 (1)

Repair or replace

NO

Grounding fault or internal short circuit in wiring harness between D15 (female) (2) – M97 (female) (26)

Repair or replace

Defective controller

Replace

YES

2 • Turn starting switch OFF. • Disconnect D15 and M97.

Is resistance between D15 (female) (1) and chassis ground and between D15 (female) (1) and M97 (female) (23) as shown in Table 2? YES

3 • Turn starting switch OFF. • Disconnect D15 and M97.

Is resistance between M97 (female) (26) and M97 (female) (23) between M97 (female) (26) as shown table 3? YES

Table 1

Table 2

Between M11 (male) (1) – (2)

5 – 25 z

Between D15 (1) – chassis ground

Between M11 (male) (2) – chassis ground

Min. 1 z

Between D15 (1) – M97 (23)

Table 3 Min. 1 Mz 5 – 25 z

Between M97 (26) – chassis ground

Min. 1 Mz

Between M97 (26) – M97 (23)

Min. 1 Mz

C-21 Electrical circuit diagram of each system

20-370 (12)

PC78US-6

C-22

TROUBLESHOOTING

C-22 [E422] Disconnection in boom raise EPC system is displayed (Only PC78UU-6) Cause

Remedy

1 • Turn starting switch OFF. • Disconnect M11. • Resistance: 5 – 25z

Is resistance between M11 (male) (1) and (2) normal?

NO

Defective boom raise EPC solenoid (Internal disconnection)

Replace

NO

Disconnection in wiring harness between D15 (female) (1) – M11 (2), D15 (female) (2) – M97 (26), or M97 (23) – M11 (1)

Repair or replace

Defective diode (Disconnection)

Replace

Defective controller

Replace

YES

2 • Turn starting switch OFF. • Disconnect D15 and M97.

Is resistance between D15 (female) (1) and M97 (female) (23) and between D15 (female) (2) and M97 (female) (26) as shown in Table 1? YES

3 • Turn starting switch OFF. • Disconnect D15. * See TESTING AND ADJUSTING.

Is diode D15 normal?

NO

YES

Table 1 Between D15 (1) – M97 (23)

5 – 25 z

Between D15 (2) – M97 (26)

Max. 1 z

C-22 Electrical circuit diagram of each system

PC78US-6

20-371 (12)

TROUBLESHOOTING

C-23

C-23 [E423] Short circuit or grounding fault in arm-in EPC system is displayed (Only PC78UU-6) Cause

Remedy

1 • Turn starting switch OFF. • Disconnect M12.

Is resistance between M12 (male) (1) and (2) and between (2) and chassis ground as shown in Table 1?

NO

Defective arm-in EPC solenoid (Internal short circuit or grounding fault)

Replace

NO

Grounding fault or internal short circuit in wiring harness between D19 (female) (1) – M12 (2) or between M97 (23) – M12 (1)

Repair or replace

NO

Grounding fault or internal short circuit in wiring harness between D15 (female) (2) – M97 (female) (5)

Repair or replace

Defective controller

Replace

YES

2 • Turn starting switch OFF. • Disconnect D19 and M97.

Is resistance between D19 (female) (1) and chassis ground and between D19 (female) (1) and M97 (female) (23) as shown in Table 2? YES

3 • Turn starting switch OFF. • Disconnect D19 and M97.

Is resistance between M97 (female) (5) and chassis ground and between M97 (female) (5) and M97 (female) (23) as shown in Table 3? YES

Table 1

Table 2

Between M12 (male) (1) – (2)

5 – 25 z

Between D19 (1) – chassis ground

Between M12 (male) (2) – chassis ground

Min. 1 z

Between D19 (1) – M97 (23)

Table 3 Min. 1 Mz 5 – 25 z

Between M97 (5) – chassis ground

Min. 1 Mz

Between M97 (5) – M97 (23)

Min. 1 Mz

C-23 Electrical circuit diagram of each system

20-372 (12)

PC78US-6

C-24

TROUBLESHOOTING

C-24 [E424] Disconnection in arm-in EPC system is displayed (Only PC78UU-6) Cause

Remedy

1 • Turn starting switch OFF. • Disconnect M12. • Resistance: 5 – 25z

Is resistance between M12 (male) (1) and (2) normal?

NO

Defective arm-in EPC solenoid (Internal disconnection)

Replace

NO

Disconnection in wiring harness between D19 (female) (1) – M12 (2), D19 (female) (2) – M97 (5), or M97 (23) – M12 (1))

Repair or replace

Defective diode (Disconnection)

Replace

Defective controller

Replace

YES

2 • Turn starting switch OFF. • Disconnect D19 and M97.

Is resistance between D19 (female) (1) and M97 (female) (23) and between D19 (female) (2) and M97 (female) (5) as shown in Table 1? YES

3 • Turn starting switch OFF. • Disconnect D19. * See TESTING AND ADJUSTING.

Is diode D19 normal?

NO

YES

Table 1 Between D19 (1) – M97 (23)

5 – 25 z

Between D19 (2) – M97 (5)

Max. 1 z

C-24 Electrical circuit diagram of each system

PC78US-6

20-373 (12)

TROUBLESHOOTING

C-25

C-25 [E425] Short circuit or grounding fault in offset left EPC system is displayed (Only PC78UU-6) Cause

Remedy

1 • Turn starting switch OFF. • Disconnect M10.

Is resistance between M10 (male) (1) and (2) and between (2) and chassis ground as shown in Table 1?

NO

Defective offset left EPC solenoid (Internal short circuit or grounding fault)

Replace

NO

Grounding fault or internal short circuit in wiring harness between D20 (female) (1) – M10 (2) or between M97 (23) – M10 (1)

Repair or replace

NO

Grounding fault or internal short circuit in wiring harness between D20 (female) (2) – M97 (female) (15)

Repair or replace

Defective controller

Replace

YES

2 • Turn starting switch OFF. • Disconnect D20 and M97.

Is resistance between D20 (female) (1) and chassis ground and between D20 (female) (1) and M97 (female) (23) as shown in Table 2? YES

3 • Turn starting switch OFF. • Disconnect D20 and M97.

Is resistance between M97 (female) (15) and chassis ground and between M97 (female) (15) and M97 (female) (23) as shown in Table 3? YES

Table 1

Table 2

Between M10 (male) (1) – (2)

5 – 25 z

Between D20 (1) – chassis ground

Between M10 (male) (2) – chassis ground

Min. 1 z

Between D20 (1) – M97 (23)

Table 3 Min. 1 Mz 5 – 25 z

Between M97 (15) – chassis ground

Min. 1 Mz

Between M97 (15) – M97 (23)

Min. 1 Mz

C-25 Electrical circuit diagram of each system

20-374 (12)

PC78US-6

C-26

TROUBLESHOOTING

C-26 [E426] Disconnection in offset left EPC system is displayed (Only PC78UU-6) Cause

Remedy

1 • Turn starting switch OFF. • Disconnect M10. • Resistance: 5 – 25 z

Is resistance between M10 (male) (1) and (2) normal?

NO

Defective offset left EPC solenoid (Internal disconnection)

Replace

NO

Disconnection in wiring harness between D20 (female) (1) – M10 (2), D20 (female) (2) – M97 (15) or M97 (23) – M10 (1)

Repair or replace

NO

Defective diode (Disconnection)

Replace

Defective controller

Replace

YES

2 • Turn starting switch OFF. • Disconnect D20 and M97.

Is resistance between D20 (female) ((1) and M97 (female) (23) and between D20 (female) (2) and M97 (female) (15) as shown in Table 1? YES

3 • Turn starting switch OFF. • Disconnect D20. * See TESTING AND ADJUSTING.

Is diode D20 normal?

YES

Table 1 Between D20 (1) – M97 (23)

5 – 25 z

Between D20 (2) – M97 (15)

Max. 1 z

C-26 Electrical circuit diagram of each system

PC78US-6

20-375 (12)

TROUBLESHOOTING

C-27

C-27 [E431] Short circuit or grounding fault in PPC basic pressure lock solenoid system is displayed (Only PC78UU-6) PC78UU-6 Serial No.: 22832 and up Cause

Remedy

1 • Turn starting switch OFF. • Disconnect M13.

Is resistance between M13 (male) (1) and (2) and between (2) and chassis ground as shown in Table 1?

NO

Defective PPC oil pressure lock solenoid (Internal short circuit or grounding fault)

Replace

NO

Defective PPC oil pressure lock switch

Replace

Grounding fault or internal short circuit in wiring harness between K55 (female) (5) – M13 (female) (2) or between M13 (female) (1) – M97 (female) (13)

Repair or replace

NO

Grounding fault or internal short circuit in wiring harness between K55 (female) (3) – M97 (female) (30)

Repair or replace

NO

Grounding fault or internal short circuit in wiring harness between D13 (female) (2) – M97 (female) (38)

Repair or replace

Defective controller

Replace

YES

• Turn starting switch OFF. • Disconnect K28. • Reset PPC oil pressure lock switch. • Resistance between K28 (female) (2) and chassis ground: Min. 1 Mz

Is PPC oil pressure lock switch insulated from chassis ground?

• Turn starting switch OFF. • Disconnect K55 and M97.

Is resistance between K55 (female) (5) and chassis ground and between K55 (female) (5) and M97 (female) (13) as shown in Table 2?

2

YES

3 NO

YES

4 • • • •

Turn starting switch OFF. Disconnect D13 and D14. Disconnect M97 and K55. Reset PPC oil pressure lock switch.

Is resistance between K55 (female) (3) and chassis ground and between M97 (female) (30) and chassis ground as shown in Table 3? YES

5 • Turn starting switch OFF. • Disconnect M97 and D13.

Is resistance between M97 (female) (38) and chassis ground and between M97 (female) (38) and M97 (female) (13) as shown in Table 4? YES

Table 1

Table 2

Table 3

Between M13 (male) (1) – (2)

35 – 80 z

Between K55 (female) (5) – chassis ground

Min. 1 Mz

Between K55 (female) (3) – chassis ground

Between M13 (male) (2) – chassis ground

Min. 1 Mz

Between K55 (female) (5) – M97 (female) (13)

35 – 80 z

Between M97 (female) (30) – chassis ground Min. 1 Mz

Min. 1 Mz

Table 4 Between M97 (38) – chassis ground

Min. 1 z

Between M97 (38) – M97 (13)

Min. 1 z

20-376 (12)

PC78US-6

TROUBLESHOOTING

C-27

C-27 Electrical circuit diagram of each system PC78UU-6 Serial No.: 22832 – 23500

PC78US-6

20-376-1 (12)

TROUBLESHOOTING

C-27

C-27 Electrical circuit diagram of each system PC78UU-6 Serial No.: 23501 and up

20-376-2 (12)

PC78US-6

C-28

TROUBLESHOOTING

C-28 Boom does not stop automatically at normal position but interferes when it is raised (Only PC78UU-6) a a a a

Check that the UU/US selection and ATT selection are normal by monitoring code 1020. Check that the boom angle sensor voltage input is normal by monitoring code 1030. (Standard value: 0.6 V when boom is at raise end) Check installation of the boom angle sensor for abnormality.

Cause

Remedy

1 When interference prevention (Front) and boom angle sensor are corrected again, does condition become normal?

NO

YES Defective correction

2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)

Is resistance of boom angle sensor normal?

NO

Defective boom angle sensor

Replace

Defective controller

Replace

YES

C-28 Electrical circuit diagram of each system

PC78US-6

20-377 (12)

TROUBLESHOOTING

C-29

C-29 Arm does not stop automatically at normal position but interferes when it is moved in (Only PC78UU-6) a Check that the UU/US selection and ATT selection are normal by monitoring code 1020. a Check that the arm angle sensor voltage input is normal by monitoring code 1032. (Standard value: At IN end; Standard arm = 0.7 V, Long arm = 0.7 V At OUT end; Standard arm = 4.1 V, Long arm = 3.7 V) a Check installation of the arm angle sensor for abnormality.

Cause

Remedy

1 When interference prevention (Front) and arm angle sensor are corrected again, does condition become normal?

NO

YES Defective correction

2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)

Is resistance of arm angle sensor normal?

NO

Defective arm angle sensor

Replace

Defective controller

Replace

YES

C-29 Electrical circuit diagram of each system

20-378 (12)

PC78US-6

C-30

TROUBLESHOOTING

C-30 Offset does not stop automatically at normal position but interferes when it is moved to left (Only PC78UU-6) a Check that the UU/US selection and ATT selection are normal by monitoring code 1020. a Check that the offset angle sensor voltage input is normal by monitoring code 1031. (Standard value: At right end; 1.3 V, At left end; 3.7 V) a Check installation of the offset angle sensor for abnormality.

Cause

Remedy

1 When interference prevention (Front) and offset angle sensor are corrected again, does condition become normal?

NO

YES Defective correction

2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)

Is resistance of offset angle sensor normal?

NO

Defective offset angle sensor

Replace

Defective controller

Replace

YES

C-30 Electrical circuit diagram of each system

PC78US-6

20-379 (12)

TROUBLESHOOTING

C-31

C-31 Work equipment stops far or near (Only PC78UU-6) a Check that the UU/US selection and ATT selection are normal by monitoring code 1020. a Check that the voltage inputs of the boom angle sensor, arm angle sensor, and offset angle sensor are normal by monitoring codes 1030, 1032, and 1031, respectively. (For the standard values, see C-27, C-28, and C-29.) a Check installation of the boom angle sensor, arm angle sensor, and offset angle sensor for abnormality.

Cause

Remedy

1 When interference prevention (Front) and interference prevention (Side) are corrected again, does condition become normal?

NO

YES Defective correction

2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)

Is resistance of boom, arm, and offset angle sensor normal?

NO

Defective offset angle sensor

Replace defective angle sensor

Defective controller

Replace

YES

C-31 Electrical circuit diagram of each system

20-380 (12)

PC78US-6

C-32

TROUBLESHOOTING

C-32 Buzzer sounds for 7 seconds while emergency work equipment operation switch is not turned ON (Only PC78UU-6) a Check that the input of the emergency work equipment operation switch is normal by monitoring code 1026.

Cause

Remedy

1 • When switch is set in lower position (Automatic returning) Between (1) and (2): Min. 1 Mz Between (2) and (3): Max. 1z

Is resistance of emergency work equipment operation switch normal?

NO

Defective emergency work equipment operation switch

Replace

Defective monitor

Replace

YES

C-32 Electrical circuit diagram of each system PC78UU-6 Serial No.: 22832 – 23500

PC78US-6

20-381 (12)

TROUBLESHOOTING

C-32

C-32 Electrical circuit diagram of each system PC78UU-6 Serial No.: 23501 and up

20-381-1 (12)

PC78US-6

TROUBLESHOOTING

C-33

C-33 Boom raise end cushion does not work at all or normally (Only PC78UU-6) a a a a

Check that the boom angle sensor voltage input is normal by monitoring code 1030. (Standard value: 0.6 V when boom is at raise end) Check that the boom raise EPC current output is normal by monitoring code 1051.) Check installation of the boom angle sensor for abnormality. Cause

Remedy

1 When boom angle sensor is corrected again, does condition become normal?

NO

YES Defective correction

–

Defective boom angle sensor

Replace

Disconnection or defective contact in wiring harness of circuit having abnormal resistance (See circuit diagram)

Repair or replace

2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)

NO

Is resistance of boom angle sensor normal?

YES

3 • Normal value: Max. 1 z

Is resistance between M29 (A) and M95 (21), between M29 (B) and M95 (3), and between M29 (C) and M95 (22) normal?

NO

YES Defective controller

C-33 Electrical circuit diagram of each system

20-382 (12)

PC78US-6

C-34

TROUBLESHOOTING

C-34 Arm-in end cushion does not work at all or normally (Only PC78UU-6) a Check that the arm angle sensor voltage input is normal by monitoring code 1032. (Standard value: At IN end; Standard arm = 0.7 V, Long arm = 0.7 V At OUT end; Standard arm = 4.1 V, Long arm = 3.7 V) a Check that the arm-in EPC current output is normal by monitoring code 1052. a Check installation of the arm angle sensor for abnormality. Cause

Remedy

1 When arm angle sensor is corrected again, does condition become normal?

NO

YES Defective correction

—

Defective arm angle sensor

Replace

Disconnection or defective contact in wiring harness of circuit having abnormal resistance

Repair or replace

Defective controller

Replace

2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)

NO

Is resistance of arm angle sensor normal?

YES

3 • Normal value: Max. 1 z

Is resistance between M72 (A) and M95 (22), between M72 (B) and M95 (20), and between M72 (C) and M95 (21) normal?

NO

YES

C-34 Electrical circuit diagram of each system

PC78US-6

20-383 (12)

TROUBLESHOOTING

C-35

C-35 Offset end cushion does not work at all or normally (Only PC78UU-6) a Check that the offset angle sensor voltage input is normal by monitoring code 1031. (Standard value: At right end; 1.3 V, At left end; 3.7 V) a Check that the offset left EPC current output is normal by monitoring code 1053. a Check installation of the offset angle sensor for abnormality. Cause

Remedy

1 When offset angle sensor is corrected again, does condition become normal?

NO

YES Defective correction

—

Defective offset angle sensor

Replace

Disconnection or defective contact in wiring harness of circuit having abnormal resistance

Repair or replace

Defective controller

Replace

2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)

NO

Is resistance of offset angle sensor normal?

YES

3 • Normal value: Max. 1 z

Is resistance between M71 (A) and M95 (21), between M71 (B) and M95 (14), and between M71 (C) and M95 (22) normal?

NO

YES

C-35 Electrical circuit diagram of each system

20-384 (12)

PC78US-6

C-36

TROUBLESHOOTING

C-36 Work equipment stops after or before set height (Only PC78UU-6) a Check that the UU/US selection and ATT selection are normal by monitoring code 1020. a Check that the voltage inputs of the boom angle sensor, arm angle sensor, and offset angle sensor are normal by monitoring codes 1030, 1032, and 1031, respectively. (For the standard values, see C-27, C-28, and C-29.) a Check installation of the boom angle sensor, arm angle sensor, and offset angle sensor for abnormality.

Cause

Remedy

1 When interference prevention (Front) and interference prevention (Side) are corrected again, does condition become normal?

NO

YES Defective correction

—

Defective angle sensor having abnormal resistance

Replace defective angle sensor

Defective controller

Replace

2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)

Is resistance of boom, arm, and offset angle sensor normal?

NO

YES

C-36 Electrical circuit diagram of each system

PC78US-6

20-385 (12)

TROUBLESHOOTING

C-37

C-37 When depth display is reset, 0.0 m is not indicated at GL (Only PC78UU-6) a Check that the UU/US selection and ATT selection are normal by monitoring code 1020. a Check that the voltage inputs of the boom angle sensor, arm angle sensor, and offset angle sensor are normal by monitoring codes 1030, 1032, and 1031, respectively. (For the standard values, see C-27, C-28, and C-29.) a Check installation of the boom angle sensor, arm angle sensor, and offset angle sensor for abnormality.

Cause

Remedy

1 When interference prevention (Front) and interference prevention (Side) are corrected again, does condition become normal?

NO

YES Defective correction

—

Defective angle sensor having abnormal resistance

Replace defective angle sensor

Defective controller

Replace

2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)

Is resistance of boom, arm, and offset angle sensor normal?

NO

YES

C-37 Electrical circuit diagram of each system

20-386 (12)

PC78US-6

C-38

TROUBLESHOOTING

C-38 Work equipment still moves after work equipment lock lever is set to LOCK PC78US-6 Serial No.: 4001 – 5500 Cause

• When pushed, (1) – (3) are connected to each other. • When released, (1) – (2) are connected to each other (Test on switch unit)

Remedy

1 Is PPC hydraulic lock switch normal?

NO

Defective hydraulic lock switch

Replace

NO

Short circuit with positive (+) wire in wiring harness between K28 (2) – M13 (2)

Repair or replace wiring harness

Defective controller

Replace

YES

2 • When locked: 0 V • When released: 20 – 29 V

Is voltage between M13 (2) – chassis ground normal? YES

C-38 Electrical circuit diagram of each system

PC78US-6

20-387 (12)

C-38

TROUBLESHOOTING

PC78US-6 Serial No.: 5501 – 6500 Cause

• When pushed, (1) – (3) are connected to each other. • When released, (1) – (2) are connected to each other (Test on switch unit)

Remedy

1 Is PPC hydraulic lock switch normal?

NO

Defective hydraulic lock switch

Replace

NO

Short circuit with positive (+) wire in wiring harness between K28 (2) – M13 (2)

Repair or replace wiring harness

Defective PPC lock solenoid valve

Replace

YES

2 • When locked: 0 V • When released: 20 – 29 V

Is voltage between M13 (2) – chassis ground normal? YES

C-38 Electrical circuit diagram of each system

20-387-1 (12)

PC78US-6

C-38

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up Cause

• When pushed, (1) – (3) are connected to each other. • When released, (1) – (2) are connected to each other (Test on switch unit)

Remedy

1 Is PPC hydraulic lock switch normal?

NO

Defective hydraulic lock switch

Replace

NO

Short circuit with positive (+) wire in wiring harness between K28 (2) – M13 (2)

Repair or replace wiring harness

Defective PPC lock solenoid valve

Replace

YES

2 • When locked: 0 V • When released: 20 – 29 V

Is voltage between M13 (2) – chassis ground normal? YES

C-38 Electrical circuit diagram of each system

PC78US-6

20-387-2 (12)

C-38

TROUBLESHOOTING

PC78UU-6 Serial No.: 22832 and up Cause

• When pushed, (1) – (3) are connected to each other. • When released, (1) – (2) are connected to each other (Test on switch unit)

Remedy

1 Is PPC hydraulic lock switch normal?

NO

Defective hydraulic lock switch

Replace

Defective controller

Replace

Defective PPC lock cut relay

Replace

Short circuit with power source in wiring harness between M13 (female) (2) - K55 (female) (5) or between K55 (female) (3) - M97 (female) (30), (38)

Repair or replace

YES

2 • When locked: 0 V • When released: 20 – 29 V

Is voltage between M13 (2) – chassis ground normal?

NO

YES

3 • Min. 1 M z • Disconnect K55.

Is resistance between PPC lock cut relay K55 (male) (3) and (5) normal? YES

NO

C-38 Electrical circuit diagram of each system

20-387-3 (12)

PC78US-6

TROUBLESHOOTING

C-39

C-39 Machine does not swing PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Carry out the following troubleshooting when [E-203] and [E-213] are not displayed.

Cause

Remedy

1 • Check swing control lever.

Is bit pattern 1023 – (4) displayed?

NO

Go to F-1

—

Go to H-34

—

YES

C-39 Electrical circuit diagram of each system

20-388 (12)

PC78US-6

C-39

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a Carry out the following troubleshooting when [E-203] and [E-213] are not displayed.

Cause

Remedy

1 • Check swing control lever.

Is bit pattern 1023 – (4) displayed?

NO

Go to F-1

—

Go to H-34

—

YES

C-39 Electrical circuit diagram of each system

PC78US-6

20-388-1 (12)

C-40

TROUBLESHOOTING

C-40 Travel speed does not rise PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Carry out the following troubleshooting when [E-206] and [E-216] are not displayed.

Cause

Remedy

1 • 20 – 29 V • Turn starting switch ON • Disconnect K3

Is voltage between K3 (Female) (2) – chassis ground normal?

NO

YES

2 • • • •

In 1-spool mode: Min. 1Mz In 2-spool mode: Max. 1z Turn starting switch OFF Disconnect K3

Is resistance between K3 (Male) (2) – (1) normal?

NO

YES

Defective 2nd travel speed selection switch

Replace

Disconnection or defective contact in wiring harness between K3 (Female) (1) – M12 – chassis ground

Repair or replace

Defective controller

Replace

Disconnection or defective contact in wiring harness between M95 (Female) (5) – K3 (Female) (2)

Repair or replace

3 • 20 – 29 V • Turn starting switch ON • Disconnect K3

Is voltage between M95 (5) – chassis ground normal. YES

NO

C-40 Electrical circuit diagram of each system

PC78US-6

20-389 (12)

C-41, C-42

TROUBLESHOOTING

C-41 Gear speed does not change automatically PC78US-6 Serial No.: 6501 and up a When [E-206], [E-216], [E-224], or [E-227] is not displayed.

Cause

Remedy

1 • Monitoring FULL: 197 – 207 SLOW: 113 –118 • Turn starting switch ON.

Is monitored value of engine speed normal? (Monitoring code: 1010)

NO

Defective engine speed sensor

Replace

NO

Defective pump pressure sensor

Replace

Defective controller

Replace

YES

2 • Monitoring relief 25.5 – 27.5 MPa {260.3 – 280.4 kg/cm2}

Is monitored value of pump pressure normal? (Monitoring code: 1042) YES

C-42 Trouble in controller power supply system (LED of controller is turned OFF) a See E-1.

20-389-1 (12)

PC78US-6

TROUBLESHOOTING FOR CONTROLLER (INPUT SIGNAL SYSTEM) (F MODE)

F-1 F-2 F-3 F-4 F-5 F-6

Bit pattern 1023-(4) Swing pressure switch does not light up.............................................................. 20-402 Bit pattern 1023-(3) Travel pressure switch does not light up.............................................................. 20-404 Bit pattern 1023-(6) Boom RAISE pressure switch does not light up .................................................. 20-406 Bit pattern 1023-(5) Arm IN pressure switch does not light up ............................................................ 20-408 Bit pattern 1026-(1) Deceleration switch of left knob does not light up................................................ 20-410 Bit pattern 1026-(4) 2nd travel speed selection switch (pedal) does not light up (US with blade and UU) ....................................................................................... 20-412 F-7 Bit pattern 1021-(3) Compressor signal does not light up ................................................................... 20-413 F-8 Bit pattern 1026-(3) Emergency work equipment operation switch does not light up (Only PC78UU-6)................................................................................................. 20-415

a When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the monitoring code is displayed normally, the condition has returned to normal. a Before carrying out troubleshooting, check that all the related connectors are properly inserted. a Always connect any disconnected connectors before going on to the next step. PC78US-6

20-401 (12)

F-1

TROUBLESHOOTING

F-1 Bit pattern 1023-(4) Swing pressure switch does not light up PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up k

Before operating the swing control lever (even a little distance), stick the bucket into the ground to lock the swing mechanism. Cause

• Disconnect M22. • Start engine. • Set swing control lever in neutral: Min. 1Mz • Move swing control lever to swing to left: Max. 1z • See note.

Is resistance between M22 (Male) (1) – (2) normal and are they insulated from chassis ground?

• Disconnect M23. • Start engine. • Set swing control lever in neutral: Min. 1 Mz • Move swing control lever to swing to right: Max. 1 z • See note.

Is resistance between M23 (Male) (1) – (2) normal and are they insulated from chassis ground?

• Turn starting switch OFF. • Disconnect M95, M22, and M23. • Between M95 – M22, M23: Max. 1 z • Between wiring harness – chassis ground: Min. 1 z

Is resistance between M95 (Female) (24) – M22, M23 (Female) (2) normal and are they insulated from chassis ground?

• Start engine. • Set swing control lever in neutral: 20 – 30 V • Move swing control lever: Max. 1 V

Remedy

1 NO

Defective left swing pressure switch

Replace

NO

Defective right swing pressure switch

Replace

NO

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (24) – M22 (Female) (2), M23 (Female) (2)

Repair or replace

NO

Disconnection or defective contact in wiring harness between M22 (Female) (1), M23 (Female) (1) – chassis ground

Repair or replace

Defective controller

Replace

YES

2

YES

3

YES

4 Is voltage between M95 (24) – chassis ground normal? YES

Note: This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (24) – chassis ground. • If 20 – 30 V : Go to YES. • If below 1 V : Go to NO.

F-1 Electrical circuit diagram of each system

20-402 (12)

PC78US-6

F-1

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up k

Before operating the swing control lever (even a little distance), stick the bucket into the ground to lock the swing mechanism. Cause

• Disconnect M22. • Start engine. • Set swing control lever in neutral: Min. 1Mz • Move swing control lever to swing to left: Max. 1z • See note.

Is resistance between M22 (Male) (1) – (2) normal and are they insulated from chassis ground?

• Disconnect M23. • Start engine. • Set swing control lever in neutral: Min. 1 Mz • Move swing control lever to swing to right: Max. 1 z • See note.

Is resistance between M23 (Male) (1) – (2) normal and are they insulated from chassis ground?

• Turn starting switch OFF. • Disconnect M95, M22, and M23. • Between M95 – M22, M23: Max. 1 z • Between wiring harness – chassis ground: Min. 1 z

Is resistance between M95 (Female) (25) – M22, M23 (Female) (2) normal and are they insulated from chassis ground?

• Disconnect M95, M22 and M23. • Max. 1z

Is resistance between M22 (female) (1) and chassis ground and between M23 (female) (1) and chassis ground normal?

Remedy

1 NO

Defective left swing pressure switch

Replace

NO

Defective right swing pressure switch

Replace

NO

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (25) – M22 (Female) (2), M23 (Female) (2)

Repair or replace

NO

Disconnection or defective contact in wiring harness between M22 (Female) (1), M23 (Female) (1) – chassis ground

Repair or replace

Defective controller

Replace

YES

2

YES

3

YES

4

YES

Note: This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (25) – chassis ground. • If 20 – 30 V : Go to YES. • If below 1 V: Go to NO.

F-1 Electrical circuit diagram of each system

PC78US-6

20-403 (12)

F-2

TROUBLESHOOTING

F-2 Bit pattern 1023-(3) Travel pressure switch does not light up PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up k

Before operating the travel lever (even a little distance), check the condition and safety around the machine.

k

Before operating the travel lever, put a block in the grouser of the track shoe or between the sprocket and frame to lock the track shoe. Cause

• Disconnect M25. • Start engine. • Set swing control lever in neutral: Min. 1 Mz • Move travel lever: Max. 1 z • See note.

• • • •

Turn starting switch OFF. Disconnect M95 and M25. Between M95 – M25: Max. 1 z Between wiring harness – chassis ground: Min. 1 Mz

Remedy

1 Is resistance between M25 (Male) (1) – (2) normal and are they insulated from chassis ground?

NO

Defective travel pressure switch

Replace

NO

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (18) – M25 (Female) (2)

Repair or replace

NO

Disconnection or defective contact in wiring harness between M25 (Female) (1) – chassis ground

Repair or replace

Defective controller

Replace

YES

2 Is resistance between M95 (Female) (18) – M25 (Female) (2) normal and are they insulated from chassis ground? YES

3 • Start engine. • Set travel lever in neutral: 20 – 30 V • Move travel lever: Max. 1 V

Is voltage between M95 (18) – chassis ground normal? YES

Note: This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (18) – chassis ground. • If 20 – 30 V : Go to YES. • If below 1 V : Go to NO.

F-2 Electrical circuit diagram of each system

20-404 (12)

PC78US-6

F-2

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up k

Before operating the travel lever (even a little distance), check the condition and safety around the machine.

k

Before operating the travel lever, put a block in the grouser of the track shoe or between the sprocket and frame to lock the track shoe. Cause

• Disconnect M25. • Start engine. • Set swing control lever in neutral: Min. 1 Mz • Move travel lever: Max. 1 z • See note.

• • • •

Turn starting switch OFF. Disconnect M95 and M25. Between M95 – M25: Max. 1 z Between wiring harness – chassis ground: Min. 1 Mz

Remedy

1 Is resistance between M25 (Male) (1) – (2) normal and are they insulated from chassis ground?

NO

Defective travel pressure switch

Replace

NO

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (15) – M25 (Female) (2)

Repair or replace

NO

Disconnection or defective contact in wiring harness between M25 (Female) (1) – chassis ground

Repair or replace

Defective controller

Replace

YES

2 Is resistance between M95 (Female) (15) – M25 (Female) (2) normal and are they insulated from chassis ground? YES

3 • Disconnect M95, M22 and M23. • Max. 1 z

Is resistance between M22 (female) (1) and chassis ground and between M23 (female) (1) and chassis ground normal? YES

Note: This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (15) – chassis ground. • If 20 – 30 V : Go to YES. • If below 1 V: Go to NO.

F-2 Electrical circuit diagram of each system

PC78US-6

20-405 (12)

F-3

TROUBLESHOOTING

F-3 Bit pattern 1023-(6) Boom RAISE pressure switch does not light up PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up k

When measuring while the engine is running, move each lever to the degree that the work equipment will not move. Cause

• Start engine. • Set boom control lever in neutral: 20 – 30 V • Move boom control lever to lower boom: Max. 1 V

Remedy

1 Is voltage between M95 (12) – chassis ground normal?

NO

YES

• Disconnect M21. • Start engine. • Set boom control lever in neutral: Min. 1 Mz • Move boom control lever to lower boom: Max. 1 z • See note.

• • • •

Turn starting switch OFF. Disconnect M95 – M21. Between M95 – M21: Max. 1 z Between wiring harness – chassis ground: Min. 1 Mz

Defective governor or pump controller

Replace

Defective boom RAISE pressure switch

Replace

2 Is resistance between M21 (Male) (1) – (2) normal and are they insulated from chassis ground?

NO

YES

3 Is resistance between M95 (Female) (12) – M21 (Female) (2) normal and are they insulated from chassis ground?

NO

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (12) – M21 (Female) (2)

Repair or replace

YES Disconnection or defective contact in wiring harness between M21 (Female) (1) – chassis ground

Repair or replace

Note: This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (12) – chassis ground. • If 20 – 30 V : Go to YES • If below 1 V : Go to NO

F-3 Electrical circuit diagram of each system

20-406 (12)

PC78US-6

F-3

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up k

When measuring while the engine is running, move each lever to the degree that the work equipment will not move. Cause

Remedy

1 • Disconnect M95, M21. • Max. 1 z

Is resistance between M21 (Female) (1) – chassis ground normal?

NO

Disconnection or defective contact in wiring harness between M21 (Female) (1) – chassis ground

Repair or replace

NO

Defective boom RAISE pressure switch

Replace

NO

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (35) – M21 (Female) (2)

Repair or replace

Defective controller

Repair or replace

YES

• Disconnect M21. • Start engine. • Set boom control lever in neutral: Min. 1 Mz • Move boom control lever to lower boom: Max. 1 z • See note.

• • • •

Turn starting switch OFF. Disconnect M95 – M21. Between M95 – M21: Max. 1 z Between wiring harness – chassis ground: Min. 1 Mz

2 Is resistance between M21 (Male) (1) – (2) normal and are they insulated from chassis ground? YES

3 Is resistance between M95 (Female) (35) – M21 (Female) (2) normal and are they insulated from chassis ground? YES

Note: This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (35) – chassis ground. • If 20 – 30 V : Go to YES • If below 1 V: Go to NO

F-3 Electrical circuit diagram of each system

PC78US-6

20-407 (12)

F-4

TROUBLESHOOTING

F-4 Bit pattern 1023-(5) Arm IN pressure switch does not light up PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up k

When measuring while the engine is running, move each lever to the degree that the work equipment will not move. Cause

• Start engine. • Set arm control lever in neutral: 20 – 30 V • Move arm control lever to move arm in: Max. 1 V

Remedy

1 Is voltage between M95 (6) – chassis ground normal?

NO

YES

• Disconnect M24. • Start engine. • Set arm control lever in neutral: Min. 1 Mz • Move arm control lever to move arm in: Max. 1 z • See note.

Is resistance between M24 (Male) (1) – (2) normal and are they insulated from chassis ground?

• Turn starting switch OFF. • Disconnect M95 – M24. • Between M95 and M24: Max. 1 z • Between wiring harness – chassis ground: Min. 1 Mz

Is resistance between M95 (Female) (6) – M24 (Female) (2) normal and are they insulated from chassis ground?

Defective governor or pump controller

Replace

NO

Defective arm IN pressure switch

Replace

NO

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (6) – M24 (Female) (2)

Repair or replace

Disconnection or defective contact in wiring harness between M24 (Female) (1) – chassis ground

Repair or replace

2

YES

3

YES

Note: This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (6) – chassis ground. • If 20 – 30 V : Go to YES • If below 1 V : Go to NO

F-4 Electrical circuit diagram of each system

20-408 (12)

PC78US-6

F-4

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up k

When measuring while the engine is running, move each lever to the degree that the work equipment will not move. Cause

Remedy

1 • Disconnect M95, M24. • Max. 1 z

Is resistance between M24 (Female) (1) – chassis ground normal?

NO

Disconnection or defective contact in wiring harness between M24 (Female) (1) – chassis ground

Repair or replace

NO

Defective arm IN pressure switch

Replace

NO

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (26) – M24 (Female) (2)

Repair or replace

Disconnection or defective contact in wiring harness between M24 (Female) (1) – chassis ground

Repair or replace

YES

• Disconnect M24. • Start engine. • Set arm control lever in neutral: Min. 1 Mz • Move arm control lever to move arm in: Max. 1 z • See note.

Is resistance between M24 (Male) (1) – (2) normal and are they insulated from chassis ground?

• Turn starting switch OFF. • Disconnect M95 – M24. • Between M95 and M24: Max. 1 z • Between wiring harness – chassis ground: Min. 1 Mz

Is resistance between M95 (Female) (26) – M24 (Female) (2) normal and are they insulated from chassis ground?

2

YES

3

YES

Note: This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (26) – chassis ground. • If 20 – 30 V : Go to YES • If below 1 V: Go to NO

F-4 Electrical circuit diagram of each system

PC78US-6

20-409 (12)

F-5

TROUBLESHOOTING

F-5 Bit pattern 1026-(1) Deceleration switch of left knob does not light up PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Check that fuse (11) is normal. Cause

Remedy

1 • Turn starting switch ON. • Turn knob switch ON: 20 – 30 V • Turn knob switch OFF: Max. 1 V

Is voltage between M97 (9) – chassis ground normal?

NO

YES Defective governor or pump controller

Replace

NO

Disconnection or defective contact in wiring harness between fuse (11) – K18 (1) – knob switch inlet

Repair or replace

NO

Defective left knob switch

Replace

Disconnection or defective contact in wiring harness between K18 (2) – M97 (Female) (9)

Repair or replace

2

• Turn starting switch ON. • 20 – 30 V

Is voltage between K18 (Male) (2) – chassis ground normal? YES

• Turn starting switch OFF. • Disconnect knob switch terminal K18. • Turn knob switch ON: Max. 1z • Turn knob switch OFF: Min. 1 Mz

3 Is resistance between K18 (Male) (1) – (2) normal? YES

F-5 Electrical circuit diagram of each system

20-410 (12)

PC78US-6

F-5

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a Check that fuse (11) is normal. Cause

• • • •

Turn starting switch OFF. Disconnect M95. Turn knob switch ON: Max. 1 z Turn knob switch OFF: Min. 1 Mz

Remedy

1 Is resistance between M95 (34) and chassis ground normal?

NO

YES Defective engine throttle and pump controller

Replace

Defective left knob switch

Replace

Disconnection or defective contact in wiring harness between K18 (female) (1) – chassis ground

Repair or replace

Disconnection or defective contact in wiring harness between M95 (female) (34) – K18 (female) (2)

Repair or replace

2 • Turn starting switch OFF. • Disconnect knob switch terminal K18. • Turn knob switch ON: Max. 1 z • Turn knob switch OFF: Min. 1 Mz

Is resistance between K18 (male) (1) and (2) normal?

NO

YES

3 • Turn starting switch OFF. • Disconnect M95 and K18. • Max. 1 z

Is resistance between K18 (1) and chassis ground normal?

NO

YES

F-5 Electrical circuit diagram of each system

PC78US-6

20-411 (12)

F-6

TROUBLESHOOTING

F-6 Bit pattern 1026-(4) 2nd travel speed selection switch (pedal) does not light up (US with blade specification and UU) PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up (PC78UU-6 serial No. 6501 and up, are not equipped with this switch.) Cause • Turn starting switch OFF. • Disconnect 2nd travel speed selection switch terminal K3. • Turn 2nd travel speed selection switch ON: Max. 1 z • Turn 2nd travel speed selection switch OFF: Min. 1 Mz

• • • •

Turn starting switch OFF. Disconnect M95 and K3. Between M95 – K3: Max. 1 z Between wiring harness – chassis ground: Min. 1 Mz

Remedy

1 Is resistance between K3 (Male) (1) – (2) normal?

NO

Defective 2nd travel speed selection switch (pedal)

Replace

NO

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (5) – K3 (Female) (2)

Repair or replace

NO

Disconnection or defective contact in wiring harness between K3 (Female) (1) – chassis ground

Repair or replace

Defective controller

Replace

YES

2 Is resistance between K3 (Female) (2) – M95 (Female) (5) normal and are they insulated from chassis ground? YES

3 • Turn starting switch ON. • Turn 2nd travel speed selection switch ON: Max. 1 V

Is voltage between M95 (Female) (5) – chassis ground normal? YES

F-6 Electrical circuit diagram of each system

20-412 (12)

PC78US-6

F-7

TROUBLESHOOTING

F-7 Bit pattern 1021-(3) Compressor signal does not light up PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Before starting measurement, check that the compressor operates normally when the air conditioner is turned ON. Cause • Turn starting switch ON. • Disconnect M97. • When compressor operates (= Just after air conditioner is turned ON): 20 – 30 V • When compressor stops (= After air conditioner is turned off): Max. 1 V

Remedy

1 Is voltage between M97 (Female) (10) – chassis ground normal?

NO

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M97 (Female) (10) – K11 (Female) (8)

Repair or replace

Defective controller

Replace

YES

F-7 Electrical circuit diagram of each system

PC78US-6

20-413 (12)

F-7

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a Before starting measurement, check that the compressor operates normally when the air conditioner is turned ON. Cause • Turn starting switch ON. • Disconnect M95. • When compressor operates (= Just after air conditioner is turned ON): 20 – 30 V • When compressor stops (= After air conditioner is turned off): Max. 1 V

Remedy

1 Is voltage between M95 (Female) (37) – chassis ground normal?

NO

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (37) – K11 (Female) (8)

Repair or replace

Defective controller

Replace

YES

F-7 Electrical circuit diagram of each system

20-414 (12)

PC78US-6

F-8

TROUBLESHOOTING

F-8 Bit pattern 1026-(3) Emergency work equipment operation switch does not light up (Only PC78UU-6) a Before measuring, check that the work equipment moves normally when the emergency work equipment operation switch is turned ON (the lever is raised). a Before measuring, check that fuse (2) is normal. Cause • Turn starting switch OFF. • Disconnect terminals T21 and T22. • When emergency work equipment operation switch is turned ON (lever is raised): Max. 1 z • When emergency work equipment operation switch is turned OFF (lever is lowered): Min. 1 Mz

Remedy

1 Is resistance between T21 and T22 normal and are they insulated from chassis ground?

NO

Defective emergency work equipment operation switch

Replace

NO

Disconnection or defective contact in wiring harness between T21 – M97 (female) (30)

Repair or replace

NO

Disconnection, defective contact, or grounding fault in wiring harness between T22 – fuse (2)

Repair or replace

Defective controller

Replace

YES

2 • Turn starting switch OFF. • Disconnect M97 and T21. • Resistance: Max. 1 z

Is resistance between T21 and M97 (female) (30) normal?

YES

• • • •

Turn starting switch ON. Release PPC lock lever. Disconnect M97. When emergency work equipment operation switch is turned ON (lever is raised): 20 – 30 V

3 Is voltage between M97 (female) (30) and chassis ground normal? YES

F-8 Electrical circuit diagram of each system

PC78US-6

20-415 (12)

TROUBLESHOOTING FOR HYDRAULIC AND MECHANICAL SYSTEMS (H MODE) Table of hydraulic failure modes and causes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-428 H-1 Speed or power of 2 or more systems of work equipment (boom, arm, bucket), travel, swing, and blade is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-430 a) Speed or power of all work equipment (including blade), travel, and swing is low. . . . . . . 20-430 b) Speed or power of all work equipment (excluding blade) and travel is low . . . . . . . . . . . . . 20-431 c) Speed or power of swing and blade is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-431 d) Speed or power of travel and blade is low. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-432 e) Speed or power of all work equipment (excluding blade) is low . . . . . . . . . . . . . . . . . . . . . . 20-432 f) Speed or power of travel and swing is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-433 g) Speed or power of all work equipment and swing is low. . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-433 H-2 Engine speed lowers extremely or engine stalls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-434 H-3 2 or more systems of work equipment (boom, arm, bucket), travel, swing, and blade do not move. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-436 a) All work equipment (including blade), travel, and swing systems do not move . . . . . . . . . 20-436 b) All work equipment (excluding blade) and travel systems do not move . . . . . . . . . . . . . . . 20-437 c) Swing and blade systems do not move . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-437 d) Travel and blade systems do not move . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-438 e) All work equipment (excluding blade) does not move . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-438 H-4 Abnormal sound comes out (from around pump) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-439 H-5 Fine controllability or response is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-440 H-6 Hydraulic drift is large (all work equipment and blade). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-441 H-7 Boom speed or power is low (other work equipment is normal) . . . . . . . . . . . . . . . . . . . . . . . . . 20-442 a) Boom RAISE speed or power is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-442 b) Boom LOWER speed or power is low. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-443 H-8 Arm speed or power is low (other work equipment is normal) . . . . . . . . . . . . . . . . . . . . . . . . . . 20-444 a) Arm IN speed or power is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-444 b) Arm OUT speed or power is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-445 H-9 Bucket speed or power is low (other work equipment is normal) . . . . . . . . . . . . . . . . . . . . . . . . 20-446 a) Bucket CURL speed or power is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-446 b) Bucket DUMP speed or power is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-447 H-10 Offset speed or power is low (other work equipment is normal) (Only PC78UU-6) . . . . . . . . 20-447-1 a) Offset left speed or power is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-447-1 b) Offset right speed or power is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-447-2 H-11 Boom does not move . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-448 a) Boom does not rise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-448 b) Boom does not lower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-449 H-12 Arm does not move . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-450 a) Arm does not move in . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-450 b) Arm does not move out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-451 H-13 Bucket does not move . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-452 a) Bucket does not curl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-452 b) Bucket does not dump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-453 H-14 Offset boom does not move (Only PC78UU-6). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-453-1 a) Offset boom left does not move . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-453-1 b) Offset boom right does not move . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-453-2 H-15 Hydraulic drift of boom is large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-454 H-16 Hydraulic drift of arm is large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-454 H-17 Hydraulic drift of bucket is large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-455 H-18 Hydraulic drift of offset is large (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-455 a) Hydraulic drift of offset to left is large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-455 b) Hydraulic drift of offset to right is large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-455 H-19 Time lage is large (engine speed is low). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-456 H-20 Part loaded more moves slower in compound operation of work equipment . . . . . . . . . . . . . . 20-456 H-21 Boom RAISE speed is low in compound operation of swing and boom RAISE . . . . . . . . . . . . . 20-457 PC78US-6

20-425 ➄

H-22 H-23 H-24 H-25 H-26 H-27 H-28 H-29 H-30 H-30 H-31 H-32 H-33 H-34 H-35 H-36 H-37

H-38 H-39 H-40 H-41 H-42 H-43 H-44 H-45 H-46 H-47

Travel speed lowers extremely in compound operation of travel and boom RAISE . . . . . . . . . 20-457 Speed is low in compound operation of work equipment relief and swing, work equipment relief and work equipment. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-457 Work equipment does not move or its speed is low in compound operation of travel and work equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-458 Travel deviation is large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-459 a) Travel deviation is large during ordinary travel. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-459 b) Travel deviation is large when machine starts (but during normal ordinary travel) . . . . . . 20-460 Travel deviation is large in compound operation of travel and swing, travel and work equipment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-461 Travel speed or power is low (work equipment, swing, and blade operations are normal) . . . 20-462 Machine cannot be steered sharply or steering force is insufficient . . . . . . . . . . . . . . . . . . . . . . 20-464 Travel speed does not change at all or does not change quickly . . . . . . . . . . . . . . . . . . . . . . . . . 20-465 Machine does not travel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-466 Supplement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-467 Overrun of travel is large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-468 Travel hydraulic drift is large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-468 Fine controllability or response is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-469 Swing speed or power is low (work equipment, travel, and blade operations are normal) . . . 20-470 Machine does not swing (work equipment, travel, and blade operations are normal) . . . . . . . 20-473 a) Swing speed or power is low in both directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-473 b) Swing speed or power is low in either direction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-474 Swing acceleration is low. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-475 a) Swing acceleration is low in both directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-475 b) Swing acceleration is low in either direction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-475 Overrun of swing is large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-476 a) Overrun of swing is large in both directions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-476 b) Overrun of swing is large in either direction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-476 Large shock is made when machine stops swinging. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-477 Large abnormal sound is made when machine stops swinging . . . . . . . . . . . . . . . . . . . . . . . . . 20-477 Swing hydraulic drift is large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-478 Fine controllability more response of swing is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-479 Blade speed or power is low (work equipment, travel, and swing operations are normal) . . . . 20-480 Blade does not move (work equipment, travel, and swing operations are normal) . . . . . . . . . . 20-481 a) Blade does not rise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-481 b) Blade does not lower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-482 Hydraulic drift of blade is large . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-483 Fine controllability or response of blade is low . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-484 Monitor panel displays error code and boom RAISE, arm IN, and offset LEFT operations stop just before interference (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-485 Machine does not stop boom RAISE, arm IN, and offset LEFT operations automatically but interferes (Only PC78UU-6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-485

20-426 ➄

PC78US-6

TROUBLESHOOTING

TABLE OF HYDRAULIC FAILURE MODES AND THEIR CAUSES

TABLE OF HYDRAULIC FAILURE MODES AND THEIR CAUSES C78UU, PC78US-6

Logic valve

Merge valve

●

Main relief circuit check valve

LS bypass choke

Pressure compensation valve

●

Spool

●

LS line choke

●

Control pump ●

Gear pump ●

Orifice

●

Servo valve

●

EPC valve

●

LS valve

●

PC valve

●

Pilot pump

Strainer

Cap

Hydraulic oil

Control Valve

Main relief valve

PC78UU-6

Hydraulic Pump

Unload valve

PC78US-6

PTO spline

Failure mode

Machine model

Tank

Engine system

Part Which May Cause Trouble

For only standard specification (Without blade) Blade specification

●

For only standard specification

●

Failure mode Speed or power of 2 or more systems or work equipment, travel, and blade is low Engine speed lowers extremely or engine stalls All work equip- 2 or more systems of work equipment, travel, swing, and blade ment, travel, do not move swing, blade Abnormal sound comes out (From around pump) Fine controllability or response is low

●

●

●

● ●

● ●

●

●

●

●

●

●

●

●

● ●

●

●

●

●

●

●

●

●

●

●

Hydraulic drift is large (All work equipment and blade) Speed or power of work equipment is low

Work equipment

Work equipment does not move

Boom

●

●

Arm

●

●

Bucket

●

●

Offset (Only UU)

●

●

Boom

●

●

Arm

●

●

Bucket

●

●

Offset (Only UU)

●

●

Boom

●

Hydraulic drift of work Arm equipment is Bucket large Offset (Only UU)

● ● ● ●

Time lag is large (When engine speed is low) Part loaded more moves slower in compound operation of work equipment Boom RAISE speed is low in compound operation of swing and boom RAISE Compound operation

●

Travel speed lowers extremely in compound operation of travel and boom RAISE Speed is low in compound operation of work equipment relief and swing, work equipment relief and other work equipment

●

●

Work equipment does not move or its speed is low in compound operation of travel and work equipment ●

Travel deviation is large

●

●

●

Travel deviation is large in compound operation of travel and swing, travel and work equipment ●

Travel speed or power is low Travel

Machine cannot be steered sharply or steering force is insufficient

●

●

●

●

● ●

●

●

●

●

●

●

●

●

●

●

●

Travel speed does not change at all or does not change quickly Machine does not travel

●

Overrun of travel is large

●

●

●

●

Travel hydraulic drift is large

Swing

Fine controllability or response is low

●

●

Swing speed or power is low

●

●

Machine does not swing

●

●

Swing acceleration is low

●

●

Overrun or swing is large Large shock is made when machine stops swinging

●

Large abnormal sound is made when machine stops swinging Swing hydraulic drift is large

Blade

Prevention of interference

20-428 ➄

Fine controllability or response of swing is low

●

Blade speed or power is low

●

Blade does not move

●

Hydraulic drift of blade is large

●

Fine controllability or response of blade is low

●

●

●

Monitor panel displays error code [61] and all operations stop just before interference Machine does not stop boom RAISE, arm IN, and LEFT offset operations automatically but interferes

PC78US-6

●

● ●

PC78US-6 ●

●

● ● ● ●

●

●

●

●

●

●

●

●

●

●

●

●

●

●

● ●

Control Valve

● ● ● ●

●

● ●

●

●

●

●

● ●

● ● ●

●

● ● ●

●

●

●

● ●

●

● ●

●

● ●

●

● ● ● ● ● ●

H-36

● ●

●

● ● ● ●

H-37

● ●

●

●

●

●

●

● ● ● ● ●

● ● ●

●

● ●

● ●

● ● ●

● ● ●

●

● ● ●

● ● ●

●

● ●

● ● ● ● H-10

● H-11

● H-12

● H-13

● H-14

● ● ● H-15

● ● H-16

● ● H-17

● ● H-18

●

● H-26

● ● ● ● ● ● ● ●

● ● ● ● ● ● ● ●

●

●

● ●

● ● ●

● ● ● ● ● ●

●

●

●

●

● ●

● ● ● ● ●

Emergency pump drive switch

PPC pressure switch

Hydraulic cylinder

Final drive

Parking brake valve

Parking brake

2nd speed select valve and piston

Swing Motor

Check valve

Counterbalance valve

Piston motor

Center swivel joint

Swing machinery

Reaction prevention valve

Parking brake

Suction valve

Check valve

Solenoid Valve

Safety valve

Piston motor

Swing holding brake solenoid valve

PPC Valve

2nd travel speed selection solenoid valve

PPC main pressure lock solenoid

● ● ●

Control relief valve

PPC valve (Blade bar)

PPC valve (Travel lever)

PPC valve (Left lever) 1 ~ 0

PPC valve (Right lever) 1 ~ 0

2nd travel speed selection choke

Swing PPC line choke

Swing PPC slow return valve

Back pressure valve

Pressure release valve

Blade safety valve

Gear pump circuit relief valve

Boom assist valve

LS select valve

Boom lock valve

Suction valve

Centralized safety valve

Travel LS bleed valve

Travel junction variable throttle valve

PPC circuit check valve

Swing holding brake check valve (Logic)

TROUBLESHOOTING TABLE OF HYDRAULIC FAILURE MODES AND THEIR CAUSES

Travel Motor

● ●

●

● ●

●

●

●

● ●

●

●

● ●

Failure mode

H-1

H-2

H-3

H-4

H-5

● ● ● H-7

H-6

● ● ● H-8

H-9

H-19

H-20

H-21

H-22

H-23

H-24

H-25

H-27

H-28

H-29

H-30

● ●

H-31

H-32

● ●

H-33

H-34

H-35

H-38

H-39

H-40

●

●

H-41

H-42

●

●

H-43

●

●

H-44

●

●

● ● ●

H-45

H-46

● ● ●

H-47

20-429

➄

TROUBLESHOOTING

H-1

H-1

Speed or power of 2 or more systems of work equipment (boom, arm, bucket), travel, swing, and blade is low

★ Before carrying out troubleshooting, check that the oil level in the tank is proper. ★ If the engine speed lowers, carry out H-2 first. ★ If "individual factor" is indicated, a trouble which occurs less frequently than the detected trouble may have occurred or several troubles may be combined. Accordingly, carry out troubleshooting for each of those troubles. ★ Select a combination of systems which have low speed or power from Table 1 before going to the next troubleshooting. ★ If the combination of the detected troubles is not in Table 1, carry out troubleshooting for the actuators of each system "which has low speed or power" (H-7 ~ H-10). Table 1 PC78US-6 without blade Work Equipment

Travel

✕

✕

✕

✕

! : Normal

! : Normal

Table 2 PC78US-6, PC78UU-6 with blade

✕ : Speed or power is low

✕ : Speed or power is low

Diagnosis Item

Work Equipment

Travel

✕

Go to a

✕

✕

✕

✕

Go to a

!

Go to b

✕

✕

!

!

Go to b

Swing

Swing

Diagnosis Item

Blade

✕

!

✕

Go to g

!

!

✕

✕

Go to c

!

✕

✕

Go to f

!

✕

!

✕

Go to d

✕

!

!

Go to e

✕

!

!

!

Go to e

!

✕

✕

!

Go to f

a) Speed or power of work equipment (including blade), travel, and swing systems is low Cause

Remedy

1 NO Is suction strainer clogged? YES

Clogged suction strainer (Defective suction by pump)

Clean or replace

Go to H-1, b)

—

Defective adjustment of control valve

Adjust

Defective pump control

Replace

Defective PPC main pressure lock solenoid

Replace

2 2

• 3.14 ± 0.3 MPa {32 ± 3 kg/cm } • Run engine at full throttle

Is output pressure of PPC main pressure lock solenoid valve normal?

NO

YES

3 NO

When control relief valve is adjusted, is trouble repaired? YES

4 When PPC lock solenoid valve is replaced, is trouble repaired? YES

20-430 ➄

NO

PC78US-6

TROUBLESHOOTING

H-1

b) Speed or power of all work equipment (excluding blade) and travel is low Cause

Remedy

1 • Curl bucket 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is work equipment relief pressure normal? YES 2

• Curl bucket 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is travel relief pressure normal?

Go to corresponding section in H-7 ~ 10, 27

—

Defective main pump (Lowering of volumetric efficiency)

Repair or replace

Defective main pump (Lowering of volumetric efficiency)

Repair or replace

Defective boom assist valve

Repair or replace

Go to corresponding section in H-7 ~ 10, 27

—

Defective main relief valve

Repair or replace

Defective unload valve

Repair or replace

Go to diagnosis No. 3

Repair or replace

YES 3 NO Does machine have blade specification? YES 4 NO

When blade is relieved in RAISE mode, does the travel speed rise? YES

5 • Curl bucket 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is travel relief pressure normal? YES

6 When travel relief valve is adjusted or replaced, is trouble repaired?

NO

YES

7 NO Does unload valve move smoothly? YES

c) Speed or power of swing and blade is low Cause

Remedy

1 • Lower blade 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle

NO Is gear pump relief pressure normal? YES

Go to corresponding section in H-27, 34

—

Defective gear pump

Repair or replace

Defective gear pump relief pressure

Adjust or replace

2 When gear pump relief valve is adjusted or replaced, is trouble repaired? YES

PC78US-6

NO

20-431 b

TROUBLESHOOTING

H-1

d) Speed or power of travel and blade is low Cause

Remedy

1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is travel relief pressure normal? YES

Go to corresponding section H-27, 42

—

Go to corresponding section H-27, 42

—

Go to corresponding section H-27, 42

—

Defective swivel joint

Repair or replace

2 • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle

NO Is blade LOWER relief pressure normal? YES

3 NO

When hose is disconnected from valve outlet and plugged, is relief pressure normal? YES

e) Speed or power of all work equipment (excluding blade) is low Cause

Remedy

1 Is all PPC pressure normal (At PPC pressure inlet of control valve?

NO

YES 2 • 2.11 ± 0.1 MPa {21.5 ± 1 kg/cm2} • Run engine at full throttle and curl bucket

Is LS differential pressure normal? NO

Defective adjustment of pump LS valve

Adjust

Go to corresponding section in H-7 ~10

—

YES 3 When compound operation of travel, work equipment, and swing is performed, is trouble repaired?

NO

YES

Defective travel pressure compensation valve 4

Is PPC pressure normal at only 1 place (When single operation is performed)?

NO

YES

Defective check valve in PPC circuit having normal PPC pressure

Replace

5 Is check valve at swing holding brake pressure inlet of logic valve normal? YES

20-432 b

NO

Leakage of PPC pressure caused by defective ball check valve Go to corresponding section in H-7 ~ 10

—

PC78US-6

TROUBLESHOOTING

f)

H-1

Speed or power of travel and swing is low Carry out the troubleshooting in b) above.

★ If the PPC main pressure is judged low by troubleshooting in b) above, this trouble can occur.

g) Speed or power of all work equipment and swing is low ★ Carry out the following troubleshooting for only PC78US-6 which does not have a blade. Cause

Remedy

1 • 2.11 ± 0.1 MPa {21.5 ± 1 kg/cm2} • Run engine at full throttle and curl bucket

NO Is LS differential pressure normal?

Defective adjustment of pump LS valve

Adjust

Go to corresponding section in H-7 ~ 10, H-34

—

Defective travel pressure compensation valve

Replace

YES 2 When compound operation of travel and work equipment, and swing is performed, is trouble repaired? YES

PC78US-6

NO

20-433 b

TROUBLESHOOTING

H-2

H-2

Engine speed lowers extremely or engine stalls Cause

Remedy

1 When bucket is relieved in CURL mode and blade is relieved in RAISE mode, does engine speed lower much?

NO

YES 2

When blade is relieved in RAISE mode or swing is relieved and work equipment is operated without relieving simultaneously, does engine speed lower much?

NO

YES Execute diagnosis No. 4 3 • 26.5 ± 1.45 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is bucket CURL relief pressure normal? YES 4

• 12.74 ± 1.47 MPa {130 ± 15 kg/cm2} • Run engine at full throttle

NO Is blade RAISE relief pressure normal? YES

5 When gear pump circuit relief valve is adjusted, repaired, or replaced, is trouble repaired?

NO

YES

Defective gear pump circuit relief valve

Adjust or replace

Defective main relief valve

Repair or replace

Defective connection

Repair

Defective TVC-EPC valve (Defective solenoid)

Replace

Defective controller

Repair or replace

6 When main relief valve is replaced, is trouble repaired?

NO

YES

7 NO

Does monitor display error code "E02" of TVC trouble? YES 8

NO Is TVC connector connected? YES

9 When engine speed changes, does TVC current change?

NO

YES

To next page

20-434 b

PC78US-6

TROUBLESHOOTING

H-2

Cause

Remedy

From previous page

10 • 0.54 ~ 0.83 MPa {5.5 ~ 8.5 kg/cm • Run engine at full throttle

2}

Is output voltage of TVC-EPC solenoid normal?

NO

YES 11 NO

When PC valve is adjusted, is trouble repaired? YES

Defective PC valve

Adjust or replace

12 When orifice of servo is cleaned, is trouble repaired?

NO

YES Clogged orifice 13 NO

When EPC valve of TVC is replaced, is trouble repaired?

Execute diagnosis No. 11

—

Defective EPC valve

Repair or replace

Defective engine system

—

Defective pump or servo

Repair or replace

YES

14 When pump assembly is replaced, is trouble repaired?

NO

YES

PC78US-6

20-435

➀

TROUBLESHOOTING

H-3

H-3

2 or more systems of work equipment (boom, arm, bucket), travel, swing, and blade do not move

★ Before carrying out troubleshooting, check that the oil level in the tank is proper. ★ Select a combination of systems which do not move from Table 1 before going to the next troubleshooting. ★ If the combination of the detected troubles is not in Table 1, carry out troubleshooting for the actuators of each system "which does not move" (H-10 ~ 13).

Table 1 PC78US-6 without blade Work Equipment

Travel

! : Normal

Swing

! : Normal

Table 2 PC78US-6, PC78UU-6 with blade

✕ : Speed or power is low Diagnosis Item

Work Equipment

Travel

✕ : Speed or power is low Swing

Diagnosis Item

Blade

✕

✕

✕

Go to a

✕

✕

✕

✕

Go to a

✕

✕

!

Go to b

✕

✕

!

!

Go to b

!

!

✕

✕

Go to c

!

✕

!

✕

Go to d

✕

!

!

!

Go to e

!

✕

✕

!

Go to f

✕

!

✕

!

✕

✕

Go to diagnosis of each system

✕

!

!

Go to e

a) All work equipment (including blade), travel, and swing systems do not move Cause

Remedy

1 When engine is cranked, does oil flow out of pump?

NO

YES 2 When oil does not flow out of any of following pumps • Main pump • Gear pump • Control pump YES 3 NO Is suction strainer clogged? YES Clogged suction strainer

Clean or adjust

Defective main pump shaft

Replace

Defective damper or spline

Replace

Defective gear pump

Replace

Defective coupling or spline

Replace

4 NO Is damper or spline damaged? YES

5 When oil flows out of main pump but does not flow out of gear pump and control pump.

NO

YES 6 Is coupling or spline between main pump and gear pump damaged?

NO

YES

To item No. 5 on next page

20-436 ➄

PC78US-6

TROUBLESHOOTING

H-3

Cause

Remedy

From item 3 on previous page

5 NO

When engine is cranked, does oil flow out of control pump?

Defective control pump

Repair or replace

Defective PPC main pressure lock solenoid valve or defective electric system

Repair or replace

Go to corresponding section in H-10 ~ 12, 27, 32, 40

—

YES 6 2}

• 3.14 ± 0.3 MPa {32 ± 3 kg/cm • Run engine at full throttle

Is output pressure of PPC main pressure lock solenoid valve normal?

NO

YES

b) All work equipment (excluding blade) and travel systems do not move Cause

Remedy

1 NO

When engine is cranked, does oil flow out of control?

Defective control

Repair or replace

Defective PPC main pressure lock solenoid valve or defective electric system

Repair or replace

Go to corresponding section in H-10 ~ 12, 27

Repair or replace

Defective check valve in PPC circuit having normal pressure

Repair or replace

YES 2 kg/cm2}

• 3.14 ± 0.3 MPa {32 ± 3 • Run engine at full throttle

Is output pressure of PPC main pressure lock solenoid valve normal?

NO

YES 3 Is only 1 part of each of work equipment and travel normal?

NO

YES

c) Swing and blade systems do not move ★ PC78US-6 with blade PC78UU-6 Cause

Remedy

1 NO

When engine is cranked, does oil flow out of pump?

Defective control pump

Repair or replace

Go to corresponding section in H-32, 40

—

Defective gear pump circuit relief valve

Adjust or replace

YES 2 When gear pump circuit relief valve is adjusted or replaced, is trouble repaired? YES

PC78US-6

NO

20-437 ➄

TROUBLESHOOTING

H-3

d) Travel and blade systems do not move Cause

Remedy

1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is travel relief pressure normal? YES

Go to corresponding section H-27

—

Go to corresponding section H-40

—

Go to corresponding section H-27, 40

—

Defective swivel joint

Repair or replace

2 • 21.08 ± 1.47 MPa {215 ± 15 • Run engine at full throttle

kg/cm2}

NO Is blade relief pressure normal? YES

3 NO

When hose is disconnected from valve outlet and plugged, is relief pressure normal? YES

e) All work equipment (excluding blade) does not move Cause

Remedy

1 • 3.14 ± 0.5 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

NO

Are all PPC pressures normal (At connected PPC pressure inlets)? YES

Go to corresponding section in H-10 ~ 12

—

Go to corresponding section in H-10 ~ 12

—

Defective check valve in PPC circuit having normal pressure

Replace

2 NO Is only 1 place normal? YES

Note: If machine is equipped with an attachment, check that attachment.

20-438 ➃

PC78US-6

TROUBLESHOOTING

H-4

H-4

Abnormal sound comes out (from around pump) Cause

Remedy

1 NO Is oil level in hydraulic tank normal?

Low hydraulic oil level

Supply hydraulic oil

Low hydraulic oil level

—

YES 2 NO Are there bubbles in hydraulic tank? YES 3 When engine is stopped, do bubbles in tank disappear?

NO

YES Go to diagnosis No. 4 4 NO Foreign matter: Cloth, etc.

Is suction strainer clogged with foreign matter? YES

Foreign matter (Cloth, etc.) clogging suction strainer

Remove

Defective inside pump

Repair or replace

Operate machine and observe condition for a while

Re-inspect (according to change of condition)

Negative pressure caused by clogging of cap

Clean or replace cap

5 NO

Is suction strainer clotted with metallic foreign matter or metal chips? YES

6 NO Is hydraulic tank cap clogged? YES

PC78US-6

20-439 b

TROUBLESHOOTING

H-5

H-5

Fine controllability or response is low (Two or more systems have low fine controllability or response simultaneously)

★ The following troubleshooting is not applicable to travel, swing, and blade systems. Cause

Remedy

1 • See TESTING AND ADJUSTING

NO Is LS differential pressure normal? YES 2 NO Is LS line choke clogged? YES Clogging of LS line choke

Clean or replace

Clogging of orifice of unload valve

Clean

Defective PC valve or servo piston

Repair or replace

Clogging of orifice or piston pump

Clean

Defective LS valve

Repair or replace

Defective adjustment of LS valve

Adjust

3 NO Is orifice of unload valve clogged? YES

4 NO Is orifice of piston pump clogged? YES

5 NO When LS valve is adjusted, is trouble repaired? YES

20-440 b

PC78US-6

TROUBLESHOOTING

H-6

H-6

Hydraulic drift is large (all work equipment and blade)

★ Before carrying out troubleshooting, check that oil level in the tank is proper. Cause

Remedy

1 NO Is pressure release plug of control valve tightened?

Leakage through pressure release circuit

Retighten

Leakage through pressure release circuit

—

YES 2 NO Is seal of pressure release plug broken? YES

3 When centralized safety valve is replaced, is trouble repaired? YES

PC78US-6

NO

Go to corresponding section in H-15 ~ H-18 Defective concentrated safety valve

Clean

20-441

➀

TROUBLESHOOTING

H-7

H-7

Boom speed or power is low (other work equipment is normal)

a) Boom RAISE speed or power is low ★ When measuring the boom RAISE relief pressure, reset the interference prevention (Only PC78UU-6). ★ When the boom speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. ★ Check that the emergency pump drive switch is turned OFF. Cause

Remedy

1 • Run engine at full throttle and set boom in neutral: 410 mA • Run engine at full throttle and raise boom: 100 mA

When boom is raised in monitoring mode 1050, does current lower?

NO Diagnose by F-3

YES 2 • 0.54 ~ 0.83 MPa {5.5 ± 8.5 kg/cm • Run engine at full throttle

2}

NO

Is output pressure of pump TVC-EPC solenoid normal?

Defective pump TVCEPC solenoid

Replace

Defective operation of control valve spool or EPC valve spool

Repair or replace

YES 3 • 26.5 ± 1.47 MPa {270 ± 15 • Run engine at full throttle

kg/cm2}

NO Is boom relief pressure normal? YES Only UU

kg/cm2

• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle

4

Is EPC valve output pressure normal? (PPC pressure inlet of control valve)

}

YES 5 NO Does control valve spool move smoothly? YES 6 Does pressure compensation valve move smoothly?

NO

Defective operation of pressure compensation valve

NO

Defective centralized safety valve

Replace

Defective suction valve (Boom LOWER side)

Repair or replace

Defective seat of check valve of boom assist valve

Repair or replace

Go to diagnosis No. 3

—

Defective boom RAISE PPC valve

Repair or replace

Defective boom cylinder packing

Repair or replace

YES

7 2

• 26.5 ± 1.47 MPa {270 ± 15 kg/cm } • Run engine at full throttle

Is boom LOWER relief pressure normal? YES

8 When pilot hose of boom assist valve is disconnected, does speed rise?

NO

YES

9 (Move boom RAISE with arm IN oil.)

When PPC hose is replaced with arm IN hose on control valve side, is trouble repaired?

NO

YES 10 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle • Measure at PPC pressure inlet of control valve

NO Is PPC valve output pressure normal? YES

20-442 ➄

PC78US-6

TROUBLESHOOTING

H-7

b) Boom LOWER speed or power is low ★ When the boom speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. Cause

Remedy

1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is boom LOWER relief pressure normal? YES 2

kg/cm2}

• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle

Is PPC valve output pressure normal? (At control valve PPC pressure inlet)

NO

YES 3 NO Does control valve spool move smoothly?

Malfunction of control valve spool or EPC valve spool

Repair or replace

Malfunction of lock valve

Repair, clean, or replace

Malfunction of spool

Check 3 again

Defective concentrated safety valve

Replace

Defective suction valve (Boom LOWER side)

Repair or replace

Go to diagnosis No. 3

—

Defective boom LOWER PPC valve

Repair or replace

YES 4 Does poppet of pilot piston of boom lock valve move smoothly and its orifice free from clogging?

NO

YES

5 • 26.5 ± 1.47 MPa {270 ± 15 • Run engine at full throttle

kg/cm2}

NO Is boom RAISE relief pressure normal? YES

6 (Move boom LOWER with arm OUT oil.)

When PPC hose of control valve is replaced with arm DUMP, is trouble repaired? (Return it immediately after testing.) YES

PC78US-6

NO

20-443

➃

TROUBLESHOOTING

H-8

H-8

Arm speed or power is low (Other work equipment is normal)

a) Arm IN speed or power is low ★ When measuring the arm IN relief pressure, reset the interference prevention (Only PC78UU-6). ★ When the arm speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. ★ Check that the emergency pump drive switch is turned OFF. Cause

Remedy

1 • Run engine at full throttle and set arm in neutral: 410 mA • Run engine at full throttle and raise boom: 100 mA

NO

When arm is moved IN in monitoring mode 1050, does current lower?

Diagnose by F-3

YES 2 • 0.54 ~ 0.83 MPa {5.5 ~ 8.5 kg/cm2} • Run engine at full throttle.

NO

Is output pressure of pump TVC-EPC solenoid normal?

Defective pump TVC-EPC solenoid

Replace

NO

Defective operation of control valve spool or EPC valve spool

Repair or replace

NO

Defective operation of pressure compensation valve

NO

Defective centralized safety valve

Replace

Defective suction valve (Boom LOWER side)

Repair or replace

Go to diagnosis No. 3

—

Defective seats of swing brake circuit check valve and swing PPC slowreturn valve

Repair or replace

YES 3 • 26.5 ± 1.49 MPa {270 ± 15 kg/cm2} • Run engine at full throttle.

NO Is arm IN relief pressure normal?

Only UU • 3.14± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle.

YES 4

Is EPC valve output pressure normal? (PPC pressure inlet of control valve) YES 5

Does control valve spool move smoothly?

YES 6 Does pressure compensation valve move smoothly? YES

7 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle.

Is arm OUT relief pressure normal?

YES

8

• (Move arm IN with boom RAISE)

When PPC hose is replaced with boom RAISE hose on control valve side, is trouble repaired? (Return it immediately after testing.)

NO

YES

9 When swing operation and arm IN operation are executed simultaneously, is trouble repaired?

NO

YES

To next page

20-444 ➄

To next page

PC78US-6

TROUBLESHOOTING

H-8

From previous No.8

From previous No.4 Cause

Remedy

10 • 3.14 ± 0.49 MPa (32 ± 5 kg/cm2) • Run engine at full throttle • Measure at PPC pressure inlet of control vaolve

NO Is output pressure of PPC valve normal?

Defective arm IN PPC valve

YES Defective arm IN PPC valve

PC78US-6

Repair or replace

20-444-1 ➄

TROUBLESHOOTING

H-8

b) Arm OUT speed or power is low ★ When the arm speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. ★ Check that the emergency pump drive switch is turned OFF. Cause

Remedy

1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is arm OUT relief pressure normal?

YES 2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

Is PPC valve output pressure normal? (At control valve PPC pressure inlet)

NO

YES

3 NO Does control valve spool move smoothly?

Malfunction of control valve spool

Repair or replace

Malfunction of pressure compensation valve

Repair or replace

Defective arm cylinder packing

Repair or replace

Defective concentrated safety valve

Replace

Defective suction valve (Arm IN side)

Repair or replace

Go to diagnosis No. 3

—

Defective arm OUT PPC valve

Repair or replace

YES 4 NO

Does pressure compensation valve move smoothly? YES

5 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO

Is arm OUT relief pressure normal?

YES

6 • (Move arm OUT with boom LOWER oil)

When PPC hose of control valve is replaced with boom LOWER, is trouble repaired? (Return it immediately after testing.)

NO

YES

PC78US-6

20-445 ➃

TROUBLESHOOTING

H-9

H-9

Bucket speed or power is low (Other work equipment is normal)

a) Bucket CURL speed or power is low ★ When the bucket speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. ★ Check that the emergency pump drive switch is turned OFF. Cause

Remedy

1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is bucket CURL relief pressure normal?

YES 2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

Is PPC valve output pressure normal? (At control valve PPC pressure inlet)

NO

YES 3 NO Does control valve spool move smoothly?

Malfunction of control valve spool

Repair or replace

Malfunction of pressure compensation valve

Repair or replace

Defective arm cylinder packing

Repair or replace

Defective concentrated safety valve

Replace

Defective suction valve (Bucket CURL side)

Repair or replace

Go to diagnosis No. 3

—

Defective bucket CURL PPC valve

Repair or replace

YES 4 NO

Does pressure compensation valve move smoothly? YES

5 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO

Is bucket DUMP relief pressure normal?

YES

6

• (Move bucket CURL with arm IN)

When PPC hose of control valve is replaced with arm IN, is trouble repaired? (Return it immediately after testing.)

NO

YES

20-446 b

PC78US-6

TROUBLESHOOTING

H-9

b) Bucket DUMP speed or power is low ★ When the bucket speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. ★ Check that the emergency pump drive switch is turned OFF. Cause

Remedy

1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is bucket DUMP relief pressure normal?

YES 2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

Is PPC valve output pressure normal? (At control valve PPC pressure inlet)

NO

YES 3 NO Does control valve spool move smoothly?

Malfunction of control valve spool

Repair or replace

Malfunction of pressure compensation valve

Repair or replace

Defective bucket cylinder packing

Repair or replace

Defective concentrated safety valve

Replace

Defective suction valve (Bucket DUMP side)

Repair or replace

Go to diagnosis No. 3

—

Defective bucket DUMP PPC valve

Repair or replace

YES 4 NO

Does pressure compensation valve move smoothly? YES

5 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO

Is bucket CURL relief pressure normal?

YES

6 • (Move bucket DUMP with arm OUT oil)

When PPC hose of control valve is replaced with arm OUT, is trouble repaired? (Return it immediately after testing.)

NO

YES

PC78US-6

20-447

➀

TROUBLESHOOTING

H-10

H-10

Offset speed or power is low (other work equipment is normal) (Only PC78UU-6)

a) Offset left speed or power is low ★ Relieve the offset left actuator in a position at which the interference prevention system does not detect the work equipment. ★ When the offset speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. ★ Check that the emergency pump drive switch is turned OFF. Cause

Remedy

1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is offset left relief pressure normal? YES 2

kg/cm2}

NO

Is solenoid valve output pressure normal? (PPC pressure inlet of control valve)

• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle

YES 3 NO Does control valve spool move smoothly?

Defective operation of control valve spool

Repair or replace

Defective operation of pressure compensation valve

Repair or replace

Defective offset cylinder packing

Repair or replace

Defective pressure compensation valve

Repair or replace

Defective packing seal near extraction end of offset cylinder

Repair or replace

Go to troubleshooting No. 3

—

Defective offset left PPC valve

Repair or replace

Defective offset left solenoid valve

Repair or replace

YES 4 NO

Does pressure compensation valve move smoothly? YES

5 • 26.5 ± 1.47 MPa {270 ± 15 • Run engine at full throttle

kg/cm2

}

NO Is offset right relief pressure normal? YES

6

(Move offset left by curling bucket)

When PPC hose and bucket CURL hose are exchanged at control valve, does condition become normal? (Return hoses immediately after testing.)

NO

YES 7 NO Is PPC valve output pressure normal?

20-447-1 ➄

PC78US-6

TROUBLESHOOTING

H-10

b) Offset right speed or power is low ★ When the offset speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. ★ Check that the emergency pump drive switch is turned OFF. Cause

Remedy

1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is offset right relief pressure normal? YES 2

kg/cm2}

NO

Is PPC valve output pressure normal? (PPC pressure inlet of control valve)

• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle

YES 3 NO Does control valve spool move smoothly?

Defective operation of control valve spool

Repair or replace

Defective operation of pressure compensation valve

Repair or replace

Defective offset cylinder packing

Repair or replace

Defective pressure compensation valve

Repair or replace

Defective suction valve (Right offset side)

Repair or replace

Go to troubleshooting No. 3

—

Defective offset right PPC valve

Repair or replace

YES 4 NO

Does pressure compensation valve move smoothly? YES

5 • 26.5 ± 1.47 MPa {270 ± 15 • Run engine at full throttle

kg/cm2

}

NO Is offset right relief pressure normal? YES

6 (Move offset right by dumping bucket)

When PPC hose and bucket DUMP hose are exchanged at control valve, does condition become normal? (Return hoses immediately after testing.) YES

PC78US-6

NO

20-447-2 ➄

TROUBLESHOOTING

H-11

H-11

Boom does not move

★ Carry out the following troubleshooting, if the boom does not move when operated singly (when the other work equipment is normal). a) Boom does not rise Cause

Remedy

1 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle.

NO

Is PPC valve output pressure normal? (At control valve PPC pressure inlet) YES 2

NO

Malfunction of control valve spool

Repair or replace

Deformation of cylinder or work equipment (Boom does not rise above the deformed part

Repair or replace

Does spool move smoothly?

Malfunction of spool in raising mode

Repair or replace

YES

Malfunction of pressure compensation valve

Repair or replace

Go to diagnosis No. 2

—

Defective boom RAISE PPC valve

Repair or replace

Defective boom EPC valve

Repair or replace

Does boom lower? YES 3 kg/cm2}

• 26.5 ± 1.47 MPa {270 ± 15 • Run engine at full throttle.

NO

When boom is raised, is pump relief pressure normal? YES

4 NO

5 (Move boom lower with arm IN oil)

When PPC hose of control valve is replaced with arm IN, is trouble repaired? (Return it immediately after testing.)

NO

YES 5 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

20-448 ➄

Is PPC valve output pressure normal?

PC78US-6

TROUBLESHOOTING

H-11

b) Boom does not lower H Cause

Remedy

1 • 2.94 ± 0.49 MPa {30 ± 5 kg/cm2} • Run engine at full throttle.

NO

Is PPC valve output pressure normal? (At control valve PPC pressure inlet) YES 2

NO

Malfunction of control valve spool or seizure of lock valve poppet

Repair or replace

Does spool move smoothly?

Malfunction of spool in lowering mode

Repair or replace

YES

Malfunction of pressure compensation valve

Repair or replace

Go to diagnosis No. 2

—

Defective boom LOWER PPC valve

Repair or replace

Defective lock valve

Repair or replace

Defective lock valve caused by clogging

Repair or replace

Does boom rise? YES 3 kg/cm2}

• 26.5 ± 1.47 MPa {270 ± 15 • Run engine at full throttle.

When boom is lowered, is pump relief pressure normal?

NO

YES

4 NO

5 (Move boom lower with arm OUT oil)

When PPC hose of control valve is replaced with arm OUT, is trouble repaired? (Return it immediately after testing.)

NO

YES

6 NO Is seal drain line of control valve clogged? YES

PC78US-6

20-449 ➄

TROUBLESHOOTING

H-12

H-12

Arm does not move

★ Carry out the following troubleshooting, if the arm does not move when operated singly (when the other work equipment is normal). a) Arm does not move in Cause US is PPC UU is EPC • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

Remedy

1 NO

Is PPC valve output pressure normal? (At control valve PPC pressure inlet.) YES 2

NO

Malfunction of control valve spool

Repair or replace

Deformation of cylinder or work equipment (Arm does not move more than deformed part)

Repair or replace

Does spool move smoothly?

Malfunction of spool in IN mode

Repair or replace

YES

Malfunction of pressure compensation valve

Repair or replace

Defective arm IN PPC valve

Repair or replace

Go to diagnosis No. 2

—

Defective seats of swing brake circuit check valve and swing PPC slow-return valve

Repair or replace

Defective arm-in PPC valve

Repair or replace

Defective arm-in EPC valve

Repair or replace

Does arm move out? YES 3 • 26.5 ± 1.47 MPa {270 ± 15 • Run engine at full throttle

kg/cm2}

NO

When arm is moved in, is pump relief pressure normal? YES

4 NO

5 (Move arm out with boom RAISE oil)

When PPC hose of control valve is replaced with boom RAISE, is trouble repaired? (Return it immediately after testing.)

NO

YES 6 When swing operation and arm IN operation are executed simultaneously, is trouble repaired?

NO

YES

7 kg/cm2}

• 3.14 ± 0.9 MPa {32 ± 5 • Run engine at full throttle

20-450 ➄

NO Is PPC valve output pressure normal?

PC78US-6

TROUBLESHOOTING

H-12

b) Arm does not move out Cause

Remedy

1 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

NO

Is PPC valve output pressure normal? (At control valve PPC pressure inlet) YES 2

NO

Malfunction of control valve spool

Repair or replace

Deformation of cylinder or work equipment (Arm does not move more than deformed part)

Repair or replace

Does spool move smoothly?

Malfunction of spool in OUT mode

Repair or replace

YES

Malfunction of pressure compensation valve

Repair or replace

Defective arm OUT PPC valve

Repair or replace

Go to diagnosis No. 2

—

Does arm move in? YES 3 • 26.5 ± 1.47 MPa {270 ± 15 • Run engine at full throttle

kg/cm2}

NO

When arm is moved out, is pump relief pressure normal? YES

4 NO

5 (Move arm out with boom LOWER oil.)

When PPC hose of control valve is replaced with boom LOWER, is trouble repaired? (Return it immediately after testing.)

NO

YES

PC78US-6

20-451

➃

TROUBLESHOOTING

H-13

H-13

Bucket does not move

★ Carry out the following troubleshooting, if the bucket does not move when operated singly (when the other work equipment is normal). a) Bucket does not curl Cause

Remedy

1 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

NO

Is PPC valve output pressure normal? (At control valve PPC pressure inlet.) YES 2

NO

Malfunction of control valve spool

Repair or replace

Deformation of cylinder or work equipment (Bucket does not move more than deformed part)

Repair or replace

Does spool move smoothly?

Malfunction of spool in CURL mode

Repair or replace

YES

Malfunction of pressure compensation valve

Repair or replace

Go to diagnosis No. 2

—

Defective bucket CURL PPC valve

Repair or replace

Is bucket dumped? YES 3 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO

When bucket is curled, is pump relief pressure normal? YES

4 NO

5 (Move bucket curl with arm IN oil)

When PPC hose of control valve is replaced with arm IN, is trouble repaired? (Return it immediately after testing.) YES

20-452 ➄

NO

PC78US-6

TROUBLESHOOTING

H-13

b) Bucket does not dump Cause

Remedy

1 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

NO

Is PPC valve output pressure normal? (At control valve PPC pressure inlet) YES 2

NO

Malfunction of control valve spool

Repair or replace

Deformation of cylinder or work equipment (Bucket does not move more than deformed part)

Repair or replace

Does spool move smoothly?

Malfunction of spool in DUMP mode

Repair or replace

YES

Malfunction of pressure compensation valve

Repair or replace

Go to diagnosis No. 2

—

Defective bucket DUMP PPC valve

Repair or replace

Is bucket curled? YES 3 • 26.5 ± 1.47 MPa {270 ± 15 • Run engine at full throttle

kg/cm2}

NO

When bucket is dumped, is pump relief pressure normal? YES

4 NO

5 (Move bucket dump with arm OUT)

When PPC hose of control valve is replaced with arm OUT, is trouble repaired? (Return it immediately after testing.) YES

PC78US-6

NO

20-453 ➄

TROUBLESHOOTING

H-14

H-14

Offset boom does not move (Only PC78UU-6)

★ Carry out the following troubleshooting when the offset boom does not move when it is operated singly (and the other work equipment is normal). a) Offset boom left does not move Cause

Remedy

1 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle.

NO

Is solenoid valve output pressure normal? (PPC pressure inlet of control valve) YES 2

NO Does offset boom right move?

Defective operation of control valve spool

Repair or replace

Deformed cylinder or work equipment (Work equipment does not move over deformed part)

Repair or replace

Defective operation of spool

Repair or replace

Defective operation of pressure compensation valve

Repair or replace

Go to troubleshooting No. 2

—

Defective offset left PPC valve

Repair or replace

Defective offset left EPC valve

Repair or replace

YES 3 kg/cm2}

• 26.5 ± 1.47 MPa {270 ± 15 • Run engine at full throttle.

NO

When offset left is operated, is pump relief pressure normal? YES

4 NO Does spool move smoothly? YES

5

(Move offset left by curling bucket)

When PPC hose and bucket CURL hose are exchanged at control valve, does condition become normal? (Return hoses immediately after testing.)

NO

YES 6 NO Is PPC valve output pressure normal? YES

20-453-1 ➄

PC78US-6

TROUBLESHOOTING

H-14

b) Offset boom right does not move Cause

Remedy

1 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle.

NO

Is PPC valve output pressure normal? (PPC pressure inlet of control valve) YES 2

NO

Defective operation of control valve spool

Repair or replace

Deformed cylinder or work equipment (Work equipment does not move over deformed part)

Repair or replace

Does spool move smoothly?

Defective operation of spool

Repair or replace

YES

Defective operation of pressure compensation valve

Repair or replace

Go to troubleshooting No. 2

—

Defective offset right PPC valve

Repair or replace

Does offset boom left move? YES 3 kg/cm2}

• 26.5 ± 1.47 MPa {270 ± 15 • Run engine at full throttle.

When offset right is operated, is pump relief pressure normal?

NO

YES

4 NO

5

(Move offset right by dumping bucket)

When PPC hose and bucket DUMP hose are exchanged at control valve, does condition become normal? (Return hoses immediately after testing.) YES

PC78US-6

NO

20-453-2 ➄

TROUBLESHOOTING

H-15

H-16

H-15, H-16

Hydraulic drift of boom is large

Cause

Remedy

1 NO

Is leakage from hydraulic cylinder normal?

Defective cylinder piston packing

Repair or replace

Defective boom lock valve

Repair or replace

Defective boom lock valve

Replace

YES 2

When centralized safety valve is replaced, is trouble repaired?

NO

YES

H-16

Hydraulic drift of arm is large

Cause

Remedy

1 NO

Is leakage from hydraulic cylinder normal?

Defective cylinder piston packing

Repair or replace

Defective centralized safety valve

Replace

Defective oil-tightness of control valve spool

Repair or replace

Defective centralized safety valve

Repair or replace

YES 2

When centralized safety valve is replaced, is trouble repaired?

NO

YES

3

When suction valve is replaced with blind plug, is trouble repaired?

NO

YES

20-454 ➄

PC78US-6

TROUBLESHOOTING

H-17

, H-18

H-17, H18

Hydraulic drift of bucket is large Cause

Remedy

1 NO

Is leakage from hydraulic cylinder normal?

Defective cylinder piston packing

Repair or replace

Defective centralized safety valve

Replace

Defective oil-tightness of control valve spool

Repair or replace

Defective suction valve

Repair or replace

YES 2

When centralized safety valve is replaced, is trouble repaired?

NO

YES

3

When suction valve is replaced with blind plug, is trouble repaired?

NO

YES

H-18

Hydraulic drift of offset is large (Only PC78UU-6)

a) Hydraulic drift of offset to left is large Cause

Remedy

1 NO

Is leakage from hydraulic cylinder normal?

Defective cylinder piston packing

Repair or replace

Defective oil-tightness of control valve spool

Repair or replace

Defective suction valve

Repair or replace

YES 2

When suction valve is replaced with blind plug, does condition become normal?

NO

YES

b) Hydraulic drift of offset to right is large Cause

Remedy

1

Is leakage from hydraulic cylinder normal?

YES

PC78US-6

NO Defective cylinder piston packing

Repair or replace

Defective oil-tightness of control valve spool

Repair or replace

20-455 ➄

TROUBLESHOOTING

H-19

H-19, H-20

Time lag is large (When engine speed is low)

-20

★ Carry out the following troubleshooting, if the work equipment speed is normal.

Cause

Remedy

1 NO

Is suction valve normal (Free from seizure)?

Defective suction valve

Replace

Defective back pressure valve

Replace

Defective pump servo piston

Replace pump assembly

Defective LS valve

Replace

YES 2

When poppet and spring of back pressure valve are replaced, is trouble repaired?

NO

YES

3

When LS valve is replaced, is trouble repaired?

NO

YES

H-20

Part loaded more moves slower in compound operation of work equipment Cause

Defective counterbalance valve on lighter load side

Compound Operation 1

Boom RAISE + Arm IN

Heavier Load Side Boom RAISE

Arm IN

Boom RAISE + Arm OUT

Arm OUT

Boom RAISE

3

Boom RAISE + Bucket CURL

Boom RAISE

Bucket CURL

4

Arm IN + Bucket DUMP

Arm OUT

Bucket CURL

5

Boom LOWER + Arm OUT

Arm OUT

Boom LOWER

➄

Replace

Lighter Load Side

2

20-456

Remedy

PC78US-6

TROUBLESHOOTING

H-21

, H-22,

H-23

H-21, H-22, H-23

Boom RAISE speed is low in compound operation of swing and boom RAISE

★ Carry out the following troubleshooting, if the swing operation and boom RAISE operation are normal when executed singly (Swing LS pressure is not generated) (Excluding PC78US-6 without blade). When this operation is executed, the gear pump assists the boom RAISE circuit. Cause

Defective boom assist valve or LS select valve

H-22

Remedy

Clean or replace

Travel speed lowers extremely in compound operation of travel and boom RAISE

★ Carry out the following troubleshooting, if the work equipment (Boom RAISE) operation and travel operation are normal when executed singly. ★ Carry out the following troubleshooting, only when the boom RAISE circuit (LS) pressure is higher than the travel circuit (LS) pressure. Cause

Malfunction of LS bleed valve (Clogged choke, etc.)

H-23

Remedy

Repair or replace

Speed is low in compound operation of work equipment relief and swing, work equipment relief and other work equipment Cause

Defective choke of LS bypass

PC78US-6

Remedy

Replace

20-457 ➄

TROUBLESHOOTING

H-24

H-24

Work equipment does not move or its speed is low in compound operation of travel and work equipment

★ Carry out the following troubleshooting, if the travel operation and work equipment operation are normal when executed singly. Cause

Remedy

1

Only PC78US-6 without blade

When emergency swing brake release switch is turned ON, is trouble repaired?

NO

YES

2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Measure at control valve PPC pressure inlet

When travel and work equipment operations are executed simultaneously, is PPC output pressure normal? YES 3 NO

Is filter of logic valve fitting face clogged?

YES

Malfunction of pump merge-divider valve caused by clogging of logic valve filter

Replace filter

Malfunction of pump merge-divider valve caused by leakage through logic valve

Repair or replace

Malfunction of pump merge-divider valve caused by malfunction of logic valve spool

Repair or replace

Go to each diagnosis item

—

Lowering of LS pressure caused by defective travel pressure compensation valve

Repair or replace

4

Only PC78US-6 without blade

NO

Is swing holding brake input check valve of logic valve clogged or scratched? YES

5 NO

Does logic valve spool move smoothly?

YES 6 When travel circuit is relieved and work equipment is operated simultaneously, does speed rise? YES

20-458 ➄

NO

PC78US-6

TROUBLESHOOTING

H-25

H-25

Travel deviation is large

a) Travel deviation is large during ordinary travel 1 • Check shoe tension difference between both sides • Check rollers for revolution trouble • Check for deformation and damage

Cause

Remedy

NO Is undercarriage troubled?

YES Defective undercarriage

Repair or replace

Wrong adjustment or breakage of pump

Adjust, repair or replace

Defective travel junction variable choke valve

Clean or replace

Defective pump merge valve

Repair or replace

Malfunction of logic valve

Check, clean, repair or replace

Defective check valve of main relief circuit

Repair or replace

Malfunction of unload valve (Clogging of hole, etc.)

Repair or replace

2 • Above 3.14 ± 0.49 MPa {Above 32 ± 5 kg/cm2} • Run engine at full throttle • Move lever to stroke end

NO

Are PPC output pressures on both sides normal?

YES 3 When both hoses are exchanged at pump outlet, does deviating direction change?

NO

YES

4 When both hoses between control valve and swivel joint are exchanged, does deviating direction change?

NO

YES 5

When only travel operation is executed

NO

Is pressure at top PP pressure pickup port of control valve same as pump pressure? YES 6

NO

Does spool of travel junction variable choke valve move smoothly and is hole free from clogging? YES 7

NO

Does spool of pump merge valve move smoothly and is hole free from clogging? YES

8 When both check valves of main relief circuit are exchanged, does deviating direction change?

NO

YES

9

Does unload valve move smoothly and is hole free from clogging?

NO

YES To 12 on next page

PC78US-6

To 10 on next page

To 13 on next page

20-459 ➄

TROUBLESHOOTING From 4 on previous page

H-25 From 9 on previous page

From 2 on previous page

Cause

Remedy

10

Does pressure compensation valve move smoothly?

NO Defective pressure compensation valve

Repair or replace

Malfunction of spool

Repair or replace

Go to diagnosis No. 11

—

Defective travel motor (Motor, counterbalance valve, final drive)

Check, repair or replace

Defective swivel joint

Repair or replace

Defective PPC circuit check valve of control valve

Repair or replace

Defective PPC valve

Repair or replace

Abnormal PPC pressure output caused by interference

Adjust

YES 11 NO Does travel spool move smoothly?

YES

12 When both hoses between swivel joint and travel motor are exchanged, does deviating direction change?

NO

YES

13 When both PPC hose are exchanged, does deviating direction change?

NO

YES 14 NO Does lever interfere with floor?

YES

b) Travel deviation is large when machine starts (but normal during ordinary travel) 1

Cause

Remedy

NO

When machine starts, is dragging sound of brake heard from travel motor on deviating side? YES

Delay of release of parking brake (Malfunction of brake, brake valve

Repair or replace

2

Does counterbalance valve of travel motor move smoothly?

NO Go to diagnosis No. 5 in (a) above

YES Malfunction of counterbalance valve

20-460 ➄

Repair or replace

PC78US-6

TROUBLESHOOTING

H-26

H-26

Travel deviation is large in compound operation of travel and swing, travel and work equipment

★ Carry out the following troubleshooting, if the travel operation is normal when executed singly. Cause Note)

Note:) Only PC78US-6 without blade

Remedy

1 NO

Does machine deviate only when travel and swing operations are executed simultaneously? YES 2

• 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

NO

Is output pressure of swing holding brake solenoid normal?

Defective swing holding brake solenoid

Replace

Seizure of filter and check valve at output pressure inlet port of swing holding brake solenoid of rotary valve

Replace

Malfunction of pump merge-divider valve

Repair or replace

Clogging or malfunction of chock of logic valve

Replace

Malfunction of logic valve caused by clogging

Clean or replace

YES

3 Does pump merge-divider spool move smoothly and is hole free from clogging?

NO

YES 4

Is filter of logic valve fitting face clogged?

YES

PC78US-6

NO

20-461 ➄

TROUBLESHOOTING

H-27

H-27

Travel speed or power is low (Work equipment, swing, and blade operations are normal)

★ If another part of the work equipment has a trouble, see H-1. ★ Check that the emergency pump drive switch is turned OFF. • Run engine at full throttle and set travel lever in neutral: 410 mA • Drive machine with engine at full throttle: 100 mA

• Run engine at full throttle and set travel lever in neutral: 0.45 ~ 0.83 MPa {5.5 ~ 8.5 kg/cm2} • Drive machine with engine at full throttle: 0 ~ 0.2 MPa {0 ~ 2 kg/cm2}

1 When machine is driven in monitoring mode 1050, does current lower?

Cause

Remedy

NO

YES 2 NO

Is output pressure of TVC-EPC solenoid normal?

Defective TVC-EPC solenoid

Replace

Omission of connection

Connect

Disconnection or defective controller

Replace

Malfunction pump merge-divider valve

Repair or replace

Malfunction logic valve

Repair or replace

Large resistance to travel motor and undercarriage

Repair or replace

Large leakage through travel motor or swivel joint

Repair or replace

Malfunction of spool

Repair or replace

YES

3 NO Is travel pressure switch connected?

YES

4 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is travel relief pressure normal?

YES 5 NO

Is pressure at top PP pressure pickup port of control valve same as port pressure? YES 6 Does pump merge-divider spool move smoothly and is hole free from clogging?

NO

YES

7 • When driven on flat concrete with engine at full throttle, if pressure is below 11.7 MPa {120 kg/cm2}

NO

Is pump pressure normal during travel?

YES

8 Above 3.14 ± 0.49 MPa {32 ± 5 kg/cm2}

Is PPC pressure normal? (At PPC pressure inlet of control valve)

NO

YES 9 NO Does spool move smoothly?

YES To 12 on next page

20-462 ➄

To 10 on next page

PC78US-6

TROUBLESHOOTING

From 8 on previous page

H-27

From 9 on previous page

Cause

Remedy

10

Does pressure compensation valve move smoothly?

NO Defective pressure compensation valve

Repair or replace

Defective unload valve

Repair or replace

YES 11 NO

Does unload valve move smoothly?

YES

Large leakage through travel motor or swivel joint

12

When PPC circuit check valve is replaced, is trouble repaired?

NO Defective PPC valve

Repair or replace

Defective PPC circuit check valve

Replace

YES

PC78US-6

20-463 ➄

TROUBLESHOOTING

H-28

H-28

Machine cannot be steered sharply or steering force is insufficient 1

Cause

Remedy

NO

Does engine speed lower (extremely only when machine is steered during travel)? YES

Defective pump servo

Repair or replace

Defective travel junction variable choke valve

Repair or replace

Malfunction pump merge-divider valve

Repair or replace

Malfunction of logic valve

Repair or replace

Defective PPC

Repair or replace

Malfunction of spool

Repair or replace

Defective unload valve

Repair or replace

Defective counterbalance valve of travel motor or swivel joint

Repair or replace

Defective main relief circuit check valve

Repair or replace

2 NO

Is pressure at top PP pressure pickup port of control valve same as port pressure? YES 3

NO

Does spool of travel junction variable choke valve move smoothly and is hole free from clogging? YES 4 Does pump merge-divider spool move smoothly and is hole free from clogging?

NO

YES

5 Is drive pump pressure of inside motor normal? (Inside pump pressure must be below above 10 MPa {100 kg/ cm2} while machine is turning on flat concrete with turning radius of about 5 m.)

NO

YES

6 NO Is inside PPC pressure low?

YES 7 NO

Does spool move smoothly?

YES

8

When main relief circuit check valve is replaced, is trouble repaired?

NO

YES

20-464 ➄

PC78US-6

TROUBLESHOOTING

H-29

H-29

Travel speed does not change at all or does not change quickly Cause

Remedy

1 • 31.4 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

Is output of 2nd travel speed selection solenoid valve normal?

NO

Electric trouble in defective 2nd travel speed selection solenoid valve, 2nd travel speed selection switch, etc.

Repair or replace

Malfunction caused by clogging

Repair or replace

Defective swivel joint

Repair or replace

Defective travel motor or 2nd travel speed selection solenoid valve piston

Repair or replace

YES 2 NO

Is outlet choke of 2nd travel speed selection solenoid valve free from clogging? YES 3 Is output pressure of 2nd travel speed selection solenoid valve at travel motor inlet normal? YES

PC78US-6

NO

20-465 ➄

TROUBLESHOOTING

H-30

H-30

Machine does not travel 1

• 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

Cause

Remedy

NO

Does pump pressure rise to relief pressure?

YES 2 NO

Is foreign matter drained from final drive?

YES Defective final drive

Repair or replace

Defective counterbalance valve

Repair or replace

Defective undercarriage

Repair or replace

Defective travel motor (Motor, parking brake system)

Repair or replace

3 NO

Does counterbalance valve of travel motor operate smoothly?

YES 4 • When driven on flat concrete with engine at full throttle, if pressure is below 11.7 MPa {120 kg/cm2}

NO

Is undercarriage deformed or damaged?

YES

See

1

5 NO

• Above 3.14 ± 0.49 MPa {Above 32 ± 5 kg/cm 2} • Run engine at full throttle • Move lever to stroke end

Is PPC pressure normal? (At PPC pressure inlet of control valve)

YES

1

[

If machine does not travel on flat concrete with engine at full throttle and pump pressure above about 10 MPa {100 kg/cm2}, perform diagnosis 2.

6

]

NO Does travel spool move smoothly?

Malfunction of spool

YES 7 NO

Does pressure compensation valve move smoothly?

Defective pressure compensation valve

YES 8 NO Does unload valve move smoothly?

Defective unload valve

Repair or replace

Defective travel motor or swivel joint

Repair or replace

YES

9 • Drive machine with boom PPC pressure (Return piping immediately after testing)

When PPC hose is replaced with boom hose on control valve side, does PPC pressure rise?

NO Defective PPC circuit check valve

YES Defective PPC valve

20-466 ➄

PC78US-6

TROUBLESHOOTING

H-30

H-30

Supplement Relationship between PPC circuit check valve and "Machine does not travel"

As shown below, PPC circuit check valves (1) ~ (4) are installed to pick up the changeover signal pressure for the pump merge-divider valve. If the checking function of these check valves is lost, the machine may not travel. Example: When checking function of (1) is lost • Normal operations: "Left forward travel", "Left forward travel + Right forward travel", "Left forward travel + Right reverse travel" • Operations where machine may not travel: "Left reverse travel", "Right forward travel", "Right reverse travel", "Left reverse travel + Right forward travel", "Left reverse travel + Right reverse travel"

PC78US-6

20-467 ➄

TROUBLESHOOTING

H-31

, H-32

H-31, H-32

Overrun of travel is large Cause

Remedy

1 NO

Does PPC pressure lower immediately after lever is returned? (At PPC pressure inlet of control valve)

Defective PPC

Repair or replace

Malfunction of spool

Repair or replace

Defective suction valve

Repair or replace

Defective back pressure valve

Repair or replace

Defective counterbalance valve

Repair or replace

Defective check valve

Repair or replace

Defective travel motor

Repair or replace

YES 2 NO Does spool move smoothly?

YES 3

When suction valve is replaced, is trouble repaired?

NO

YES

4 NO

When back pressure valve is replaced, is trouble repaired?

YES

5 NO

Does travel motor counterbalance valve move smoothly?

YES 6

Does travel motor check valve move smoothly?

NO

YES

H-32

Travel hydraulic drift is large Cause

Defective parking brake or parking brake valve of travel motor

20-468 ➄

Remedy

Repair or replace

PC78US-6

TROUBLESHOOTING

H-33

H-33

Fine controllability or response is low Cause

Remedy

1 NO

When air is bled from PPC, is trouble repaired?

YES Air in PPC

Bleed PPC

Malfunction of pump merge-divider valve

Repair or replace

Defective logic valve

Repair or replace

Malfunction of unload valve

Repair or replace

Malfunction of pressure compensation valve

Repair or replace

Malfunction of spool

Repair or replace

Defective travel motor

Repair or replace

Defective PPC

Repair or replace

2

Is pressure at top PP pressure pickup port of control valve same as port pressure?

NO

YES 3 Does spool of pump merge-divider valve move smoothly and is hole free from clogging?

NO

YES

4

Does unload valve move smoothly and is hole free from clogging?

NO

YES 5

Does pressure compensation valve move smoothly?

NO

YES 6 NO Does spool move smoothly?

YES 7

When PPC valve is replaced, is trouble repaired?

NO

YES

PC78US-6

20-469 ➄

TROUBLESHOOTING

H-34

H-34

Swing speed or power is low (Work equipment, travel, and blade operations are normal)

★ If there is any other trouble in the work equipment, travel system, or blade system, see H-1.

Note) 1 PC78US without blade

• LS differential pressure: 2.1 ± 0.1 MPa {21.5 ± 1 kg/cm2}

Cause Note) 1

Remedy

1 NO

When only swing operation is executed, is LS pressure generated?

Defective LS select valve

Repair or replace

Malfunction of pressure compensation valve

Repair or replace

Malfunction of unload valve

Repair or replace

Defective boom assist valve

Repair or replace

YES 2

Does pressure compensation valve move smoothly and is hole free from clogging?

NO

YES 3

Does unload valve move smoothly and is hole free from clogging?

NO

YES

To 5 on next page

Note) 2 Note) 2 PC78US with blade PC78UU

4 NO

When work equipment is relieved, does speed rise?

YES

To 5 on next page

20-470 ➄

PC78US-6

TROUBLESHOOTING

H-34

H-34 From previous page

Cause

Note) 1 Without blade • 23 ± 1.47 MPa {235 ± 15 kg/cm2} With blade • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle

Remedy

5 NO

Is swing relief pressure normal?

YES 6

Does pressure rise to near relief pressure during stable swing?

NO

YES 7 NO Is swing dragging sound heard?

Defective motor unit, brake, or swing machinery circle

Repair or replace

Defective swing brake release solenoid

Replace

Malfunction of swing holding brake

Repair or replace

Malfunction of controller

Replace

Clogging of choke Malfunction of slow return valve

Clean repair or replace

Malfunction of spool

Repair or replace

Defective swing motor

Repair or replace

Defective PPC valve

Repair or replace

Clogging of choke

Clean repair or replace

YES 8 NO Is swing brake release pressure output?

YES 9 NO

When controller is replaced, is trouble repaired?

YES

10 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle.

Is PPC pressure at PPC control valve normal?

NO

YES 11 NO

When fixed choke of swing PPC slowreturn valve is cleaned, is trouble repaired? YES

12 NO Does spool move smoothly?

YES

13

When choke of swing PPC line is cleaned, is trouble repaired?

NO

YES

To 14 on next page

PC78US-6

20-471 ➄

TROUBLESHOOTING

H-34

From 5 on previous page

Cause

Remedy

14

When safety valve of swing motor is adjusted or replaced, is trouble repaired?

NO

YES Defective safety valve

Adjust or replace

Defective check valve or suction valve

Repair or replace

Malfunction of reverse prevention valve

Repair or replace

15 NO

When check valve and suction valve of swing motor are replaced, is trouble repaired? YES

16

When reverse prevention valve is replaced, is trouble repaired?

NO

YES

20-472 ➄

PC78US-6

TROUBLESHOOTING

H-35

H-35

Machine does not swing (Work equipment, travel, and blade operations are normal)

★ If there is any other trouble in the work equipment, travel system, or blade system, see H-1. ★ Carry out the following troubleshooting, if the electric system is normal. (If the electric system is defective, carry out E first.) a) Swing speed or power is low in both directions Cause

Remedy

1 NO

When swing operation and operation other than boom RAISE operation are executed, does machine move? YES

Defective LS select valve

Replace

Defective pressure compensation valve

Replace

2

Does pressure compensation valve move smoothly and is hole free from clogging?

NO

YES 3 Without blade • 23 ± 1.47 MPa {235 ±15 kg/cm2} With Blade • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle.

NO Is swing relief pressure normal?

YES 4 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

NO

Is swing holding brake relief pressure normal? (At motor inlet)

YES

Malfunction of swing holding brake solenoid valve

Malfunction of motor unit, brake, or swing machinery

5 NO Is swing motor turning? (Judge by sound)

YES

Damage of motor shaft or swing machinery

Repair or replace

Defective safety valve

Repair or replace

Go to diagnosis No. 6

—

Defective check valve or suction valve

Clean repair or replace

6

When safety valve of swing motor is adjusted or replaced, is trouble repaired?

NO

YES

7 When check valve and suction valve of swing motor are adjusted or replaced, is trouble repaired?

NO

YES

PC78US-6

20-473 ➄

TROUBLESHOOTING

H-35

b) Swing speed or power is low in either direction Cause

Remedy

1 Without blade • 23 ± 1.47 MPa {235 ± 15 kg/cm2} With Blade • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle

NO Is swing relief pressure normal?

YES 2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

NO

Are swing brake release pressures on both sides normal? (At solenoid outlet)

YES Note that swing timer is set to 5 seconds

Defective swing motor or swing machinery circle

Replace

Malfunction of spool

Repair or replace

Disconnection of wiring harness

Repair or replace

Malfunction of spool

Repair or replace

Defective check valve or suction valve

Repair or replace

3

• Since motor may be broken, operate in fine control mode

NO

When lever is moved to right and left, does work equipment move for 5 seconds? YES

4 When check valve and suction valve of swing motor are replaced, is trouble repaired?

NO

YES

20-474 ➄

PC78US-6

TROUBLESHOOTING

H-36

H-36

Swing acceleration is low

a) Swing acceleration is low in both directions Cause

Remedy

1

When swing motor safety valve is replaced, is trouble repaired?

NO Execute diagnosis in H-34, H-41

YES Defective swing motor safety valve

Replace

b) Swing acceleration is low in either direction Cause

Remedy

Execute diagnosis in H-34, H-41

PC78US-6

20-475 ➄

TROUBLESHOOTING

H-37

H-37

Overrun of swing is large

a) Overrun of swing is large in both directions

Cause

Remedy

1 Without blade • 23 ± 1.47 MPa {235 ± 15 kg/cm2} With blade • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle

NO Is swing relief pressure normal?

Defective swing motor safety valve

Replace

Go to b)

Repair or replace

YES

b) Overrun of swing is large in either direction Cause

Remedy

1 NO

Does control valve spool move smoothly?

Malfunction of control valve spool

Repair or replace

Defective swing motor suction valve

Repair or replace

Defective reverse prevention valve

Repair or replace

Defective swing motor check valve

Repair or replace

Defective PPC valve

Repair or replace

Clogging of swing PPC slow-return valve, swing PPC line choke, or swing PPC circuit choke

Repair or replace

YES 2 NO

When swing motor suction valve is replaced, is trouble repaired?

YES

3 NO

When reverse prevention valve is replaced, is trouble repaired?

YES

4 NO

When swing motor check valve is replaced, is trouble repaired?

YES

5 When swing PPC slow-return valve, swing PPC line, and swing PPC circuit choke are cleaned, is trouble repaired? YES

20-476 ➄

NO

PC78US-6

TROUBLESHOOTING

H-38

, H-39

H-38, H-39

Large shock is made when machine stops swinging Cause

Remedy

1 NO Does control valve spool move smoothly?

Malfunction of control valve spool

Repair or replace

Go to H-34

Replace

Defective swing motor safety valve

Repair or replace

YES 2 NO When swing motor safety valve is replaced, is trouble repaired?

YES

H-39

Large abnormal sound is made when machine stops swinging

Cause

Remedy

1 NO

When safety valve is replaced, is trouble repaired?

Defective swing motor safety valve

Replace

Defective swing motor suction valve

Repair or replace

Defective reverse prevention valve

Repair or replace

Defective swing machinery

Repair or replace

Defective swing motor, swing machinery, or swing circle

Repair or replace

Defective back pressure compensation valve

Replace

YES 2

When suction valve is replaced, is trouble repaired?

NO

YES

3 NO

When reverse prevention valve is replaced, is trouble repaired?

YES

4 NO Is foreign matter drained from final drive?

YES

5

Only PC78US-6 without blade

When back pressure compensation valve is replaced, is trouble repaired?

YES

PC78US-6

NO

20-477 ➄

TROUBLESHOOTING

H-40

H-40

Swing hydraulic drift is large

★ Check that the emergency swing brake release switch is turned OFF. Cause

Remedy

1 NO

When connector of swing pressure switch is disconnected, is trouble repaired? YES

Defective swing pressure switch

Replace

Defective controller or wiring

Replace

Defective swing motor brake

Repair or replace

Malfunction of solenoid

Replace valve assembly

2 NO

When connector of swing brake release solenoid is disconnected, is trouble repaired? YES

3

When hose of swing brake release line is disconnected, is trouble repaired?

NO

YES

20-478 ➄

PC78US-6

TROUBLESHOOTING

H-41

H-41

Fine controllability or response of swing is low

Cause

Remedy

1 NO

When air is bled from PPC, is trouble repaired?

YES Air in PPC

Bleed Air

Malfunction of pump merge-divider valve

Repair or replace

Malfunction of logic valve

Repair or replace

Malfunction of unload valve

Repair or replace

Malfunction of pressure compensation valve

Repair or replace

Malfunction of spool

Repair or replace

Defective travel motor

Repair or replace

Defective PPC valve

Repair or replace

2

Is pressure at top PP pressure pickup port of control valve same as port pressure?

NO

YES 3 Does spool of pump merge-divider valve move smoothly and is hole free from clogging?

NO

YES

4

Does unload valve move smoothly and is hole free from clogging?

NO

YES 5

Does pressure compensation valve move smoothly and is hole free from clogging?

NO

YES 6 NO Does spool move smoothly?

YES 7

When PPC valve is replaced, is trouble repaired?

NO

YES

PC78US-6

20-479 ➄

TROUBLESHOOTING

H-42

H-42

Blade speed or power is low (Work equipment, travel, and swing operations are normal)

★ If there is any other trouble in the work equipment, travel system, or swing system, see H-1.

Cause

Remedy

1 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

NO Is blade PPC pressure normal?

Defective PPC valve

Repair or replace

Go to diagnosis 5

—

Malfunction of check valve in spool or clogging of hole of spool

Repair or replace

Flattened or deformed hose

Replace

Execute diagnosis in H-41 (Hydraulic drift of blade is large)

—

Leakage in control valve (Leakage from line between swing valve and blade valve)

Repair or replace

YES 2 • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle

NO Is blade LOWER relief pressure normal?

YES 3

Does pump pressure reach relief pressure during operation?

NO

YES 4 NO

Is hose between control valve and cylinder flattened or deformed?

YES

5 NO Is hydraulic drift normal?

YES

20-480 ➄

PC78US-6

TROUBLESHOOTING

H-43

H-43

Blade does not move (Work equipment, travel, and swing operations are normal)

★ If there is any other trouble in the work equipment, travel system, or swing system, see H-1. a) Blade does not rise Cause

Remedy

1 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle

NO Is blade PPC pressure normal?

Defective PPC valve

Repair or replace

Deformed cylinder or work equipment

Repair or replace

Malfunction of control valve spool

Repair or replace

Flattened or deformed hose

Replace

Leakage in control valve (Large leakage from line between swing valve and blade valve)

Repair or replace

YES 2 • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle

NO Is blade LOWER relief pressure normal?

YES 3 NO Is cylinder or work equipment deformed?

YES

4 NO Is hose flattened or deformed?

YES

5

Check hydraulic drift by H-41.

YES If trouble is not repaired by H-41

PC78US-6

20-481 ➄

TROUBLESHOOTING

H-43

b) Blade does not lower Cause

Remedy

1 NO Is blade held in air?

YES 2 NO Is blade PPC normal?

Defective blade PPC valve

Repair or replace

Deformed cylinder or work equipment

Repair or replace

Malfunction of spool

Repair or replace

Flattened or deformed hose

Replace

Execute diagnosis in H-41 (Hydraulic drift of blade is large)

Repair or replace

YES 3 NO Is cylinder or work equipment deformed?

YES

4 NO Is hose flattened or deformed?

YES

5

Is it impossible to raise machine by bracing blade on ground?

YES

20-482 ➄

PC78US-6

TROUBLESHOOTING

H-44

H-44

Hydraulic drift of blade is large

Cause

Remedy

1 NO Is leakage from cylinder normal?

Defective cylinder piston packing

Repair or replace

Large leakage through swivel joint

Repair or replace

Defective centralized safety valve

Replace

Low oil-tightness of spool

Repair or replace

Defective suction safety valve

Repair or replace

Low oil-tightness of spool

Repair or replace

Defective blade safety valve

Replace

YES 2 NO

When hose is disconnected from valve outlet and plugged, is hydraulic drift large? YES

3

• If blade is held in air and hydraulic drift is large

When centralized safety valve is replaced, is trouble repaired?

NO

YES

4

When suction valve is replaced with plug, is trouble repaired?

NO

YES

5 • If hydraulic drift is large when machine body is raised with blade

When blade safety valve is replaced, is trouble repaired?

NO

YES

PC78US-6

20-483 ➄

TROUBLESHOOTING

H-45

H-45

Fine controllability or response of blade is low Cause

Remedy

1 NO

When air is bled from PPC, is trouble repaired?

YES Air in PPC

Bleed Air

Malfunction of pump merge-divider valve

Repair or replace

Malfunction of logic valve

Repair or replace

Malfunction of unload valve

Repair or replace

Malfunction of pressure compensation valve

Repair or replace

Malfunction of spool

Repair or replace

Defective travel motor

Repair or replace

Defective PPC

Repair or replace

2

Is pressure at top PP pressure pickup port of control valve same as port pressure?

NO

YES 3 Does spool of pump merge-divider valve move smoothly and is hole free from clogging?

NO

YES

4

Does unload valve move smoothly and is hole free from clogging?

NO

YES 5

Does pressure compensation valve move smoothly and is hole free from clogging?

NO

YES 6 NO Does spool move smoothly?

YES 7

When PPC valve is replaced, is trouble repaired?

NO

YES

20-484 ➄

PC78US-6

TROUBLESHOOTING

H-46

, H-47

H-46, H-47

Monitor panel displays error code and boom RAISE, arm IN, and offset LEFT operations stop just before interference (Only PC78UU-6)

★ Check that any water is not in the potentiometer connectors (M29, M71, M72) of the boom, arm, and offset. Cause

Malfunction of solenoid valve

H-47

Remedy

Repair or replace

Machine does not stop boom RAISE, arm IN, and offset LEFT operations automatically but interferes (Only PC78UU-6)

★ If this trouble occurs, the trouble in H-46 occurs, too. Cause

Remedy

1

Does PPC lock solenoid valve move smoothly?

NO

Malfunction of PPC lock solenoid valve (It does not return)

Repair or replace

Defective controller

Replace

YES

PC78US-6

20-485 ➄

TTROUBLESHOOTING FOR MACHINE MONITOR SYSTEM (M MODE) Action taken by controller when trouble occurs and problems on machine . . . . . . . . . . . . . . . . . . . . . . . . 20-502 Electric circuit diagram of M mode system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-504 M- 1 [E101] (Error history data are abnormal) is displayed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-510 M- 2 [E108] (Engine coolant temperature is 105 °C) is displayed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-512 M- 3 [E112] (Wiper forward output is shorted) is displayed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-512 M- 4 [E113] (Wiper reverse output is shorted) is displayed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-512 M- 5 [E114] (Contact with washer output of 24 V) is displayed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-512 M- 6 [E115] (Wiper does not start wiping in 10 seconds) is displayed . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-512 M- 7 [E116] (Wiper is not retracted in 10 seconds) is displayed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-512 M- 8 When starting switch is turned to ON position, monitor panel segments do not light up for 3 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-513 a) Monitor panel segments do not light up at all . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-513 b) Some monitor panel segments do not light up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-513 M- 9 When starting switch is set to ON position, all monitor panel segments light up but do not go off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-515 M-10 While preheating is not executed, "Preheater monitor" lights up . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-515 M-11 When starting switch is set to ON position and engine is started, basic check items flash . . . . . . . 20-516 a) Alternator system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-516 b) Engine oil system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-518 M-12 When starting switch is set to ON position (but engine is stopped), caution items and emergency stop items (excluding battery and engine oil) flash . . . . . . . . . . . . . 20-520 a) Alternator system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-520 b) Engine oil pressure sensor system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-522 M-13 When starting switch is set to ON position and engine is started, caution items and emergency stop items flash (When there is not abnormality in inspection items and engine before troubleshooting however) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-524 a) "Engine oil" flashes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-524 b) "Charge level" flashes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-524 c) "Coolant temperature" flashes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-525 d) "Fuel level" flashes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-527 M-14 When starting switch is set to ON position (but engine is stopped), buzzer does not sound for 1 second While caution item is flashing, buzzer does not sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-529 M-15 Monitor plane lamp for nighttime is not turned on (LC display is normal) . . . . . . . . . . . . . . . . . . . . 20-531 M-16 Coolant temperature gauge does not rise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-533 M-17 Coolant temperature gauge is not displayed (Gauge does not rise to 1st line during operation) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-535 M-18 Fuel level gauge always displays full . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-537 M-19 Fuel level gauge is not displayed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-539 M-20 While engine is running, service meter does not advance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-541 M-21 Trouble in fuel level sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-542 M-22 Trouble in coolant temperature sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-544 M-23 Wiper does not operate or operates while wiper switch is turned off . . . . . . . . . . . . . . . . . . . . . . . . 20-545 a) Wiper does not operate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-545 b) Wiper operates while wiper switch is turned off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-545 M-24 Washer motor does not operate or operates while washer switch is turned off . . . . . . . . . . . . . . . . 20-550 a) Washer motor does not operate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-550 b) Washer operates while wiper switch is turned off . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20-550 M-25 Depth set 0 mode and height mode cannot be selected and set (Only PC78UU-6) . . . . . . . . . . . . 20-553 a When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the service code "E" is not displayed, the condition has returned to normal. a If the starting switch was turned off after the trouble occurred, turn the starting switch ON and check that the service code displays "E" at the head. (If "E" is not displayed, the condition has returned to normal.) a Before carrying out the troubleshooting, check that all the related connectors are properly inserted. a Always connect any disconnected connectors before going on to the next step. PC78US-6

20-501 (12)

TROUBLESHOOTING

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE User Code

Service Code

Troubled System

Contents of Trouble

—

E101

Error history data are abnormal

1. 2. 3. 4.

—

E108

Engine coolant temperature is 105 °C

1. Coolant temperature sensed by coolant temperature sensor is above 105 °C

—

E112

—

E113

—

E114

—

E115

—

E116

20-502 (1)

Trouble in internal memory Overvoltage (Above 36 V) Undervoltage (Above 12 V) Disconnection of connector

1. Short circuit or short circuit with chassis ground in wiring between 2. Short circuit or short circuit with chassis ground Short circuit in forward system of wiper motor drive in wiring between monitor panel P01 (Female) (9) – wiper motor W04 (Female) (3) 3. Defective monitor panel 1. Short circuit or short circuit with chassis ground in wiper motor 2. Short circuit or short circuit with chassis ground Short circuit in reverse system of wiper motor drive in wiring between monitor panel P01 (Female) (10) – wiper motor W04 (Female) (1) 3. Defective monitor panel 1. Short circuit in washer motor 2. Short circuit with power source in wiring harness Short circuit in windshield washer drive system between monitor panel P01(Female) (3) – M31 (Female) (1) 3. Defective monitor panel 1. Defective wiper motor 2. Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring harness between monitor panel P01 (Female) (5) – W04 (6) Wiper does not start wiping in 10 seconds 3. Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring harness between monitor panel P01 (Female) (12) – W04(4) 4. Defective monitor panel 1. Defective wiper motor 2. Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring harness between monitor panel P01 (Female) (5) – W04 (6) Wiper is not retracted in 10 seconds 3. Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring harness between monitor panel P01 (Female) (12) – W04 (4) 4. Defective monitor panel

PC78US-6

TROUBLESHOOTING

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

Normal Condition (Voltage, Current, Resistance)

•

Action Taken By Controller When Abnormality is Detected

Resistance between M18 (Male) (1) ~ (2): Min. 3.70 kΩ (With engine started)

Voltage between W04 (3) ~ (5): Max. 3 V ↕ 20 ~ 30 V a Repeated at regular intervals.

Problem That Appears on Machine When There is Abnormality

—

1. Service code cannot be cleared

—

1. If abnormality is detected continuously, coolant temperature caution lamp flashes and buzzer sounds. 2. If abnormality is detected continuously, engine speed is set to low idling.

•

Voltage between W04 (1) ~ (5): Max. 3 V ↕ 20 ~ 30 V a Repeated at regular intervals.

Stops outputting to wiper motor Wiper stops

•

Same as [E112]

Same as [E112]

•

Voltage between P01 (3) ~ chassis ground When washer switch is turned OFF: 20 ~ 30 V When washer switch is turned ON: Max. 1 V

1. Stops outputting to washer motor

1. Stops outputting to washer motor

•

Timing chart of setting wiper switch to ON and INT is conformed to Tables 1 and 2 in M-23

Same as [E112]

Same as [E112]

•

Timing chart of setting wiper switch to ON and INT is conformed to Tables 1 and 2 in M-23

Same as [E112]

Same as [E112]

PC78US-6

20-503

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM PC78US-6 (1/2) Serial No.: 4001 – 6500

20-504 (12)

PC78US-6

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

PC78US-6 (2/2)

PC78US-6

20-505 (12)

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

PC78US-6 (1/2) Serial No.: 6501 and up

20-506 (12)

PC78US-6

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

PC78US-6 (2/2)

PC78US-6

20-507 (12)

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

PC78UU-6 (1/2)

20-508 (12)

PC78US-6

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

PC78UU-6 (2/2)

PC78US-6

20-509 (12)

M-1

TROUBLESHOOTING

M-1 [E101] (Error history data are abnormal) is displayed PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a If connector P01, connector K1, fuse 18, connector M6, connector M2, connector M27, battery relay terminal B, or battery terminal in the monitor panel power supply system is disconnected or connected for troubleshooting, this error is displayed. This phenomenon does not indicate an actual error, however. (When the monitor panel power circuit is broken by turning off the starting switch.) a If the service code is displayed again after the resetting operation, check by the following procedure. Cause

Remedy

1 • After resetting operation, operate machine normally and observe its condition for a while. (See Note 1.)

After "resetting operation", is service code displayed NO again?

Normal

—

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between battery – battery relay B – M27 (1), (2) – P01 (Female) (8)

Repair or replace

Defective monitor panel

Replace

YES 2 • Turn starting switch OFF • 20 – 30 V

Is voltage between P01 (8) – chassis ground normal?

NO

YES

Note: Resetting operation: Turn the starting switch to OFF position, then turn it to the ON position again, with the buzzer cancel switch pushed, and keep pressing the buzzer cancel switch for 5 seconds. (All the service codes saved in the memory are deleted by this operation.)

M-1 Electrical circuit diagram of each system

20-510 (12)

PC78US-6

M-1

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a If connector P01, connector K1, fuse 18, connector M6, connector M2, connector M27, battery relay terminal B, or battery terminal in the monitor panel power supply system is disconnected or connected for troubleshooting, this error is displayed. This phenomenon does not indicate an actual error, however. (When the monitor panel power circuit is broken by turning off the starting switch.) a If the service code is displayed again after the resetting operation, check by the following procedure. Cause

Remedy

1 • After resetting operation, operate machine normally and observe its condition for a while. (See Note 1.)

After "resetting operation", is service code displayed NO again?

Normal

—

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between battery – battery relay B – M27 (1), (2) – P01 (Female) (8)

Repair or replace

Defective monitor panel

Replace

YES 2 • Turn starting switch OFF • 20 – 30 V

Is voltage between P01 (8) – chassis ground normal?

NO

YES

Note: Resetting operation: Turn the starting switch to OFF position, then turn it to the ON position again, with the buzzer cancel switch pushed, and keep pressing the buzzer cancel switch for 5 seconds. (All the service codes saved in the memory are deleted by this operation.)

M-1 Electrical circuit diagram of each system

PC78US-6

20-511 (12)

M-2, M-3, M-4, M-5, M-6, M-7

TROUBLESHOOTING

M-2 [E108] (Engine coolant temperature is 105 °C) is displayed Cause

Remedy

1 Does coolant temperature gauge of monitor indicate NO red range and is caution lamp flashing? YES See M-13, c)

—

Trouble in engine unit (See Note 1)

—

Defective monitor panel

Replace

2 • Turn starting switch ON

Is "E" attached to head of service code?

NO

YES

Note 1: The display of the monitor panel has been reset normally. Since the coolant temperature sensor detected coolant temperature above 105 °C, remove the cause of that temperature rise by troublshooting the engine unit.

M-3 [E112] (Wiper forward output is shorted) is displayed a See M-23.

M-4 [E113] (Wiper reverse output is shorted) is displayed a See M-23.

M-5 [E114] (Contact with washer output of 24 V) is displayed a See M-24.

M-6 [E115] (Wiper does not start wiping in 10 seconds) is displayed a See M-23.

M-7 [E116] (Wiper is not retracted in 10 seconds) is displayed a See M-23.

20-512 (12)

PC78US-6

M-8

TROUBLESHOOTING

M-8 When starting switch is turned to ON position, monitor panel segments do not light up for 3 seconds PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Check that fuses 6, 13, and 18 are normal. a) Monitor panel segments do not light up at all Cause

Remedy

1 • Turn starting switch ON • 20 – 30 V

Is voltage between P01 (8) – (6), (7) and between P02 (1), (2) – (6), (7) normal?

NO

YES 2 • Turn starting switch ON • 20 – 30 V

NO

Is voltage between P01 (6), (7) – chassis ground normal? YES

Defective monitor panel

Replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between fuse 13 – battery relay M

Repair or replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between P01 (Female) (7) – fuse 13

Repair or replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between fuse 18 – battery relay B

Repair or replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between P02 (Female) (19) – fuse 6

Repair or replace

3 • Turn starting switch ON • 20 – 30 V

NO

Is voltage between fuse 13 – chassis ground normal? YES

4 • Turn starting switch ON • 20 – 30 V

Is voltage between fuse 18 – chassis ground normal? YES

NO

b) Some monitor panel segments do not light up Cause Defective monitor panel

PC78US-6

Remedy Replace

20-513 (12)

M-8

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a Check that fuses 11, and 18 are normal. a) Monitor panel segments do not light up at all Cause

Remedy

1 • Turn starting switch ON • 20 – 30 V

NO

Is voltage between P01 (8) – (6), (7) normal? YES 2

• Turn starting switch ON • 20 – 30 V

NO

Is voltage between P01 (1), (2) – (6), (7) – chassis ground normal? YES

Defective monitor panel

Replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between fuse 11 – battery relay M

Repair or replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between P01 (Female) (8) – fuse 11

Repair or replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between fuse 18 – battery relay B

Repair or replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between P01 (Female) (8) – fuse 18

Repair or replace

3 • Turn starting switch ON • 20 – 30 V

NO

Is voltage between fuse 11 – chassis ground normal? YES

4 • Turn starting switch ON • 20 – 30 V

Is voltage between fuse 18 – chassis ground normal? YES

NO

b) Some monitor panel segments do not light up Cause Defective monitor panel

Remedy Replace

M-8 a) Electrical circuit diagram of each system

20-514 (12)

PC78US-6

M-9, M10

TROUBLESHOOTING

M-9 When starting switch is set to ON position, all monitor panel segments light up but do not go off Cause Defective monitor panel

M-10 While preheating is not executed,

Remedy Replace

"Preheater monitor" lights up Cause

Remedy

1 • Disconnect terminal R1 • Turn starting switch ON • Max. 1 V

Is voltage between starting switch R1 – chassis ground normal?

NO

Defective starting switch

Replace

NO

Short circuit with power source in wiring harness between starting switch R1 – P02 (Female) (18)

Repair or replace

Defective monitor panel

Replace

YES 2 • Turn starting switch ON • Max. 1 V

Is voltage between P02 (18) – chassis ground normal? YES

M-10 Electrical circuit diagram of each system

PC78US-6

20-515 (12)

M-11

TROUBLESHOOTING

M-11 When starting switch is set to ON position and engine is started, basic check items flash a Inspect both alternator system and engine hydraulic system. a) Alternator system PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Check monitoring code "0043". If it is 100 or larger while the engine speed is above the medium level, the monitor panel is defective. Cause

Remedy

1 • Run engine above medium speed level • 20 – 30 V

Is voltage between alternator terminal R – chassis ground normal?

NO

Defective alternator

Replace

NO

Disconnection or defective contact in wiring harness between alternator terminal R – P02 (Female) (11)

Repair or replace

Defective monitor panel

Replace

YES 2 • Run engine above medium speed level • 20 – 30 V

Is voltage between P02 (11) – chassis ground normal? YES

M-11 a) Electrical circuit diagram of each system

20-516 (12)

PC78US-6

M-11

TROUBLESHOOTING

a) Alternator system PC78US-6 Serial No.: 6501 and up a Check monitoring code "0043". If it is 100 or larger while the engine speed is above the medium level, the monitor panel is defective. Cause

Remedy

1 • Run engine above medium speed level • 20 – 30 V

Is voltage between alternator terminal R – chassis ground normal?

NO

Defective alternator

Replace

NO

Disconnection or defective contact in wiring harness between alternator terminal R – P02 (Female) (11)

Repair or replace

Defective monitor panel

Replace

YES 2 • Run engine above medium speed level • 20 – 30 V

Is voltage between P02 (11) – chassis ground normal? YES

M-11 a) Electrical circuit diagram of each system

PC78US-6

20-517 (12)

M-11

TROUBLESHOOTING

b) Engine oil system PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Carry out the following troubleshooting when the engine oil pressure is normal. a Check bit (3) of monitoring code "0046". If it is lighting up, the monitor panel is defective. Cause

Remedy

1 • Run engine at low speed

When engine speed is low, if oil pressure sensor terminal T6 is disconnected, does error disappear?

NO

YES

2 • Turn starting switch OFF • Disconnect sensor wiring harness and P02

Is there continuity between P02 (7) – chassis ground normal?

NO

Defective oil pressure sensor (Low pressure)

Replace

Short circuit with chassis ground in wiring harness between P02 (Female) (7) – sensor terminal T6

Repair or replace

Defective monitor panel

Replace

YES

M-11 b) Electrical circuit diagram of each system

20-518 (12)

PC78US-6

M-11

TROUBLESHOOTING

b) Engine oil system PC78US-6 Serial No.: 6501 and up a Carry out the following troubleshooting when the engine oil pressure is normal. a Check bit (3) of monitoring code "0046". If it is lighting up, the monitor panel is defective. Cause

Remedy

1 • Run engine at low speed

When engine speed is low, if oil pressure sensor terminal T6 is disconnected, does error disappear?

NO

YES

2 • Turn starting switch OFF • Disconnect sensor wiring harness and P02

Is there continuity between P02 (7) – chassis ground normal?

NO

Defective oil pressure sensor (Low pressure)

Replace

Short circuit with chassis ground in wiring harness between P02 (Female) (7) – sensor terminal T6

Repair or replace

Defective monitor panel

Replace

YES

M-11 b) Electrical circuit diagram of each system

PC78US-6

20-519 (12)

M-12

TROUBLESHOOTING

M-12 When starting switch is set to ON position (but engine is stopped), caution items and emergency stop items (excluding battery and engine oil) flash a Inspect both alternator system and engine hydraulic system. a) Alternator system PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Check monitoring code "0043". If it is 100 or larger while the engine speed is above the medium level, the monitor panel is defective. Cause

Remedy

1 • Disconnect terminal R • Turn starting switch ON • Max. 1 V

Is voltage between alternator terminal R – chassis NO ground normal?

Defective alternator

Replace

Short circuit with power source in wiring harness between P02 (Female) (11) – alternator terminal R

Repair or replace

Defective monitor panel

Replace

YES 2 • Disconnect P02 • Turn starting switch ON • Max. 1 V

Is voltage between P02 (Female) (11) – chassis ground normal?

NO

YES

M-12 a) Electrical circuit diagram of each system

20-520 (12)

PC78US-6

M-12

TROUBLESHOOTING

a) Alternator system PC78US-6 Serial No.: 6501 and up a Check monitoring code "0043". If it is 100 or larger while the engine speed is above the medium level, the monitor panel is defective. Cause

Remedy

1 • Disconnect terminal R • Turn starting switch ON • Max. 1 V

Is voltage between alternator terminal R – chassis NO ground normal?

Defective alternator

Replace

Short circuit with power source in wiring harness between P02 (Female) (11) – alternator terminal R

Repair or replace

Defective monitor panel

Replace

YES 2 • Disconnect P02 • Turn starting switch ON • Max. 1 V

Is voltage between P02 (Female) (11) – chassis ground normal?

NO

YES

M-12 a) Electrical circuit diagram of each system

PC78US-6

20-521 (12)

M-12

TROUBLESHOOTING

b) Engine oil pressure sensor system PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Carry out the following troubleshooting when the engine oil pressure is normal. a Check bit (3) of monitoring code "0046". If it is lighting up, the monitor panel is defective. Cause

Remedy

1 • Turn starting switch OFF • Disconnect sensor terminal T6

Is there continuity between sensor terminal T6 – chassis ground?

NO

Defective oil pressure sensor

Replace

Disconnection or defective contact in wiring harness between P02 (Female) (7) – sensor terminal T6

Repair or replace

Defective monitor panel

Replace

YES 2 • Turn starting switch OFF • Disconnect P02 – sensor terminal T6

Is there continuity between P02 (Female) (11) – sensor terminal T6?

NO

YES

M-12 b) Electrical circuit diagram of each system

20-522 (12)

PC78US-6

M-12

TROUBLESHOOTING

b) Engine oil pressure sensor system PC78US-6 Serial No.: 6501 and up a Carry out the following troubleshooting when the engine oil pressure is normal. a Check bit (3) of monitoring code "0046". If it is lighting up, the monitor panel is defective. Cause

Remedy

1 • Turn starting switch OFF • Disconnect sensor terminal T6

Is there continuity between sensor terminal T6 – chassis ground?

NO

Defective oil pressure sensor

Replace

Disconnection or defective contact in wiring harness between P02 (Female) (7) – sensor terminal T6

Repair or replace

Defective monitor panel

Replace

YES 2 • Turn starting switch OFF • Disconnect P02 – sensor terminal T6

Is there continuity between P02 (Female) (11) – sensor terminal T6?

NO

YES

M-12 b) Electrical circuit diagram of each system

PC78US-6

20-523 (12)

M-13

TROUBLESHOOTING

M-13 When starting switch is set to ON position and engine is started, caution items and emergency stop items flash (When there is not abnormality in inspection items and engine before troubleshooting, however) a)

"Engine oil" flashes a Before carrying out the troubleshooting, check that the engine oil pressure is normal. Cause See M-11-b)

b)

Remedy —

"Charge level" flashes Cause See M-11-a)

20-524 (12)

Remedy —

PC78US-6

M-13

TROUBLESHOOTING

c)

"Coolant temperature" flashes PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Before carrying out the troubleshooting, check that the coolant temperature is normal. Cause

Remedy

1 • Start engine • Set engine speed to medium or higher

NO

Is coolant temperature gauge in red range?

Defective monitor panel

Replace

Defective coolant temperature sensor system (See M-22)

—

Disconnection or defective contact in wiring harness between P02 (Female) (1) – M18 (Female) (1)

Repair or replace

Disconnection or defective contact in wiring harness between M18 (Female) (2) – chassis ground

Repair or replace

YES 2 • Start engine

When M18 is disconnected, does gauge indicate only level 1 (Lowest line)?

NO

YES

3 • Turn starting switch OFF • Disconnect P02 and M18 • Max. 1 z

Is resistance between P02 (Female) (1) – M18 (Female) (1) normal? YES

NO

M-13 c) Electrical circuit diagram of each system

PC78US-6

20-525 (12)

M-13

TROUBLESHOOTING

c)

"Coolant temperature" flashes PC78US-6 Serial No.: 6501 and up a Before carrying out the troubleshooting, check that the coolant temperature is normal. Cause

Remedy

1 • Start engine • Set engine speed to medium or higher

NO

Is coolant temperature gauge in red range?

Defective monitor panel

Replace

Defective coolant temperature sensor system (See M-22)

—

Disconnection or defective contact in wiring harness between P02 (Female) (1) – M18 (Female) (1)

Repair or replace

Disconnection or defective contact in wiring harness between M18 (Female) (2) – chassis ground

Repair or replace

YES 2 • Start engine

When M18 is disconnected, does gauge indicate only level 1 (Lowest line)?

NO

YES

3 • Turn starting switch OFF • Disconnect P02 and M18 • Max. 1 z

Is resistance between P02 (Female) (1) – M18 (Female) (1) normal? YES

NO

M-13 c) Electrical circuit diagram of each system

20-526 (12)

PC78US-6

M-13

TROUBLESHOOTING

d)

"Fuel level" flashes PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Before carrying out the troubleshooting, check that there is fuel in the fuel tank. Cause

Remedy

1 • Start engine

NO

Is fuel level gauge in red range?

Defective monitor panel

Replace

Defective fuel level sensor system (See M-21)

—

Disconnection or defective contact in wiring harness between P02 (Female) (2) – M9 (Female) (1)

Repair or replace

Defective monitor panel

Repair or replace

YES • Start engine • Wait for 2 minutes. (Since fuel level fluctuates, its display is delayed.)

2 When M9 (Female) (1) is connected to chassis ground, do gauge segments light up to level 9 (Right end)?

NO

YES

3 • Connect M9 (Female) (1) to chassis ground • Turn starting switch ON • Max. 0.3 V

Is voltage between P02 (2) – chassis ground normal?

NO

YES

M-13 d) Electrical circuit diagram of each system

PC78US-6

20-527 (12)

M-13

TROUBLESHOOTING

d)

"Fuel level" flashes PC78US-6 Serial No.: 6501 and up a Check that there is fuel in the fuel tank before carrying out troubleshooting. Cause

Remedy

1 • Start engine

NO

Is fuel level gauge in read range?

Defective monitor panel

Replace

Defective fuel level sensor system (See M-21)

—

Disconnection or defective contact in wiring harness between P02 (female) (2) – M9 (female) (1)

Repair or replace

Disconnection or defective contact in wiring harness between M9 (female) (2) – chassis ground

Repair or replace

Defective monitor panel

Replace

YES • Start engine. • Wait for 2 minutes (Display is delayed since fuel level fluctuates).

2 When M9 (female) (1) is connected to chassis ground, does gauge light up to level 9 (top)?

NO

YES

3 • Turn starting switch OFF. • Disconnect M9 and P02. • Max. 1 z

Is resistance between P02 (female) (2) and M9 (female) (1) and chassis ground normal?

NO

YES 4 • Turn starting switch OFF. • Disconnect M9. • Max. 1 z

Is resistance between M92 (female) (1) and chas- NO sis ground normal? YES

M-13 d) Electrical circuit diagram of each system

20-528 (12)

PC78US-6

M-14

TROUBLESHOOTING

M-14 When starting switch is set to ON position (but engine is stopped), buzzer does not sound for 1 second While caution item is flashing, buzzer does not sound PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Even if the charge level and fuel level among the caution items become abnormal, the buzzer does not sound. a The buzzer is controlled by the monitor panel and turned on when it is required to sound or when the voltage at P01 (11) is 20 – 30 V. Cause • Turn starting switch OFF • Disconnect K53 • When buzzer cancel switch is ON: Max. 1 z • When buzzer cancel switch is OFF: Min. 1 Mz

Remedy

1 Is resistance between K53 (Female) (1) – (2) normal?

NO

Defective buzzer cancel switch

Replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between P02 (Female) (16) – K53 (Male) (2)

Repair or replace

Defective monitor panel

Replace

YES 2 • Disconnect K53 • Turn starting switch ON • 20 – 30 V

Is voltage between P02 (16) – chassis ground nor- NO mal? YES

M-14 Electrical circuit diagram of each system

PC78US-6

20-529 (12)

M-14

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a Even if the charge level and fuel level among the caution items become abnormal, the buzzer does not sound. a The buzzer is controlled by the monitor panel and turned on when it is required to sound or when the voltage at P01 (11) is 20 – 30 V. Cause • Turn starting switch OFF • Disconnect K53 • When buzzer cancel switch is ON: Max. 1 z • When buzzer cancel switch is OFF: Min. 1 Mz

Remedy

1 Is resistance between K53 (Female) (1) – (2) normal?

NO

Defective buzzer cancel switch

Replace

Disconnection, defective contact, or short circuit with chassis ground in wiring harness between P02 (Female) (16) – K53 (Male) (2)

Repair or replace

Defective monitor panel

Replace

YES 2 • Disconnect K53 • Turn starting switch ON • 20 – 30 V

Is voltage between P02 (16) – chassis ground nor- NO mal? YES

M-14 Electrical circuit diagram of each system

20-530 (12)

PC78US-6

M-15

TROUBLESHOOTING

M-15 Monitor plane lamp for nighttime is not turned on (LC display is normal) PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Carry out the following troubleshooting when the headlamp and working lamp light up normally. Cause

Remedy

1 • Turn starting switch ON • Set monitoring code to "0045"

NO

Is bit (4) of monitoring code "0045" turned off? YES

Defective monitor panel

Replace

Disconnection, defective contact in wiring harness between P02 (Female) (19) – K52 (Male) (1)

Repair or replace

Defective monitor panel

Replace

2 • Turn starting switch ON • Turn light switch ON • 20 – 30 V

Is voltage between P02 (19) – chassis ground nor- NO mal? YES

M-15 Electrical circuit diagram of each system

PC78US-6

20-531 (12)

M-15

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a Carry out the following troubleshooting when the headlamp and working lamp light up normally. Cause

Remedy

1 • Turn starting switch ON • Set monitoring code to "0045"

NO

Is bit (4) of monitoring code "0045" turned off? YES

Defective monitor panel

Replace

Disconnection, defective contact in wiring harness between P02 (Female) (19) – K52 (Male) (1)

Repair or replace

Defective monitor panel

Replace

2 • Turn starting switch ON • Turn light switch ON • 20 – 30 V

Is voltage between P02 (19) – chassis ground nor- NO mal? YES

M-15 Electrical circuit diagram of each system

20-532 (12)

PC78US-6

M-16

TROUBLESHOOTING

M-16 Coolant temperature gauge does not rise PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a When the engine coolant temperature does not rise actually, inspect the engine system. Cause

Remedy

1 • Disconnect M18 • Turn starting switch ON

When short connector is connected to M18 (Female), does gauge rise 1 level by 1 and go off at last?

NO

YES

Defective coolant temperature sensor system (See M-22)

—

Disconnection or defective contact in wiring harness between P02 (Female) (1) – M18 (Female) (1)

Repair or replace

Disconnection or defective contact in wiring harness between M18 (Female) (2) – chassis ground

Repair or replace

Defective monitor panel

Replace

2 • Turn starting switch OFF • Disconnect P02 and M18

Is there continuity between P02 (Female) (1) – M18 (Female) (1)?

NO

YES 3 • Turn starting switch OFF • Disconnect M18

Is resistance between M18 (Female) (2) – chassis ground normal? YES

NO

M-16 Electrical circuit diagram of each system

PC78US-6

20-533 (12)

M-16

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a When the engine coolant temperature does not rise actually, inspect the engine system. Cause

Remedy

1 • Disconnect M18 • Turn starting switch ON

When short connector is connected to M18 (Female), does gauge rise 1 level by 1 and go off at last?

NO

YES

Defective coolant temperature sensor system (See M-22)

—

NO

Disconnection or defective contact in wiring harness between P02 (Female) (1) – M18 (Female) (1)

Repair or replace

NO

Disconnection or defective contact in wiring harness between M18 (Female) (2) – chassis ground

Repair or replace

Defective monitor panel

Replace

2 • Turn starting switch OFF • Disconnect P02 and M18

Is there continuity between P02 (Female) (1) – M18 (Female) (1)? YES 3

• Turn starting switch OFF • Disconnect M18

Is resistance between M18 (Female) (2) – chassis ground normal? YES

M-16 Electrical circuit diagram of each system

20-534 (12)

PC78US-6

M-17

TROUBLESHOOTING

M-17 Coolant temperature gauge is not displayed (Gauge does not rise to 1st line during operation) PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up Cause

Remedy

1 • Disconnect M18 • Turn starting switch ON

NO

When M18 is disconnected, is gauge displayed? YES

Defective coolant temperature sensor system (See M-22)

—

Defective monitor panel

Replace

Short circuit with chassis ground in wiring harness between P02 (Female) (1) – M18 (Female) (1)

Repair or replace

2 • Turn starting switch ON • Disconnect P02 and M18

Is there continuity between P02 (Female) (1) – chassis ground? YES

NO

M-17 Electrical circuit diagram of each system

PC78US-6

20-535 (12)

M-17

TROUBLESHOOTING

PC78US-6Serial No.: 6501 and up Cause

Remedy

1 • Disconnect M18 • Turn starting switch ON

NO

When M18 is disconnected, is gauge displayed? YES

Defective coolant temperature sensor system (See M-22)

—

Defective monitor panel

Replace

Short circuit with chassis ground in wiring harness between P02 (Female) (1) – M18 (Female) (1)

Repair or replace

2 • Turn starting switch ON • Disconnect P02 and M18

Is there continuity between P02 (Female) (1) – chassis ground? YES

NO

M-17 Electrical circuit diagram of each system

20-536 (12)

PC78US-6

M-18

TROUBLESHOOTING

M-18 Fuel level gauge always displays full PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a Before carrying out the troubleshooting, see if the fuel tank is actually full. Cause • Turn starting switch ON • Wait for 2 minutes. (Since fuel level fluctuates, its display is delayed.)

Remedy

1 When M9 is disconnected, does gauge rise 1 level NO by 1 and go off at last? YES

Defective fuel level sensor system (See M-21)

—

Defective monitor panel

Replace

Short circuit with chassis ground in wiring harness between P02 (Female) (2) – M9 (Female) (1)

Repair or replace

2 • Turn starting switch OFF • Disconnect P02 and M9

Is there continuity between P02 (Female) (2) – chassis ground? YES

NO

M-18 Electrical circuit diagram of each system

PC78US-6

20-537 (12)

M-18

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 andup a Before carrying out the troubleshooting, see if the fuel tank is actually full. Cause • Turn starting switch ON • Wait for 2 minutes. (Since fuel level fluctuates, its display is delayed.)

Remedy

1 When M9 is disconnected, does gauge rise 1 level NO by 1 and go off at last? YES

Defective fuel level sensor system (See M-21)

—

Defective monitor panel

Replace

Short circuit with chassis ground in wiring harness between P02 (Female) (2) – M9 (Female) (1)

Repair or replace

2 • Turn starting switch OFF • Disconnect P02 and M9

Is there continuity between P02 (Female) (2) – chassis ground? YES

NO

M-18 Electrical circuit diagram of each system

20-538 (12)

PC78US-6

M-19

TROUBLESHOOTING

M-19 Fuel level gauge is not displayed PC78US-6 Serial No.: 4001 – 6500 PC78UU-6Serial No.: 22832 and up a Before carrying out the troubleshooting, check that there is fuel in the fuel tank. Cause

Remedy

1 • Disconnect M9 • Turn starting switch ON

When M9 (Female) (1) is connected to chassis ground, does gauge display?

NO

YES

2 • Turn starting switch OFF • Disconnect M9

Is there continuity between M9 (Female) (2) – chassis ground?

NO

Defective fuel level sensor (See M-21)

—

Disconnection or defective contact in wiring harness between M9 (Female) (2) – chassis ground

Repair or replace

Defective monitor panel

Replace

YES

M-19 Electrical circuit diagram of each system

PC78US-6

20-539 (12)

M-19

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 andup a Before carrying out the troubleshooting, check that there is fuel in the fuel tank. Cause

Remedy

1 • Disconnect M9 • Turn starting switch ON

When M9 (Female) (1) is connected to chassis ground, does gauge display?

NO

YES

2 • Turn starting switch OFF • Disconnect M9

Is there continuity between M9 (Female) (2) – chassis ground?

NO

Defective fuel level sensor (See M-21)

—

Disconnection or defective contact in wiring harness between M9 (Female) (2) – chassis ground

Repair or replace

Defective monitor panel

Replace

YES

M-19 Electrical circuit diagram of each system

20-540 (12)

PC78US-6

M-20

TROUBLESHOOTING

M-20 While engine is running, service meter does not advance Cause

Remedy

1 • Start engine • Set engine speed to medium or higher

Does charge level caution lamp flash?

NO

Defective monitor panel

Replace

See M-13 c)

—

YES

PC78US-6

20-541 (12)

M-21

TROUBLESHOOTING

M-21 Trouble in fuel level sensor PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a When carrying out the following troubleshooting, remove the fuel level sensor. Cause

Remedy

1 When float is moved up and down, does resistance between connector (1) – flange change as shown in Table 1?

NO

YES 2 Does arm move smoothly?

NO

Defective sensor (See Note 2)

Replace

NO

Bad contact of connector

Clean or replace connector

Interference of sensor in tank

Replace (See Note 2)

Defective sensor

Replace

Breakage of wiring harness (See Note 3) (Defective clamp) (Application of external force)

Replace sensor

YES 3 Is float cracked, broken off, or scratched badly? YES

4 Is breakage of wiring harness detected by visual inspection?

NO

YES

Table At upper (FULL) stopper

Approx. 12 z or below

At lower (EMPTY) stopper

Approx. 85 – 110 z

Note1. Difference between actual fuel level and level indicated by gauge When the gauge indicates 14 (F), the fuel level is 78 – 100%. When the former indicates 1 (E), the latter is below 14.5%. If the machine body is slanted, the displayed fuel level is different from the actual fuel level. Accordingly, stop the machine on a level place and check the fuel level gauge after waiting for at least 2 minutes. (Since fuel level fluctuates, its display is delayed.) Note2. Since the sensor may be interfering in the tank or it may be installed wrongly, install it very carefully. Note3. Check the installation position of the connector for vibration. If it vibrates remarkably, take proper measures to suppress the vibration.

20-542 (12)

PC78US-6

M-21

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 andup a When carrying out the following troubleshooting, remove the fuel level sensor. Cause

Remedy

1 When float is moved up and down, does resistance between connector (1) – flange change as shown in Table 1?

NO

YES 2 Does arm move smoothly?

NO

Defective sensor (See Note 2)

Replace

NO

Bad contact of connector

Clean or replace connector

Interference of sensor in tank

Replace (See Note 2)

Defective sensor

Replace

Breakage of wiring harness (See Note 3) (Defective clamp) (Application of external force)

Replace sensor

YES 3 Is float cracked, broken off, or scratched badly? YES

4 Is breakage of wiring harness detected by visual inspection?

NO

YES

Table At upper (FULL) stopper

Approx. 9.5 – 11 z

At lower (EMPTY) stopper

Approx. 82 – 92 z

Note1. Difference between actual fuel level and level indicated by gauge When the gauge indicates 14 (F), the fuel level is 78 – 100%. When the former indicates 1 (E), the latter is below 14.5%. If the machine body is slanted, the displayed fuel level is different from the actual fuel level. Accordingly, stop the machine on a level place and check the fuel level gauge after waiting for at least 2 minutes. (Since fuel level fluctuates, its display is delayed.) Note2. Since the sensor may be interfering in the tank or it may be installed wrongly, install it very carefully. Note3. Check the installation position of the connector for vibration. If it vibrates remarkably, take proper measures to suppress the vibration.

PC78US-6

20-543 (12)

M-22

TROUBLESHOOTING

M-22 Trouble in coolant temperature sensor Cause

Remedy

1 Is resistance between temperature sensor connec- NO tor (Male) (1) – (2) normal? YES

Bad contact of connector (See Note 1)

Clean connector or replace sensor

Defective sensor

Replace

Breakage of wiring harness (See Note 2) (Defective clamp) (Application of external force)

Replace sensor

2 Is breakage of wiring harness detected by visual inspection?

NO

YES

Table Normal Temperature (25 °C)

Approx. 37 – 50 kz

100 °C

Approx. 3.5 – 4.0 kz

Note1. If this error is displayed repeatedly, the connector (Female) on the machine side may be defective. Accordingly, inspect the connector and wiring harness on the machine side. Note2. Check the installation position of the connector for vibration. If it vibrates remarkably, take proper measures to suppress the vibration.

20-544 (12)

PC78US-6

M-23

TROUBLESHOOTING

M-23 Wiper does not operate or operates while wiper switch is turned off PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22832 and up a) Wiper does not operate a Check that fuse 14 is normal. a If service code "E112", "E113", "E115", or "E116" is displayed, carry out the following troubleshooting. Cause

Remedy

1 • Close front window • Turn starting switch ON • Set monitoring code to "0049"

NO

Does bit (3) of monitoring code "0049" light up? YES

• Turn starting switch ON • Set wiper switch to "ON" or "INT" position • Set monitoring code to "0049"

2 When wiper switch is set to "ON" or "INT" position, NO do bits (4), (5) of monitoring code "0049" go off?

Defective monitor panel

Replace

Defective wiper motor

Replace

Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring having improper resistance

Repair or replace

Defective monitor panel

Replace

NO

Defective rear limit switch or opening of front window

Inspection or replace

NO

Disconnection or defective contact in wiring harness having improper resistance

Repair or replace

Defective monitor panel

Replace

YES 3 • Turn starting switch ON

Is voltage between pins of W04 as shown in Table NO 1? YES

4 • Turn starting switch OFF • Disconnect P02 and W04

Is voltage between pins of P01 (Female) – W04 (Male) as shown in Table 2?

NO

YES

• Max. 1 z • Turn starting switch OFF • Disconnect terminals (1), (2) of W03.

5 Is resistance between rear limit switch terminals W03 (1) – (2) normal? YES

• Max. 1 z • Turn starting switch OFF • Disconnect terminals (1), (2) of P02 and W03

6 Is resistance between rear limit switch terminal W03 (1) – P02 (Female) (15), between W03 (2) – chassis ground normal? YES

b) Wiper operates while wiper switch is turned off Cause

Remedy

1 • Close front window • Turn starting switch ON • Set monitoring code to "0049"

NO

Defective monitor panel

Replace

When wiper switch is set to "ON" or "INT" position, NO do bits (4), (5) of monitoring code "0049" go off?

Defective monitor panel

Replace

Short circuit with power source in wiring harness between P01 (Female) (9) – W04 (Female) (3) or between P01 (Female) (10) – W04 (Female) (1)

Repair or replace

Does bit (3) of monitoring code "0049" light up? YES

• Turn starting switch ON • Set wiper switch to "ON" or "INT" position • Set monitoring code to "0049"

2

YES

PC78US-6

20-545 (12)

M-23

TROUBLESHOOTING

PC78US-6 Serial No.: 6501 and up a) Wiper does not operate a Check that fuse 14 is normal. a If service code "E112", "E113", "E115", or "E116" is displayed, carry out the following troubleshooting. Cause

Remedy

1 • Close front window • Turn starting switch ON • Set monitoring code to "0049"

NO

Does bit (3) of monitoring code "0049" light up? YES

• Turn starting switch ON • Set wiper switch to "ON" or "INT" position • Set monitoring code to "0049"

2 When wiper switch is set to "ON" or "INT" position, NO do bits (4), (5) of monitoring code "0049" go off?

Defective monitor panel

Replace

Defective wiper motor

Replace

Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring having improper resistance

Repair or replace

Defective monitor panel

Replace

NO

Defective rear limit switch or opening of front window

Inspection or replace

NO

Disconnection or defective contact in wiring harness having improper resistance

Repair or replace

Defective monitor panel

Replace

YES 3 • Turn starting switch ON

Is voltage between pins of W04 as shown in Table NO 1? YES

4 • Turn starting switch OFF • Disconnect P02 and W04

Is voltage between pins of P01 (Female) – W04 (Male) as shown in Table 2?

NO

YES

• Max. 1 W • Turn starting switch OFF • Disconnect terminals (1), (2) of W03.

5 Is resistance between rear limit switch terminals W03 (1) – (2) normal? YES

• Max. 1 W • Turn starting switch OFF • Disconnect terminals (1), (2) of P02 and W03

6 Is resistance between rear limit switch terminal W03 (1) – P02 (Female) (15), between W03 (2) – chassis ground normal? YES

b) Wiper operates while wiper switch is turned off Cause

Remedy

1 • Close front window • Turn starting switch ON • Set monitoring code to "0049"

NO

Defective monitor panel

Replace

When wiper switch is set to "ON" or "INT" position, NO do bits (4), (5) of monitoring code "0049" go off?

Defective monitor panel

Replace

Short circuit with power source in wiring harness between P01 (Female) (9) – W04 (Female) (3) or between P01 (Female) (10) – W04 (Female) (1)

Repair or replace

Does bit (3) of monitoring code "0049" light up? YES

• Turn starting switch ON • Set wiper switch to "ON" or "INT" position • Set monitoring code to "0049"

2

YES

20-546 (12)

PC78US-6

M-23

TROUBLESHOOTING

Table 1 Timing chart of ON-OFF operation of wiper Symbol

Set Time

Stop time up to next operation

Item

Tia

0.13 sec

Safety circuit during operation of wiper [Safety function (1)]

Tsa

10 sec

Stop time up to retraction of wiper blade

Tip

1.5 sec

Safety circuit during retraction of wiper [Safety function (2)]

Tsp

10 sec

Item

Symbol

Set Time

Stop time up to next operation

Tia

4 sec

Safety circuit during operation of wiper [Safety function (1)]

Tsa

10 sec

Stop time up to retraction of wiper blade

Tip

1.5 sec

Safety circuit during retraction of wiper [Safety function (2)]

Tsp

10 sec

Table 2 Diagnosis 4

Resistance

Between P01 (Female) (10) – W04 (Female) (1) Between P01 (Female) (9) – W04 (Female) (3) Between P01 (Female) (12) – W04 (Female) (4)

Max. 1 z

Between P01 (Female) (6), (7) – W04 (Female) (5) Between P01 (Female) (5) – W04 (Female) (6) Between W04 (Female) (1), (3), (4), (5), (6) – GND

PC78US-6

Min. 1 Mz

20-547 (7)

TROUBLESHOOTING

M-23

M-23 Electrical circuit diagram of each system PC78UU-6

PC78US-6 Serial No.: 4001 – 6500

20-548 (12)

PC78US-6

TROUBLESHOOTING

M-23

M-23 Electrical circuit diagram of each system PC78US-6 Serial No.: 6501 and up

PC78US-6

20-549 (12)

M-24

TROUBLESHOOTING

M-24 Washer motor does not operate or operates while washer switch is turned off a) Washer motor does not operate a Check that fuse 4 is normal. a)-1 When [E114] is displayed Cause

Remedy

1 • Max. 1 V • Turn starting switch ON • Disconnect P02 and M31

NO

Is voltage between P01 (Female) (3) – M31 (Female) (1) – chassis ground normal?

Short circuit with power source in wiring harness between P01 (Female) (3) – M31 (Female) (1)

Repair or replace

Defective monitor panel

Replace

YES

a)-2 When [E114] is not displayed Cause

1 • 20 – 30 V • Turn starting switch ON • Disconnect M31

NO

Is voltage between fuse 4 – M31 (Female) (2) – chassis ground normal?

Remedy

Disconnection or defective contact in wiring harness between fuse 4 – M31 (Female) (2)

Repair or replace

Disconnection or defective contact in wiring harness between P01 (Female) (3) – M31 (Female) (1)

Repair or replace

Defective washer motor

Replace

Defective monitor panel

Replace

YES 2 • Max. 1 z • Turn starting switch OFF • Disconnect P01 and M31

NO

Is resistance between P01 (Female) (3) – M31 (Female) (1) normal? YES 3

• Max. 1 V • Turn starting switch ON • Turn washer switch ON

NO

Is voltage between P01 (Female) (3) – chassis ground normal? YES

b) Washer operates while wiper switch is turned off Cause 1 • Min. 1 Mz • Turn starting switch OFF • Disconnect P02 and M31

Is resistance between M31 (Female) (1) – chassis NO ground normal?

Remedy

Short circuit with chassis ground in wiring harness between P01 (Female) (3) – M31 (Female) (1)

Repair or replace

Defective monitor panel

Replace

YES

20-550 (12)

PC78US-6

TROUBLESHOOTING

M-24

M-24 Electrical circuit diagram of each system PC78UU-6

PC78US-6 Serial No.: 4001 – 6500

PC78US-6

20-551 (12)

TROUBLESHOOTING

M-24

M-24 Electrical circuit diagram of each system PC78US-6 Serial No.: 6501 and up

20-552 (12)

PC78US-6

M-25

TROUBLESHOOTING

M-25 Depth set 0 mode and height mode cannot be selected and set (Only PC78UU-6) a Before carrying out troubleshooting, check that all the related connectors are properly inserted. a Always connect any disconnected connectors before going on to the next step. a Check that each mode is selected and set while the work equipment is out of the interference zone. Cause

Remedy

1 • Bit patter 1022 (4) SET/CLEAR switch (5) Mode selector switch ( (6) Mode selector switch (

) )

NO

Is monitor normal?

Defective monitor (Defective switch)

Replace

Disconnection or defective contact in wiring harness between P02 (female) (9), (10) – M96 (female) (21) or between P02 (female) (20) – M96 (female) (31)

Repair or replace wiring harness

Defective controller

Replace

YES 2 • Turn starting switch OFF • Disconnect P02 and M96 • Resistance: Max. 1 z

• Is there continuity between following? • P02 (9), (10) and M96 (21) • P02 (20) and M96 (31)

NO

YES

M-25 Electrical circuit diagram of each system

PC78US-6

20-553 (12)

30 DISASSEMBLY AND ASSEMBLY METHOD OF USING MANUAL ....................... 30- 2 PRECAUTIONS WHEN CARRYING OUT OPERATION............................................ 30- 3 SPECIAL TOOL LIST....................................... 30- 7 COUNTERWEIGHT Removal and Installation ............................ 30-15 INJECTION PUMP Removal and Installation ............................ 30-17 CYLINDER HEAD Removal and Installation ............................ 30-21 MAIN PUMP Removal and Installation ............................ 30-29 CONTROL PUMP Removal and Installation ............................ 30-31 ENGINE AND MAIN PUMP Removal and Installation ............................ 30-32 ENGINE HOOD ASSEMBLY Removal and Installation .........................30-34-1 HYDRAULIC OIL COOLER Removal and Installation ............................ 30-35 RADIATOR Removal and Installation ............................ 30-37 SWING MOTOR AND SWING MACHINERY Removal and Installation ............................ 30-39 SWING MACHINERY Disassembly and Assembly........................ 30-40 SWING MOTOR Removal and Installation ............................ 30-50 CENTER SWIVEL JOINT Removal and Installation ............................ 30-51 Disassembly and Assembly........................ 30-52 CONTROL VALVE Removal and Installation ............................ 30-53 Assembly .................................................... 30-54 WORK EQUIPMENT PPC VALVE Assembly .................................................... 30-55 TRAVEL PPC VALVE Assembly .................................................... 30-57 HYDRAULIC TANK Removal and Installation ............................ 30-58 FUEL TANK Removal and Installation ............................ 30-61 CONTROLLER Removal and Installation ............................ 30-65

PC78US-6

MONITOR PANEL Removal and Installation ..........................30- 66 AIR CONDITIONER UNIT Removal and Installation ..........................30- 67 OPERATOR'S CAB Removal and Installation ..........................30- 69 FLOOR FRAME Removal and Installation ..........................30- 71 OPERATOR'S CAB GLASS (STUCK GLASS) Removal and Installation ..........................30- 74 FRONT WINDOW Removal and Installation ..........................30- 83 REVOLVING FRAME Removal and Installation ..........................30- 84 SWING CIRCLE Removal and Installation ..........................30- 87 WORK EQUIPMENT Removal and Installation ..........................30- 88 FIRST BOOM Removal and Installation ..........................30- 94 SECOND BOOM Removal and Installation ..........................30- 97 OFFSET BRACKET Removal and Installation ..........................30- 98 STEEL SHOE, RUBBER PAD SHOE, ROAD LINER Expansion and Installation ........................30-100 RUBBER SHOE Removal and Installation ..........................30-101 FINAL DRIVE AND TRAVEL MOTOR Removal and Installation ..........................30-101 TRAVEL MOTOR Disassembly and Assembly......................30-103 IDLER Assembly ..................................................30-154 RECOIL SPRING Disassembly and Assembly......................30-156 TRACK ROLLER Disassembly and Assembly......................30-158 HYDRAULIC CYLINDER Disassembly and Assembly......................30-161

30-1 (18)

DISASSEMBLY AND ASSEMBLY

METHOD OF USING MANUAL

METHOD OF USING MANUAL 1. When removing or installing unit assemblies (1) When removing or installing a unit assembly, the order of work and techniques used are given for the removal operation; the order of work for the installation operation is not given. (2) Any special techniques applying only to the installation procedure are marked [*1], and the same mark is placed after the relevant step in the removal procedure to indicate which step in the installation procedure it applies to. (Example) REMOVAL OF Q Q Q ASSEMBLY ..................................Title of operation

k ...................................................................................Precautions related to safety when carrying out the operation 1. (1) ................................................................Step in operation a .............................................................................Technique or important point to remember when removing (1). 2. E E E (2): ...............................................................[*1].....Indicates that a technique is listed for use during installation 3. T T T T assembly (3) 6 .........................................................................See Lubricant and Coolant Table

INSTALLATION OF Q Q Q ASSEMBLY ..........................Title of operation • Carry out installation in the reverse order of removal [*1] ......................................................................Technique used during installation

•

a .......................................................................Technique or important point to remember when installing E E E (2). Adding water, oil ..................................................Step in operation a .......................................................................Point to remember when adding water or oil 5......................................................................Quantity when filling with oil and water

2. General precautions when carrying out installation or removal (disassembly or assembly) of units are given together as PRECAUTION WHEN CARRYING OUT OPERATION, so be sure to follow these precautions when carrying out the operation. 3. Listing of special tools (1) For details of the description, part number, and quantity of any tools (A1, etc.) that appear in the operation procedure, see the SPECIAL TOOL LIST given in this manual.

30-2 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

PRECAUTIONS WHEN CARRYING OUT OPERATION

PRECAUTIONS WHEN CARRYING OUT OPERATION [When carrying out removal or installation (disassembly or assembly) of units, be sure to follow the general precautions given below when carrying out the operation.] 1. Precautions when carrying out removal work • • • • • • • • • •

If the coolant contains antifreeze, dispose of it correctly. After disconnecting hoses or tubes, cover them or fit blind plugs to prevent dirt or dust from entering. When draining oil, prepare a container of adequate size to catch the oil. Confirm the match marks showing the installed position, or make match marks in the necessary places before removal to prevent any mistake when assembling. To prevent any excessive force from being applied to the wiring, disconnect connectors by grasping the connector, not the wire. Tag wires and hoses to show their installed position to prevent any mistake when reinstalling. Check the number and thickness of the shims, and keep in a safe place. When raising components, be sure to use lifting equipment of ample strength. When using forcing screws to remove any components, tighten the forcing screws alternately. Before removing any unit, clean the surrounding area and fit a cover to prevent any dust or dirt from entering after removal.

a Precautions when handling piping during disassembling Fit the following blind plugs into the piping after disconnecting it during disassembly operations. 1) Face seal type hoses and tubes Nominal number

Plug (nut end)

Nut (elbow end)

02

07376-70210

02789-00210

03

07376-70315

02789-00315

04

07376-70422

02789-00422

05

07376-70522

02789-00522

06

07376-70628

02789-00628

2) Hoses and tubes using sleeve nuts Nominal number

Plug (nut end)

Sleeve nut (elbow end) Use the two items below as a set

02

07376-50210

07221-20210 (Nut), 07222-00210 (Plug)

03

07376-50315

07221-20315 (Nut), 07222-00312 (Plug)

04

07376-50422

07221-20422 (Nut), 07222-00414 (Plug)

05

07376-50522

07221-20522 (Nut), 07222-00515 (Plug)

06

07376-50628

07221-20628 (Nut), 07222-00616 (Plug)

10

07376-51034

07221-21034 (Nut), 07222-01018 (Plug)

12

07376-51234

07221-21234 (Nut), 07222-01219 (Plug)

3) Split flange type hoses and tubes Nominal number

Flange (hose end)

Sleeve head (tube end)

Split flange

04

07379-00400

07378-10400

07371-30400

05

07379-00500

07378-10500

07371-30500

PC78US-6

30-3 (11)

DISASSEMBLY AND ASSEMBLY

PRECAUTIONS WHEN CARRYING OUT OPERATION

4) If the part is not under hydraulic pressure, the following corks can be used. Dimensions

Nominal number

Part Number

06

D

d

L

07049-00608

6

5

8

08

07049-00811

8

6.5

11

10

07049-01012

10

8.5

12

12

07049-01215

12

10

15

14

07049-01418

14

11.5

18

16

07049-01620

16

13.5

20

18

07049-01822

18

15

22

20

07049-02025

20

17

25

22

07049-02228

22

18.5

28

24

07049-02430

24

20

30

27

07049-02734

27

22.5

34

30-4 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

2. • • • • • • • • • • • • •

PRECAUTIONS WHEN CARRYING OUT OPERATION

Precautions when carrying out installation work Tighten all bolts and nuts (sleeve nuts) to the specified (KES) torque. Install the hoses without twisting or interference. Replace all gaskets, O-rings, cotter pins, and lock plates with new parts. Bend the cotter pin or lock plate securely. When coating with adhesive, clean the part and remove all oil and grease, then coat the threaded portion with 2 - 3 drops of adhesive. When coating with gasket sealant, clean the surface and remove all oil and grease, check that there is no dirt or damage, then coat uniformly with gasket sealant. Clean all parts, and correct any damage, dents, burrs, or rust. Coat rotating parts and sliding parts with engine oil. When press fitting parts, coat the surface with anti-friction compound (LM-P). After fitting snap rings, check that the snap ring is fitted securely in the ring groove. When connecting wiring connectors, clean the connector to remove all oil, dirt, or water, then connect securely. When using eye bolts, check that there is no deformation or deterioration, screw them fully, and align the direction of the hook. When tightening split flanges, tighten uniformly in turn to prevent excessive tightening on one side.

3. Precautions when completing the operations • If the coolant has been drained, tighten the drain valve, and add water to the specified level. Run the engine to circulate the water through the system. Then check the coolant water level again. • If the hydraulic equipment has been removed and installed again, add hydraulic oil to the specified level. Run the engine to circulate the oil through the system. Then check the oil level again. • If the piping or hydraulic equipment, such as hydraulic cylinders, pumps, or motors, have been removed for repair, always bleed the air from the system after reassembling the parts. a For details, see TESTING AND ADJUSTING, Bleeding air. • Add the specified amount of grease (molybdenum disulphide grease) to the work equipment related parts. 4. Other precautions • To maintain the performance of the machine and to prevent failures, it is particularly important to pay attention to the degree of cleanliness of the oil in the hydraulic circuits. When adding oil or changing the oil, or when replacing the filters, check that the oil container and area around the filler of the hydraulic tank are clean. • To keep the hydraulic circuits clean and to protect the hydraulic equipment, be careful of the following points when disassembling or assembling. • Before disassembling, wash the machine. Be particularly careful to completely clean the area that is to be disassembled. • Do not let dirt or dust get into the hydraulic circuits when disassembling or assembling. • Carry out thorough flushing of the parts, and be particularly careful to do this thoroughly for the circuits of parts that have failed. • When disassembling or after flushing, always mask the openings of the piping or hydraulic equipment completely. • Do not use the seal tape for the thread of the plug mounts or connectors. • If any internal part of the hydraulic equipment breaks, disassemble and clean all the hydraulic equipment and circuits to remove any dirt or pieces from the circuit. If any parts of the hydraulic circuits are disassembled and assembled, also carry out thorough flushing of the hydraulic circuits. • When changing the oil in the hydraulic tank, or when removing the piston pump or piston pump piping, always bleed the air before starting the engine to prevent seizure of the pump. For details, see TESTING AND ADJUSTING, Bleeding air from piston pump.

PC78US-6

30-5 (11)

DISASSEMBLY AND ASSEMBLY

PRECAUTIONS WHEN CARRYING OUT OPERATION

a After replacing or flushing the hydraulic tank oil, filter element, or strainer, or when removing and installing any hydraulic cylinder, hydraulic pump or any other hydraulic equipment or work equipment piping, always bleed the air as follows after completion of installation. 1. Run the engine at low idling, and extend and retract the steering, bucket, and lift arm cylinders 4 - 5 times without going to the end of this strike. (Stop approx. 100 mm before the end of the stroke.) 2. Operate the steering, bucket, and lift arm cylinders 3 - 4 times to the end of the stroke, then stop the engine and bleed the air from the plugs at the top of the hydraulic tank filter. 3. Raise the engine speed and repeat Step 2. to bleed the air. Repeat this procedure until no more air comes out from the plugs. 4. After completing bleeding the air, tighten the plugs

3 Plug: 11.3 ± 1.5 N.m {1.15 ± 0.15 kgm}

a If the engine is run at high speed from the start, or the cylinders are operated to the end of their stroke, the air inside the cylinder will cause damage to the piston packing. a After repair or long storage, follow the same procedure.

30-6 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

SPECIAL TOOL LIST

SPECIAL TOOL LIST a Tools with part number 79OT-OOO-OOOO cannot be supplied (they are items to be locally manufactured). a Necessity: t: Cannot be substituted, should always be installed (used). q: Very convenient if available, can be substituted with commercially available part. a New/remodel:N: Tools with new part numbers, newly developed for this model. R: Tools with upgraded part numbers, remodeled from items already available for other models. Blank: Tools already available for other models, used without any modification. a Tools marked Q in the Sketch column are tools introduced in special sketches (See SKETCHES OF SPECIAL TOOLS). Component Installation of cylinder head assembly

Symbol A

Part No.

1 790-331-1110

Part Name Wrench

1 796T-226-1120 Push tool

Necessity

Qty.

q

1

q

1

790-101-3400

Bearing puller

q

1

790-101-3220

Screw

q

1

790-101-5201

Push tool KIT

q

1

2

New/ Sketch remodel

Tightening of cylinder head bolt N

Q

• 790-101-5281 • Plate

1

• 790-101-5221 • Grip

1

• 01010-51225

• Bolt

1

790-101-5201

Push tool KIT

Installation of oil seal

q

1

• 790-101-5331 • Plate

1

• 790-101-5221 • Grip

1

• 01010-51225

• Bolt

1

790-101-5401

Push tool KIT

Press fitting of sub bearing outer race

4

q

1

• 790-101-5431 • Plate

1

• 790-101-5421 • Grip

1

• 01010-51240

1

Press fitting of main bearing outer race

5 • Bolt

F Push tool

t

1

N

Q

Press fitting of main bearing inner race

7 792T-413-1120 Push tool

t

1

N

Q

Press fitting of sub bearing inner race

6 796-765-1110

796-730-2300

Wrench assembly

t

1

795-630-1803

Torque wrench

t

1

Spacer

q

1

t

1

q

1

8 9 790-201-2770

10 796T-226-1210 Wrench 790-101-5201

Push tool KIT

• 790-101-5311 • Plate

1

• 790-101-5221 • Grip

1

• 01010-51225

• Bolt

1

790-101-5401

Push tool KIT

Measurement of running torque of shaft Installation of dust seal N

Q

Removal, installation of nut and measurement of starting torque of shaft

Installation of oil seal

11

q

1

• 790-101-5471 • Plate

1

• 790-101-5421 • Grip

1

• 01010-51240

1

12

PC78US-6

Removal, installation of spacer Removal of bearing outer race

3

Disassembly, assembly of swing machinery assembly

Nature of work, remarks

• Bolt

Press fitting of sub bearing outer race

30-7 (11)

DISASSEMBLY AND ASSEMBLY

Component

Symbol

Part No. 790-101-5401

Disassembly, assembly of swing machinery assembly

F

1

• 790-101-5421 • Grip

1

• 01010-51240

1

• Bolt Push tool

q

1

Push tool KIT

q

1

• 790-101-5141 • Plate

1

• 790-101-5021 • Grip

1

New/ Sketch remodel

• 01010-50816

1

L

Press fitting of main bearing inner race

Press fitting of sub bearing outer race

• Bolt Installer

t

1

Push tool KIT

q

1

• 790-101-5111 • Plate

1

• 790-101-5021 • Grip

1

• 01010-50816

1

Installation of floating seal

Press fitting of bushing

3

Disassembly, assembly of track roller assembly

R

T

• Bolt

Installer

q

1

5 796T-230-1210 Installer

q

1

4 796-230-1120

M

Nature of work, remarks

Press fitting of bushing

790-101-5001

(11)

q

1

2 796-230-1110

30-8

Qty.

1

Disassembly, assembly of idler assembly

Disassembly, assembly of center swivel joint assembly

Push tool KIT

Necessity

• 790-101-5451 • Plate

790-101-5001

Expansion, installation of track shoe assembly

Part Name

13

14 790-201-2240

Disassembly, assembly of recoil spring assembly

SPECIAL TOOL LIST

791-685-8005

Compressor (B)

t

1

790-201-2860

Spacer

t

1

791-635-3160

Extension assembly

t

1

790-101-1600

Cylinder (686kN{70ton})

t

1

790-101-1102

Pump

t

1

791-616-1030

Remover and installer

t

1

790-105-1100

Cylinder (294kN{30ton})

t

1

790-101-1102

Pump

t

1

790-101-2501

Push puller KIT

q

1

• 790-101-2510 • Block

1

• 790-101-2520 • Screw

1

• 791-112-1180 • Nut

1

• 790-101-2540 • Washer

1

• 790-101-2630 • Leg

2

• 790-101-2570 • Washer

4

• 790-101-2560 • Nut

2

• 790-101-2650 • Adapter

2

Installation of floating seal PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22001 and up N

Q

Installation of floating seal PC78US-6 Serial No.: 6501 and up

Compression of spring

Pulling out and press fitting of master pin

Separation of rotor and shaft

PC78US-6

DISASSEMBLY AND ASSEMBLY

Component

SPECIAL TOOL LIST

Part Name

Necessity

Qty.

790-502-1003

Cylinder repair stand

t

1

790-101-1102

Pump

t

1

790-102-3802

Wrench assembly

t

1

790-330-1100

Wrench assembly

t

1

790-302-1340

Socket (Width across flats: 80mm)

t

1

Boom Blade *1

790-102-1470

Socket (Width across flats: 70mm)

t

1

Arm *1

790-102-1320

Socket (Width across flats: 70mm)

t

1

Boom *2

3 790-302-1320

Socket (Width across flats: 65mm)

t

1

Arm *2

790-102-1330

Socket (Width across flats: 75mm)

t

1

Blade *2

790-302-1290

Socket (Width across flats: 60mm)

t

1

Bucket

790-302-1280

Socket (Width across flats: 55mm)

t

1

Offset

Expander

q

1

Expansion of piston ring

796-720-1670

Band

q

1

07281-01279

Clamp

q

1

796-720-1660

Band

q

1

07281-01159

Clamp

q

1

796-720-1650

Band

q

1

07281-01029

Clamp

q

1

796-720-1660

Band

q

1

07281-01159

Clamp

q

1

796-720-1670

Band

q

1

07281-01279

Clamp

q

1

790-201-1702

Push tool KIT

q

1

Symbol

Part No.

1

2

4 790-720-1000

Disassembly, assembly of hydrauU lic cylinder assembly 5

q

Installation of piston ring

Offset Boom *2 Arm *2

Boom and blade *1

1

• 790-101-5021 • Grip

1

• 01010-50816

1

• Bolt

• 790-201-1791 • Push tool Push tool KIT

Removal, installation of piston nylon nut

1

6

790-201-1702

Removal, installation of cylinder Arm, bucket head assembly and offset

Blade

1

Push tool KIT

Boom and blade

Bucket

• 01010-50816

790-201-1702

Disassembly, assembly of hydraulic cylinder

Arm *1

1

• 790-201-1811 • Push tool

Nature of work, remarks

Boom *1

• 790-101-5021 • Grip • Bolt

New/ Sketch remodel

Arm *1 Boom *2 Blade *2

Press fitting of cylinder head bushing

1

q

1

• 790-101-5021 • Grip

1

• 01010-50816

1

Arm *2 • Bolt

• 790-201-1781 • Push tool

1

*1 PC78UU-6 *2 PC78US-6

PC78US-6

30-9 (11)

DISASSEMBLY AND ASSEMBLY

Component

Symbol

Part No. 790-201-1702

SPECIAL TOOL LIST

Part Name Push tool KIT

Necessity

Qty.

q

1

• 790-101-5021 • Grip

1

• 01010-50816

1

6 • Bolt

• 790-201-1771 • Push tool 790-201-1500

Push tool KIT

New/ Sketch remodel

Nature of work, remarks

Bucket and offset

Press fitting of cylinder head bushing

1

q

1

• 790-201-1620 • Plate

1

• 790-101-5021 • Grip

1

• 01010-50816

• Bolt

1

790-201-1500

Push tool KIT

q

Boom and blade

1

• 790-201-1610 • Plate

1

• 790-101-5021 • Grip

1

• 01010-50816

• Bolt

1

790-201-1500

Push tool KIT

Arm

Disassembly, assembly of hydrauU lic cylinder assembly

q

1

• 790-201-1580 • Plate

1

• 790-101-5021 • Grip

1

• 01010-50816

• Bolt

1

790-201-1500

Push tool KIT

q

1

• 790-201-1620 • Plate

1

• 790-101-5021 • Grip

1

• 01010-50816

• Bolt

1

790-201-1500

Push tool KIT

7

q

Boom and Blade *1

Press fitting of cylinder head dust seal

1

• 790-201-1610 • Plate

1

• 790-101-5021 • Grip

1

• 01010-50816

• Bolt

1

790-201-1500

Push tool KIT

q

Bucket and offset

Arm *1 Boom *2 Blade *2

1

• 790-201-1590 • Plate

1

• 790-101-5021 • Grip

1

• 01010-50816

• Bolt

1

790-201-1500

Push tool KIT

Arm *2

Removal of work equipment and first boom assembly

V

q

1

• 790-201-1580 • Plate

1

• 790-101-5021 • Grip

1

• 01010-50816

• Bolt

1

790-441-1802

Remover

t

Bucket and Offset

1

• 790-441-1810 • Sleeve

1

• 792-900-1530 • Screw

1

• 796-900-1240 • Adapter

1

• 01803-13034

• Nut

1

• 01643-33080

• Washer

1

790-101-4000

Puller (490kN{50ton})

t

1

790-101-1102

Pump

t

1

Pulling out of first boom foot pin

1

*1 PC78UU-6 *2 PC78US-6

30-10 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

Component

Symbol

Removal of second boom assembly

Part No.

Qty.

t

1

790-438-1110

Screw

t

1

791-735-2110

Adapter

t

1

2 790-101-2540

Washer

t

1

791-112-1180

Nut

t

1

790-101-2102

Puller (294kN{30ton})

t

1

790-101-1102

Pump

t

1

790-201-2850

Spacer

t

1

791-535-1170

Plug

t

1

791-520-4140

Screw

t

1

790-101-2420

Adapter

t

1

790-101-2540

Washer

t

1

791-112-1180

Nut

t

1

790-101-2102

Puller (294kN{30ton})

t

1

790-101-1102

Pump Lifter (Suction cup)

t

2

2 20Y-54-13180

Adapter (Stopper rubber)

t

2

799-703-1200

Service tool KIT

t

1

799-703-1110

Vacuum pump (220V)

t

1

799-703-1120 Vacuum pump (240V)

t

1

799-703-1400 Gas leak tester

t

1

3

New/ Sketch remodel

Nature of work, remarks

Pulling out of second boom pin and offset bracket pin

Pulling out of arm cylinder trunnion pin

1

1 793-498-1210

X

PC78US-6

Necessity

Sleeve

3

Operator's cab glass

Air conditioner unit assembly and floor frame assembly

Part Name

791-735-1123

V

Removal of second boom assembly and arm cylinder assembly

SPECIAL TOOL LIST

Removal, installation of operator's cab glass (stuck glass)

Collection and supply of air conditioner gas

30-11 (11)

DISASSEMBLY AND ASSEMBLY

SPECIAL TOOL LIST

Note: Komatsu cannot accept any responsibility for special tools manufactured according to these drawings. F-1 Push tool

F-6 Push tool

30-12 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

SPECIAL TOOL LIST

F-7 Push tool

F-10 Wrench

PC78US-6

30-13 (11)

DISASSEMBLY AND ASSEMBLY

SPECIAL TOOL LIST

L-5 Installer

30-14 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

COUNTERWEIGHT ASSEMBRY PC78US-2 Serial No. : 4001 – 6500 PC78UU-2 Serial No. : 22001 and up REMOVAL a Stop the machine on a level place and set the upper structure in parallel with the track, then swing to the right about 20 degrees (since the mounting bolts are above the track) and lower the work equipment to the ground and stop the engine.

COUNTERWEIGHT

8. Remove fuel filler mounting cover (9) of the fuel tank. 9. Remove clamp (11) and float gauge hose (10). Loosen the clamp of the hose connected to the fuel filler tube on the back side of the fuel filler mounting cover, then remove the tube and cover together. a When removing the float gauge hose, check that the fuel level is below the connecting position of the hose.

1. Remove cover (1) from the top of the hydraulic tank. 2. Remove engine cover (2). 3. Remove the bracket of damper case breather (3). 4. Remove 2 mounting bolts of air cleaner bracket (4) from the right front end of weight (5). 10. Using sling [1], hang weight (5) temporarily and remove the 3 weight mounting bolts. 11. Lift off weight assembly (5).

4 Counterweight assembly: 1,170 kg

[*1]

(With auxiliary weight)

5. Remove the bolt of air conditioner hose clamp. 6. Remove radiator support bracket (7) from the weight. 7. Remove air inlet cover (8) of the radiator, oil cooler, etc.

INSTALLATION

PC78US-6

•

Carry out installation in the reverse order to removal.

[*1]

4 Weight mounting bolt: 1,150 – 1,440 Nm {118 – 147 kgm}

30-15 (11)

DISASSEMBLY AND ASSEMBLY

PC78US-2

Serial No. : 6501 and up

REMOVAL a Stop the machine on a level place and set the upper structure in parallel with the track, then swing to the right about 20 degrees (since the mounting bolts are above the track) and lower the work equipment to the ground and stop the engine.

COUNTERWEIGHT

8. Hang counterweight (5) temporarily and remove the 3 mounting bolts. 9. Lift off weight assembly (5).

4 Counterweight assembly: 1,105 kg

[*1]

1. Remove cover (1) from the top of the hydraulic tank. 2. Remove engine cover (2). 3. Remove the bracket of damper case breather (3). 4. Remove 2 mounting bolts of air cleaner bracket (4) from the right front end of weight (5).

INSTALLATION •

Carry out installation in the reverse order to removal.

[*1]

4 Counterweight mounting bolt: 1,150 – 1,440 Nm {118 – 147 kgm}

5. Remove the bolt of air conditioner hose clamp. 6. Remove radiator support bracket (7) from the weight. 7. Remove air inlet cover (8) of the radiator, oil cooler, etc.

30-16 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

INJECTION PUMP

INJECTION PUMP ASSEMBLY

5. Remove the cylinder head cover.

REMOVAL

6. Set the No. 1 cylinder to the compression top dead center. 1) Rotate the crankshaft forward with bolt (30) to match the stamped fuel injection timing line of 1.4TOP (31) to pointer (32). 2) Check that there is clearance in the intake vale and exhaust valve of the No. 1 cylinder. a If there is not valve clearance, rotate the crankshaft one more turn.

PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22001 – 23500 a Disconnect the wiring harness from the negative terminal of the battery. a Remove the counterweight. (See REMOVAL OF COUNTERWEIGHT.) 1. Remove the nut of the rod of engine stop solenoid (1) and the nut of accelerator cable (2) from the lever side, then remove the rod and cable assembly. 2. Remove the connectors of the air conditioner, water temperature sensor, and glow plug and wire harness clamp (3), then remove stop solenoid (1) and bracket together.

7. When the No. 1 cylinder is at the compression top dead center, timing check hole (17) (the drilled through hole for bolt hole on this side) of tachometer removing opening (16) on front cover (9) must be matched to the hole of the gear. Insert round bar about 100 mm long (18) in the holes to check that those holes are matched.

3. Remove injection pipe clamp (4) and loosen the 4 sleeve nuts each on the pump side and nozzle side of injection pipe (5), then remove injection pipe (5). [*1] 4. Remove inlet and outlet tubes (6) of the feed pump. Remove lubrication tube (7) and rear bracket (8) of the pump. [*2]

PC78US-6

30-17 (11)

DISASSEMBLY AND ASSEMBLY

8. Remove 6 bolts (11) used to install pump holder (10) to front cover (9). 9. Remove bolt (12) used to install the holder from the pump side, then remove the pump assembly and holder drive gear together. [*3] a When the drive gear and idler gear are installed, their marks C must be matched to each other. Since those marks are not seen actually, however, make match marks on the gear and pump in white paint when the pump is removed.

INJECTION PUMP

INSTALLATION PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22001 – 23500 •

Carry out installation in the reverse order to removal.

[*1]

3 Sleeve nut: 19.6 – 24.5 Nm {2 – 2.5 kgm}

[*2]

3 Outlet and inlet tube bolts of feed pump: 19.6 – 24.5 Nm {2 – 2.5 kgm}

[*3] 1. If the stud bolt comes off the holder during the removal work, apply gasket sealant to its threaded part (indicated by the arrow) and reinstall it to the holder. 2 Threaded part of stud bolt: Gasket sealant (LG-7) 3 Stud bolt: 58.8 – 73.5 Nm {6.0 – 7.5 kgm}

2. When installing holder (10) to pump (13), match the engraved lines (14) on them to each other. 3. Before installing the pump to the front cover, match the timing of the gear on the pump side as shown below. • Remove the bolt at position A of pump holder (10) and tighten an M6 bolt 35 mm or longer (33) to fix the gear. (Compression top dead center of No. 1 cylinder)

30-18 (15)

PC78US-6

DISASSEMBLY AND ASSEMBLY

INJECTION PUMP

4. When installing the pump to the front cover, match the match marks made on the gear and pump when the pump was removed. Furthermore, match the stamped lines of holder (10) and plate to each other and tighten the mounting bolts temporarily.

PC78US-6

30-18-1 (15)

DISASSEMBLY AND ASSEMBLY

REMOVAL PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up a Disconnect the wiring harness from the negative terminal of the battery. a Remove the counterweight. (See REMOVAL OF COUNTERWEIGHT.) 1. Remove the nut (1) of the rod of engine stop solenoid and the nut of accelerator cable (2) from the lever side, then remove the rod and cable assembly.

INJECTION PUMP

4. Remove engine stop solenoid (8) and bracket together. 5. Remove injection pipe clamp and loosen the 4 sleeve nuts each on the pump side and nozzle side of injection pipe (9), then remove injection pipes (9). [*1] 6. Disconnect inlet and outlet hoses (10) of the feed pump and lubrication tube (11). [*2] 7. Remove rear braket (12) of the pump.

2. Disconnect 3 terminals (PULL, HOLD, and GND) (3) from the engine stop solenoid.

8. Remove the of cylinder head cover.

3. Disconnect air compressor wiring connector (M19) (4), coolant temperature sensor (M18) (5), glow plug (M17) (6), and wire harness clamp (7).

PC78US-6

9. Set the No. 1 cylinder to the compression top dead center. 1) Rotate the crankshaft forward with bolt (30) to match the stamped fuel injection timing line of 1.4TOP (31) to pointer (32). 2) Check that there is clearance in the intake vale and exhaust valve of the No. 1 cylinder. a If there is not valve clearance, rotate the crankshaft one more turn.

30-19 (11)

DISASSEMBLY AND ASSEMBLY

10. When the No. 1 cylinder is at the compression top dead center, timing check hole (20) (the drilled through hole for bolt hole on this side) of tachometer removing opening (19) on front cover (12) must be matched to the hole of the gear. Insert round bar about 100 mm long (21) in the holes to check that those holes are matched.

INJECTION PUMP

INSTALLATION PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up •

Carry out installation in the reverse order to removal.

[*1]

3 Sleeve nut: 19.6 – 24.5 Nm {2 – 2.5 kgm}

[*2]

3 Outlet and inlet tube bolts of feed pump: 19.6 – 24.5 Nm {2 – 2.5 kgm}

[*3]

11. Remove 6 bolts (14) used to install pump holder (13) to front cover (12).

1. If the stud bolt comes off the holder during the removal work, apply gasket sealant to its threaded part (indicated by the arrow) and reinstall it to the holder. 2 Threaded part of stud bolt: Gasket sealant (LG-7) 3 Stud bolt: 58.8 – 73.5 Nm {6.0 – 7.5 kgm}

12. Remove bolt (15) used to install the holder from the pump side, then remove the pump assembly and holder drive gear together. [*3] a When the drive gear and idler gear are installed, their marks C must be matched to each other. Since those marks are not seen actually, however, make match marks on the gear and pump in white paint when the pump is removed.

2. When installing holder (13) to pump (16), match the engraved lines (17) on them to each other. 3. Before installing the pump to the front cover, match the timing of the gear on the pump side as shown below. • Remove the bolt at position A of pump holder (13) and tighten an M6 bolt 35 mm or longer (33) to fix the gear. (Compression top dead center of No. 1 cylinder)

30-20 (15)

PC78US-6

DISASSEMBLY AND ASSEMBLY

INJECTION PUMP

4. When installing the pump to the front cover, match the match marks made on the gear and pump when the pump was removed. Furthermore, match the stamped lines of holder (13) and plate to each other and tighten the mounting bolts temporarily.

PC78US-6

30-20-1 (15)

DISASSEMBLY AND ASSEMBLY

CYLINDER HEAD ASSEMBLY REMOVAL

CYLINDER HEAD

5. Remove the 3 bolts and protector (8) of the air conditioner compressor. 6. Remove fuel filter (9) from the bracket.

PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22001 – 23500 a Remove the mounting bolts on both sides of the engine hood bracket to remove the engine hood. Loosen the coolant drain plug to drain the coolant into a container. 1. Remove the 4 mounting bolts of the air intake pipe (1) and loosen hose clamp (2) to remove air intake pipe (1).

7. Remove 1 mounting bolt and 1 lock bolt of air conditioner compressor (10) and loosen the adjustment bolt to remove the belt. 8. Disconnect wiring harness connector (11) and remove the compressor assembly and move it so that it will not be an obstacle. Remove bracket (12).

2. Remove protector (4) of exhaust muffler (3) and 2 muffler mounting bolts (5). [*1]

9. Remove coolant temperature sensor connector (13) and glow plug connector (14). Remove the clamp and heater hose (15).

3. Loosen the bolts of joint (7) of the muffler and exhaust pipe (6) to remove the muffler assembly. [*2] 4. Remove the 4 mounting nuts and exhaust pipe (6).

PC78US-6

30-21 (11)

DISASSEMBLY AND ASSEMBLY

10. Remove clamp (17) of fuel injection pipes (16), then remove the sleeve nuts on the pump side and nozzle side to remove the 4 injection pipes. Remove the spill pipe on the drain side. [*3]

CYLINDER HEAD

13. Loosen locknuts (30) and adjustment screws (31). (8 places) 14. Remove the 8 mounting bolts of rocker arm (20), and then remove the rocker arm, push rod, and lead (21) of the glow plug. [*6]

11. Remove the 8 mounting bolts and exhaust manifold (18). [*4] 12. Remove the 3 mounting bolts and head cover (19). [*5]

15. Remove the 17 mounting bolts of cylinder head (22), and then lift off the cylinder head assembly. [*7] 4 Cylinder head assembly: 40 kg

16. Remove air intake manifold (23) and disassemble the cylinder head. [*8]

30-22 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

CYLINDER HEAD 2. 3 Rocker arm adjusting nut (25): 39.2 – 49Nm {4 – 5 kgm}

INSTALLATION PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22001 – 23500 •

Carry out installation in the reverse order to removal.

[*1]

3 Muffler mounting bolt and nut: 7.8 – 9.8 Nm {0.8 – 1.0 kgm}

[*2]

[*3]

[*4]

3 Joint clamp mounting bolt and nut: 1st time: 39.2 – 49 Nm {4 – 5 kgm} 2nd time: 68.6 – 122.5 Nm {7 – 12.5 kgm}

3 Sleeve nut: 19.6 – 24.5 Nm {2 – 2.5 kgm}

3 Manifold mounting bolt: 34.3 – 53.9 Nm {3.5 – 5.5 kgm}

[*5] 1. Insert the cylinder head cover O-ring in the O-ring groove, taking care not to expand or contract it, and fit it to the cylinder head. Apply adhesive, if necessary. 2. 3 Head cover mounting bolt (26): 7.84 – 9.8 Nm {0.8 – 1.0 kgm}

[*6]

1. 3 Rocker arm shaft mounting bolt (24): 19.6 – 29.4 Nm {2 – 3 kgm}

[*7] 1. Tighten the cylinder head mounting bolts in the following order. 1) Apply molybdenum disulphide LM-P all over the threads and seating face of each bolt and the seats of the cylinder head holes. 2) Turn the bolts with the fingers until they are screwed in the threaded holes of the cylinder head by 2 – 3 threads in the order of [1] – [17] shown in the figure. 3) Tighten the bolts to 68.6 ± 9.8 Nm {7 ± 1 kgm} in the order of [1] – [17] shown in the figure. 4) Tighten the bolts to 107.8 ± 4.9 Nm {11 ± 0.5 kgm} in the order of [1] – [17] shown in the figure. a (1): Exhaust side, (2): Air intake side, (3): Front, (4): Rear

5) Make marks (f) with paint on the bolt heads and their seats on the cylinder head, and then tighten the bolts in the order of [1] – [17] so that the mark of each bolt will be at 90° +30° from the mark 0 of the cylinder head.

PC78US-6

30-23 (11)

DISASSEMBLY AND ASSEMBLY

a After tightening the bolts, make 1 punch mark (g) on each bolt head. a If there are 5 or more punch marks on a bolt head, do not use that bolt again but replace it.

CYLINDER HEAD

PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up REMOVAL

k Disconnect the cable from the negative (–) terminal of the battery. 1. Remove the engine hood. For details, See REMOVAL, INSTALLATION OF COUNTERWEIGHT. 2. Drain the coolant.

6 Coolant: 10.5 l

3. Remove air intake hose (1) between the air cleaner and turbocharger.

4. Remove muffler protector (2). [*8]

2 Gasket sealant (LG-7)

5. Remove 2 U-clamps (3).

Apply lines of the gasket sealant 1 mm in diameter as shown below.

6. Remove clamp (4) between the turbocharger and muffler and loosen the 4 exhaust pipe mounting nuts on the turbocharger side. [*2]

[*1]

7. Remove muffler (5).

30-24 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

8. Remove air intake connector (6) between the turbocharger and exhaust manifold.

CYLINDER HEAD

12. Loosen the 2 air conditioner compressor mounting bolts and adjustment bolt and remove air conditioner compressor belt (12). 13. Disconnect 3 hoses (13) from the fuel filter. 14. Remove air conditioner compressor bracket, and fuel filter together.

(14),

9. Disconnect wiring connectors (M17) (7), (M18) (8), and (M19) (9). 10. Remove guard (10). 11. Remove oil feed pipe (11). 15. Disconnect 3 terminals (PULL, HOLD, and GND) (16) and linkage mounting nut (18) from engine stop solenoid (15). 16. Remove engine stop solenoid (15) and bracket (17) together.

PC78US-6

30-25 (11)

DISASSEMBLY AND ASSEMBLY

CYLINDER HEAD

17. Disconnect blow-by hose (19).

24. Loosen 2 mounting bolts of alternator (27) and remove fan belt (28).

18. Remove fuel injection pipe clamp (20) and fuel injection pipes (21). [*3]

25. Remove fan (29).

19. Disconnect spill hose (22).

26. Disconnect heater hoses (30) and (31). 27. Disconnect radiator upper hose (32) and lower hose (33). 28. Remove water pump assembly (34).

20. Remove the inspection cover on the back side of the turbocharger. 21. Disconnect turbocharger lubrication tubes (23) and (24). [*4] 22. Remove turbocharger and exhaust manifold assembly (25). [*5]

29. Loosen locknuts (40) and adjustment screws (41). (8 places) 30. Remove the 8 mounting bolts, rocker arm (35), and push rod. [*7] 31. Remove lead (36) of the glow plug.

23. Remove cylinder head cover (26).

30-26 (11)

[*6]

PC78US-6

DISASSEMBLY AND ASSEMBLY

CYLINDER HEAD

32. Remove the 17 mounting bolts of cylinder head (37) and lift off the cylinder head assembly. [*8]

INSTALLATION •

Carry out installation in the reserve order to removal.

33. Remove air intake manifold (38) from the cylinder head assembly.

[*1]

3 U-clamp nut: 7.8 – 9.8 Nm {0.8 – 1.0 kgm}

4 Cylinder head assembly: 40 kg

[*2]

[*3]

a See Installation of cylinder head [*8].

[*4]

[*5]

[*6]

3 Mounting bolt of clamp between turbocharger and muffler: 1st time: 39.2 – 49 Nm {4 – 5 kgm} 2nd time: 68.6 – 122.5 Nm {7 – 12.5 kgm} 3 Exhaust pipe mounting nut on turbocharger side: 27 – 34 Nm {2.8 – 3.5 kgm}

3 Fuel injection pipe sleeve nut: 19.6 – 24.5 Nm {2 – 2.5 kgm} 3 Joint bolt of turbocharger lubrication inlet tube: 9.8 – 12.7 Nm {1.0 – 1.3 kgm}

3 Mounting bolt of exhaust manihold and turbocharger: 34.3 – 53.9 Nm {3.5 – 5.5 kgm} a Insert the cylinder head cover O-ring in the O-ring groove, taking care not to expand or contact it, and fit it to the cylinder head. Apply adhesive, if necessary.

3 Head cover mounting bolt: 7.84 – 9.8 Nm {0.8 – 1.0 kgm}

[*7]

PC78US-6

3 Rocker arm shaft mounting bolt: 19.6 – 29.4 Nm {2 – 3 kgm} 3 Rocker arm adjusting nut: 39.2 – 49 Nm {4 – 5 kgm}

30-27 (11)

DISASSEMBLY AND ASSEMBLY

CYLINDER HEAD

[*8] 1. Tighten the cylinder head mounting bolts in the following order. 1) Apply molybdenum disulphide LM-P all over the threads and seating face of each bolt and the seats of the cylinder head holes. 2) Turn the bolts with the fingers until they are screwed in the threaded holes of the cylinder head by 2 – 3 threads in the order of [1] – [17] shown in the figure. 3) Tighten the bolts to 68.6 ± 9.8 Nm {7 ± 1 kgm} in the order of [1] – [17] shown in the figure. 4) Tighten the bolts to 107.8 ± 4.9 Nm {11 ± 0.5 kgm} in the order of [1] – [17] shown in the figure. a (1): Exhaust side, (2): Air intake side, (3): Front, (4): Rear

5) Make marks (f) with paint on the bolt heads and their seats on the cylinder head, and then tighten the bolts in the order of [1] – [17] so that the mark of each bolt will be at 90° +30° from the mark 0 of the cylinder head. a After tightening the bolts, make 1 punch mark (g) on each bolt head. a If there are 5 or more punch marks on a bolt head, do not use that bolt again but replace it.

30-28 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

MAIN PUMP

MAIN PUMP ASSEMBLY

3. Remove drain plug (6) from the bottom of the suction tube of pump (5) to drain the oil.

REMOVAL

4. Remove drain plug (7) from the PTO case to drain the oil.

a Remove the engine hood and counterweight (See REMOVAL OF COUNTERWEIGHT). a Swing the upper structure from the parking position to the right by 30 degrees and lower the work equipment to the ground and stop the engine (so that the hydraulic oil will be drained easily).

6 Hydraulic oil: Approx. 80 l 6 PTO: 0.5 l

k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank.

1. Remove air cleaner (1) and its bracket and air intake hose (2). 2. Remove oil splash protector (3) from the top of the pump and bottom plate (4) from the bottom of the pump. a Cover the manifold from which the air intake pipe is removed. PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22001 – 23500

5. Remove protector (9), joint (10), and 2 U-bolts (11) from muffler (8), then remove muffler (8) and bracket (12). [*1] (Since the engine mount is an obstacle to removal of the pump, remove the bracket.) PC78US-6 Serial No.: 4001 – 5500 PC78UU-6 Serial No.: 22001 – 23500

PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up

PC78US-6 Serial No.: 5501 and up PC78UU-6 Serial No.: 23501 and up

PC78US-6

30-29 (11)

DISASSEMBLY AND ASSEMBLY

6. Remove the wiring harness connector of TVC solenoid (13). Remove 6 hoses (14) from the pump. [*2] a Mask the removed connector and fit male or female plugs to the hoses and nipple elbows.

MAIN PUMP

INSTALLATION •

Carry out installation in the reverse order to removal. a When assembling, take care fully so that dirt, rust, flaw, etc. will not cause a trouble. [*1] 1. Tighten the mounting bolts of clamp (10) of the joint between exhaust muffler (8) and exhaust pipe to 39.2 – 49 Nm {4 – 5 kgm} first, then tighten to 68.6 – 122.5 Nm {7 – 12.5 kgm}. 2. Tighten the nuts of mounting U-bolts (11) of exhaust muffler (8) to 7.8 – 9.8 Nm {0.8 – 1.0 kgm}. [*2] When installing the rubber hoses, be careful not to twist them.

7. Hang pump (5) temporarily and remove suction tube (15) and pump mounting bolts, then remove pump (5). [*3]

[*3] After supplying hydraulic oil and before starting the engine, bleed air from the main pump.

4 Main pump assembly: 75 kg

30-30 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

CONTROLL PUMP

CONTROLL PUMP ASSEMBLY REMOVAL 1. Remove the right side cover. 2. Remove hose (2) of control pump (1). 3. Remove the 4 mounting bolt and the control pump assembly (1). a Fit male or female plugs to the removed hoses and elbows.

a If the blade or another attachment is installed, control pump (1) is different from the above one and cannot be removed easily. In this case, remove the counterweight, referring to REMOVAL OF COUNTERWEIGHT, then remove the control pump.

INSTALLATION •

Carry out installation in the reverse order to removal.

PC78US-6

30-31 (11)

DISASSEMBLY AND ASSEMBLY

ENGINE AND MAIN PUMP ASSEMBLY

ENGINE AND MAIN PUMP

6. Remove the 2 bolts from the bottom of the engine to remove centralized wiring harness bracket (8) from the engine block.

REMOVAL a The shapes of the parts of PC78US-6, Serial No. 5501, and up and PC78UU-6, Serial No. 23501 and up, are a little different from the shapes of the parts in the following figures. a Remove the engine hood and counterweight (See REMOVAL OF COUNTERWEIGHT). a Swing the upper structure from the parking position to the right by 30 degrees and lower the work equipment to the ground and stop the engine (so that the hydraulic oil will be drained easily).

k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank. a Disconnect the cable from the negative (–) terminal of the battery. 1. Remove bottom plate (2) from the bottom of main pump (1) and drain plug (3) from the bottom of the suction tube to drain the hydraulic oil.

7. Remove the adjustment bolt of alternator (9). 8. Loosen the alternator mounting bolts through the hole of the partition and remove the V-belt. 9. Remove the mounting bolts to remove the alternator. (This work is required since the engine mount bolts cannot be removed.)

2. Loosen plug (4) of the remote hose to drain the cooling water from the radiator. a If the cooling water contains antifreeze, handle it as harmful liquid. Do not handle it illegally. 6 Hydraulic oil: 80 l

6 Cooling water: 8 l

10. Remove the wiring harnesses and connectors of air conditioner compressor (10), stop solenoid (11), TVC solenoid (12), water temperature gauge, glow plug, starting motor, etc.

3. Remove the covers from the boom foot, swing motor top, and inspection hole on the engine side. 4. Remove wiring harness (6) of alternator (5). 5. Remove the wiring harness of hydraulic switch (7) and the rotation sensor connector.

30-32 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

11. Remove guard (13) of air conditioner compressor (10) from the fan guard. 12. Remove the mounting bolt of the adjustment bolt and air conditioner compressor (10).

ENGINE AND MAIN PUMP

20. Remove protector (25) of exhaust muffler (24). Remove the clamp of the muffler and exhaust pipe to remove the muffler. Remove the exhaust pipe from the exhaust manifold. [*2]

13. Remove return hose (15) for the tank from fuel filter (14). 14. Remove the 2 mounting bolts and fuel filter (14). 15. Remove 2 heater hoses (16) from the valves on the thermostat side and engine block side.

21. Remove protector (26) of the pump hose. Remove the mounting bolts and suction tube (27) from the pump.

16. Loosen the clamps and disconnect upper hose (17) and lower hose (18) of the radiator from the engine. 17. Remove the 6 mounting bolts and fan (19). 18. Remove fuel hose (20) connected to the feed pump. Remove accelerator wire (21) from the governor lever. Loosen the locknut of bracket (22) and remove the wire. [*1]

22. Remove the 6 hoses (28) of pump (1). 23. Remove the 4 bolts of engine support (29). a Fit male or female plugs to the removed hoses and elbows.

19. Remove air cleaner (23), bracket, and air intake hose together from the air intake manifold.

PC78US-6

30-33 (11)

DISASSEMBLY AND ASSEMBLY

24. Install the hook to engine assembly (30) and a sling to main pump (1) and lift off the engine and pump assembly, hanging it by 3 points. 4 Engine • Main pump assembly: 370 kg

ENGINE AND MAIN PUMP

INSTALLATION • [*1]

Carry out installation in the reverse order to removal. 3 Fuel hose bolt: 19.6 – 24.5 Nm {2 – 2.5 kgm}

[*2] 1. Tighten the mounting bolts of the clamp of the joint between exhaust pipe and muffler to 39.2 – 49 Nm {4 – 5 kgm} first, then tighten to 68.6 – 122.5 Nm {7 – 12.5 kgm}. 2. Tighten the nuts of the mounting U-bolts of the muffler to 7.8 – 9.8 Nm {0.8 – 1.0 kgm}. [*3] After installing the engine mount to the revolving frame, apply clear lacquer to the unpainted engine mount fitting face.

3 Mounting bolt: 249 – 309 Nm {25 – 31.5 kgm}

2 Mounting bolt: Apply liquid adhesive LT-2

30-34 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

ENGINE HOOD ASSEMBLY REMOVAL

k Park the machine on level ground, lower the work equipment to the ground completely, stop the engine, and set the lock lever in the LOCK position. k Disconnect the cable from the negative (–) terminal of the battery.

ENGINE HOOD

INSTALLATION •

Carry out installation in the reverse order to removal.

[*1] • Adjust the hood catch. For details, see Testing and adjusting, "Testing and adjusting hood catch".

1. Open engine hood assembly (1) and lock it with the lock bar. a Fix the lock bar securely. 2. Remove cover (2).

3. Sling engine hood assembly (1) by passing the sling through the hole apeared by removing cover (2). 4. Remove lock bar (3). 5. Remove the mounting bolts for two hinges (4) and lift off engine hood assembly (1). [*1] 4 Engine hood assembly: 30 kg

PC78US-6

30-34-1 (18)

DISASSEMBLY AND ASSEMBLY

HYDRAULIC OIL COOLER ASSEMBLY

HYDRAULIC OIL COOLER

INSTALLATION •

Carry out installation in the reverse order to removal.

PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22001 and up REMOVAL a Remove the engine hood and counterweight (See REMOVAL OF COUNTERWEIGHT). 1. Disconnect the hose of reserve tank (1) from the radiator and remove it together with the tank bracket. 2. Remove receiver tank (2) from the frame. 3. Remove condenser (3) and arrange it and receiver tank so that they will not be obstacles. 4. Remove net (4) of the oil cooler.

5. Remove the bottom plate of oil cooler (5) and prepare an oil receiving container, then remove cooler inlet hose (6) and outlet hose (7). 6. Remove condenser bracket (8). Remove the 4 bolts used to secure the brackets on the top and bottom of the oil cooler, then remove the oil cooler.

PC78US-6

30-35 (11)

DISASSEMBLY AND ASSEMBLY

HYDRAULIC OIL COOLER

PC78US-6 Serial No.: 6501 and up REMOVAL

8. Remove the bottom plate of oil cooler (12) and prepare an oil receiving container, and then remove outlet hose (8) and cooler inlet hose (9).

a Swing the upper structure by 20 degrees.

9. Remove net bracket (10).

1. Remove the engine hood and open the vent of the hydraulic oil cooler.

10. Remove 2 mounting bolts (11) of oil cooler (12), and then remove oil cooler (12).

2. Remove reservoir tank (1) of the radiator and its bracket together. 3. Remove bracket (2). 4. Remove battery cover (3) and 2 batteries (4). 5. Remove condenser (5) and bind it to the vent of the hydraulic oil cooler. a Do not disconnect the piping. 6. Remove the oil cooler and radiator net (6). 7. Remove bracket (7).

INSTALLATION •

30-36 (11)

Carry out installation in the reverse order to removal.

PC78US-6

DISASSEMBLY AND ASSEMBLY

RADIATOR ASSEMBLY PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22001 and up

RADIATOR

3. Remove the 6 mounting bolts and fan (5). Loosen the clamps on the engine side and remove upper hose (6) and lower hose (7). [*2]

REMOVAL Remove the hydraulic oil cooler. For details, see REMOVAL OF HYDRAULIC OIL COOLER. [*1] 1. Move oil cooler (2) removed from radiator (1) to the left, without disconnecting the inlet and outlet hoses.

4. Remove the 2 bolts and bracket (8) installed to the partition under the operator's cab. Remove 2 mounting bolts (9) on the underside and radiator (1).

2. Loosen remote plug (3) on the bottom of the radiator to drain the cooling water into a container. Remove protector (4) of the air conditioner compressor from fan guard (1). 6 Cooliant: Approx. 4 l

a If the coolant contains antifreeze, handle it as harmful liquid. Do not handle it illegally.

INSTALLATION •

Carry out installation in the reverse order to removal.

[*1] When installing the radiator and oil cooler, check that the sealing material (sponge) between them is not deformed or broken but normal. [*2] 1. When inserting each hose, apply LG-6 to the adapter of the mating part. When tightening each clamp, check that it is not over the tube lock part. 2. 3 Hose clamp: 8.8 Nm {0.9 kgm}

PC78US-6

30-37 (11)

DISASSEMBLY AND ASSEMBLY

RADIATOR

REMOVAL PC78US-6 Serial No.: 6501 and up 1. Remove the counterweight. Removal of counterweight.

For details, see [*1]

2. Drain the coolant.

5 Coolant: Approx. 4 l a If the coolant contains antifreeze, handle it as harmful material according to the law.

3. Disconnect reservoir tank hose (1) of the radiator. 4. Loosen the clamps of upper hose (2) lower hose (3) on the engine side and disconnect those hoses. [*2]

13. Remove radiator (13) so that radiator outlet A will move around shroud (7).

5. Remove cushion (4). 6. Remove fan guard (5). 7. Remove cover (6). 8. Remove the 4 mounting bolts and shroud (7).

INSTALLATION •

9. Remove net (8).

[*1] When installing the radiator and oil cooler, check that the sealing material (sponge) between them is not deformed or broken but normal.

10. Disconnect clamp (9) and remove bracket (10). 11. Remove plug (11) from the bottom of the radiator. 12. Remove 2 radiator mounting bolts (12).

30-38 (11)

Carry out installation in the reverse order to removal.

[*2]

2 Mating face of hose:Gasket sealant (ThreeBond 1208E or equivalent)

3 Hose clamp: 8.8 ± 0.5 Nm {0.9 ± 0.5 kgm}

PC78US-6

DISASSEMBLY AND ASSEMBLY

SWING MOTOR AND SWING MACHINERY ASSEMBLY

SWING MOTOR AND SWING MACHINERY

6. Lift off swing motor and swing machinery assembly (6). [*1] 4 Swing motor and assembly: 77 kg

REMOVAL

swing

machinery

a Extend the work equipment to the maximum reach and lower it to the ground and stop the engine. k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank. 1. Remove the top cover of the swing motor 2. Disconnect hoses (1), (2), (3), (4), and (5) of the swing motor. a Fit male or female plugs to the removed hoses and elbows. a Record the disconnected hoses to prevent a mistake in re-connecting them.

INSTALLATION • [*1]

Carry out installation in the reverse order to removal.

2 Contact faces on underside of swing machinery case and frame: Apply gasket sealant (LG-6) 3 Swing machinery case mounting bolt: 245 – 308.7 Nm {25 – 31.5 kgm}

3. Remove the (9) swing machinery mounting bolts. 4. Pull the plugs out of the forcing screw holes of the swing machinery and hang the body of the swing machinery with 2 slings wound onto it.

a When installing the assembly, take care not to break the drain tube of the swing machinery case. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.

5. Using 2 forcing screws, disconnect the swing motor and swing machinery assembly (6) from the frame.

PC78US-6

30-39 (11)

DISASSEMBLY AND ASSEMBLY

SWING MACHINERY

SWING MACHINERY ASSEMBLY PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22001 and up DISASSEMBLY 1. Draining oil Remove the drain plug and drain the oil from the swing machinery. 6 Swing machinery case: Approx. 2 l

2. Swing motor assembly Remove swing motor assembly (1).

4) Drive in pin (9) to push out shaft (10). a After removing the shaft, remove pin (9). 5) Remove thrust washer (11) from carrier (12).

3. No. 1 sun gear and No. 1 carrier assembly 1) Remove No. 1 sun gear (2). 2) Remove No. 2 carrier (3).

3) Disassemble No. 1 carrier assembly according to the following procedure. i) Remove snap ring (4), thrust washer (5), gear (6), bearing (7), and thrust washer (8).

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PC78US-6

DISASSEMBLY AND ASSEMBLY

4. No. 2 sun gear Remove No. 2 sun gear (13).

SWING MACHINERY

2) Remove 2-piece collar (26).

5. Ring gear Remove ring gear (14). 6. No. 2 carrier assembly 1) Remove No. 2 carrier assembly (15).

8. Shaft assembly 1) Set block [1] to shaft and case assembly (27). Using push tool [2] and the press, remove shaft assembly (28). 2) Remove sub bearing (25). 2) Disassemble No. 2 carrier assembly according to the following procedure. i) Remove snap ring (16), thrust washer (17), gear (18), bearing (19), and thrust washer (20). ii) Drive in pin (21) to push out shaft (22). a After removing the shaft, remove pin (21). iii) Remove thrust washer (23) from carrier (24).

3) Set the shaft assembly to the press. Using push tool [3], remove main bearing (29) and collar (30) from shaft (31).

7. Collar 1) Set the shaft and case assembly to a press and push sub bearing (25) with tool F1. a Operate the press slowly and push the bearing until the 2-piece collar can be removed.

PC78US-6

30-41 (11)

DISASSEMBLY AND ASSEMBLY

9. Dust seal, oil seal, and bearing outer race 1) Remove dust seal (32) and oil seal (33) from case (34).

SWING MACHINERY

ASSEMBLY a Clean the all parts and check them for dirt or damage. Coat their sliding surfaces with engine oil before installing. 1. Oil seal Using tool F3, press fit oil seal (33) to case (34). a Replace the oil seal with new one. 3 Lip of oil seal:Grease (G2-LI)

3 Periphery of oil seal: Gasket sealant (LG-6)

2) Using tool F2, remove bearing outer races (35) and (36) from case (34).

2. Sub bearing outer race Using tool F4, press fit outer race (36) to case (34). a Press fitting force: Max. 8.82 kN {Max. 0.9 tons} 3. Main bearing outer race Using tool F5, press fit outer race (35) to case (34). a Press fitting force: Max. 19.6 kN {Max. 2.0 tons}

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PC78US-6

DISASSEMBLY AND ASSEMBLY

SWING MACHINERY

4. Shaft assembly 1) Install collar (30) to shaft (31). 2) Using tool F6 and the press, press fit main bearing (29). a Press fitting force: Max. 65.7 – 178.4 kN {Max. 6.7 – 18.2 tons}

5. Dust seal Using tool F9, press fit dust seal (32). a Replace the dust seal with new one.

3) Set case assembly (37) to shaft assembly (28). a Press fitting force: Max. 27.4 – 116.6 kN {Max. 2.8 – 11.9 tons} 4) Using tool F7 and the press, press fit sub bearing (25) until the 2-piece collar can be installed. a Press fitting force: Max. 27.4 – 116.6 kN {Max. 2.8 – 11.9 tons} a Turning the case, press fit the bearing slowly. 5) Install 2-piece collar (26).

6) Using tool [8] and the press, press fit shaft (31) until 2-piece collar (26) is secured. 7) Using tool F8, measure the running torque of the shaft. a Running torque: Max. 19.6 Nm {Max. 2.0 kgm}

PC78US-6

30-43 (11)

DISASSEMBLY AND ASSEMBLY

SWING MACHINERY

6. No. 2 carrier assembly 1) Assemble No. 2 carrier assembly according to the following procedure. i) Install thrust washer (23) to carrier (24). ii) Match shaft (22) to the pin hole of the carrier and install it by hitting it lightly with a plastic hammer. iii) Insert pin (21). a After inserting the pin, bend the pin of the carrier. iv) Install thrust washer (20), bearing (19), gear (18), thrust washer (17), and snap ring (16).

9. No. 1 carrier assembly 1) Assemble No. 1 carrier assembly according to the following procedure. i) Install thrust washer (11) to carrier (12). ii) Match shaft (10) to the pin hole of the carrier and install it by hitting it lightly with a plastic hammer. iii) Insert pin (9). a After inserting the pin, bend the pin of the carrier.

2) Install No. 2 carrier assembly (15) to the shaft and case assembly. 7. Ring gear Install ring gear (14).

2 Fitting face of ring gear: Gasket sealant (LG-6)

3 Ring gear mounting bolt: 58.5 – 73.5 Nm {6 – 7.5 kgm} 8. No. 2 sun gear Install No. 2 sun gear (13). a Take care not to install the sun gear and planetary gear upside down.

30-44 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

iv) Install thrust washer (8), bearing (7), gear (6), thrust washer (5), and snap ring (4).

SWING MACHINERY

a Supplying oil and grease Tighten the drain plug and supply engine oil through the oil filler. 6 Swing machinery case: Approx. 2 l

a Apply LG-5 to the fitting part of the drain tube.

3 Drain plug: 44.1 – 93.1 Nm {4.5 – 9.5 kgm}

a When mounting the assembly on the machine, apply gasket sealant LG-6 to the fitting face of the revolving frame.

2) Install No. 1 carrier assembly (3). 3) Install No. 1 sun gear (2).

10. Swing motor assembly Install swing motor assembly (1).

3 Mounting bolt: 58.8 – 73.5 Nm {6 – 7.5 kgm}

2 Fitting face of motor: Gasket sealant (LG-6)

PC78US-6

30-45 (11)

DISASSEMBLY AND ASSEMBLY

SWING MACHINERY

PC78US-6 Serial No.: 6501 and up DISASSEMBLY 1. Draining oil Remove the drain plug and drain the oil from the swing machinery. 6 Swing machinery case: Approx. 2 l

2. Swing motor assembly Remove swing motor assembly (1).

4. No. 2 sun gear Remove No. 2 sun gear (13). 5. Ring gear Remove ring gear (14).

3. No. 1 sun gear and No. 1 carrier assembly 1) Remove No. 1 sun gear (2). 2) Remove snap ring (3). 3) Remove No. 1 carrier (4).

6. No. 2 carrier assembly 1) Disassemble No. 2 carrier assembly according to the following procedure. • Remove snap ring (16), thrust washer (17), gear (18), bearing (19), and thrust washer (20). 2) Using tool F10, remove nut (21). 3) Remove carrier (22). 4) Remove sub bearing (25) from carrier (22). 3) Disassemble No. 1 carrier assembly (4) according to the following procedure. • Remove snap ring (5), thrust washer (6), gear (7), bearing (8), and thrust washer (9).

30-46 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

7. Shaft assembly 1) Set block [1] to shaft and case assembly (27). Using push tool [2] and the press, remove shaft assembly (28).

SWING MACHINERY

8. Oil seal, and bearing outer race 1) Remove oil seal (33) from case (34).

2) Using tool F2, remove bearing outer races (35) and (36) from case (34). 2) Remove main bearing (29) and grease seal (30) from shaft (31).

PC78US-6

30-47 (11)

DISASSEMBLY AND ASSEMBLY

ASSEMBLY a Clean the all parts and check them for dirt or damage. Coat their sliding surfaces with engine oil before installing. 1. Oil seal Using tool F11, press fit oil seal (33) to case (34). a Replace the oil seal with new one.

SWING MACHINERY

4. Shaft assembly 1) Install grease seal (30) to shaft (31). 2) Using tool F6 and the press, press fit main bearing (29). a Press fitting force: Max. 12.7 – 34.3 kN {Max. 1.3 – 3.5 tons}

3 Lip of oil seal:Grease (G2-LI)

3 Periphery of oil seal: Gasket sealant (LG-6)

2. Sub bearing outer race Using tool F12, press fit outer race (36) to case (34). a Press fitting force: Max. 5.88 kN {Max. 0.6 tons}

5. No. 2 carrier assembly 1) Using tool F7 and the press, press fit sub bearing (25) to No. 2 carrier (22). a Press fitting force: Max. 3.92 – 14.7 kN {Max. 0.4 – 1.5 tons} 2) Using tool [3] and the press, press fit No. 2 carrier (22) to spline of shaft. a Press fitting force: Max. 6.08 – 26.4 kN {Max. 0.62 – 2.69 tons} a Turning the case, press fit the bearing slowly.

3. Main bearing outer race Using tool F13, press fit outer race (35) to case (34). a Press fitting force: Max. 11.8 kN {Max. 1.2 tons}

30-48 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

3) Using tool F10, install nut (21). 2 Nut (21): LT-2

3 Nut (21): 784 – 833 Nm {80 – 85 kgm} 4) Using tools F8 and F10, measure the starting torque. a Starting torque: Max. 19.6 Nm {Max. 2.0 kgm}

5) Assemble the No. 2 carrier assembly according to the following procedure. • Install thrust washer (20), bearing (19), gear (18), and thrust washer (17) to carrier (22), and then install snap ring (16).

PC78US-6

SWING MACHINERY

6. Ring gear Install ring gear (14).

2 Mating face of ring gear: Gasket sealant (LG-6)

7. No. 2 sun gear Install No. 2 sun gear (13). a Take care not to assemble the sun gear and planetary gear up side down.

8. No. 1 carrier assembly 1) Assemble No. 1 carrier assembly (4) according to the following procedure. • Install thrust washer (9), bearing (8), gear (7), and thrust washer (6) to No. 1 carrier (10), and then install snap ring (5).

30-49 (11)

DISASSEMBLY AND ASSEMBLY

2) Install No. 1 carrier assembly (4). 3) Install snap ring (3). 4) Install No. 1 sun gear (2).

SWING MACHINERY, SWING MOTOR

SWING MOTOR ASSEMBLY REMOVAL a Remove the hoses of the swing motor. For details, see REMOVAL OF SWING MOTOR AND SWING MACHINERY ASSEMBLY. 1. Remove the 8 swing motor mounting bolts (1). 2. Remove the swing motor assembly. a After removing the swing motor, cover the swing machinery.

9. Swing motor assembly Install swing motor assembly (1).

3 Mounting bolt: 58.8 – 73.5 Nm {6 – 7.5 kgm}

INSTALLATION •

a Supplying oil and grease Tighten the drain plug and supply engine oil through the oil filler.

Carry out installation in the reverse order to removal. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.

6 Swing machinery case: Approx. 2 l

a Apply LG-5 to the fitting part of the drain tube.

3 Drain plug: 44.1 – 93.1 Nm {4.5 – 9.5 kgm} a When mounting the assembly on the machine, apply gasket sealant LG-6 to the fitting face of the revolving frame.

30-50 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

CENTER SWIVEL JOINT ASSEMBLY REMOVAL a Extend the work equipment to the maximum reach and lower it to the ground and stop the engine. k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank. 1. Remove the top cover of the center swivel joint. 2. Remove travel drain hose (1) and swing motor hose (2).

CENTER SWIVEL JOINT

4. Remove the bottom plate of the center swivel. 5. Remove the 4 travel forward/reverse and lateral hoses, 2 2nd travel speed selection hoses, 2 drain hoses, etc. (4) from the underside of the swivel. 6. Remove the cotter pin of the lock pin of the center swivel from above, then pull out the lock pin and disconnect the lock plate. 7. Hang the center swivel joint temporarily and remove the 4 mounting bolts from plate (5). a Fit male or female plugs to the removed hoses, nipples, and elbows and record the disconnected hoses to prevent a mistake in re-connecting them.

3. Remove 5 hoses (3) of the control valve, travel forward/reverse, lateral hose, and 2nd travel speed selection from the top one. a Fit male or female plugs to the removed hoses, nipples, and elbows. a Record the disconnected hoses to prevent a mistake in re-connecting them.

8. Lift off center swivel joint assembly (6).

4 Center swivel joint assembly: 18.5 kg

INSTALLATION •

Carry out installation in the reverse order to removal. a When installing the rubber hoses, be careful not to twist them. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.

PC78US-6

30-51 (11)

DISASSEMBLY AND ASSEMBLY

CENTER SWIVEL JOINT

DISASSEMBLY

ASSEMBLY

1. Remove cover (1).

1. Install slipper seal (7) and O-ring (6) to swivel shaft (5).

2. Remove snap ring (2). 3. Using tool T, pull swivel rotor (4) and ring (3) out of swivel shaft (5). 4. Remove O-ring (6) and slipper seal (7).

2. Set swivel shaft (5) to the block. Using the push tool, hit swivel rotor (4) with a plastic hammer lightly to install it. a Apply grease (G2-LI) to the contact surfaces of swivel shaft (5) and swivel rotor (4). a When installing the rotor, take care fully not to damage the lips of the slipper seal and oil seal. 3. Install ring (3) and secure it with snap ring (2). 4. Install the O-ring and cover (1).

3 Mounting bolt: 31.4 ± 2.94 Nm {3.2 ± 0.3 kgm} a When assembling, take care fully so that dirt, rust, flaw, etc. will not cause a trouble. a After assembling, seal each port with a polyethylene plug.

30-52 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

CONTROL VALVE

CONTROL VALVE ASSEMBLY REMOVAL

k Lower the work equipment to the ground and stop the engine, then loosen the oil filler cap gradually to release the residual pressure from the hydraulic tank. a Disconnect the wiring harness from the negative (-) terminal of the battery. 1. Remove the top cover of the hydraulic tank. 2. Remove the right side cover. 3. Remove 5 connectors (1) of the hydraulic switches and the wiring harness bracket.

8. Remove the 4 control valve mounting bolts from the underside of control valve stand (9) and lift off control valve assembly (10), using sling [1]. 4 Control valve assembly: 65 kg

4. Remove each pilot hose (2). 5. Remove hoses (3) between the pump and merge-divider valve. a Mask the removed connectors.

INSTALLATION 6. Remove hoses (5), (6), and (7) of attachment selector valve (4).

•

Carry out installation in the reverse order to removal.

[*1] 1. When assembling, take care fully so that dirt, rust, flaw, etc. will not cause a trouble. 2. When installing the rubber hoses, take care fully not to twist them. 3. Bleed all air from the swing PPC circuit. 4. After assembling, flush the all piping circuit. a The number of the control valves and pipes of a machine equipped with an attachment and those of Model UU are different from the above. 7. Remove hoses (8) on the operator's cab side of the control valve in order from the top one. [*1] a Fit male or female plugs to the removed hoses and nipples.

PC78US-6

30-53 (11)

DISASSEMBLY AND ASSEMBLY

CONTROL VALVE

ASSEMBLY a When disassembling and assembling the precision parts of the hydraulic system, keep them clean extremely and work in a clean place. a Take care fully not to hurt your fingers with the edges of the machines parts. a Check the fitting surfaces of the all parts. If a part has a scratch or a burr, replace it with new one since it can cause a trouble. Take care fully not to bruise or damage a part by dropping or hitting it. a Wash the all metallic parts in clean solvent and dry them with compressed air. If they are wiped with cloths or paper, fibers of the cloths and paper enter the product and contaminate the hydraulic system and can cause a trouble. Accordingly, never wipe the parts with cloths or paper. a When assembling, replace the consumable parts such as the O-rings and seals with new ones, as a rule. Apply a little amount of clean grease to the O-rings. a Take care of the installing direction of each spool. 1. When loosening or tightening mounting bolt (1) used to install the retainer of the spool return spring to each spool, be sure to put spool (2) in valve chest (3) (to prevent deformation of the spool). 3 : 6.9 – 9.8 Nm {0.7 – 1.0 kgm}

3. When loosening or tightening plug (10) of spool (9) of bucket valve (8), be sure to put spool (9) in valve chest (8). 4. When loosening or tightening plugs (13) and (14) of spool (12) of arm valve (11), be sure to put spool (12) in valve chest (11). 5. When loosening or tightening plugs (17) and (18) of spool (16) of boom valve (15), be sure to put spool (16) in valve chest (15). a When tightening each of the orifices and plugs described above, apply 1 drop (approx. 0.02 g) of LOCTITE (No. 638) to it. Thoroughly degrease and dry the plug and the f e m a l e s c r e w o f t h e v a l v e c h e s t wi t h DRYSOL. Do not apply pressure to them for 2 hours after they are tightened. 3 Orifice and plug: 14.7 – 19.6 Nm {1.5 – 2.0 kgm}

2. When loosening or tightening orifice (5) and plug (6) of merge-divider valve (4), be sure to put spool (7) in valve chest (4) (to prevent deformation of the spool).

30-54 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

6. Tighten the combination bolts (1) and (2) in the order of [1] – [4] gradually in 3 times. 1) Combination bolt (1) tightening torque. 1st tightening torque: 19.6 – 29.4 Nm {2 – 3 kgm} 2nd tightening torque: 39.2 – 49.0 Nm {4 – 5 kgm} 3rd tightening torque: 58.8 – 73.5 Nm {6 – 7.5 kgm} 2) Combination bolt (2) tightening torque 29.4 – 34.3 Nm {3 – 3.5 kgm}

CONTROL VALVE, WORK EQUIPMENT PPC VALVE

WORK EQUIPMENT PPC VALVE ASSEMBLY ASSEMBLY a When assembling, clean and inspect the parts closely and take care fully so that dirt, rust, flaw, etc. will not cause a trouble. 1. When installing plug (2) to body (1), take care that its tip will not enter the hole of the body 20 mm in diameter. 3 Plug (2): 4 – 9 Nm {0.4 – 0.9 kgm}

2. The head of plug (3) must no project from the body surface. 3 Plug (3): 6 – 11 Nm {0.6 – 1.1 kgm}

3. When installing piston (8), apply grease (G2-LI) to the outside of the piston and inside of the body hole.

a For the tightening torque of the auxiliary valves (Relief valve, suction safety valve, pressure compensation valve, etc.), see STRUCTURE AND OPERATION, MAINTENANCE STANDARD. a After assembling, seal each port with a nylon cap, etc. a When hanging the valve assembly, use eyebolts (04530-10815).

4. Install spring (5) with its small diameter side on the shim (4) side. • Diameter of spring (Inside diameter) Small diameter side: 4.9 mm Large diameter side: 5.55 mm 5. Different springs (6) and (7) are used for different hydraulic ports. Take care when installing them. PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22001 and up • •

Installed height: 34 mm Installed load Spring (6) (P1, P2): 29 N {3 kg} Spring (7) (P3, P4): 17.7 N {1.8 kg}

PC78US-6 Serial No.: 6501 and up • •

Installed height: 32 mm Installed load Spring (6) (P1, P2): 35 N {3.57 kg} Spring (7) (P3, P4): 21.77 N {2.22 kg}

3 Bolt (9): 11.8 – 14.7 Nm {1.2 – 1.5 kgm} 6. When installing joint (10) to body (1), apply LOCTITE as shown below. 1) When installing the joint, apply 1 drop (approx. 0.02 g) of LOCTITE (No. 262 or No. 648) each to 2 places of the female screw of the body. Before installing the joint, thoroughly degrease and dry its male screw and the female screw of the body with DRYSOL. 2) Drop LOCTITE to the following positions. Female screw of body

PC78US-6

30-55 (11)

DISASSEMBLY AND ASSEMBLY

WORK EQUIPMENT PPC VALVE

PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22001 and up

3 Joint (10): 39 – 49 Nm {4 – 5 kgm} 7. Apply grease (G2-LI) to the sliding parts of joint (10) and contact parts of disc (11) and piston (8). 2 Application rate of grease (G2-LI) 1) Sliding parts of joint: 2 - 4 cc/periphery 2) Contact parts of disc and piston: 0.3 - 0.8 cc/ place

8. When installing disc (11), adjust it so that the play at the lever end will be 0.5 - 3 mm (200 mm from the rotation center of the lever).

3 Nut (12): PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22001 and up 98 – 127 Nm {10 – 13 kgm} PC78US-6 Serial No.: 6501 and up 69 – 88 Nm {7 – 9 kgm}

30-56 (11)

PC78US-6 Serial No.: 6501 and up

PC78US-6

DISASSEMBLY AND ASSEMBLY

TRAVEL PPC VALVE ASSEMBLY ASSEMBLY a When assembling, clean and inspect the parts closely and take care fully so that dirt, rust, flaw, etc. will not cause a trouble.

TRAVEL PPC VALVE

8. Tighten each part to the following torque. • Plug (11): 6 – 11 Nm {0.6 – 1.1 kgm} • Bolt (12): 3.9 – 4.9 Nm {0.4 – 0.5 kgm} (Apply LOCTITE #262.) • Screw (13): 7.8 – 9.8 Nm {0.8 – 1.0 kgm} • Plug (14): 4 – 9 Nm {0.4 – 0.9 kgm} • Bolt (15): 25 – 30 Nm {2.5 – 3.2 kgm} • Bolt (16): 27 – 34 Nm {2.8 – 3.5 kgm}

1. When installing piston (1), apply grease (G2-LI) to its outside and the inside of the body hole. 2. Install spring (2) with its small diameter side on the shim (3) side. • Diameter of spring (Inside diameter) Small diameter side: 4.9 mm Large diameter side: 5.55 mm 3. Use the insertion jig to insert bushing (4). (Do not drive in the bushing with impact loads of a hammer, etc.) 4. Use the insertion jig to insert pin (5). (Do not drive in the pin with impact loads of a hammer, etc.) 5. Apply grease (G2-LI) to the rocking part of shaft (6) and the contact surfaces of lever (7) and piston (1) and the contact surfaces of plate (8) and pin of lever (9). 2 Quantity of grease (G2-LI) Rocking part of shaft:4 – 8 cc/periphery Contact surfaces of lever and piston: 0.3 – 0.8 cc/place Contact surfaces of plate and pin: 0.3 – 0.8 cc/place

6. Install washer (10) 1.6 mm thick first. If the difference between both sides at the stroke end of the lever exceeds 0.7°, change the washer thickness to reduce the difference to below 0.7°. (If the washer thickness is reduced by 0.3 mm, the stroke end angle is increased by 0.39°.) • Thickness of washer t: 1.0, 1.3, 1.6 mm 7. After assembling, seal the ports (P1 – P4, T, P) with nylon caps, etc.

PC78US-6

30-57 (11)

DISASSEMBLY AND ASSEMBLY

HYDRAULIC TANK ASSEMBLY PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22001 and up

HYDRAULIC TANK

8. Remove hose (6) from the oil cooler and the other hoses. a Fit male or female plugs to the removed hoses, elbows, etc. a Record the disconnected hoses to prevent a mistake in re-connecting them.

REMOVAL a Swing the work equipment to a position at which the hydraulic oil can be drained easily and lower the work equipment to the ground. k Stop the engine and loosen the hydraulic oil filler cap gradually to release the residual pressure from the hydraulic tank. 1. Drain the oil from the hydraulic tank. 2. Remove the top cover and right side cover of the hydraulic tank. 3. Remove the wiring harness clamp and washer tank (1).

9. Using sling (1), remove the mounting bolts and lift off hydraulic tank assembly (7).

4. Loosen the clamp and remove pump suction hose (2). 6 Hydraulic tank: 64 l

INSTALLATION •

5. Remove partition cover (3) of the boom. 6. Remove work equipment attachments selector valve (4).

Carry out installation in the reverse order to removal. a When installing the rubber hoses, be careful not to twist them. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.

7. Remove 5 return hoses (5), including the swing hose.

30-58 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

PC78US-6 Serial No.: 6501 and up

HYDRAULIC TANK

6. Remove hose clamp (7) and slacken hose (8).

REMOVAL a Swing the upper structure by to the right by 90 degrees and lower the work equipment to the ground. k Stop the engine and loosen the hydraulic tank cap gradually to release the residual pressure in the tank. a Disconnect the wiring harness from the negative (-) terminal of the battery. 1. Drain the oil from the hydraulic tank. 6 Hydraulic tank: 70 l

2. Remove top cover (1), right side cover (2), and cover (3) from the hydraulic tank.

3. Remove the wiring harness clamp of washer tank (4), disconnect the washer tank, and put it on the control valve.

7. Disconnect hoses (9) and (10). 8. Disconnect clamp (11).

9. Remove cover (12) and disconnect fuel level sensor connector (13) from inside.

4. Loosen the clamp of pump suction hose (5) and disconnect the hose. 5. Disconnect 8 return hoses (6), including the swing return hose. a Install a male or female plug to each of the disconnected hoses and elbows. a Record the positions of the disconnected hoses so that you can correctly connect them again.

PC78US-6

30-59 (11)

DISASSEMBLY AND ASSEMBLY

10. Move fuel tank (14) in the direction of the arrow and stabilize it with block [1]. 11. Remove the 4 mounting bolts and lift off hydraulic tank (15). [*1] 4 Hydraulic tank: 70 kg

HYDRAULIC TANK

INSTALLATION •

Carry out installation in the reverse order to removal.

[*1]

2 Mounting bolt: Adhesive (LT-2)

3 Mounting bolt: 98 – 123 Nm {10 – 12.5 kgm} a Connect the hoses so carefully that they will not be twisted. a Refilling with oil (Hydraulic tank) Add oil to the specified level. Run the engine to circulate the oil through the piping. Then, check the oil level again and add oil to the specified level.

30-60 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

FUEL TANK ASSEMBLY PC78US-6 Serial No.: 4001 – 4903 PC78UU-6 Serial No.: 22001 – 22788

FUEL TANK

7. Remove the inspection cover of fuel suction hose (7) and drain hose (8) from the underside of the revolving frame under the fuel tank, then remove the suction hose and drain hose.

REMOVAL a Disconnect the wiring harness from the negative terminal of the battery. a Drain the fuel through the drain valve. 6 When fuel tank is full: 125 l

1. Remove the front and left deck covers. 2. Remove the mounting bolts of fuel filler mounting cover (1) and loosen the hose clamp of the fuel filler tube and pull out the tube. 3. Remove the clamp and hose (2) of the fuel spill prevention gauge and take out cover (1). 4. Loosen the clamp of fuel supply hose (3) on the fuel tank (4) side and remove the hose from the tank.

8. Remove the 2 mounting bolts of fuel tank bracket (9) on this side from the underside of the revolving frame. 9. Remove the 2 bolts of PPC hose bracket (10) and move them to the left (to secure a wider work space).

5. Remove the clamp of PPC hose (5) from the underside of the floor.

10. Remove the nut and fuel tank band (11) on the deeper side from the tank. [*1] 6. Remove the fuel sensor top cover of the floor and disconnect sensor connector (6).

PC78US-6

30-61 (11)

DISASSEMBLY AND ASSEMBLY

11. Pull out and remove fuel tank (4). a Fuel tank air bleeding hose (12) is not installed.

FUEL TANK

PC78US-6 Serial No.: 4904 – 6500 PC78UU-6 Serial No.: 22789 and up REMOVAL a Disconnect the wiring harness from the negative (-) terminal of the battery. 6 Drain the fuel. When fuel tank is full: 125 l

1. Remove the front and left deck covers. 2. Remove the mounting bolts of fuel filler mounting cover (1). Loosen the hose clamp of the fuel filler tube and pull out the tube.

INSTALLATION •

Carry out installation in the reverse order to removal.

3 Tightening torque of tank mounting band (11): Nut (23): 0.98 ± 0.49 Nm {0.1 ± 0.05 kgm} Nut (24): 58.8 ± 9.8 Nm {6.0 ±1.0 kgm}

30-62 (11)

3. Remove the clamp of fuel spill prevention check gauge hose (2), and then remove the hose and cover (1) together. 4. Loosen the clamp of fuel feed hose (3) installed to fuel tank (4), and the remove the hose from the tank. 5. Remove the fuel level sensor top cover on the floor and disconnect sensor connector (6).

PC78US-6

DISASSEMBLY AND ASSEMBLY

FUEL TANK

6. Remove the mounting bolts of P-block (21) and T-block (22) for the PPC piping from under the front of the operator's cab. a Perform this work to avoid tensing the hose between P-block (21), T-block (22), and solenoid valve (A). (In the photo, the plate is removed.)

9. Remove the inspection cover of fuel suction hose (7) and drain hose (8) from the underside of the revolving frame under the fuel tank, then remove the suction hose and drain hose.

10. Remove the 2 mounting bolts of the fuel tank bracket (9) on this side from the underside of the revolving frame. 7. Remove 4 operator's cab assembly mounting bolts (27) marked with #. [*1] a Do not remove 6 mounting bolts (28) marked with .

8. Install a sling to the top of the operator's cab assembly and lift up the operator's cab assembly and floor frame assembly together to about 100 mm above the chassis and stabilize them with blocks. a Since the wires and hoses are still connected, take care not to tense any of them. 4 Operator's cab and assembly : 480 kg

PC78US-6

floor

11. Remove the 2 bolts of PPC hose bracket (10) and move them to the left (to secure a wider work space).

12. Remove the nut and fuel tank band (11) on the deeper side from the tank. [*2]

frame

30-63 (11)

DISASSEMBLY AND ASSEMBLY

13. Pull out fuel tank (4) and remove the clamp and tank air bleed hose (12), then remove the fuel tank.

FUEL TANK

PC78US-6 Serial No.: 6501 and up REMOVAL a Swing the upper structure by to the right by 90 degrees and lower the work equipment to the ground. a Disconnect the wiring harness from the negative (-) terminal of the battery. 1. Drain the fuel.

6 When fuel tank is full: 125 l

2. Remove top cover (1), right side cover (2), cover (3), and bottom cover (4) from fuel tank (11).

INSTALLATION •

Carry out installation in the reverse order to removal.

[*1]

3 Operator's cab mounting nut: 235 – 309 Nm {24 – 31.5 kgm}

[*2]

3 Tightening torque of tank mounting band (11): Nut (23): 0.98 ± 0.49 Nm {0.1 ± 0.05 kgm} Nut (24): 58.8 ± 9.8 Nm {6.0 ±1.0 kgm}

30-64 (11)

3. Remove cover (5) and disconnect fuel level sensor connector (6) from inside.

PC78US-6

DISASSEMBLY AND ASSEMBLY

FUEL TANK, CONTROLLER

4. Disconnect hoses (7) and (8) from fuel tank (11).

CONTROLLER ASSEMBLY

5. Disconnect fuel feed hose (9) and fuel drain hose (10) from under fuel tank (11).

REMOVAL PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22001 and up a Disconnect the wiring harness from the negative (-) terminal of the battery. 1. Remove 4 bolt caps (2) of cover (1) at the rear of the operator's seat. 2. Remove the 4 bolts and cover (1).

6. Sling fuel tank (11) temporarily and remove the 4 mounting bolts. 7. Lift off fuel tank (11).

4 Fuel tank: 50 kg

3. Loosen the mounting bolts and remove connectors (4), (5), and (6) of controller (3). 4. Remove the 4 mounting bolts and controller assembly (3).

INSTALLATION •

Carry out installation in the reverse order to removal. 3 Mounting bolt: Adhesive (LT-2)

INSTALLATION •

Carry out installation in the reverse order to removal. a Do not tighten the mounting bolts of connectors too strongly.

PC78US-6

30-65 (11)

DISASSEMBLY AND ASSEMBLY

PC78US-6 Serial No.: 6501 and up a Disconnect the wiring harness from the negative (-) terminal of the battery. 1. Remove 4 bolt caps (2) of cover (1) at the rear of the operator's seat. 2. Remove the 4 bolts and cover (1).

CONTROLLER, MONITOR PANEL

MONITOR PANEL ASSEMBLY REMOVAL a Disconnect the wiring harness from the negative (-) terminal of the battery. 1. Pull cover (2) of monitor panel (1) and remove the claw stopper. 2. Remove side cover (3). 3. Remove the stopper of cover (4).

3. Loosen the mounting bolts and remove connectors (4) of controller (3). 4. Remove the 4 mounting bolts and controller assembly (3).

4. Remove the 3 mounting bolts of monitor panel (1) and connectors (5) and (6) on the back side, then remove monitor panel assembly (1).

INSTALLATION •

Carry out installation in the reverse order to removal. a Do not tighten the mounting bolts of connectors too strongly.

30-66 (11)

INSTALLATION •

Carry out installation in the reverse order to removal.

PC78US-6

DISASSEMBLY AND ASSEMBLY

AIR CONDITIONER UNIT

AIR CONDITIONER UNIT ASSEMBLY

8. Loosen the clamp and remove heater hose (8) under the rear part of the operator's seat.

REMOVAL

9. Remove 3 wiring harness connectors (9) for the air conditioner under the rear part of the operator's seat.

a Disconnect the wiring harness from the negative terminal of the battery. a Using tool X3, collect air conditioner refrigerant (R134a). [*1] 1. Remove floor mat (1). 2. Move the right console toward the inside of the cab. 3. Remove duct covers (2) (having the cigarette lighter connector) and (3). 4. Remove air conditioner unit cover (4).

10. Remove duct connector (14) and 2 mounting bolts (15) from under the rear of the operator's seat, and then remove duct assembly (16).

5. Remove duct (5) and the rear duct. 6. Remove cover (6). 7. Remove 2 tubes (7) and push them in under the floor. [*2] a Fit male or female plugs to the removed tubes.

PC78US-6

30-67 (11)

DISASSEMBLY AND ASSEMBLY

11. Remove 5 mounting bolts of operator's seat stand (10). 12. Raise the operator's seat stand to 60 mm above the floor by using 4 forcing screws (11) having screwing length of 70 – 80 mm, and the unit can be taken out. a If the operator's seat stand is raised too high, it will interfere with the wiring harnesses on both sides.

AIR CONDITIONER UNIT

INSTALLATION •

Carry out installation in the reverse order to removal. a Using tool X3, collect air conditioner refrigerant (R134a). [*1] 1. Connect the power cable for the compressor after charging the air conditioner with refrigerant gas (R134a). 2. Do not connect the outlet and inlet hoses of the receiver drier before the air conditioner is charged with refrigerant gas. 3. When assembling, take care that water (moisture), dirt, or air will not enter the air conditioner cycle. [*2] 1. When fitting the pipes, apply compressor oil (SNISO 5GS) to the flared parts and threaded parts.

13. Remove the 3 front mounting bolts and 3 rear ones and air conditioner unit assembly (12).

2. Tighten the nuts on both ends of the refrigerant circuit hose to the following torque. Size

30-68 (11)

Width Dimensions across of thread flats

Tightening torque Nm {kgm}

# 08

16 X 1.5

19

11.8 – 14.7 {1.2 – 1.5}

# 11

20 X 1.5

24

19.6 – 24.5 {2.0 – 2.5}

# 14

22 X 1.5

27

29.4 – 34.3 {3.0 – 3.5}

PC78US-6

DISASSEMBLY AND ASSEMBLY

OPERATOR'S CAB ASSEMBLY REMOVAL

OPERATOR'S CAB

7. Disconnect monitor panel connectors (8), (9), and (10) from the right rear.

a Disconnect the wiring harness from the negative terminal of the battery.

8. Disconnect radio connectors (11) and (12) from the left rear, and then disconnect radio cable from jack (13).

1. Remove the floor mat.

9. Disconnect duct connector (14).

2. Move right console (1) toward the inside of the cab.

10. Remove 2 mounting bolts (15) and duct assembly (16).

3. Remove monitor panel undercover (2). a Disconnect cigarette lighter connector (3) without fail. 4. Remove cover (4). 5. Remove connector (5) and air conditioner duct (6). 6. Disconnect washer tank hose (7).

11. Remove the seat rear cover and wiring harness clamp (21). 12. Remove controller (22) and mounting plate (23) together and put them down.

a Controllers (22) on PC78US-6, serial No. 4001 – 6500, and on PC78UU-6, serial No. 22001 and up, are different, but they are removed by the same procedure. 13. Remove the 6 mounting bolt on the operator's cab floor. 14. Remove the operator's cab mount nut.

PC78US-6

[*1]

30-69 (11)

DISASSEMBLY AND ASSEMBLY

OPERATOR'S CAB

15. Using lever block [1], lift off operator's cab assembly (24). 4 Operator's cab assembly: 280 kg

INSTALLATION •

Carry out installation in the reverse order to removal.

[*1]

3 Operator's cab mount nut: 235 – 309 Nm {24 – 31.5 kgm}

30-70 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

FLOOR FRAME ASSEMBLY REMOVAL a Remove the operator's cab assembly. (See REMOVAL OF OPERATOR CAB.) a Using tool X3, collect air conditioner refrigerant (R134a). [*1]

FLOOR FRAME

8. Remove 8 hoses (8) of the work equipment control valve from the couplers. a Record the connecting mates of the hoses. 9. Disconnect 4 hoses (21) from under the blade lever. a Record the connecting mates of the hoses.

1. Remove the air conditioner unit cover from the seat. 2. Remove front deck cover (1) and left deck cover (2). 3. Remove 8 wiring harness connectors (3) of engine and pump control systems. a Only 1 connector is used on PC78US-6, serial No. 6501 and up. 4. Remove 3 solenoid connectors (4) and cable clamp (5). 5. Remove the wiring harness connector of horn (6). 6. Remove 2 air conditioner gas tubes (7). (Fit male or female plugs to the removed tubes.)

10. Remove the 4 hoses connected to travel right and left control valves (9). 11. Remove the 2 hoses connected to the attachment control valve (10).

7. Disconnect 2 hoses (20). a Record the connecting mates of the hoses.

12. Loosen the clamps and remove 2 heater hoses (11). (At the rear of the operator's seat)

PC78US-6

30-71 (11)

DISASSEMBLY AND ASSEMBLY

13. Remove the 4 mounting bolts used to install the floor frame to floor mount (12).

FLOOR FRAME

INSTALLATION •

Carry out installation in the reverse order to removal.

[*1] a See INSTALLATION OF AIR CONDITIONER UNIT ASSEMBLY. [*2] a See TESTING AND ADJUSTING, Adjusting fuel control linkage. 3 Locknuts of bracket (15) (2 pieces): 9.8 – 14.7 Nm {1.0 – 1.5 kgm}

14. Open the engine top cover. 15. Remove the 2 locknuts from fuel injection pump bracket (15). [*2] 16. Remove nut (16) and pull out accelerator wires (14) from the injection pump through the hole of the revolving frame toward the floor. [*2] a This work is not necessary for PC78US-6, serial No. 6501 and up.

17. Install 4 eyebolts (1) to floor frame (13) and lift off the floor frame assembly. 4 Floor frame assembly: 200 kg

30-72 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

OPERATOR'S CAB GLASS (STUCK GLASS)

OPERATOR’S CAB GLASS (STUCK GLASS)

Amoung the panes of window glass on the 4 sides of the operator’s cab, 5 panes (1) – (5) are stuck. In this section, the procedure for replacing the stuck glass is explained. When replacing front window glass (5), remove front window assembly (6). (It is impossible to replace only the front window glass while the front window assembly is installed to the operator’s cab.) For the procedure for replacing the front window assembly, see REMOVAL AND INSTALLATION OF FRONT WINDOW ASSEMBLY.

PC78US-6

(1): (2): (3): (4): (5): (6):

Right side window glass Left side rear window glass Door upper window glass Door lower window glass Front window glass Front window assembly (Front window glass + Front frame) ( 7 ) : Both-sided adhesive tape (16) : Center trim seal

30-73 (11)

DISASSEMBLY AND ASSEMBLY

OPERATOR'S CAB GLASS (STUCK GLASS)

1 793-498-1210 Y

2

t

2

2 20Y-54-13180 Adapter

(The figure shows the operator’s cab of a wheel loader.) Sketch

Lifter t (Suction cup)

Part name

New/Removal

Q’ty

Part No.

Necessity

Symbol

SPECIAL TOOLS

REMOVAL a Remove the window glass to be replaced accoring to the following procedure. 1. Using seal cutter [1], cut the adhesive between broken window glass (7) and operator’s cab (metal sheet) (8).

a If the window glass is broken finaly, it may be removed with knife [4] and a screwdriver. a Widening the cut with a screwdriver, cut the adhesive and both-sided adhesive tape with knife [4]. (The figure shows the operator’s cab of a wheel loader.)

a If a seal cutter is not available, make holes on the adhesive and both-sided adhesive tape with a drill and pass a fine wire (piano wire, etc.) [2] through the holes. Grip the both ends of the wire with priors [3], etc. (or hold them by winding them onto something) and move the wire to the right and left to cut the adhesive and both-sided adhesive tape. Since the wire may be broken by the frictional heat, apply lubricant to it.

30-74 (11)

2. Remove the window glass.

PC78US-6

DISASSEMBLY AND ASSEMBLY

OPERATOR'S CAB GLASS (STUCK GLASS)

INSTALLATION 1. Using a knife and scraper [5], remove the remaining adhesive and both-sided adhesive tape from the metal sheets (glass sticking surfaces) of the operator’s cab. a Remove the adhesive and both-sided adhesive tape to a degree that they will not affect adhesion of the new adhesive. Take care not to scratch the painted surfaces. (If the painted surfaces are scratched, adhesion will be lowered.) (The figure shows the operator’s cab of a wheel loader.)

2. Remove oil, dust, dirt, etc. from the sticking surfaces of cab (8) and window glass (9) with white gasoline. a If the sticking surfaces are not cleaned well, the glass may not be stuck perfectly. a Clean the all back part on the back side of the window glass. a After cleaning the sticking surfaces, leave them for at least 5 minutes to dry.

PC78US-6

3. Apply primer (10). a The using limit of primer (10) is 4 months after the date of manufacture. Do not use primer (10) after this limit. a Use the primer within 2 hours after unpacking it. a Even if the primer is packed again just after it is unpacked, use it within 24 hours after it is unpacked for the first time. (Discard the primer 24 hours after it is packed.) 1) Stir the primers for paint and glass sufficiently before using them. a If the primer has been stored in a refrigerator, leave it at the room temperature for at least half a dry before stirring it. (If the primer is unpacked just after taken out of the refrigertor, water will be condensed. Accordingly, leave the primer at the room temperature for a sufficient time.) 2) When reusing primer brush (11), wash it in white gasoline. a After washing the brush, check it again for dirt and foreign matter. a Prepare respective brushes for the paint primer glass primer.

30-75 (11)

DISASSEMBLY AND ASSEMBLY

3) Evenly apply paint primer to the surfaces to stick both-sided adhesive tapes and the surfaces out of those surfaces on operator’s cab (8) which will be coated with the adhesive.

2 Paint primer: SUNSTAR PAINT PRIMER 580 SUPER or equivalant a Do not apply the primer more than 2 times. (If it is applied more than 2 times, its performance will be lowered.)

a Parts to be coated with primer: Apply the primer all over dimension (a). • Dimension to apply primer (a): 25 mm

30-76 (11)

OPERATOR'S CAB GLASS (STUCK GLASS)

a As for right side window glass (1), apply the primer to only the periphery of the glass to stick the both-sided adhesive tapes and the areas out of it to apply the adhesive. • Part (b) a After applying the primer, leave it for at least 5 minutes (within 8 hours) to dry.

a Never apply wring primer. If the glass primer is applied by mistake, wipe it off with white gasoline. 4) Evenly apply glass primer to the sticking surfaces of window glass (9).

2 Glass primer: SUNSTAR GLASS PRIMER 580 SUPER or equivalant a Do not apply the primer more than 2 times. (If it is applied more than 2 times, its performance will be lowered.)

PC78US-6

DISASSEMBLY AND ASSEMBLY

a Parts to be coated with primer: Apply the primer to the sticking surfaces of window glass (9) and all over dimension (d) which will be on both-sided adhesive tape (7) and operator’s cab (8). a Do not apply the primer to the boarder about 5 mm wide between the black part and transparent part of the glass. a After applying the primer, leave it for at least 5 minutues (within 8 hours) to dry. a Never apply wring the primer. If the glass primer is applied by mistake, wipe it off with white gasoline.

OPERATOR'S CAB GLASS (STUCK GLASS)

a When sticking both-sided adhesive tape (7) around a frame, do not lap its finishing end over the starting end but make clearance e of about 5 mm between them. 1) Stick both-sided adhesive tape (7) for right side window glass (1) as shown in the figure.

a Stick both-sided adhesive tape (7a) additionally for right side window glass (1). • Positions to stick additional both-sided adhesive tape for right side window glass. (f) : 140 mm (g) : 500 mm 4. Stick both-sided adhesive tape (7) along the inside edge of the glass sticking section. a Do not remove the release tape of the bothsided adhesive tape on the glass sticking side before stiking the glass. a When sticking the both-sided adhesive tape, do not touch the cleaned surface as long as possible. a Take that the both-sided adhesive tape will not float at each corner of the window frame.

PC78US-6

30-77 (11)

DISASSEMBLY AND ASSEMBLY

2) Stick both-sided adhesive tape (7) for left side rear window glass (2) as shown in the figure.

3) Stick both-sided adhesive tape (7) for door upper window glass (3) and lower window glass (4) as shown in the figure. (The figure shows the door upper window glass.)

OPERATOR'S CAB GLASS (STUCK GLASS)

4) Stick both-sided adhesive tape (7) for front window glass (5) as shown i the figure. a Both-sided adhesive tape: 1,004 mm × 2 pieces

•

Details of the sticking positions are as follows. (h) :Stick to inside end of right and left front frames (17). (j) : Retract by "3.0 mm" from the end of front frame (17).

(The figure shows the door lower window glass.)

30-78 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

OPERATOR'S CAB GLASS (STUCK GLASS)

5. Possition the new window glass. 1) Check the clearance between the window glass and the operator’s cab on the right, left, upper, and lower sides, and then adjust it evenly. 2) Stick tapes [6] between window glass (9) and operator’s cab (8) and draw positioning line n. a Stick tapes [6] to the right, left, and lower parts of the right side window glass, left side rear window glass, and door lower window glass for accurate positioning. 3) Cut the tape between window glass (9) and operator’s cab (8) with a knife, and then remove the window glass. a Do not remove the tapes left on the window glass and operator’s cab before installing the window glass.

6. Apply adhesive. a Use either of the 2 types of the adhesive. a When positioning front window glass (5), set its horizontal and vertical positions as shown below. Part (m) (Right side):Project by "3.8 mm" from the frame end. Part (o) (Upper side):Retract by "3.0 mm" from the frame end.

PC78US-6

2 Adhesive (Summer): SUNSTAR PENGUINE SEAL 580 SUPER "S" 2 Adhesive (Winter): SUNSTAR PENGUINE SEAL 580 SUPER "W" a The using limit of the adhesive is 4 months after the date of manufacture. Do not use the adhesive after this limit. a Keep the adhesive in a dark place where the temperaure is below 25°C. a Never heat the adhesive higher than 30°C. a When reusing the adhesive, remove the all hardened part from the nozzle tip.

30-79 (11)

DISASSEMBLY AND ASSEMBLY

OPERATOR'S CAB GLASS (STUCK GLASS)

1) Break aluminum seal (13) of the outlet of adhesive cartridge (12) and install the nozzle.

2) Cut the tip of the adhesive nozzle (14) so that dimension q and r will be as follows. • Dimension (q) : 10 mm • Dimension (r) : 15 mm

3) Set adhesive cartridge (12) to caulking gun [7]. a An electric caulking gun is more efficient.

a Apply adhesive (15) to dimensions s and t of both-sided adhesive tape (7) of operator’s cab (8). • Dimension (s) : 10 mm • Dimension (t) : 15 mm a Apply adhesive (15) higher than bothsided adhesive tape (7). a Apply the adhesive evenly.

a As for the right side window glass, apply the adhesive to the outside of the bothsided adhesive tape on the periphery of the glass.

4) Remove the release tape of the both-sided adhesive tape on the glass side. 5) Apply adhesive (15) to the outside of bothsided adhesive tape (7) of the operator’s cab.

30-80 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

7. Install the window glass. 1) Install window glass (9), matching it to the lines of the positioning tapes drawn in step 5. a Sine the window glass cannot be removed and stuck again, stick it very carefully. a Stick the glass within 5 minutes after applying the adhesive. 2) After sticking window glass (9), press all around it until it is stuck to the both-sided adhesive tape. a Press the corners of the window glass firmly.

OPERATOR'S CAB GLASS (STUCK GLASS)

a After installing front window glass (5), install the center trim seal to its bottom. Then, apply caulking material all around the glass to fill part U between the glass and center trim seal. a When caulking, neatly arrange the form of the adhesive at the right and left ends with a rubber spatula. 2 Adhesive: Sikaflex 256HV manufactured by Sika Japan

a You can perform this work efficiently by pulling window glass (9) from inside of the operator’s cab with suction cup X1. (The figure shows the operator's cab of PC200-7.)

PC78US-6

30-81 (11)

DISASSEMBLY AND ASSEMBLY

8. Fix the window glass. 1) After installing right window glass (1) to the operator’s cab, insert stopper rubbers X2 to 2 places (v) at the bottom of the glass to fix the glass. (The figure shows the operator's cab of PC2007.)

OPERATOR'S CAB GLASS (STUCK GLASS)

9. After installing the window glass, remove the primer and adhesive from the operator’s cab and window glass. a Using white gasoline, wipe off the adhesive before it is dried up. a When cleaning the glass, do not give an impact to it. 10. Protect the stuck window glass. 1) Keep the stopper rubbers, styrene form blocks, and rubber bands installed for 10 hours (at temperature of 20°C and humidity of 60%). 2) After removing the stopper rubbers, styrene foam blocks, and rubber bands, wait at least 14 hours, at least 24 hours in total, before operating the machine actually.

(The figure shows the operator's cab of PC2007.)

2) Using styrene foam blocks [9] and rubber bands [10], fix the window glass and bothsided adhesive tape of fit them completely. (The figure shows the operator's cab of PC2007.)

30-82 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

FRONT WINDOW

FRONT WINDOW ASSEMBLY

k Lower the work equipment to the ground and stop the engine. a To replace the front window glass, the front window assembly must be removed from the operator’s cab. The procedure for removing and installing the front window assembly (front frame and front window glass) is explained below.

REMOVAL 1. Raise the front window assembly to the ceiling and fix it with the rear locks (on both sides). [*1] 2. Remove left lower block (1) and right lower block (2). [*2]

3. Reset the lock at the rear of the cab. 4. Lower front window assembly (3) carefully a little. Put out rollers (4) and (5) under the right and left sides of the front window through the portion from which the right and left lower blocks were removed in step 2 (the bottom of the rails).

5. Twist front window assembly (3) to the right and left to remove right and left upper rollers (6) and (7) from the rails, and then remove front window assembly (3). a For (6) and (7), see the figure above.

INSTALLATION •

PC78US-6

Carry out installation in the reverse order to removal.

30-83 (11)

DISASSEMBLY AND ASSEMBLY

REVOLVING FRAME ASSEMBLY REMOVAL

REVOLVING FRAME

5. Remove fuel filler mounting cover (4). 6. Remove receiver drier (5) and bracket together from the revolving frame and place them on their side.

PC78US-6 Serial No.: 4001 – 6500 PC78UU-6 Serial No.: 22001 and up a Disconnect the wiring harness from the negative terminal of the battery. a Remove the work equipment assembly. (See REMOVAL OF WORK EQUIPMENT ASSEMBLY.) a Remove the operator's cab assembly. (See REMOVAL OF OPERATOR'S CAB ASSEMBLY.) 1. Remove the engine hood. 2. Remove air cleaner assembly (1) and bracket hose together. 3. Remove engine ventilator cover (2).

7. Remove the top cover of the center swivel joint. 8. Remove travel drain hose (11) and swing motor hose (12). 9. Remove 5 hoses (13) for the control valve, forward and reverse, right and left, 2nd travel speed selection, etc. in order from the top. a Install a male or female plug to each of the disconnected hoses, nipples, and elbows. a Record the positions of the disconnected hoses so that you can correctly connect them again.

4. Hang boom cylinder assembly (3) temporarily and remove the hoses on the head side and bottom side. Pull out the mounting pin on the bottom side and lift off the cylinder assembly.

30-84 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

10. Remove the mounting bolts of swing circle outer race (6) on the revolving frame, leaving 3 each at the front and rear. [*1]

REVOLVING FRAME

REMOVAL PC78US-6 Serial No.: 6501 and up a Disconnect the wiring harness from the negative terminal of the battery. a Remove the work equipment assembly. (See REMOVAL OF WORK EQUIPMENT ASSEMBLY.) a Remove the operator's cab assembly. (See REMOVAL OF OPERATOR'S CAB ASSEMBLY.) 1. Remove the engine hood. 2. Remove air cleaner assembly (1) and bracket hose together. 3. Remove engine ventilator cover (2).

11. Install a sling to the boom foot mounting unit and both sides of counterweight (7) and lift off the revolving frame assembly, hanging it by 3 points. a Use the hole of the revolving frame on the left rear side from which the receiver drier was removed. 12. Remove the remaining revolving frame mounting bolts and lift off the revolving frame assembly.

4. Hang boom cylinder assembly (3) temporarily and remove the hoses on the head side and bottom side. Pull out the mounting pin on the bottom side and lift off the cylinder assembly.

5. Remove the left deck cover.

PC78US-6

30-85 (11)

DISASSEMBLY AND ASSEMBLY

6. Remove the top cover of the center swivel joint. 7. Remove travel drain hose (11) and swing motor hose (12). 8. Remove 5 hoses (13) for the control valve, forward and reverse, right and left, 2nd travel speed selection, etc. in order from the top. a Install a male or female plug to each of the disconnected hoses, nipples, and elbows. a Record the positions of the disconnected hoses so that you can correctly connect them again.

REVOLVING FRAME

10. Install sling wires to 3 points of revolving frame assembly (7) and lift up the revolving frame temporarily. a Install the sling wires to the boom foot mounting part and hanging hole of the counterweight. a Install the other sling wire to the hole of the revolving frame for the rear left side and use pad [1], shackles [2], etc. 11. Remove the remaining revolving frame mounting bolts and lift off revolving frame assembly (7). [*1]

9. Remove the mounting bolts of swing circle outer race (6) on the revolving frame, leaving 3 each at the front and rear. [*1]

INSTALLATION

30-86 (11)

•

Carry out installation in the reverse order to removal.

[*1]

2 Revolving frame mounting bolt: Adhesive (LT-2) 3 Revolving frame mounting bolt: 245 – 309 Nm {25 – 31.5 kgm} Target: 279.5 Nm {28.5 kgm}

PC78US-6

DISASSEMBLY AND ASSEMBLY

SWING CIRCLE

SWING CIRCLE ASSEMBLY

INSTALLATION

REMOVAL 1. Remove the revolving frame assembly. For details, see REMOVAL OF REVOLVING FRAME ASSEMBLY. 2. Hang swing circle assembly (1) temporarily and remove the 24 mounting bolts. [*1] 3. Remove swing circle assembly (1).

4 Swing circle assembly: 115 kg

[*2]

•

Carry out installation in the reverse order to removal.

[*1]

2 Threads of swing circle mounting bolt: Liquid adhesive (LT-2)

3 Swing circle mounting bolt: 245 – 309 Nm {25 – 31.5 kgm} Target: 279.5 Nm {28.5 kgm} [*2] a Hang swing circle assembly (1) and install it to the track frame, directing mark S of the inner race to the just right side of the machine body as shown below. 2 Quantity of grease to be applied to circle: Apply sufficient quantity of grease (G2-LI).

PC78US-6

30-87 (11)

DISASSEMBLY AND ASSEMBLY

WORK EQUIPMENT

WORK EQUIPMENT ASSEMBLY REMOVAL PC78UU-6 Serial No.: 4001 – 6500 a Extend the work equipment to the maximum reach and lower it to the ground and stop the engine. k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank. 1. Remove the top cover of the hydraulic tank. 2. Loosen the sleeve nut of each work equipment hose (1) on the right side of the boom and remove the hose. [*1]

6. Remove the lock plate of the boom foot pin. 7. Hang work equipment assembly (5) temporarily. 8. Using tool V1, remove foot pin (6).

[*3]

3. Cut the bands of the wiring harness of working lamp (2) and hydraulic tubes and remove the connectors. Place those connectors together with the hoses on a place where they will not be obstacles. a Fit male or female plugs to the removed hoses and tubes. a Record the disconnected hoses to prevent a mistake in re-connecting them. k Since an accumulator is not installed, loosen the sleeve nut of each hose gradually and check that oil will not spout out, then remove the hose.

9. Lift off work equipment assembly (5). a Check the quantity and positions of the inserted shims. 4 Work equipment assembly: 1,110 kg

4. Remove the rod pin stopper used to hang boom cylinder (3) temporarily and pull out rod pin (4). [*2] 5. Lift off boom cylinder (3) onto a stable stand of proper height. a Check the quantity and positions of the inserted shims.

30-88 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

PC78US-6 Serial No.: 6501 and up a Set the work equipment on the sprocket side at the maximum reach, lower it to the ground, and stop the engine. a Disconnect the wiring harness from the negative (-) terminal of the battery. k Loosen the hydraulic tank cap gradually to release the residual pressure in the tank. 1. Remove hydraulic tank top cover (1). 2. Remove right side cover (2) and cover (3).

WORK EQUIPMENT

8. Loosen sleeve nuts of 6 hoses (8) for work equipment on the right side of the boom and remove the hoses. [*1] a Disconnect the hydraulic hose bands. a Install a male or female plug to each of the disconnected hoses and tubes. a Record the positions of the disconnected hoses so that you can correctly connect them again. k Since an accumulator is not installed, loosen the sleeve nut of each hose gradually and check that oil will not spout out, and then remove the hose.

3. Remove cover (4), and then remove quilt to set cover (4) free. 4. Sling boom cylinder (5) temporarily. 5. Remove the rod pin stopper and pull out rod pin (6). [*2]

9. Remove boom-side plate (9) of potentiometer A at the boom foot from the base of the boom. 10. Remove connector (10). 11. Remove 2 mounting bolts (12) of potentiometer mounting plate/boom foot pin lock plate (11). 6. Sling boom cylinder (5) and lower it to stable supports [1] of the same height. a Check the quantity and positions of the inserted shims.

12. Remove plate (11).

7. Sling work equipment (7) temporarily.

PC78US-6

30-89 (11)

DISASSEMBLY AND ASSEMBLY

WORK EQUIPMENT

13. Disconnect connectors (13) and (14).

INSTALLATION

14. Remove clamp (16) and work equipment wiring harness (15).

PC78US-6

15. Remove boom foot pin (17).

•

Carry out installation in the reverse order to removal.

[*1] 1. Check that the O-rings are fitted to the sealing parts of each hose. 2. When installing the rubber hoses, take care not to twist them. [*2] 1. When assembling, apply LM-P to the sliding surfaces of the pins. 2. Supply grease until it comes out through the dust seals on both sides of each bushing. a When removing the pin with tool V1, remove the hydraulic tank, referring to Removal of hydraulic tank. [*3]

k When aligning the pin holes, never insert your fingers in the pin holes. a Adjust the shims so that the clearance between the cylinder rod head and bracket will be less than 1 mm.

[*3] 1. When assembling, apply LM-P to the sliding surfaces of the pins. 2. Supply grease until it comes out through the dust seals on both sides of each bushing. 3. After supplying grease, change the position of the boom and supply grease further.

16. Taking care of cover (4), lift and remove work equipment assembly (7) from the chassis. a Check the quantity and positions of inserted spacers (18). 4 Work equipment assembly: 1,340 kg

30-90 (11)

k When aligning the pin holes, never insert your fingers in the pin holes.

a Adjust the shims so that the clearance between the boom and bracket will be less than 1 mm. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.

PC78US-6

DISASSEMBLY AND ASSEMBLY

PC78UU-6 REMOVAL a Reach the work equipment to the maximum on the sprocket side and lower it to the ground, and then stop the engine. a Connecting the wiring harness of the negative (-) terminal of the battery.

WORK EQUIPMENT

5. Remove the connectors of the potentiometers and working lamp of the arm and offset. Remove the clamps of the wiring harness and cut the bands to remove the wiring harness toward the boom foot. [*1]

k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank.

6. Hang boom cylinder (5) temporarily and pull out rod pin (6). a If the pin cannot be pulled out easily, prepare an oil receiver and loosen the sleeve nut of the hose on the bottom side gradually to give some play to the rod.

1. Open right side inspection cover (1) and lock it with the bar.

7. Set stable stand [1] to receive the boom cylinder horizontally and lift off cylinder assembly (5).

2. Remove right side cover (2). 3. Remove hose protector (3) on the right side of the boom. 4. Remove boom cylinder protector (4).

8. Remove each work equipment hose (7) on the right side of the boom from the joint. [*2]

k Loosen the sleeve nut of each hose gradually and check that oil will not spout out, then remove the hose. a Record the disconnected hoses to prevent a mistake in re-connecting them. a Fit male or female plugs to the removed hoses and tubes.

PC78US-6

30-91 (11)

DISASSEMBLY AND ASSEMBLY

9. Remove wiring harness connector (10) of potentiometer (9) at the boom foot. a Mask the removed connectors.

WORK EQUIPMENT

13. Using tool V1, pull out first boom foot pin (13). [*3] a Check the quantity and positions of the inserted shims.

10. Remove the 2 mounting bolts of potentiometer mounting plate which is also used as boom foot pin lock plate (11). 11. Operating plate (11), pull the end pin of potentiometer lever (12) out of the plate on the boom side, then remove potentiometer assembly (9). a Before removing the potentiometer, secure its lever with a sealing tape, etc.

12. Install slings to the first boom top and bucket tooth adapter and hang the work equipment assembly (8) temporarily.

k Fix the offset unit securely so that the work equipment will not offset. 14. Lift off work equipment assembly (8).

4 Work equipment assembly: 1,340 kg

30-92 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

WORK EQUIPMENT

INSTALLATION PC78UU-2 •

Carry out installation in the reverse order to removal.

[*1] When binding the electric wiring harness to the hydraulic hoses or tubes, use double bands. [*2] When installing the rubber hoses, be careful not to twist them. [*3]

k When aligning the pin holes, never insert your fingers in the pin holes. 1) When assembling, apply G1-T to the sliding surfaces of the pins. 2) Use G1-T HYPER WHITE GREASE. Supply it until it comes out through the dust seals on both sides of each bushing. 3) After supplying grease to the boom foot, change the position of the arm and supply grease further. 4) Reduce the clearance between the spacer and arm/bucket to below 0.5 mm. Reduce the clearance at another boss or spacer to below 1 mm.

•

Refilling with oil (Hydraulic tank) Check the hydraulic oil level gauge and run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level. a After assembling, check that the electric system works normally.

PC78US-6

30-93 (11)

DISASSEMBLY AND ASSEMBLY

FIRST BOOM

FIRST BOOM ASSEMBLY REMOVAL a Remove the bucket, arm assembly, and offset bracket assembly. (See REMOVAL OF OFFSET BRACKET.) a Remove the second boom assembly. (See REMOVAL OF SECOND BOOM ASSEMBLY.) 1. Open right side inspection cover (1) and lock it with the bar. 2. Remove right side cover (2). 3. Remove hose protector (3) on the right side of the boom.

7. Set a stable stand to receive boom cylinder (6) horizontally and lift off the cylinder.

4. Remove boom cylinder protector (4).

a Connect the wiring harness of the negative (-) terminal of the battery.

8. Cut the bands of the potentiometer wiring harness on the work equipment hose and remove the wiring harness. [*1]

5. Start the engine and operate the boom cylinder. Set strong and stable stand [1] to the top of the first boom (5) and secure the boom. a Stop the engine and disconnect the wiring harness from the negative (-) terminal of the battery.

k Loosen the oil filler cap of the hydraulic tank gradually to relea-se the residual pressure from the hydraulic tank.

6. Hang boom cylinder (6) temporarily and remove the lock plate of rod pin (7) and pull out the pin. a If the pin cannot be pulled out easily, loosen the sleeve nut on the bottom side of cylinder (6) gradually to give some play to the rod.

30-94 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

9. Disconnect the 6 work equipment hoses on the right side of the first boom from joints (8).

k Loosen the sleeve nut of each hose gradually and check that oil will not spout out, then remove the hose.

FIRST BOOM

13. Using belts, hang first boom assembly (5) temporarily.

a Record the disconnected hoses to prevent a mistake in re-connecting them. a Fit male or female plugs to the removed hoses and tubes.

14. Using tool V1, pull out first boom foot pin (13).

10. Remove wiring harness connector (10) of potentiometer (9) at the boom foot. a Mask the removed connector. 11. Remove the 2 mounting bolts of potentiometer mounting plate which is also used as boom foot pin lock plate (11). 12. Operating plate (11), pull the end pin of potentiometer lever (12) out of the plate on the boom side, then remove potentiometer assembly (9). a Before removing the potentiometer, secure its lever with a sealing tape, etc.

PC78US-6

30-95 (11)

DISASSEMBLY AND ASSEMBLY

15. Lift of first boom assembly (5).

4 First boom assembly: 320 kg

FIRST BOOM

[*2]

INSTALLATION •

Carry out installation in the reverse order to removal.

[*1] When binding the potentiometer wiring harness to the hydraulic hoses, use double bands. [*2] 1) When assembling, apply G1-T to the sliding surfaces of the pins. 2) Use G1-T HYPER WHITE GREASE. 3) Supply grease to the second boom joint with the machine at the central offset position, then supply further with the machine at the right offset position. In each position, supply grease with the bucket lowered to the ground and with the bucket floated. 4) Reduce the clearance between the spacer and arm/bucket to below 0.5 mm. Reduce the clearance at another spacer to below 1 mm. 5) When installing the rubber hoses, take care not to twist them. k When aligning the pin holes, never insert your fingers in the pin holes.

a Check that the hydraulic oil level is normal. a Check that the electric system works normally.

30-96 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

SECOND BOOM ASSEMBLY REMOVAL a Remove the bucket, arm assembly, and offset bracket assembly. (See REMOVAL OF OFFSET BRACKET.)

SECOND BOOM

6. Hang second boom (10) temporarily and remove the upper and lower mounting pins (11). 7. Lift off second boom assembly (10). Removing the second boom, remove hose (12) installed through it. [*2]

1. Remove 2 hoses (2) of offset cylinder (1). Remove the clamp and pull out the cylinder toward the boom side.

k Loosen the sleeve nut of each hose gradually and check that oil will not spout out, then remove the hose. a Fit male or female plugs to the removed hoses and cylinder tubes. 2. Hang offset cylinder (1) temporarily and remove the lock plate of cylinder bottom pin (3) and then lift off offset cylinder (1). [*1] 4 Offset cylinder assembly: 55 kg

3. Remove the 4 clamps of potentiometer wiring harness (5) installed to the inside of offset link (4). 4. Remove connector (7) of offset potentiometer (6) and the bolt of potentiometer lever (8). 5. Hang offset link (4) temporarily and pull out mounting pin (9) and lift off the offset link assembly. 4 Offset link assembly: Approx. 30 kg

INSTALLATION •

Carry out installation in the reverse order to removal.

[*1] [*2] 1) When assembling, apply G1-T to the sliding surfaces of the pins. 2) Use G1-T HYPER WHITE GREASE. 3) Supply grease to the second boom joint with the machine at the central offset position, then supply further with the machine at the right offset position. In each position, supply grease with the bucket lowered to the ground and with the bucket floated. 4) Reduce the clearance between the spacer and arm/bucket to below 0.5 mm. Reduce the clearance at another spacer to below 1 mm. 5) When installing the rubber hoses, be careful not to twist them.

k When aligning the pin holes, never insert your fingers in the pin holes. a Check that the hydraulic oil level is normal. a Check that the electric system works normally.

PC78US-6

30-97 (11)

DISASSEMBLY AND ASSEMBLY

OFFSET BRACKET

OFFSET BRACKET ASSEMBLY REMOVAL a Extend the work equipment to the maximum reach and lower it to the ground and stop the engine. k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank. a Disconnect the wiring harness from the negative (-) terminal of the battery. (Connect it when necessary, however.) 6. Remove the 2 hoses of arm cylinder (10). 1. Remove the 2 bucket cylinder hoses.

k Loosen the sleeve nut of each hose gradually and check that oil will not spout out, then remove the hose. a Fit male or female plugs to the removed hoses and cylinder tubes.

2. Disconnect arm potentiometer rod (1) and wiring harness connector (2) and remove wiring harness clamp (3). 3. Remove bracket (4) and pull out wiring harness (5) and 2 hoses (6) toward the offset bracket.

k Loosen the sleeve nut of each hose gradually and check that oil will not spout out, then remove the hose. a Fit male or female plugs to the removed hoses and cylinder tubes.

7. Hang arm cylinder (10) temporarily. Remove both lock plates of mounting pins (11) and pull out mounting pins (11) on both sides. Lift off arm cylinder assembly (10). 4 Arm cylinder assembly: 95 kg

8. Remove arm cylinder hose bracket (12) to set the hoses and wiring harnesses free. 9. Remove the clamp of potentiometer wiring harness (13) and pull the wiring harness out of the bracket.

4. Hang the arm and bucket assembly temporarily and remove arm cylinder rod pin (7) and arm foot pin (8). [*1] 5. Lift off arm and bucket assembly (9). a When removing the arm, take care that the arm potentiometer lever will not interfere with another part. 4 Arm and bucket assembly: Approx. 500 kg

30-98 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

OFFSET BRACKET

10. Hang offset bracket (14) temporarily and remove offset cylinder rod pin (15) and rod pin (16) from bracket (14). 11. Pull out the upper and lower mounting pins (18) used to install the offset bracket to second boom (17). 12. Lift off offset bracket assembly (14).

4 Offset bracket assembly: 135 kg

[*1]

a When removing the bracket, take care not to damage the hydraulic hoses.

INSTALLATION •

Carry out installation in the reverse order to removal.

[*1] [*2] 1) When assembling, apply G1-T to the sliding surfaces of the pins. 2) Use G1-T HYPER WHITE GREASE. 3) Supply grease to the second boom joint with the machine at the central offset position, then supply further with the machine at the right offset position. In each position, supply grease with the bucket lowered to the ground and with the bucket floated. 4) Reduce the clearance between the spacer and arm/bucket to below 0.5 mm. Reduce the clearance at another spacer to below 1 mm. 5) When installing the rubber hoses, be careful not to twist them.

k When aligning the pin holes, never insert your fingers in the pin holes. a After installing the work equipment, check that the hydraulic oil level is normal. a After installing the work equipment, check that the electric system works normally.

PC78US-6

30-99 (11)

DISASSEMBLY AND ASSEMBLY

STEEL SHOE, RUBBER PAD SHOE, ROAD LINER

STEEL SHOE, RUBBER PAD SHOE, ROAD LINER ASSEMBLY EXPANSION 1. Stop the machine so that the master pin will be between the idler and carrier roller and the track shoe can be expanded forward and backward. 2. Lower the work equipment to the ground and loosen lubricator (1) to lower the track shoe tension. [*1]

k Since the internal pressure of the adjustment cylinder is very high, do not loosen the lubricator more than 1 turn. If the grease does not come out easily, move the machine forward and in reverse.

INSTALLATION •

[*1]

Carry out installation in the reverse order to removal. a Adjust the tension of the steel shoe and road liner. For details , s ee TESTING AND ADJUSTING, Testing and adjusting track shoe tension.

3. Using tool R, pull out the master pin.

4. Remove tool R and move the machine forward so that the temporary pin will be in front of the idler and set block [1]. 5. Pull out the temporary pin and move the machine in reverse to expand track shoe (2).

30-100 (11)

PC78US-6

DISASSEMBLY AND ASSEMBLY

RUBBER SHOE ASSEMBLY REMOVAL 1. Lower the work equipment to the ground and loosen lubricator (1) to lower the track shoe tension. [*1]

k Since the internal pressure of the adjustment cylinder is very high, do not loosen the lubricator more than 1 turn. If the grease does not come out easily, move the machine forward and in reverse.

2. Swing the work equipment by 90 degrees and raise the machine body a little. 3. Put steel pipes in rubber shoe (2) and turn the sprocket in the reverse direction. If the rubber shoe is floated from the idler by the steel pipes, slide off the rubber shoe sideways.

RUBBER SHOE, FINAL DRIVE AND TRAVEL MOTOR

FINAL DRIVE AND TRAVEL MOTOR ASSEMBLY REMOVAL 1. Expand the track shoe assembly. (See EXPANSION OF TRACK SHOE.) 2. Swing the work equipment by 90 degrees from the parking position and raise the machine body by pressing the work equipment against the ground and set block [1] between the track frame and track link to float sprocket (1) above the link tread.

k Lower the work equipment to the ground and stop the engine. Loosen the oil filler cap of the hydraulic tank to release the residual pressure from the hydraulic tank. 3. Remove travel motor side cover (2).

INSTALLATION • [*1]

Carry out installation in the reverse order to removal. a Adjust the rubber shoe tension. For details, see TESTING AND ADJUSTING, Testing and adjusting track shoe tension.

PC78US-6

30-101 (16)

DISASSEMBLY AND ASSEMBLY

4. Hang final drive and travel motor assembly (3) temporarily.

FINAL DRIVE AND TRAVEL MOTOR

INSTALLATION •

Carry out installation in the reverse order to removal.

[*1]

2 Final drive and travel motor assembly mounting bolt: Liquid adhesive (LT-2)

3 Final drive and travel motor assembly: 245 – 309 Nm {25 – 31.5 kgm} a Bleed air from the travel motor. For details, see TESTING AND ADJUSTING, Bleeding air from each part.

5. Remove 4 travel motor hoses (4). a Remove the nipples. a Stop the hoses with plugs.

• Refilling with oil (Hydraulic tank) a Add oil through the oil filler to the specified level. Run the engine to circulate the oil through the system. Then, check the oil level again.

6. Remove 14 final drive and travel motor assembly mounting bolts (5). [*1] 7. Lift off the final drive and travel motor assembly. 4 Final drive assembly: 105 kg

30-102 (16)

PC78US-6

DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

DISASSEMBLY AND ASSEMBLY OF TRAVEL MOTOR GM09VN2 CONTENTS Sectional drawing, single view drawing, and parts list 1. Sectional drawing of assembly ........................................................................................................ 30-105 2. Single view disassembly drawing of reduction gear assembly ........................................................ 30-107 3. Parts list ........................................................................................................................................... 30-109 Outline of maintenance 1. Tools..................................................................................................................................................30-112 2. Tightening torque ..............................................................................................................................30-117 3. Weight table ......................................................................................................................................30-117 Disassembly.................................................................................................................................................30-118 Maintenance standard................................................................................................................................. 30-133 Assembly .................................................................................................................................................... 30-135 Performance test......................................................................................................................................... 30-152 Clearance adjustment parts dimension table .............................................................................................. 30-153

PC78US-6

30-103 (16)

DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

SECTIONAL DRAWING, SINGLE VIEW DRAWING 1. SECTIONAL DRAWING OF ASSEMBLY

PC78US-6

30-105 (16)

DISASSEMBLY AND ASSEMBLY

30-106 (16)

TRAVEL MOTOR

PC78US-6

DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

2. SINGLE VIEW DISASSEMBLY DRAWING OF REDUCTION GEAR ASSEMBLY

PC78US-6

30-107 (16)

DISASSEMBLY AND ASSEMBLY

30-108 (16)

TRAVEL MOTOR

PC78US-6

DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

3. PARTS LIST Model GM09VN Symbol

Parts name

NABTSCO Serial number KOMATSU Serial number 505D0000-02-GD

TZ505D000002GD

NABTESCO Parts number KOMATSU Parts number

Q'ty

Class

Adjustment symbol

Reduction gear unit

502D1000-00

TZ502D1000-00

500D1102-00 500D1132-00 500D1002-00 500D1003-00 500D1019-00

TZ500D1102-00 TZ500D1132-00 TZ500D1002-00 TZ500D1003-00 TZ500D1019-00

1 1 1 1 3

F F X X B

20 20

2 3 19

Spindle kit • Spindle assembly •• Spindle •• Hold flange • Reamer bolt

500D1104-00 500D1204-00 500D1004-00 500D1005-00 410D1009-00 910B1012-00 500D1102-00 410D1023-00

TZ500D1104-00 TZ500D1204-00 TZ500D1004-00 TZ500D1005-00 TZ410D1009-00 TZ910B1012-00 TZ500D1102-00 TZ410D1023-00

1 1 1 1 3 6 6 6

F F X X X X X X

20 20

4 5 9 12 22 23

RV gear assembly • RV gear kit •• RV gear A •• RV gear B • Crankshaft • Spacer • Tapered roller bearing • Needle roller bearing Spur gear kit • Spur gear

502D1107-00 502D1007-00

TZ502D1107-00 TZ502D1007-00

1 3

C X

31

Floating seal kit • Floating seal

ES100-204x232x32-B ES100-204-B

TZES20423232-B TZES100-204-B

1 2

C X

1 6 8 15 17 18

Hub Input gear Cover Shaft Pin Ring

500D1001-00 502D1006-00 500D1008-00 500D1015-00 500D1017-00 810B1018-00

TZ500D1001-00 TZ502D1006-00 TZ500D1008-00 TZ500D1015-00 TZ500D1017-00 TZ810B1018-00

1 1 1 1 28 1

E B B B B B

20

Snap ring

860A1013-00

TZ860A1013-00

3

E

TZ500D1021-00 TZJB2804-S19 04064-02512 07000-11008 07000-15230 TZJW1516-G35-5 TZ410D1033-00 TZ810B2021-00 07000-12014 04260-00952 TZJB1354-8-22

2 1 6 2 1 1 1 2 3 1 2

E A A A A A B B A A A

7

t: Above 1.75, below 1.80 O t: Above 2.45, below 2.50 21 24 25 28 29 30 33 34 35 36 43

Ball bearing C-ring for shaft C-ring for shaft O-ring O-ring O-ring Flanged plug Plug O-ring Steel ball Parallel pin

PC78US-6

3,20

(Select from 15 kinds)

500D1021-00 JIS B 2804-jig19 JIS B 2804-jig25 JIS B 2401-P8-90 JIS B 2401-G230-70 JIS W 1516-G35-70 410D1033-00 810B2021-00 JIS B 2401-P14-90 JIS B 1501-3/8 JIS B 1354-8 x 22

3,20

30-109 (16)

DISASSEMBLY AND ASSEMBLY

Symbol

Parts name

TRAVEL MOTOR

NABTESCO Parts number KOMATSU Parts number

Q'ty

Class

Hydraulic motor

500D2000-00-G

TZ500D200000-G

1

105 106

Piston kit • Piston assembly •• Piston •• Shoe

500D2105-00 500D2140-00 500D2005-00 500D2006-00

TZ500D2105-00 TZ500D2140-00 TZ500D2005-00 TZ500D2006-00

1 9 1 1

C X X X

161 162

Piston assembly • Piston • Shoe

500D2070-00 500D2071-00 500D2072-00

TZ500D2070-00 TZ500D2071-00 TZ500D2072-00

1 1 1

C X X

102 103 104 107 108 109 110 112 113 114 115 116 132 135 141 146 149 150 151 176 177 185

Shaft Swash plate Cylinder block Retainer plate Thrust ball Timing plate Washer Piston Spring Spring Friction plate Mating plate Oil seal O-ring O-ring Round R-ring Deep groove ball bearing Deep groove ball bearing Needle roller Pivot Parallel pin Spring

500D2002-00 500D2003-00-G 500D2004-00 500D2007-00 500D2008-00 500D2009-00 500D2010-00 500D2012-00 500D2013-00 500D2014-00 500D2015-00 500D2016-00 15Z-22X42X10 500D2035-00 500D2039-00 IRTW-36 880A2029-00 JIS B 1521-6301 500D2098-00 500D2076-00 263B2077-01 844B2085-00

TZ500D2002-00 TZ500D200300-G TZ500D2004-00 TZ500D2007-00 TZ500D2008-00 TZ500D2009-00 TZ500D2010-00 TZ500D2012-00 TZ500D2013-00 TZ500D2014-00 TZ500D2015-00 TZ500D2016-00 TZ15Z-22-42-10 TZ500D2035-00 TZ500D2039-00 TZIRTW-36 TZ880A2029-00 06000-06301 TZ500D2098-00 TZ500D2076-00 TZ263B2077-01 TZ844B2085-00

1 1 1 1 1 1 2 1 8 1 2 2 1 1 1 1 1 1 3 2 2 1

B B B B B B B B B B B B A B B A B A B B B B

Control valve

505D4000-02-D

TZ505D400002-D

1

Rear flange assembly • Rear flange kit •• Rear flange •• Spool • Spool kit •• Spool •• Oil stopper • Plug • Plug • Plug • Spring retainer • Valve • Spring • Spring • O-ring

505D4100-02-D 505D4101-02-D 505D4001-00 505D4050-00-A 502D4110-00 502D4069-00 AOS-4 100A2021-00 810B2021-00 860A2051-00 869A2052-00-B 500D4054-00 860A2056-00 500D4055-00 JIS B 2401-P26-90

TZ505D410002-D TZ505D410102-D TZ505D4001-00 TZ505D405000-A TZ502D4110-00 TZ502D4069-00 TZAOS-4 TZ100A2021-00 TZ810B2021-00 TZ860A2051-00 TZ869A205200-B TZ500D4054-00 TZ860A2056-00 TZ500D4055-00 TZJB2401-P26-90

1 1 1 1 1 1 1 1 1 2 2 2 2 2 2

201 223 271 272 221 222 224 225 227 228 230 236

30-110 (16)

Adjustment symbol

C C X X C X X B B B B B B B A

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DISASSEMBLY AND ASSEMBLY

Symbol 238 252 268 273 275 279 280 281 282 283 292 299 242 245

Parts name

TRAVEL MOTOR

NABTESCO Parts number KOMATSU Parts number

• O-ring • Hexagon socket head plug • Steel ball • O-ring • Hexagon socket head plug • Filter • Orifice • Spring • Plug • Flanged plug • O-ring • Nameplate

JIS B 2401-P18-90 GM-1/8-S JIS B 1501-3/16 07002-12034 GDL-1/16-S 976B2079-00 S0505 500D4089-00 610B2021-00 571B2079-00 JIS B 2401-P14-90 850A0006-00

07000-12018 TZGM1-8-S TZJB1501-3-16 07002-12034 TZGDL1-16-S TZ976B2079-00 TZS0505 TZ500D4089-00 TZ610B2021-00 TZ571B2079-00 07000-12014 TZ850A0006-00

Parallel pin Hexagon socket head bolt

JIS B 1354-4 x 10 TZJB1354-4-10 JIS B 1176-M12 x 32-12.9 TZJB1176M12-32

Q'ty

Class

2 3 1 1 5 1 1 1 2 1 1 1

A A A A A B A B B B A B

2 6

A A

Adjustment symbol

(Notes) 1. An assembly in the part name column must not be disassembled further and must be handled as a part, as a rule. 2. A kit in the part name column must not be disassembled further, although it can be disassembled, and must be handled as a part similarly to an assembly, as a rule. 3. The category shows the supply range of parts for repair. A: Parts can be supplied (Parts replaceable with ones that are conformed to JIS and available in Japan or ones which are supplied by original manufacturer and commercially available) B: Parts can be supplied (Replaceable parts that we can supply) C: Parts can be supplied (Replaceable parts that we can supply by assembly or kit for parts replacement) E: Parts can be supplied conditionally (Replaceable parts that can be supplied loose for parts replacement on condition that clearance will be adjusted as specified) F: Parts can be supplied conditionally (Replaceable parts that can be supplied by assembly or kit for parts replacement on condition that clearance will be adjusted as specified) X: Parts cannot be supplied (Parts that cannot be supplied loose but can be supplied by assembly or kit) 4. A number in the adjustment symbol column indicates a part that needs specified clearance adjustment when it is replaced. 5. When snap rings (20) are to be used for repair of parts which need clearance adjustment, we will supply them as a set in which they are classified by the thickness.

PC78US-6

30-111 (16)

DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

OUTLINE OF MAINTENANCE 1. TOOLS 1) Standard tools Applicable parts (Title No. of structural drawing/ disassembly drawing)

Name

Type/Standard

Q'ty

33,34,221,245,252,275,282

Torque wrench

Nominal torque: 1,800, dial type

1

19,224

Torque wrench

Nominal torque: 5,500, dial type

1

275

Hexagonal wrench

Nominal size: 4

1

252

Hexagonal wrench

Nominal size: 5

1

33,34,222

Hexagonal wrench

Nominal size: 8

1

245,282

Hexagonal wrench

Nominal size: 10

1

252

Hexagon socket

Nominal size: 5, Insertion angle: 12.7

1

33,34,222

Hexagon socket

Nominal size: 8, Insertion angle: 12.7

1

245,282

Hexagon socket

Nominal size: 10, Insertion angle: 12.7

1

19,224

Socket

Nominal size: 36, Insertion angle: 12.7

1

221

Socket

Nominal size: 30, Insertion angle: 12.7

1

19

Extension bar

Insertion angle: 12.7

1

221

Spanner

Nominal size: 30

1

224

Spanner

Round type strong spanner

1

1,21

Hammer

Nominal size: 12

1

8,102

Plastic hammer

L = About 300

1

24,25

Snap ring pliers

For shaft

1

20,146

Snap ring pliers

For hole

1

1

Center punch [20]

ø9.5 x 100

1

21

Pin punch

ø3 x 150

1

For slinging travel motor, 1, 2

Sling

Hook, wire rope

Cleaning of travel motor and parts

Washing brush

1

Cleaning of travel motor and parts

Wire brush

1

Draining of lubricating oil and hydraulic oil Receiving of steel balls (36, 268)

Container

Common vat W450 x D300 x H120

3

For making match mark

Marker

Oil-based, white

1

17

Wire basket

1 piece

Removal of parts

Rubber mat

1

149

Leather gloves

Addition of oil

Can

30-112 (16)

1 set

1 pair For hydraulic oil and lubricating oil

2

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DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

2) Devices Applicable parts (Title No. of structural drawing/ disassembly drawing)

Name

Type/Standard

Disassembly and assembly of travel Common work stand motor

Q'ty

1 set

Cleaning of travel motor and parts

Washing tank

For rough washing and finish washing

1 set

104,149

Press stand

Pressing capacity: Min. 200 kg

1 set

149

Heating tank

Heating temperature: Min. 100 °C Capacity: 500 x 500 x 500

1 set

1

Electric drill [21]

Portable electric drill (Max. drill diameter: ø10)

1

1

Drill

ø2

1

Disassembly of travel motor, 161, 162, 112 Drying of washed parts

Compressed air

Pressure: 0.29 – 0.49 MPa

3

Lathe

1 set

3) Measuring tools Applicable parts (Title No. of structural drawing/ disassembly drawing)

Name

Type/Standard

Q'ty

For adjustment of snap ring [20]

Thickness gauge [17]

Measurement range: 0.04 – 0.3 mm

2

For adjustment of snap ring [20]

Outside micrometer [18]

Measurement range: 0 – 25 mm Minimum division: 0.01 mm

1

For adjustment of preload on ball bearing [21]

Unit type depth micrometer [19]

Measurement range: 0 – 25 mm Minimum division: 0.01 mm

1

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30-113 (16)

DISASSEMBLY AND ASSEMBLY

4) Tools to be manufactured Name: Work stand for travel motor [1] • A work stand for easier and safer disassembly and assembly of the travel motor.

Name: Fixer [2] • A tool to connect spindle (2) and hub (1).

Name: Holder [3] • A tool to insert spring (114), washer (110) and round type R-ring (146) in cylinder block (104). • A tool to remove spring (114) from cylinder block (104).

30-114 (16)

TRAVEL MOTOR

Name: Holder [4] • A tool to pull out deep groove ball bearing (149) from shaft (102).

Name: Holder [5] • A tool to insert oil seal (132) in oil seal hole of spindle (2).

Name: Holder [6] • A tool to fit tapered roller bearing (22) securely. Apply it to the outer race of tapered roller bearing (22) installed to crankshaft [9] of the RV gear assembly and hit it lightly with a hammer to fit the bearing.

PC78US-6

DISASSEMBLY AND ASSEMBLY

Name: Main bearing preload adjustment jig [7] • A tool to press fit ball bearing (21) to hub (1). • A tool to measure the axial clearance of ball bearing (21).

TRAVEL MOTOR

Name: Long eyebolt [10] • A tool to sling the travel motor, spindle (2) and hub (1). Use

"A"

Hub

M14

Spindle

M16

Travel motor

M16

Name: Steel bar [8] • A tool to take out ring (18) from hub (1).

Name: Spatula [11] • A tool to remove timing plate (109) from rear flange (201).

Name: Eyebolt for PF [9] • A tool used together with wires and a crane to remove cover (8) from hub (1). • The thread size must be PF3/8. Name: Pin punch [12] • A tool to remove the outer race of ball bearing (21).

PC78US-6

30-115 (16)

DISASSEMBLY AND ASSEMBLY

Name: Cover removing jig [13] • A jig to remove cover (8) from hub (1).

TRAVEL MOTOR

Name: Floating seal installer [16] • A tool to install floating seal (31) to spindle (2).

Name: Floating seal installer [14] • A tool to install floating seal (31) to hub (1).

Name: Floating seal installer [15] • A tool to install floating seal (31) to hub (1) and spindle (2).

30-116 (16)

PC78US-6

DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

2. TIGHTENING TORQUE Bolt/Nut used

Applicable parts (Structural drawing)

Name

Nominal size

Width across flats of hexagon

Tightening torque (Nm {kgm})

19

Reamer bolt

M24 P2.0

36

794 ± 49.0 {81 ± 5.0}

33

Flanged plug

PF3/8

8

58.8 ± 9.81 {6.0 ± 1.0}

34,222

Plug

PF3/8

8

58.8 ± 9.81 {6.0 ± 1.0}

221

Plug

M20 P1.5

30

78.5 ± 9.81 {8.0 ± 1.0}

224

Plug

M30 P1.5

36

353 ± 39.2 {36 ± 4.0}

245

Hexagon socket head bolt

M12 P1.75

10

102 ± 15.7 {10.4 ± 1.6}

252

Hexagon socket head plug

PF1/8

5

12.3 ± 2.45 {1.25 ± 0.25}

275

Hexagon socket head plug

NPTF1/16

4

9.81 ± 1.96 {1.0 ± 0.2}

282

Plug

PT1/2

10

98.1 ± 19.6 {10 ± 2.0}

3. WEIGHT TABLE Applicable parts (Structural drawing)

Name Travel motor assembly

Approx. 81

1

Hub

19

2

Spindle

27

Rear flange assembly

9.7

201

PC78US-6

Weight (kg)

30-117 (16)

DISASSEMBLY AND ASSEMBLY

a Refer index number to "SECTIONAL DRAWING, SINGLE VIEW DRAWING", if it is not shown in figure at each procedure.

DISASSEMBLY 1. Preparation Perform the following preparation before disassembling. 1) Preparation of work stand • Prepare a work stand for the travel motor. • The work stand must be so rigid that the internal parts of the travel motor can be disassembled and assembled on it and must have sufficient area for placing the parts. • Spread a rubber sheet, vinyl sheet, etc. over the work stand. 2) Preparation of tools and materials Prepare the tools and materials shown in "1. Tools" of "OUTLINE OF MAINTENANCE".

TRAVEL MOTOR

7) Replace each seal once the travel motor is disassembled as a rule, even if they are not damaged. Prepare new seals before starting the disassembly. 8) The photos and drawings of typical models are shown in this manual. Even if they are different from the model being disassembled, the disassembly procedure is not different.

2. General precautions for work

k The disassembled internal parts are coated with hydraulic oil and thus slippery. If they slip off your hands, they can injure you and themselves. Accordingly, handle them with extreme care.

k Kerosene and other combustible materials are used to wash the parts. Since they are flammable and can cause a fire and a burn, handle them with extreme care. 1) Fully understand the inspection items and the type of the detected trouble before disassembling, and then work according to the disassembly procedure. 2) Since the parts are made very precisely, handle them with extreme care not to hit them against each other or drop them. 3) Even if a part sticks firmly and cannot be removed, do not hit or pry it off forcibly. If it is removed so, it may not be installed again because of burrs made on its surfaces when removed and the performance of the travel motor may decrease. Accordingly, work carefully and patiently. 4) If the travel motor is left disassembled halfway or fully, their parts may be rusted by moisture and dirt. If it is obliged to stop the work, take rust and dirt prevention measures. 5) When disassembling, make a match mark on each mating section. 6) While disassembling, arrange the removed parts so that they will not be damaged or lost.

30-118 (16)

PC78US-6

DISASSEMBLY AND ASSEMBLY

3. Cleaning of travel motor 1) Install the eyebolts [10] to the holes for installing spindle (2). a Install the 2 eyebolts symmetrically to the spindle installation holes. 2) Install wires to the eyebolts, sling the travel motor with a crane, and carry it to the washing tank.

3) Clean each part of the travel motor with a car washing brush. a Clean the space between hub (1) and spindle (2) (where the floating seal is installed) very carefully since dirt and sand are accumulated in it.

PC78US-6

TRAVEL MOTOR

4. Installation of travel motor 1) Set the travel motor on the work stand. a While setting the bolt holes of hub (1) to those of the work stand [1], insert the travel motor in the mounting hole of the work stand slowly.

2) Install the travel motor to the work stand so that 2 hexagon socket head bolts [20] will be set symmetrically.

k Tighten the hexagon socket head bolts sufficiently. If they are not tightened sufficiently, the travel motor may fall and hurt you when it is reversed.

30-119 (16)

DISASSEMBLY AND ASSEMBLY

5. Draining of lubricating oil 1) Reverse the travel motor. 2) Loosen flanged plug (33) (1 piece) and plugs [34] (2 pieces). a If flanged plug (33) and plugs (34) are removed and the travel motor is reversed, the oil will flow out. Accordingly, just loosen those plugs to the degree that you can remove them with the fingers but do not remove them.

TRAVEL MOTOR

6. Removal of cover 1) Reverse the travel motor. 2) Make match mark (a) at the mating section of hub (1) and cover (8) with an oil-based marker.

3) Locate the abutment joint of ring (18) and make a punch hole for drilling on outside of hub (1) about 20 mm inward from the end of ring (18) with a punch [20] and a hammer. 3) Reverse the travel motor. a When draining the lubricating oil, place a container under the work stand. 4) Remove flanged plug (33) (1 piece) and plugs (34) (2 pieces) from cover (8) to drain the lubricating oil. 5) Remove O-ring (35) from flanged plug (33) (1 piece). 6) Remove O-rings (35) from plugs (34) (2 pieces). a Do not reuse removed O-rings (35).

30-120 (16)

PC78US-6

DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

4) Using electric drill [21], drill a hole 2mm in diameter from outside of hub (1) toward ring (18). a Apply a drill to the punch hole and make a hole accurately until the ring (18) is pushed and floated above cover (8). a Clean the punch hole off.

7) Tighten the 2 central bolts of the cover removing jig [13] into the bolt holes for installing flanged plugs (33) and (34). a If cover (8) cannot be removed because of the resistance of O-ring (29), hit the rim of the cover lightly with a plastic hammer and sling the cover.

5) Insert the steel bar [8] in the hole to push out ring (18). a At this time, the end of ring (18) is pushed out of cover (8) by the steel bar.

8) Apply a block to the 2 outer bolts of the cover removing jig [13] and tighten those bolts, and cover (8) floats gradually. 9) Remove O-ring (29) from cover (8). a Do not reuse removed O-ring (29).

6) Hold the end of ring (18) pushed out of cover (8) and take the ring (18) out of the ring groove of hub (1).

PC78US-6

30-121 (16)

DISASSEMBLY AND ASSEMBLY

7. Removal of input gear 1) Remove shaft c-ring (24) from shaft (15).

k If the pliers' noses come off the holes of the c-ring, the c-ring may fly out. Take care.

TRAVEL MOTOR

2) Remove spur gears (7) (3 pieces) from crankshaft (9).

3) Remove hole c-rings (25) (3 pieces) from crankshaft (9). 2) Remove steel ball (36) and input gear (6) from shaft (15).

8. Removal of spur gear 1) Remove hole c-rings (25) (3 pieces) from crankshaft (9).

k If the pliers' noses come off the holes of the c-ring, the c-ring may fly out. Take care.

9. Removal of shaft 1) Remove shaft (15).

k If the pliers' noses come off the holes of the c-ring, the c-ring may fly out. Take care.

30-122 (16)

PC78US-6

DISASSEMBLY AND ASSEMBLY

10. Removal of rear flange 1) Reverse the travel motor. a This work is performed so that the plugs will be removed easily when the inside of the rear flange is disassembled. At this time, loosen the plugs to the degree that you can remove them with the fingers. a If the rear flange is not being disassembled, do not loosen the plugs. 2) Loosen 2 plugs (282).

TRAVEL MOTOR

5) Remove rear flange (201) from spindle (2). a Hold the rear flange with your both hands and lift it up slowly to remove. If it is hit or pried off forcibly, timing plate (109) may fall and may be damaged. Take care.

6) Remove 2 pieces of parallel pins (43) from spindle (2). 3) Loosen 2 plugs (224). 4) Loosen hexagon socket head bolts (245) (6 pieces) and remove them from rear flange (201).

7) Remove 2 pieces of O-rings (28) and (30) from spindle (2). a Do not reuse removed O-rings (28) and (30).

PC78US-6

30-123 (16)

DISASSEMBLY AND ASSEMBLY

11. Disassembly of rear flange parts 1) Place rear flange (201) on the work stand with its mating face to spindle (2) up. 2) Remove timing plate (109) from rear flange (201). a The timing plate may not be removed easily because of fitting force of oil to the rear flange. In this case, insert a spatula [11] in the molded groove to raise the timing plate, and the timing plate comes off. If a screwdriver or another sharp tool is inserted between the mating faces, the mating faces may be scratched and oil may leak. Accordingly, do not use a sharp tool such as a screwdriver.

TRAVEL MOTOR

4) Remove deep groove ball bearing (150) from rear flange (201).

12. Disassembly of brake valve in rear flange 1) Remove 2 pieces of plugs (224) from rear flange (201). 2) Remove O-rings (236) from plugs (224). a Do not reuse removed O-rings (236).

3) Remove 2 pieces of parallel pins (242) from rear flange (201).

3) Remove 2 spring retainers (225) and 2 springs (228) from rear flange (201). 4) Remove spool (223) from rear flange (201). a Slant rear flange (201) toward either plug hole, and spool (223) slides down. Hold its end and take it out.

30-124 (16)

PC78US-6

DISASSEMBLY AND ASSEMBLY

5) Remove plugs (282) (2 pieces) from rear flange (201). 6) Remove O-ring (238) from plug (282). a Do not reuse the removed O-ring (238). 7) Remove 2 springs (230) and 2 valves (227) from rear flange (201).

TRAVEL MOTOR

14. Disassembly of parking brake section

k If compressed air is supplied suddenly, piston (112) may jump out spindle (2) and hurt you. Accordingly, put a protection cover on piston (112). 1) Supply compressed air through the passage for the parking brake on spindle (2) to take spindle (2) out of piston (112).

2) Take O-rings (135) and (141) out of piston (112). a Do not reuse removed O-rings (135) and (141).

13. Taking pilot valve out of rear flange 1) Remove plug (222), spool (271) and spring (281) in order from rear flange (201). 2) Take O-ring (292) out of plug (222). a Do not reuse removed O-ring (292).

PC78US-6

30-125 (16)

DISASSEMBLY AND ASSEMBLY

15. Disassembly of hydraulic motor parts a When the travel motor is placed on its side, oil will flow out. Accordingly, place a container under the travel motor. 1) Turn the travel motor 90 degrees. 2) Drain the oil from the travel motor. 3) Take out mating plates (116) and friction plates (115) (2 pieces each).

4) Hold cylinder block (104) with your both hands and give it 2 – 3 turns in both directions to disconnect shoe (106) from swash plate (103). a If cylinder block (104) is pulled out as it is, shoe (106) is left on the swash plate (103) and the parts (piston, shoe, etc.) sticking to cylinder block (104) come off and fall into spindle (2). Take care. 5) Pull out cylinder block (104) from shaft (102).

30-126 (16)

TRAVEL MOTOR

6) Remove piston assembly (piston (105) and shoe (106)) and retainer plate (107) from cylinder block (104). a Hold retainer plate (107) and remove it and piston assembly (piston (105) and shoe (106)) together. a Piston (105) and shoe (106) are made one by narrowing the spherical part of the piston. It is impossible to separate the piston and shoe without damaging the shoe. If either of them needs to be replaced, replace them as a set. (Hereinafter, the set of these parts is refereed to as the piston assembly.)

7) Pull out piston assembly ((105) and (106)) from retainer plate (107). (9 sets)

PC78US-6

DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

8) Take thrust ball (108) out of cylinder block (104).

9) Take rollers (151) (3 pieces) out of cylinder block (104).

3) Take round R-ring (146), washer (110), spring (114) and washer (110) out of cylinder block (104). 16. Removal of spring in cylinder block 1) Place cylinder block (104) on the press stand. a Remove the spring (114) only when it needs to be replaced. a When removing the spring (114), align holder [3] with washer (110) so that the spring will not scratch the cylinder block (104). a Cover the cylinder block (104) with a vinyl sheet so that its surface will not be damaged. 2) Place holder [3] on washer (110). While pressing holder [3] with the press, remove round R-ring (146) with snap ring pliers from the snap ring groove of cylinder block (104). k If the press is loosened suddenly, the spring may jump out and hurt you. Accordingly, loosen the press slowly.

PC78US-6

30-127 (16)

DISASSEMBLY AND ASSEMBLY

17. Removal of swash plate 1) Remove swash plate (103) from shaft (102). a When swash plate (103) is removed, pivot (176) may stick to it.

TRAVEL MOTOR k In the following case, the 2nd speed piston assembly may jump out because of compressed air and may hurt you. Accordingly, place a protection cover on the part from which the piston assembly will jump out. 4) Supply compressed air through the passage of spindle (2) to take 2nd speed selector piston assembly (piston and shoe) and spring (185) out of spindle (2). Piston assembly

• Piston (161) • Shoe (162)

a Compressed air: 0.29 – 0.49 MPa {3 – 5 kg/cm2} 2) Pull shaft (102) out of spindle (2). At this time, deep groove ball bearing (149) comes off together with shaft (102). k If the shaft end on the reduction gear unit side is hit lightly with a plastic hammer in advance, the shaft can be pulled out easily. If the shaft end is hit strongly, however, the shaft may jump out. Take care.

3) Take 2 pivots (176) and 2 parallel pins (177) out of spindle (2). 18. Removal of deep groove ball bearing a Remove deep groove ball bearing (149) only when it needs to be replaced. 1) Place holder [4] on the press stand and put shaft (102) in it. 2) Hold the end of shaft (102) with the press and remove deep groove ball bearing (149) from shaft (102). a Do not reuse deep groove ball bearing (149).

30-128 (16)

PC78US-6

DISASSEMBLY AND ASSEMBLY

19. Removal of hold flange 1) Turn the travel motor 90 degrees. 2) Tighten holders [2] (3 pieces) into hub (1) and spindle (2) to fix. At this time, install the holders [2] symmetrically. k If hold flange (3) is removed without tightening the holders [2], spindle (2) will separate from hub (1) and fall from the work stand. Accordingly, be sure to install the holders [2].

3) Reverse the travel motor.

k If the pliers' noses come off the holes of the snap ring, the snap ring may fly out and hurt you. Take care.

4) Remove snap rings (20) (3 pieces) from hold flange (3).

PC78US-6

TRAVEL MOTOR

5) Make match marks (a) on snap rings (20) and hold flange (3) with an oil-based marker. a Make the match marks so that you can install the snap rings to the same positions.

6) Turn the travel motor 90 degrees. 7) Loosen reamer bolts (19) (3 pieces). a Adhesion is applied to the bolt holes for reamer bolts (19). When the reamer bolts are loosened, they may be seized because of the adhesive and disassembly may become difficult. Accordingly, loosen reamer bolts (19) as slowly as possible. If they become heavy before they are removed, do not loosen them forcibly but tighten them and then loosen again slowly. a Although the reamer bolts are tightened to torque of 794 ± 49.0 Nm {81.0 ± 5.0 kgm}, more torque is required to loosen them because of the adhesive applied to the threaded parts.

30-129 (16)

DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

8) Turn the travel motor 90 degrees again to return it to the original position. 9) Remove hold flange (3) from spindle (2).

20. Removal of holders 1) Reverse the travel motor. 2) Remove the holders [2] (3 pieces).

10) Make match marks (b) on hold flange (3) and spindle (2) with an oil-based marker. a Make the match marks so that you can assemble hold flange (3) and spindle (2) to the same positions as before. a The holes for reamer bolts (19) (3 pieces) on spindle (2) are made simultaneously. a Replace spindle (2) and hold flange (3) as an assembly. (Hereinafter, this assembly is referred to as the spindle assembly.)

21. Removal of spindle 1) Place a clean container under the travel motor. 2) Install the eyebolts [10] symmetrically to the holes for installing spindle (2). 3) Install hooks to the eyebolts [10] and sling spindle (2) to remove it from hub (1). At this time, floating seal (31) and outer race and oil seal of tapered roller bearing (22) come off, too.

22. Removal of ball bearing, RV gear assembly and pin 1) Remove floating seal (31) from hub (1).

30-130 (16)

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DISASSEMBLY AND ASSEMBLY

2) Hit the end of pin (17) with a pin punch [12] and a hammer to remove ball bearing (21) from hub (1). At this time, RV gear assembly (RV gear A (4), RV gear B (5), crankshaft (9), tapered roller bearing (22), needle roller bearing (23) and spacer (12)) and pin (17) can be removed, too. a When removing ball bearing (21), hit 3 – 4 places of the periphery at the pin end lightly and evenly so that the ball bearing will not be scratched. a If the fitted part of ball bearing (21) comes off hub (1), ball bearing (21), RV gear assembly and pin (17) fall from hub (1). Accordingly, place a container under the work stand and spread a rubber mat on it so that the parts will not be damaged. 3) Remove ball bearing (21), RV gear assembly and pin (17) which fell into the container. RV gear A (4) and RV gear B (5) of the RV gear assembly are separated from crankshaft (9). a Remove tapered roller bearing (22), needle roller bearing (23) and spacer (12) from crankshaft (9) only when they need to be replaced.

TRAVEL MOTOR

4) Reverse the travel motor. 5) Remove ball bearing (21). a When removing ball bearing (21), hit 3 – 4 places of the periphery at the pin end lightly and evenly so that the ball bearing will not be scratched.

23. Removal of spindle parts 1) Remove oil seal (132) from spindle (2). a Never reuse removed oil seal (132).

2) Take floating seal (31) out of spindle (2).

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30-131 (16)

DISASSEMBLY AND ASSEMBLY

3) Take outer races (3 pieces) of tapered roller bearing (22) out of spindle (2). a The outer race of tapered roller bearing (22) may stick to the spindle because of the lubricating oil and it may not be removed easily. In this case, give a light impact to the center of the mounting hole of spindle (2) with an aluminum bar, and the oil film is broken and the outer race can be removed easily.

24. Disassembly of hold flange parts 1) Take the outer race of tapered roller bearing (22) out of hold flange (3).

TRAVEL MOTOR k Kerosene is combustible. Take care extremely that kerosene will not catch fire and you will not be burnt or injured by the fire. 3) Put the internal parts in the rough washing tank filled with kerosene and clean them.

26. Finish cleaning 1) Put each part in the finish washing tank filled with kerosene and turn it slowly to clean to its inside. 2) Wipe off kerosene from each part with clean cloths. a Blow compressed air against the inside of hub (1), spindle (2) and hold flange (3) to dry in a clean and dry place. After drying each part, apply hydraulic oil to them. a Dry the inside of rear flange (201), hydraulic motor parts and RV gear assembly in air of a clean and dry place. After drying each part, apply hydraulic oil to them. a If pins (17) (28 pieces) are handled roughly, they contact with each other and their surfaces may be scratched and some of them may be lost. Accordingly, handle them with extreme care.

25. Rough cleaning of parts 1) Separate hub (1), spindle (2), cover (8) and rear flange (201) (4 parts) from the other parts (hereinafter, referred to as the internal parts). 2) Put hub (1), spindle (2), cover (8) and rear flange (201) in the washing tank and clean them. a Remove all dirt and sand from these parts. a If the dirty parts are washed in the oil t a n k i m m e d i a t e l y, t h e y m a y b e scratched. Accordingly, leave them submerged in the oil until dirt, grease, etc. come off and float.

30-132 (16)

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DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

MAINTENANCE STANDARD When disassembling and servicing the GM motor, observe the following standard. Handle the parts carefully and do not scratch the moving parts and sliding parts, in particular. 1. Seals Replace the seals (O-rings, oil seals and floating seals) once the travel motor is disassembled as a rule, even if they are not damaged. 2. Maintenance standard for wear parts 1) If a part has an extreme outside damage, replace it. 2) If a part has the following trouble (phenomenon), replace it. Part No.

Part name

Phenomenon

(2) (3) (19)

Spindle kit Spindle Hold flange Reamer bolt

• There is serious damage on outside. • Surface is scuffed or worn abnormally.

(4) (5) (9) (22) (23)

RV gear assembly RV gear A RV gear B Crankshaft Tapered roller bearing Needle roller bearing

• RV gear tooth surface is worn unevenly. • When crankshaft (9) is rotated, each part does not move smoothly.

(20)

Snap ring

• Periphery of end face is worn abnormally.

(21)

Ball bearing

• There is press mark. • Surface is flaking. • Worn unevenly.

(201)

Rear flange kit Rear flange

• There is flaw on sliding surface against spool (223). • Clearance to spool is wide. • There is flaw on contact surface against valve (227). • Depth to contact surface against valve (227) is large. • There is flaw on periphery. • Periphery is worn unevenly.

(223)

Spool

(102)

Shaft

(104)

Cylinder block

(105) (106)

Piston assembly Piston Shoe

(107)

Retainer plate

• Periphery of end face is worn unevenly.

(108)

Thrust ball

• Spherical sliding surface against retainer plate (107) is worn unevenly.

PC78US-6

Standard value Tolerance (Standard dimension) (Judgment value)

Clearance in diameter 9 – 5 µ

Clearance in diameter 35 µ

• Contact surface against oil seal (132) is worn. • Spline is worn. • Spline is worn. • Inside surface is worn remarkably. • There are flaws and uneven wear on sliding surface against timing plate (109). • There is clearance axial between piston (105) and shoe (106). • Shoe is worn abnormally. • Shoe is worn unevenly.

Clearance 0.04 mm Clearance 0.14 mm

30-133 (16)

DISASSEMBLY AND ASSEMBLY

Part No.

Part name

TRAVEL MOTOR

Phenomenon

(109)

Timing plate

• There is trace of seizure and uneven wear on sliding surface.

(115) (116)

Friction plate Mating plate

• Both end faces are worn unevenly. • Specified torque cannot be obtained. • There is trace of seizure.

(227)

Valve

• There is flaw on seat surface.

(149)

Deep groove ball bearing • There is press mark. • Surface is flaking. Deep groove ball bearing • Worn unevenly.

(150)

30-134 (16)

Standard value Tolerance (Standard dimension) (Judgment value)

Braking torque 97.1 Nm {9.9 kgm}

Braking torque 97.1 Nm {9.9 kgm}

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DISASSEMBLY AND ASSEMBLY

ASSEMBLY Carry out assembly in the reverse order to disassembly as a rule. 1. Preparation Prepare the work stand, tools and materials as in preparation for disassembly. 2. General precautions for work 1) Observe the general precautions for disassembly. 2) Before assembling, remove metal chips and foreign matter from all the parts and check that a burr, a bruise, etc. are not made on any part. If there is any burr or bruise, remove it with an oilstone. 3) Replace the O-rings, oil seals and floating seals with new ones. 4) Replace the reamer bolts with new ones as a rule. If it is obliged to reuse them, remove all adhesive from them. If there is any flaw on a reamer bolt seat, remove it with an oilstone. 5) Since reamer bolt holes of spindle (2) and the threaded parts of reamer bolts (19) are coated with adhesive when assembled, degrease them. 6) When installing the O-rings, oil seals and floating seals, take care not to damage them. (Apply a little grease to them so that they will be installed smoothly.) 7) Be sure to coat the moving parts and sliding parts of the hydraulic motor and valves with clean hydraulic oil (NAS Standard Class 9 or higher) before assembling. 8) Do not put on cloth gloves for assembly work. (A fiber can cause a malfunction.) 9) Tighten bolts and plugs to the torque shown in "2. Tightening torque table" of "OUTLINE OF MAINTENANCE". 10) After finishing assembly, plug all the ports to prevent dirt from entering them. 11) The photos and drawings of typical models are shown in this manual. Even if they are different from the model being disassembled, the assembly procedure is not different.

PC78US-6

TRAVEL MOTOR

3. Assembly procedure a If any part was replaced, the preload on the ball bearing and the thickness of the snap rings must be adjusted before assembly. Accordingly, check to see if any of the following parts was replaced before starting assembly. 1) Replacement parts that need adjustment of preload on ball bearing ------ Hub (1), spindle (2), hold flange (3) and ball bearing (21) 2) Replacement parts that need adjustment of thickness of snap ring ------ Spindle (2), hold flange (3), crankshaft (9), spacer (12) and tapered roller bearing (22) a When assembling after replacing the above parts, be sure to perform the necessary adjustment. If the parts are installed without adjustment, the travel motor will malfunction and will be broken in a short period.

30-135 (16)

DISASSEMBLY AND ASSEMBLY

4. Assembly of hub section 1) Install 2 eyebolts [10] symmetrically to the bolt holes of hub (1). 2) Install hooks and wires to the eyebolts and sling hub (1) with the crane and set it on the work stand. a While setting the bolt holes of hub (1) to those of the work stand, insert the hub in the mounting hole of the work stand slowly.

TRAVEL MOTOR

4) Insert ball bearing (21) in hub (1). a Apply the pin punch [12] to the periphery of ball bearing (21) and hit it lightly all around to press fit the bearing little by little.

5) Using floating seal installer [14] and [15], install floating seal (31) to hub (1).

3) Install hub (1) to the work stand by tightening the hexagon socket head bolts symmetrically.

k Tighten the hexagon socket head bolts sufficiently. If they are not tightened sufficiently, the travel motor may fall and hurt you when it is reversed.

5. Assembly of spindle section 1) Apply hydraulic oil to the O-ring of floating seal (31) and install the floating seal to the floating seal groove of spindle (2) by using floating seal installer [15] and [16]. a Remove the O-ring from the floating seal and apply hydraulic oil to it thinly. a Fit the O-ring first to the groove of the spindle and then install the floating seal so that its surface will be parallel with the spindle groove surface.

30-136 (16)

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DISASSEMBLY AND ASSEMBLY

2) Fit outer races (3 pieces) of tapered roller bearing (22) to their respective mounting holes in spindle (2).

3) Install 2 eyebolts [10] symmetrically to spindle (2). 4) Install hooks and wires to the eyebolts, sling spindle (2) with the crane, and insert it in hub (1) slowly.

5) Tighten hub (1) and spindle (2) with the fixers [2]. At this time, tighten the fixers symmetrically. 6) Reverse the travel motor. a If travel motor is reversed without tightening the fixers, spindle (2) will separate from hub (1) and fall from the work stand. Accordingly, be sure to install the fixers.

PC78US-6

TRAVEL MOTOR

6. Installation of RV gear assembly 1) Insert RV gear A (4) in hub (1).

2) Fit crankshafts (9) (3 pieces) to the outer race mounting holes of tapered roller bearings (22) in spindle (2). a At this time tapered roller bearing (22), needle roller bearing (23) and spacer (12) are installed to the crankshaft.

3) Insert RV gear (5) in hub (1). a Since the tooth phases of RV gear A (4) and RV gear B (5) are matched to each others, set the punch holes on the end faces to the same position when installing.

30-137 (16)

DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

4) Insert pins (17) (28 pieces) between the pin groove of hub (1) and tooth space of the gear. a When inserting pins (17), apply lubricating oil to them.

5) Insert ball bearing (21) in hub (1). a Apply the pin punch to the periphery of ball bearing (21) and hit it lightly all around to press fit the bearing little by little.

8. Tightening of reamer bolts 1) Apply anti-seize compound to the reamer part of reamer bolt (19) and apply adhesive to the threaded part the reamer bolt. a If the threaded part of the reamer bolt (19) is stained with oil or grease, degrease it. After degreasing and drying thoroughly, apply adhesive to the threaded part. a Tighten 3 reamer bolts (19) evenly little by little. If only one of them is tightened first, hold flange (3) will slant and ball bearing (21) cannot be fitted correctly to hold flange (3) and the reamer bolts (19) may be seized. Take care. 2) Tighten reamer bolts (19) (3 pieces) until hold flange (3) is fitted to ball bearing (21) perfectly. 3) Tighten reamer bolts (19) (3 pieces) to the specified torque. 3 Tightening torque: 794 ± 49.0 Nm {81.0 ± 5.0 kgm}

7. Installation of hold flange 1) Check to see if hub (1), spindle (2), hold flange (3) and ball bearings (21) (2 pieces) are replaced with new ones. a If none of the above parts is replaced, go to next step 2). a If any of the above parts is replaced, perform "22. Adjustment of preload on ball bearing (Pages 30-149 – 150)" and then go to next step 2). 2) Fit hold flange (3) to the inner race of ball bearing (21) in hub (1). a When fitting hold flange (3) to ball bearing (21), line up the match marks on spindle (2) and crankshaft (9) so that the hold flange will be installed to the same position as before. a If hold flange (3) is not fitted easily to the inner race of ball bearing (21), hit it lightly and evenly with a plastic hammer to fit it.

30-138 (16)

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DISASSEMBLY AND ASSEMBLY

4) 5) 6) 7)

Reverse the travel motor. Remove fixers (3 pieces). Reverse the travel motor. Fit the outer race of tapered roller bearing (22) to hold flange (3).

9. Installation of snap rings 1) Check to see if spindle (2), hold flange (3), crankshaft (9), tapered roller bearing (22) and spacer (12) are replaced with new ones. a If none of the above parts is replaced, go to next step 2). a If any of the above parts is replaced, perform "(20) Adjustment of axial clearance of tapered roller bearing (Pages 30-150 – 30-151)" and then go to next step 2). a When replacing only snap ring (20), select the same thickness as ever or similar thickness to it from the prepared 15 thicknesses. 2) Install snap ring (20) to the snap ring groove in hold flange (3). a When installing 3 snap rings (20), line up the match marks on them and those on hold flange (3). If snap ring (20) is replaced, fit new one of the thickness selected in the previous step to the snap ring groove.

PC78US-6

TRAVEL MOTOR

3) Install shaft c-rings (25) (3 pieces) to c-ring grooves on crankshaft (9).

10. Installation of spur gears 1) Install spur gears (7) (3 pieces) to crankshaft (9), while setting the match marks on them. a When installing spur gears (7) (3 pieces) to crankshaft (9), set the match marks (M) (punch holes) on them as shown below.

30-139 (16)

DISASSEMBLY AND ASSEMBLY

2) Install shaft c-rings (25) (3 pieces) to the cring grooves on crankshaft (9).

TRAVEL MOTOR

12. Installation of shaft

k When inserting the shaft, put on leather gloves to avoid burning your hands. a Insert deep groove ball bearing (149) until it is fitted to the flange surface of shaft (102). 1) Put deep groove ball bearing (149) in an oven and heat it at 100 ± 10 °C for 10 minutes and then install it to shaft (102).

11. Insertion of oil seal 1) Reverse the travel motor. 2) Apply lithium grease to the lip of oil seal (132) and press fit oil seal (132) to the oil seal fitting hole of spindle (2) with holder [5] and a hammer. 2) Insert parallel pins (177) (2 pieces) in the pin holes of spindle (2). 3) Apply lithium grease to pivots (176) (2 pieces) to prevent them from falling and fit them to parallel pin (177) of spindle (2). 4) Install spring (185) and piston assembly (piston (161) and shoe (162)) to spindle (2). 5) Turn the travel motor 90 degrees.

30-140 (16)

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DISASSEMBLY AND ASSEMBLY

6) Install shaft (102). a Fit shaft (102) to spindle (2) slowly and carefully, taking care not to damage the lip of oil seal (132). Damage of the lip can cause oil leakage and travel motor breakage in a short period. 7) Fit shaft (102) to spindle (2). 8) Apply lithium grease to the spline of shaft (102).

TRAVEL MOTOR

9) Install swash plate (103) to spindle (2). a Apply grease to mating faces of swash plate (103) and spindle (2). a When installing swash plate (103) to spindle (2), set its pivot mounting holes to pivots (176) (2 pieces) fitted to spindle (2).

13. Assembly of cylinder block 1) Insert washer (110), spring (114), washer (110) and round R-ring (146) in cylinder block (104) in order. 2) Place cylinder block (104) on the press stand.

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30-141 (16)

DISASSEMBLY AND ASSEMBLY

3) Place holder [3] on washer (110). While holding it with the press, install round R-ring (146) to the snap ring groove of cylinder block (104) with the snap ring pliers. a Cover cylinder block (104) with a vinyl sheet so that its contacting face to timing plate (109) will not be damaged.

TRAVEL MOTOR

4) Install 9 piston assemblies ((105) and (106)) to cylinder block (104). a Fit retainer plate (107) to the spherical part of thrust ball (108).

5) Install cylinder block (104) to shaft (102). a Align the spline hole of cylinder block (104) with the spline shaft of shaft (102). a After installing the cylinder block, rotate it with the hand and check that it has no play. If it has any play, inspect and eliminate it.

14. Assembly of hydraulic motor parts 1) Fit rollers (151) (3 pieces) to the holes of cylinder block (104). 2) Place thrust ball (108) on cylinder block (104). 3) Fit 9 piston assemblies to retainer plate (107). a After assembling, soak the whole assembly in hydraulic oil.

30-142 (16)

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DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

15. Assembly of parking brake section a Before installing friction plate (115), soak it in hydraulic oil. 1) Slant the work stand 90 degrees. 2) Install friction plate (115) and mating plate (116) alternately to the outside grooves of cylinder block (104). 3) Install O-rings (135) and (141) to the O-ring grooves of piston (112). a At this time, thinly apply grease to Orings (135) and (141).

16. Assembly of brake valve parts in rear flange 1) Install O-rings (238) (2 pieces) to plugs (282) (2 pieces). a Apply grease to O-rings (238).

4) Slant the travel motor 90 degrees. 5) Install piston (112) in spindle (2). a If piston (112) cannot be installed in spindle (2) because of resistance of O-rings (135) and (141), hit the end of the piston (112) lightly with a plastic hammer. a When installing piston (112), take care not to damage the O-rings.

PC78US-6

2) Install valve (227) and spring (230) to rear flange (201). a At this time, apply grease to connect valve (227) and spring (230) by the adhesion of the grease. 3) Tighten plugs (282) into rear flange (201). 4) After inserting plugs (282) (2 pieces), tighten them lightly into rear flange (201) with the hexagonal wrench.

30-143 (16)

DISASSEMBLY AND ASSEMBLY

5) Insert spool (223) in rear flange (201). a Apply hydraulic oil to the spool and insert the spool in the rear flange. a When installing the spool, align the rear flange hole with the spool shaft so that the inside surface of the rear flange and the outside surface of the spool will not be damaged by contacting. a Contact damage of the hole of the rear flange and the outside of the spool can cause internal leakage and decrease of the travel motor performance after assembly. Take care.

6) Install rings (236) to plugs (224). a Apply grease to O-rings (236). 7) Install spring retainers (225) and springs (228) to plugs (224).

30-144 (16)

TRAVEL MOTOR

8) Screw plugs (224) (2 pieces) into rear flange (201). a When tightening the plugs into the rear flange, take care not to deform the springs. 9) Tighten plugs (224) (2 pieces) lightly into rear flange (201) with the spanner.

17. Assembly of rear flange parts 1) Installation of rear flange parts i) Place the rear flange with the mating face to spindle (2) down. ii) Insert spring (281) and spool (271) in rear flange (201). a When tightening the plug into the rear flange, take care not to deform the spring.

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DISASSEMBLY AND ASSEMBLY

iii) Install O-ring (292) to plug (222). a Apply grease to O-ring (292). iv) Tighten plug (222) into rear flange (201) to the specified torque.

3 Tightening torque: 58.8 ± 9.8 Nm {6.0 ± 1.0 kgm}

TRAVEL MOTOR

4) Apply grease to the mating faces of timing plate (109) and rear flange (201). 5) Install timing plate (109) to rear flange (201) by using parallel pins (242) as guides. a Install timing plate (109) until it is fitted to rear flange (201). a Fit the timing plate to the rear flange so that it will not fall from the rear flange when the rear flange is installed to spindle (2).

2) Apply hydraulic oil to deep groove ball bearing (150) and fit deep groove ball bearing (150) to rear flange (201). 18. Connection of rear flange and spindle 1) Fit O-rings (30) and (28) to the O-ring grooves of spindle (2). a Fit O-ring (30) without applying grease to it. If grease is applied at this time, it may ooze out through the joint of the rear flange and spindle while the travel motor is running, and the operator may mistake it for oil leakage. Accordingly, do not apply grease.

3) Fit parallel pins (242) (2 pieces) to the pin holes of rear flange (201).

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30-145 (16)

DISASSEMBLY AND ASSEMBLY

2) Fit parallel pins (43) (2 pieces) to spindle (2). 3) Pour hydraulic oil of 0.5 l into spindle (2).

TRAVEL MOTOR

5) Tighten hexagon socket head bolts (245) (6 pieces) into spindle (2) to the specified torque. 3 Tightening torque: 102 ± 15.7 Nm {10.4 ± 1.6 kgm}

a When installing rear flange (201) to spindle (2), install springs (113) (8 pieces) to the rear flange. At this time, fix springs (113) with grease so that they will not fall from the rear flange. 4) While setting parallel pins (43) (2 pieces) fitted to spindle (2) to the pin holes of rear flange (201), install rear flange (201) to spindle (2).

6) Tighten plugs (282) to the specified torque.

3 Tightening torque: 98.1 ± 19.6 Nm {10 ± 2.0 kgm}

7) Tighten plugs (224) to the specified torque.

3 Tightening torque: 353 ± 39.2 Nm {36 ± 4.0 kgm}

30-146 (16)

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DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

19. Assembly of input gear 1) Reverse the travel motor. 2) Install shaft (15) to shaft (102). 3) Install input gear (6) to shaft (15). a When installing input gear (6), mesh it with 3 spur gears (7). If it is not meshed, check and correct it.

20. Assembly cover 1) Pour lubricating oil of 1.3 l into hub (1). 2) Install O-ring (29) to the O-ring groove of cover (8). a Apply grease to O-ring (29).

4) Install shaft c-ring (24) to the snap ring groove of shaft (15). 5) Coat steel ball (36) with grease and place it on the hollow part of input gear (6).

PC78US-6

3) Install cover (8) to hub (1). a Line up the match marks on cover (8) and hub (1). a While hitting the periphery of cover (8) lightly with a plastic hammer, install cover (8). If the cover is hit strongly, the O-ring will be broken and oil will leak. Take care.

30-147 (16)

DISASSEMBLY AND ASSEMBLY

4) Fit ring (18) to the ring groove of hub (1).

5) Fit O-ring (35) to flanged plug (33). Tighten flanged plug (33) into cover (8) to the tightening torque.

3 Tightening torque: 58.8 ± 9.81 Nm {6 ± 1.0 kgm}

6) Fit O-ring (35) to plug (34). Tighten plug (34) into cover (8) to the tightening torque.

TRAVEL MOTOR

21. Removal of travel motor 1) Remove the travel motor mounting bolts from the work stand.

2) Tighten eyebolts [10] (2 pieces) into the bolt holes of spindle (2). a Install the 2 eyebolts symmetrically. 3) Install hooks and wires to the eyebolts and remove the travel motor from the work stand with the crane.

3 Tightening torque: 58.8 ± 9.81 Nm {6 ± 1.0 kgm}

30-148 (16)

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DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

22. Adjustment of preload on ball bearing a A proper preload must be given to ball bearing (21) to secure a proper service life. Accordingly, if a part which affects the preload is replaced, assemble the travel motor temporarily according to the following procedure and check the preload. If the GM motor is assembled without checking the preload, it will malfunction and will be broken in a short period. Take care extremely. a Parts which affect preload on ball bearing Hub (1), spindle (2), hold flange (3), ball bearing (21) a If none of the above parts is replaced, skip this step and go to 7-2) in page 30-138. a The procedure for checking and adjusting the preload is described below. Procedure for adjusting preload on ball bearing 1) Install the main bearing preload adjustment jig [7] to spindle (2) and tighten the special nut to press fit ball bearing (21) to hub (1). 3 Tightening torque of special nut: 58.8 Nm {6 kgm}

2) Insert a depth micrometer [19] in the measurement hole of the main bearing preload adjustment jig [7] to measure depth A. 3) Since dimension B of the main bearing preload adjustment jig [7] is known, clearance C can be given by the following formula. A: Measured value C=A–B

B: Dimension of jig C: Specified dimension

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30-149 (16)

DISASSEMBLY AND ASSEMBLY

4) Obtain dimension D of hold flange (3). 5) Adjust hold flange (3) from the result of 2) – 4), according to the following procedure.

TRAVEL MOTOR

6) Remove the main bearing preload adjustment jig [7] from spindle (2).

Dimension C is the specified dimension of the hold flange. i)

ii)

iii)

a

a

30-150 (16)

When dimension D of actual hold flange (3) is at least 0.02 mm less than specified dimension C, cut face E of hold flange (3) to the specified dimension with a lathe, etc. When dimension D of actual hold flange (3) is in the tolerance (± 0.02 mm) of specified dimension C, use hold flange (3) as it is. When dimension D of actual hold flange (3) is at least 0.02 mm more than specified dimension C, replace the spindle assembly with new one. A new hold flange (3) has adjustment allowance. Since the hold flange and spindle are disassembled together, they are an assembly. Accordingly, it is not allowed to replace only the hold flange. The hold flange and spindle must be replaced together. This assembly of these parts is called the spindle assembly. When replacing the spindle assembly, perform the disassembly and assembly procedure again.

7) After adjusting the hold flange by the adjustment work in i), ii) and iii), go to 7-2) in page 30-138. 23. Adjustment of axial clearance of tapered roller bearing a If any on the following parts is replace, the axial clearance of tapered roller bearing (22) must be adjusted to the specification value by adjusting the thickness of snap ring (20). GM motor is assembled without adjusting the axial clearance, it will malfunction and will be b r o k e n i n a s h o r t p e r i o d . Ta k e c a r e extremely. Spindle (2), hold flange (3), crankshaft (9), spacer (12), tapered roller bearing (22) a If none of the above parts is replaced, the snap ring does not need to be adjusted. In this case, go to step 9 in page 30-139. a The procedure for adjusting the axial cleara n c e o f t h e ta p e r e d r o l l e r b e a r i n g i s described below. 1) Lightly hit the outer race of tapered roller bearing (22) installed to crankshaft (9) with a hammer and holder [6]. a Perform this step to insert the RV gear assembly in spindle (2) securely.

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DISASSEMBLY AND ASSEMBLY

2) Install thinnest snap ring (20) to the snap ring groove in hold flange (3).

TRAVEL MOTOR

4) Insert a thickness gauge [17] between snap ring (20) and tapered roller bearing (22) to measure the clearance. 5) Measurement of snap ring thickness • Set thickness of snap ring (Max.) Thickness of Thickness of Max. = thickness + current snap gauge ring

•

Set thickness of snap ring (Min.)

Thickness of Thickness of Min. = thickness + current snap – gauge ring

0.05

3) Lightly hit the periphery of snap ring (20) with the hammer and holder [6]. a Check that the RV gear assembly is inserted in spindle (2) securely.

6) After deciding the snap ring (20) thickness, select one from the snap rings of 15 thicknesses and install it to hold flange (3). (See 6. Clearance adjustment parts dimension table) 7) After installing the snap ring of the selected thickness, go to 9-2) in page 30-139.

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30-151 (16)

DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

PERFORMANCE TEST •

After finishing maintenance of the GM motor, test its performance according to the following procedure.

1. Necessary measuring tools 1 Pressure gauge --- For 3.43 MPa {35 kg/cm2}

2 pieces

2 Measuring cylinder --- For 5 l

1 piece

3 Stopwatch

1 piece

2. Test procedure

1

Installation and piping of GM motor

Install GM motor to machine (frame) and fit piping. Do not install tracks, however. [Since GM motor performance test (no-load operation) is being performed]

Notes) 1. Fit piping so that pressure gauge can be installed (to main circuit) and drainage from hydraulic motor can be measured. 2. Do not install GM motor by hitting it with hammer but installed it carefully by using bolt holes.

GM motor speed Running-in of GM motor

2

1 2

Pressure

Turning direction

Operating time

No-load

Left/Right

1 minute each or more

10 rpm 20 rpm

GM motor speed

3

Preparation operation before test … Continue preparation operation until temperature rises as follows. 1

2

30-152 (16)

Hydraulic oil temperature: 45 ― 55 °C Outside temperature of reduction gear hub: 40 ― 80 °C Performance test ………………Measure following items and judge result. Criteria — GM motor drive pressure … Max.1.57 MPa at 10 rpm … (Max.16 kg/cm² at 10 rpm) Hydraulic motor drainage … Max. 0.5 /min at 10 rpm

OK

NG

Install tracks.

Disassemble and adjust again.

PC78US-6

DISASSEMBLY AND ASSEMBLY

TRAVEL MOTOR

CLEARANCE ADJUSTMENT PARTS DIMENSION TABLE Part name

Dimensions

Snap ring (20)

PC78US-6

Classification symbol

Dimension (T)

X

Above 1.75, below 1.80

Y

Above 1.80, below 1.85

Z

Above 1.85, below 1.90

A

Above 1.90, below 1.95

B

Above 1.95, below 2.00

C

Above 2.00, below 2.05

D

Above 2.05, below 2.10

E

Above 2.10, below 2.15

F

Above 2.15, below 2.20

G

Above 2.20, below 2.25

H

Above 2.25, below 2.30

I

Above 2.30, below 2.35

J

Above 2.35, below 2.40

K

Above 2.40, below 2.45

L

Above 2.45, below 2.50

30-153 (16)

DISASSEMBLY AND ASSEMBLY

IDLER ASSEMBLY ASSEMBLY

IDLER

a When installing the floating seal, thoroughly clean, degrease, and dry the parts marked with the thick lines (the load ring and faces in contact with the load ring).

1. Using tool L1, press fit bushings (9) and (10) to idler (4). a Press fitting force: 26 – 53 kN {2.6 – 5.4 tons}

2. Fit the O-ring and install support (7) to shaft (5) with dowel pin (8).

3. Using tool L2, install floating seal (6) to idler (4) and assembly of shaft (5) and support (7). a Apply oil to the sliding surface of the floating seal and take care that dirt will not stick to that surface.

30-154 (16)

a When inserting the floating seal assembly in the housing, use the push jig. This push jig must push the load ring. [1]: Cylindrical push jig

a The metallic faces of the floating seal which are in contact with each other must be free from dirt. a After the floating seal is inserted, check that it does not slant more than 1 mm and its projection is as follows.

PC78US-6

DISASSEMBLY AND ASSEMBLY

4. Install the assembly of shaft (5) and support (7) to idler (4).

IDLER

6. Using tool L2, install floating seal (3) to idler (4) and support (2). a Apply oil to the sliding surfaces of the floating seal and take care that dirt will not stick to the floating seal. a Degrease the contact faces of the floating seal and O-ring.

5. Supply oil between shaft (5) and idler (4). 6 Quantity of oil: 60 cc (EO-30CD)

7. Fit the O-ring and install support (2) with dowel pin (1).

PC78US-6

30-155 (16)

DISASSEMBLY AND ASSEMBLY

RECOIL SPRING ASSEMBLY DISASSEMBLY 1. Remove lubricator (1). 2. Remove yoke piston assembly (3) from recoil spring assembly (2). 3. Disassembly of recoil spring assembly 1) Remove set bolt (4).

RECOIL SPRING

3) Apply hydraulic pressure slowly. After the spring is compressed, remove nut (5). a Compress the spring until the nut is loosened. a Release the hydraulic pressure slowly to eliminate the spring force. 4) Remove pilot (7) and cylinder (8) from spring (6). a Remove O-ring (13) from the cylinder. 4. Disassembly of yoke piston assembly 1) Remove wear ring (10) from yoke piston (9). 2) Remove snap ring (11) and U-packing (12).

2) Set recoil spring assembly (2) to tool M.

k Since the installing load of the spring is heavy and dangerous, set the spring securely. a Installing load of spring: 69.2 kN {7,061 kg} (Rubber shoe) 47.4 kN {4,837 kg} (Steel shoe)

30-156 (16)

PC78US-6

DISASSEMBLY AND ASSEMBLY

ASSEMBLY 1. Assembly of yoke piston assembly 1) Fit U-packing (12) to yoke piston (9) and secure it with snap ring (11). 2) Install wear ring (10). 2. Assembly of recoil spring assembly 1) Fit O-ring (13) to cylinder (8). 2) Install cylinder (8) and pilot (7) to spring (6).

3) Set recoil spring (2) to tool M.

RECOIL SPRING

4) Apply hydraulic pressure slowly to compress the spring. Tighten nut (5) so that the installing length of the spring will be a. a Installing length a of spring: 283 mm (Rubber shoe) 323 (Steel shoe) 2 Nut: Lubricant containing disulphide (LM-P)

molybdenum

5) Remove recoil spring assembly (2) from tool M. 6) Install set bolt (4). 3 : 58.8 – 73.5 Nm {6 – 7.5 kgm}

7) Fill cylinder (8) with grease (G2-L1). a Quantity of grease (G2-L1): Approx. 232 cc (Rubber shoe) Approx. 96 cc (Steel shoe) 8) Loosen lubricator (1) and insert yoke piston assembly (3) in recoil spring assembly (4) until grease comes out through part B.

2 Sliding parts of yoke piston and wear ring: Grease (G2-L1) 9) Tighten lubricator (1).

3 : 58.8 – 88.2 Nm {6.0 – 9.0 kgm} a Install the valve so that the fitting will be on the outside.

PC78US-6

30-157 (16)

DISASSEMBLY AND ASSEMBLY

TRACK ROLLER ASSEMBLY DISASSEMBLY

TRACK ROLLER

5. Remove floating seal (7a) from roller (5), then remove floating seal (7b) from shaft and collar assembly (6).

1. Remove pin (2) from track roller assembly (1), then remove collar (3).

6. Pull out pin (8) and remove collar (10) from shaft (9). 2. Remove floating seal (4a) from collar (3).

7. Remove the O-ring from shaft (9).

3. Remove floating seal (4b) from roller (5).

8. Remove bushings (11) and (12) from roller (5).

4. Remove shaft and collar assembly (6) from roller (5).

30-158 (16)

PC78US-6

DISASSEMBLY AND ASSEMBLY

ASSEMBLY a When installing the floating seal, thoroughly clean, degrease, and dry the parts marked with the thick lines (the load ring and faces in contact with the load ring). Check that the contact surfaces of the floating seal are free from dirt.

a When inserting the floating seal assembly in the housing, use the push jig. This push jig must push the load ring. • PC78US-6 Serial No. : 4001 – 6500 PC78UU-6 Serial No. : 22001 and up Tool L4 ( 80 mm) • PC78US-6 Serial No. : 6501 and up Tool L5 ( 70 mm)

TRACK ROLLER

a The metallic faces of the floating seal which are in contact with each other must be free from dirt. a Thoroughly clean the parts to be in contact with the supplied oil. After cleaning them, the dirt remaining on these parts of 1 roller assembly must be below 25 mg and the size of the dirt must be below 0.3. a Set plug (2) on the outside of the machine body.

1. Using tool L3, press fit bushing (12) to roller (5). a Press fit bushing (11) similarly. 2. Fit the O-ring to shaft (9), then install collar (10) and pin (8) to shaft (9).

a After the floating seal is inserted, check that it does not slant more than 1 mm and its projection a is as follows. • PC78US-6 Serial No. : 4001 – 6500 PC78UU-6 Serial No. : 22001 and up a : 5 – 7 mm • PC78US-6 Serial No. : 6501 and up a : 6 – 10 mm

a In steps 3, 4, and 7 below, use tool L5 instead of tool L4 for PC78US-6, serial No. 6501 and up.

PC78US-6

30-159 (16)

DISASSEMBLY AND ASSEMBLY

3. Using tool L4, press fit floating seal (7b) to shaft (9).

TRACK ROLLER

8. Install collar (3) to shaft (9), then install pin (2). 9. Fill the roller with oil and tighten plug (13).

4. Using tool L4, press fit floating seal (7a) to roller (5). a Press fit floating seal (4b) similarly.

5 Track roller: PC78US-6 Serial No.:4001 – 6500 PC78UU-6 Serial No.:22001 and up 210 – 230 cc (GO-140) PC78US-6 Serial No.:6501 and up 160 – 180 cc (GO-140)

5. Install shaft and collar assembly (6) to roller (5). 6. Turn over the assembly of roller (5) and shaft (6).

7. Using tool L4, install floating seal (4a) to collar (3).

30-160 (16)

PC78US-6

DISASSEMBLY AND ASSEMBLY

HYDRAULIC CYLINDER

HYDRAULIC CYLINDER ASSEMBLY DISASSEMBLY 1. Cylinder assembly 1) Set cylinder assembly (1) to tool U1. 2) Using a hydraulic pump or a power wrench and tool U2, loosen head assembly (2).

3) Remove piston assembly (6) from piston rod (5). 4) Remove head assembly (2).

3) Pull out piston rod assembly (3). a Place an oil pan, etc. under the cylinder to receive the oil.

5) Remove cap (6) and take out 9 balls (7), then remove plunger (8). • Perform this work for only arm cylinder. a Since cap (6) is made of nylon, tighten a screw into it and pull it out with pliers.

2. Piston rod assembly 1) Set piston rod assembly (3) to tool U1. 2) Using a hydraulic pump or a power wrench and tool U3, remove nylon nut (4). a Width across flats of nut: Cylinder

Boom

Arm

Width across flats

80 *1

75 *1

70 *2

65 *2

Bucket

Offset

Blade

60

55

75

*1 : PC78UU-6 *2 : PC78US-6

PC78US-6

30-161 (16)

DISASSEMBLY AND ASSEMBLY

3. Disassembly of piston assembly 1) Remove wear ring (9). 2) Remove piston ring (10). a Apply a screwdriver, etc. to the piston ring and hit it with a hammer to break off the piston ring.

HYDRAULIC CYLINDER

ASSEMBLY a Apply engine oil to the sliding surfaces of each part and take care not to damage the packing, dust seals, O-rings, etc. a Do not insert the backup ring forcibly. Heat it in water at 50 – 60°C, then insert it carefully. 1. Assembly of cylinder head assembly 1) Using tool U6, press fit bushing (16). 2) Install rod packing (15). 3) Using tool U7, install dust seal (14) and secure it with snap ring (13). 4) Fit O-ring (12). 5) Fit the backup ring and O-ring (11).

4. Disassembly of cylinder head assembly 1) Remove the O-ring and backup ring (11). 2) Remove O-ring (12). 3) Remove snap ring (13) and dust seal (14). 4) Remove rod packing (15). 5) Remove bushing (16).

30-162 (16)

PC78US-6

DISASSEMBLY AND ASSEMBLY

2. Assembly of piston assembly 1) Using tool U4, expand piston ring (10). a Set the piston ring to tool U4 and revolve the handle by 8 – 10 turns to expand the piston ring. 2) Using tool U5, contract piston ring (10).

HYDRAULIC CYLINDER

2) Install head assembly (2) to piston rod (5). 3) Install piston assembly (6) to piston rod (5).

4) Set piston rod assembly (3) to tool U1. 5) Using tool U3, tighten nylon nut (4). 3) Install wear ring (9). a Take care not to open the closed gap of the ring too much.

2 Nylon nut: Liquid adhesive (Equivalent to LOCTITE 262) 3 Nylon nut: Cylinder name

Tightening torque

Boom *1

3.97 ± 0.4 kNm {405 ± 40.5 kgm}

Boom *2

2.60 ± 0.26 kNm {265 ± 26.5 kgm}

Arm *1

4.12 ± 0.41 kNm {420 ± 42.0 kgm}

Arm *2

2.65 ± 0.26 kNm {270 ± 27.0 kgm}

Bucket

2.16 ± 0.22 kNm {220 ± 22 kgm}

Offset

1.42 ± 0.14 kNm {145 ± 14.5kgm}

Blade

3.14 ± 0.31 kNm {320 ± 32.0 kgm}

*1 : PC78UU-6, *2 : PC78US-6

3. Piston rod assembly 1) Set plunger (8) to the piston rod and install 9 balls (7) and secure them with cap (6). a Check that there is some play at the plunger tip. • Perform this work for only arm cylinder.

PC78US-6

30-163 (16)

DISASSEMBLY AND ASSEMBLY

HYDRAULIC CYLINDER

6. Cylinder assembly 1) Set the cylinder to tool U1. 2) Install piston rod assembly (3). a Push in the piston rod to the end.

3) Using a hydraulic pump or a power wrench and tool U2, tighten head assembly (2).

3 Head assembly: Cylinder name

Tightening torque

Boom *1

980 ± 98 Nm {100 ± 10 kgm}

Boom *2

961 ± 96.1 Nm {98 ± 9.8 kgm}

Arm *1

1,107 ± 110 Nm {113 ± 11.2 kgm}

Arm *2

785 ± 78.5 Nm {80 ± 8.0 kgm}

Bucket

1st time: Tighten to 1,176 – 1,372 Nm {120 – 140 kgm}. 2nd time: Loosen to 0 Nm {0 kgm}. 3rd time: Tighten to 392 Nm {40 kgm} 4th time: Apply angle tightening (Tighten periphery of cylinder head by 3.5 – 4.5 mm).

Offset

931 ± 93.1 Nm {95 ± 9.5 kgm}

Blade

1.03 ± 0.10 Nm {105 ± 10.5 kgm}

*1: PC78UU-6 *2: PC78US-6

a After assembling, clean each part and mask the piping ports and pin hole.

30-164 (16)

PC78US-6

50 OTHER SPECIFICATIONS PC78US-6 (For Norway & EU)............................ 50-3

PC78US-6

50-1 (10)

PC78US-6 (For Norway & EU)

MACHINE MODEL

SERIAL NUMBER

PC78US-6 PC78US-6

4809 and up (For Norway) 4809 and up (For EU)

•

PC78US-6

This section contains only information related to the Norway specification. For other information, see the PC78US-6 Shop Manual.

50-3 (10)

CONTENTS GENERAL Specification dimensions drawing .............................................................................................................. 50- 5 Working range drawing .............................................................................................................................. 50- 6 Specifications ........................................................................................................................................... 50-6-2 Weight table .............................................................................................................................................. 50-10

STRUCTURE, FUNCTION, AND MAINTENANCE STANDARD Arrangement of hydraulic components ..................................................................................................... 50-12 Solenoid valve........................................................................................................................................ 50-13-1 Accumulator for PPC.............................................................................................................................. 50-13-5 Dimensions of each part of work equipment ............................................................................................. 50-14 Boom hydraulic anti-burst valve ................................................................................................................ 50-16 Electric control system .............................................................................................................................. 50-21 General system diagram ........................................................................................................................... 50-22 Overload alarm function ............................................................................................................................ 50-24 Overload alarm pressure sensor............................................................................................................... 50-25 Meter display unit ...................................................................................................................................... 50-26

TROUBLESHOOTING Connector types and mounting locations ................................................................................................ 50-101 Connector arrangement diagram ............................................................................................................ 50-104 Explanation of functions of electric system control mechanism .............................................................. 50-108 Dysplay and special functions of monitor panel ...................................................................................... 50-109 Troubleshooting for controller pump control system (C mode) ............................................................... 50-117 Troubleshooting for machine monitor system (M mode) ......................................................................... 50-133

50-4 (14)

PC78US-6

SPECIFICATION DIMENSIONS DRAWING

GENERAL

SPECIFICATION DIMENSIONS DRAWING

Item

Unit

PC78US-6

Machine weight

kg

7,325

Bucket capapcity

m3

0.20

Engine model Rated engine output

(*1) (*2)

—

KOMATSU 4D95LE-2 Diesel engine KOMATSU S4D95LE-3-A Diesel engine

kW{HP}/rpm

40.5 {54.0}/1,850

A

Overall length

mm

6,265

B

Overall height

mm

2,870 (2,730)

C

Overall width

mm

2,330

D

Shoe width

mm

450

E

Tail swing radius

mm

1,240

F

Overall length of track

mm

2,840

G

Distance between tumbler centers

mm

2,235

Minimum ground clearance

mm

360

Travel speed (Low/High)

km/h

3.0/4.5

Continuous swing speed

rpm

10.0

Figures in ( ): EU specification *1. Serial No.: 4809 – 5500 *2. Serial No.: 5501 and up

PC78US-6

50-5 (10)

WORKING RANGE DRAWING

GENERAL

WORKING RANGE DRAWING

Unit: mm Working range

PC78US-6

A

Max. digging reach

6,920

B

Max. digging depth

4,710

C

Max. digging height

7,600

D

Max. vertical wall depth

4,030

E

Max. dumping height

5,490

F

Min. swing radius of work equipment

2,050

G

Max. reach at ground level

6,790

H

Max. blade lifting height

380

I

Max. blade lowering depth

245

50-6 (10)

PC78US-6

SPECIFICATIONS

GENERAL

Dimension

Machine model

PC78US-6

Serial Number

4809 – 5500

Bucket capacity

m3

0.20

Machine weight

kg

7,325

Max. digging depth

mm

4,710

Max. vertical wall depth

mm

4,030

Max. digging reach

mm

6,920

Max. reach at ground level

mm

6,790

Max. digging height

mm

7,600

Max. dumping height

mm

5,490

Max. blade lifting height

mm

380

Max. blade lowering depth

mm

245

kN {kg}

61.29 {6,250}

Continuous swing speed

rpm

10.0

Max. slope angle for swing

deg.

19.0

Travel speed (Low/High)

km/h

3.0/4.5

Gradeability

deg.

35

Ground pressure

{kg/cm2}

Working range

Performance

SPECIFICATIONS

Max. digging force (Bucket)

kPa

32.4 {0.33}

Overall length (for transport)

mm

6,265

Overall width

mm

2,330

Overall height (for transport)

mm

2,850

Overall height (for operation)

mm

2,870

Ground clearance of counterweight

mm

760

Min. ground clearance

mm

360

Tail swing radius

mm

1,240

Min. swing radius of work equipment

mm

2,050

Height of work equipment at min. swing radius

mm

5,500

Overall width of track

mm

2,320

Overall length of track

mm

2,840

Distance between tumbler centers

mm

2,235

Track gauge

mm

1,870

Machine cab height

mm

1,745

Blade width × height

mm

2,320 × 470

50-6-2 (10)

PC78US-6

GENERAL

SPECIFICATIONS

PC78US-6 5501 and up 0.20

7,325 4,710 4,030 6,920 6,790 7,600 5,490 380 245 61.29 {6,250} 10.0 19.0 3.0/4.5 35 32.4 {0.33} 6,265 2,330 2,850 2,870 760 360 1,240 2,050 5,500 2,320 2,840 2,235 1,870 1,745 2,320 × 470

PC78US-6

50-6-3

SPECIFICATIONS

GENERAL

Machine model

PC78US-6

Serial Number

4809 – 5500

Model

4D95LE-2

Type

4-cycle, water-cooled, in-line vertical type, direct injection

No. of cylinders - bore × stroke

Engine

Performance

Total displacement

mm {cc} kW/rpm {HP/rpm}

Max. torque

Nm/rpm {kgm/rpm}

40.5/1,850 {54.0/1,850} 226/1,500 {23.0/1,500}

rpm

2,020

Min. speed at no load

rpm

1,130

Min. fuel consumption

g/kWh {g/HPh}

231 {172}

Max. speed at no load

24 V, 3.0 kw

Alternator

24 V, 35 A

Battery (*1)

12 V, 55 Ah × 2

Type of radiator core

CF29-3

Carrier roller

1 on each side

Track roller

5 on each side

Track shoe (Steel shoe)

Hydraulic motor Control valve

Hydraulic pump

Undercarriage

3.26 {3,260}

Rated output

Starting motor

Hydraulic system

4-95 × 115

Assembly-type triple grouser, 39 on each side

Type × No. Discharge Set pressures (Work equipment, travel) (Swing, blade) (Control) Type × No. Control method

Variable-capacity piston pump × 1 {cc}

MPa {kg/cm2}

Gear pump × 2 80× 2+60+12.7 26.5 {270} 21.1 {215} 3.1 {32} 7-spool type × 1 Hydraulically assisted

Travel motor

Variable-capacity piston motor (with brake valve, parking brake) × 2

Swing motor

Fixed-capacity piston motor (with safety valve, pivot shaft brake) × 1

Hydraulic tank Hydraulic oil filter Oil cooler

Box-shaped, open Tank return side Air-cooled (CF40-1)

*1: Battery capacity (Ah) shows the rate of 5 hours.

50-6-4 (13)

PC78US-6

SPECIFICATIONS

GENERAL

PC78US-6

PC78US-6

6501 and up

5501 – 6500

S4D95LE-3-A

S4D95LE-3-A

4-cycle, water-cooled, in-line vertical type, direct injection, with turbocharger

4-cycle, water-cooled, in-line vertical type, direct injection, with turbocharger

4-95 × 115

4-95 × 115

3.26 {3,260}

3.26 {3,260}

40.5/1,850 {54.0/1,850} 237/1,500 {24.2/1,500}

40.5/1,850 {54.0/1,850} 237/1,500 {24.2/1,500}

2,020

2,020

1,130

1,130

227 {169}

227 {169}

24 V, 3.0 kw

24 V, 3.0 kw

24 V, 35 A

24 V, 35 A

12 V, 55 Ah × 2

12 V, 55 Ah × 2

ALW-4

CF29-3

1 on each side

1 on each side

5 on each side

5 on each side

Assembly-type triple grouser, 39 on each side

Assembly-type triple grouser, 39 on each side

Variable-capacity piston pump × 1

Variable-capacity piston pump × 1

Gear pump × 2 80× 2+60+12.7

Gear pump × 2 80× 2+60+12.7

26.5 {270} 21.1 {215} 3.1 {32}

26.5 {270} 21.1 {215} 3.1 {32}

7-spool type × 1

7-spool type × 1

Hydraulically assisted

Hydraulically assisted

Variable-capacity piston motor (with brake valve, parking brake) × 2

Variable-capacity piston motor (with brake valve, parking brake) × 2

Fixed-capacity piston motor (with safety valve, pivot shaft brake) × 1

Fixed-capacity piston motor (with safety valve, pivot shaft brake) × 1

Box-shaped, open

Box-shaped, open

Tank return side

Tank return side

Air-cooled (CF42)

Air-cooled (CF40-1)

PC78US-6

50-7 (13)

SPECIFICATIONS

GENERAL

Machine model

PC78US-6

Serial Number

4809 – 5500

Boom cylinder

Type

Reciprocating piston

Inside diameter of cylinder

mm

ø 115

Diameter of piston rod

mm

ø 65

Stroke

mm

858

Max. distance between pins

mm

2,143

Min. distance between pins

mm

1,285

Arm cylinder

Reciprocating piston

Inside diameter of cylinder

mm

ø 100

Diameter of piston rod

mm

ø 60

Stroke

mm

865

Max. distance between pins

mm

2,193

Min. distance between pins

mm

1,328

Type Bucket cylinder

Work equipment cylinder

Hydraulic system

Type

Reciprocating piston

Inside diameter of cylinder

mm

ø 90

Diameter of piston rod

mm

ø 55

Stroke

mm

710

Max. distance between pins

mm

1,765

Min. distance between pins

mm

1,055

Blade cylinder

Type

50-8 (6)

Reciprocating piston

Inside diameter of cylinder

mm

ø 130

Diameter of piston rod

mm

ø 65

Stroke

mm

130

Max. distance between pins

mm

679

Min. distance between pins

mm

549

PC78US-6

SPECIFICATIONS

GENERAL

PC78US-6 5501 and up Reciprocating piston ø 115 ø 65 858 2,143 1,285 Reciprocating piston ø 100 ø 60 865 2,193 1,328 Reciprocating piston ø 90 ø 55 710 1,765 1,055 Reciprocating piston ø 130 ø 65 130 679 549

PC78US-6

50-9 (6)

WEIGHT TABLE

GENERAL

WEIGHT TABLE This mass list is for reference in handling or transporting these components. Unit: kg Machine model Serial Number

PC78US-6 4809 – 5500

5501 – 6500

6501 and up

Engine assembly (without water and oil)

403

404

404

• Engine (without water and oil)

300

300

300

• Engine mount

30

30

30

• PTO

7

7

7

• Hydraulic pump

66

67

67

Cooling assembly (without coolant and oil)

29

29

29

• Radiator (without coolant)

6.3

6.3

5.8

• Oil cooler (without oil)

5.2

5.2

5.5

Revolving frame

930

930

984

Operator's cab

260

260

260

Operator's seat

18

18

18

Fuel tank (without fuel)

11

11

48

Hydraulic tank (without hydraulic oil)

75

75

70

Control valve

58

58

58

Counterweight

800

800

732

Additional counterweight (OPT)

220

220

220

Swing motor (Including brake valve)

22

22

22

Swing circle

104

104

104

Swing machinery

47

47

46

Center swivel joint

17

17

17

1,142

1,142

1,142

779

779

779

• Idler assembly

54 × 2

54 × 2

54 × 2

• Recoil spring assembly

40 × 2

39 × 2

39 × 2

• Carrier roller

3.4 × 2

3.4 × 2

3.4 × 2

• Track roller

13 × 10

13 × 10

12.4 × 10

• Travel motor (with reduction gears)

81 × 2

81 × 2

81 × 2

• Sprocket

19 × 2

19 × 2

19 × 2

• City pad shoe (450 mm)

410 × 2

410 × 2

410 × 2

• Road liner (450 mm)

450 × 2

450 × 2

450 × 2

• Rubber shoe (450 mm)

385 × 2

385 × 2

385 × 2

• Triple grouser (600 m)

495 × 2

495 × 2

495 × 2

Track frame assembly (without track shoe) • Track frame

Track shoe assembly

50-10 (13)

PC78US-6

WEIGHT TABLE

GENERAL

Unit: kg Machine model Serial Number

PC78US-6 4809 – 5500

5501 – 6500

6501 and up

Boom assembly

418

418

418

Long arm assembly

240

240

240

Bucket link assembly

56

56

54

Bucket assembly (with side cutter)

210

210

204

Blade assembly

374

374

358

Boom cylinder assembly

86

86

86

Arm cylinder assembly

72

72

72

Bucket cylinder assembly

51

51

51

Blade cylinder assembly

46

46

46

PC78US-6

50-11 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ARRANGEMENT OF HYDRAULIC COMPONENTS

ARRANGEMENT OF HYDRAULIC COMPONENTS PC78US-6 Serial No.: 4809 – 6500

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Bucket cylinder Arm cylinder Boom cylinder Hydraulic tank Control valve Swing motor Hydraulic pump Oil cooler Travel motor Accumulator

50-12 (14)

11. 12. 13. 14. 15. 16. 17.

Left work equipment PPC valve Blade PPC valve (Blade specification) Right work equipment PPC valve Center swivel joint Travel PPC valve 3-spool solenoid valve Service PPC valve (Machine to which attachments can be installed) 18. Blade cylinder (Blade specification) 19. Boom hydraulic anti-burst valve

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ARRANGEMENT OF HYDRAULIC COMPONENTS

PC78US-6 Serial No.: 6501 and up

1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Bucket cylinder Arm cylinder Boom cylinder Hydraulic tank Control valve Swing motor Hydraulic pump Oil cooler Travel motor Left work equipment PPC valve

PC78US-6

11. 12. 13. 14. 15. 16. 17.

Blade PPC valve (Blade specification) Accumulator Right work equipment PPC valve Center swivel joint Travel PPC valve 3-spool solenoid valve Service PPC valve (Machine to which attachments can be installed) 18. Blade cylinder (Blade specification) 19. Boom hydraulic anti-burst valve

50-13 (14)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SOLENOID VALVE

SOLENOID VALVE PC78US-6 a The diagram shows a machine equipped with the accumulator

50-13-1 (14)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

A1: A2: B1: B2: B3: T:

SOLENOID VALVE

To accumulator (for PPC circuit) From control pump To PPC valve To 2nd travel speed selection valve To swing holding brake To hydraulic tank

1. Swing holding brake solenoid valve 2. 2-stage travel speed selector solenoid valve 3. PPC lock solenoid valve Solenoid valve 4. Coil (ON-OFF type) 5. Push pin 6. Valve spool 7. Return spring 8. Valve body Control relief valve 9. Adjustment screw 10. Locknut 11. Guide 12. Return spring 13. Valve spool

PC78US-6

50-13-2 (14)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

SOLENOID VALVE

PPC LOCK SOLENOID VALVE 2-STAGE TRAVEL SPEED SELECTOR SOLENOID VALVE SWING HOLDING BRAKE SOLENOID VALVE Operation When solenoid is de-energized (circuit is broken) • While a signal current does not flow from the PPC hydraulic lock switch or travel speed boost pedal, solenoid (1) is de-energized. Accordingly, spool (2) is pressed up by spring (3). • Under this condition, port A is closed and the pilot hydraulic oil does not flow into the actuator. At the same time, the oil from the actuator is drained through ports B and T into the tank.

50-13-3 (14)

When solenoid is energized (circuit is made) • If a signal current flows from the PPC hydraulic lock switch or travel speed boost pedal to solenoid (1), solenoid (1) is energized. • Accordingly, spool (2) is pushed down by push pin (4). • Under this condition, the pilot hydraulic oil flows through port A, spool (2), and port B into the actuator. At the same time, port T is closed and the oil does not flow into the tank.

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

When signal current is 0 (When coil is de-energized and circuit cut out) • If the signal current flowing from the controller into coil (1) becomes 0, coil (1) is deenergized. • As a result, spool (2) is pressed up by return spring (4). • Accordingly, port A is closed and the pressurized oil from the PPC valve does not flow into the control valve. At this time, the oil from the control valve is drained through ports B and T into the tank.

SOLENOID VALVE

Control relief valve •

If the pressure of the hydraulic oil from the control pump rises, the oil in port A pushes spool (1). The reaction force of spool (1) compresses spring (2) and moves spool (1) to the right to open ports A and T to relieve the circuit. Set pressure: 3.1 MPa {32 kg/cm²}

Signal current is 0 o increased o maximum • The valve operates in the order of 3, 2, and 1 explained above.

PC78US-6

50-13-4 (14)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ACCUMULATOR FOR PPC

ACCUMULATOR FOR PPC (for PPC circuit)

1. 2. 3. 4. 5. 6.

Gas plug Shell Poppet Holder Bladder Oil port

Outline • The accumulator is installed to the PPC lock solenoid valve. Even if the engine is stopped while the work equipment is raised, the work equipment can be lowered under its weight by applying the pilot oil pressure to the control valve to operate with the pressure of the nitrogen gas compressed in the accumulator. Specifications Gas used: Nitrogen gas Volume of gas: 300 cc Gas pressure: 1.18 MPa {12 kg/cm²} (at 80 °C) Max. using pressure: 6.86 MPa {70 kg/cm²}

50-13-5 (14)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

DIMENSIONS OF EACH PART OF WORK EQUIPMENT

DIMENSIONS OF EACH PART OF WORK EQUIPMENT ARM SECTION PC78US-6 Long arm

*1. Serial No.: 4809 – 4927

50-14 (6)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

DIMENSIONS OF EACH PART OF WORK EQUIPMENT

Unit: mm PC78US-6 No.

Measuring point

Basic dimension

–

ø 60

Arm side

71.5

1 2

Cylinder head side 3

–

Allowance Shaft

Hole

– 0.030 – 0.100

+ 0.100 0 +1.0 0

70

ø 60

± 1.2 – 0.030 – 0.100

+ 0.100 0 +0.5 0 – 0.5 – 1.0

Boom side

220

Arm side

220

5

–

228.2

± 2.0

6

–

239.5

± 1.0

7

–

465.5

± 1.0

8

–

2,250

–

9

–

2,702.7

± 3.0

10

–

1,652.1

± 1.3

11

–

259

± 0.3

12

–

7.6

± 0.5

13

–

395.1

± 0.1

14

–

342

± 0.1

15

–

312.2

–

16

–

1,066.9

–

17

–

ø 50

Link side

200

Bucket side

200

4

– 0.225 – 0.285 – 1.0 – 2.0 +2.0 0

18

–

ø 50

Arm side

188

Bucket side

211

19

20

21

PC78US-6

0 – 0.150

– 0.225 – 0.285

0 – 0.150 – 0.50 – 1.0 +3.0 0

Min.

1,055

± 1.5

Max.

1,765

–

50-15 ➂

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

BOOM HYDRAULIC ANTI-BURST VALVE

BOOM HYDRAULIC ANTI-BURST VALVE

V T CY PI PCY

: From control valve : To hydraulic tank : To hydraulic cylinder : From PPC valve : For pressure pickup and equalizer circuits

50-16 ➂

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

BOOM HYDRAULIC ANTI-BURST VALVE

PC78US-6 Serial No.: 4809 – 6765

1. 2. 3. 4. 5. 6.

Pilot spool Spring (1st stage of spool) Spring (2nd stage of spool) Safety valve Check valve Spring Unit: mm

No.

Item

Criteria Basic dimensions

7

Check valve spring

Free length × Outside diameter

Installed length

16.4 × 8.9

11.5

8

Spool return spring

19.1 × 8

14.0

9

Spool return spring

24.8 × 16.8

22.5

PC78US-6

Remedy Allowable limits

Installed load 13.7 N {1.4 kg} 22.6 N {2.3 kg} 55.4 N {5.65 kg}

Free length — — —

Installed load 11.0 N {1.12 kg} 18.0 N {1.84 kg} 44.3 N {4.52 kg}

If damaged or deformed, replace spring

50-17 (13)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

BOOM HYDRAULIC ANTI-BURST VALVE

PC78US-6 Serial No.: 6766 and up

1. 2. 3. 4. 5. 6.

Pilot spool Spring (1st stage of spool) Spring (2nd stage of spool) Safety valve Check valve Spring Unit: mm

No.

Item

Criteria Basic dimensions

7

Check valve spring

Free length × Outside diameter

Installed length

31.9 × 5.4

26.5

8

Spool return spring

19.1 × 8

14.0

9

Spool return spring

24.8 × 16.8

22.5

50-17-1 (13)

Remedy Allowable limits

Installed load 15.1 N {1.54 kg} 22.6 N {2.3 kg} 55.4 N {5.65 kg}

Free length — — —

Installed load 12.1 N {1.23 kg} 18.0 N {1.84 kg} 44.3 N {4.52 kg}

If damaged or deformed, replace spring

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

BOOM HYDRAULIC ANTI-BURST VALVE

Function If the piping between the main valve and a work equipment cylinder bursts, this valve prevents the oil from flowing back from the work equipment cylinder to prevent sudden fall of the work equipment. Operation 1. When the work equipment is in neutral [When piping is normal] • Check valve (5) is closed by the work equipment cylinder holding pressure applied through port CY to chamber b. • When the work equipment is in neutral, no pilot pressure is applied from the PPC valve to port PI. Accordingly, pilot spool (1) is moved to the left end by the force of springs (2) and (3), then chambers a and b are shut off from each other. • Accordingly, oil does not flow from the main valve to the work equipment cylinder, thus the work equipment cylinder is held. • If the pressure in the work equipment cylinder rises high abnormally, work equipment cylinder holding pressure Pb operates safety valve (4). [When piping bursts] • Even if piping A between the main valve and work equipment cylinder bursts, chamber a is shut off from chanber b as in the case where the piping is normal. Accordingly, the work equipment cylinder is held. • When the engine is stopped and the work equipment is held in air, if port PCY is opened, oil in chamber b flows out through orifice (7) and port PCY. Accordingly, the work equipment lowers slowly.

*1. Serial No.: 6766 and up

50-18 (13)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

BOOM HYDRAULIC ANTI-BURST VALVE

2. When oil is sent from main valve to cylinder [When piping is normal] • If pressure Pa of the oil sent from the main valve to chamber a is higher than the total of pressure Pb in chamber b connected to the work equipment cylinder and the force of spring (6), check valve (5) opens and chambers a and b are connected to each other and the oil flows from the main valve to the work equipment cylinder. [When piping bursts] • If piping A between the main valve and the work equipment cylinder bursts, the oil in chamber a flows out through the burst part and pressure Pa in chamber a lowers. • If Pa lowers below the total of pressure Pb in chamber b and the force of spring (6), check valve (5) closes and chambers a and b are shut off from each other. Accordingly, pressure Pb in the cylinder is held and the work equipment does not fall suddenly.

*1. Serial No.: 6766 and up

PC78US-6

50-19 (13)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

BOOM HYDRAULIC ANTI-BURST VALVE

3. When oil is returned from work equipment cylinder to main valve [When piping is normal] • The work equipment cylinder holding pressure is applied to chamber b and check valve (5) closes. • The pilot pressure from the PPC valve is applied to port PI. If it is higher than the force of spring (2) (area of ø d), spool (1) moves to the right standby position (1st-stage stroke). • At this time, chambers a and b are not connected to each other. • If the pilot pressure rises higher than the force of spring (3) (area of ø d), spool (1) moves further to the right and chambers a and b are connected to each other (2ndstage stroke). • Accordingly, the oil is returned from the work equipment cylinder to the main valve. [When piping bursts] • If piping A between the main valve and work equipment cylinder bursts, the oil in chamber a flows out through the burst part. Since oil supplied from chamber b to chamber a flows through opening c of spool (1), however, the work equipment does not fall suddenly. •

If the PPC valve is returned to the neutral position, spool (1) returns to the left end to shut off chambers a and b from each other. Accordingly, the work equipment stops.

*1. Serial No.: 6766 and up

50-20 (13)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

ELECTRIC CONTROL SYSTEM

ELECTRIC CONTROL SYSTEM Engine control function

Engine and pump compound control function

Overheat prevention function

Swing control function

Travel control function

PPC lock function (*1) Electric control system

Automatic gear shift system (*1) Turbocharger protection function

Overload alarm function

Error code display and alarm function Self-diagnosis function Error code memory func

*1. For PC78US-6 Serial No.: 6501 and up

PC78US-6

50-21 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

GENERAL SYSTEM DIAGRAM

GENERAL SYSTEM DIAGRAM PC78US-6 Serial No.: 4809 – 5500 a This drawing shows the PC78US-6 of blade specification.

50-22 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

GENERAL SYSTEM DIAGRAM

1. Battery 2. Battery relay 3. Fusible link 4. Starting switch 5. Fuse box 6. Controller 7. Emergency pump drive switch 8. Swing holding brake release switch 9. Resistor (For emergency pump drive) 10. Safety lock lever 11. PPC lock switch 12. Starting motor cut relay 13. Safety relay 14. One-touch deceleration switch 15. Fuel control motor relay (For drive) 16. Fuel control motor relay (For accelerator) 17. Fuel control motor relay (For deceleration) 18. Fuel control dial 19. Fuel control motor 20. Monitor panel 21. Travel speed boost pedal [Blade specification] 22. Travel alarm 23. PPC lock solenoid valve 24. 2-stage travel speed selector solenoid valve 25. Swing holding brake solenoid valve 26. TVC-EPC valve 27. Right work equipment PPC valve 28. Travel PPC valve 29. Left work equipment PPC valve 30. Blade PPC valve [Blade specification] 31. Boom RAISE PPC oil pressure switch 32. Travel PPC oil pressure switch 33. Arm IN PPC oil pressure switch 34. Swing PPC oil pressure switch 35. Engine stop solenoid 36. Starting motor 37. Engine speed sensor 38. Coolant temperature sensor 39. Hydraulic pump 39a. Servo piston 39b. LS valve 39c. TVC valve 40. Control valve 40a. Pump merge-divider valve 41. Travel motor 42. Swing motor 43. Overload alarm actuation switch 44. Overload alarm pressure sensor

PC78US-6

50-23 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

GENERAL SYSTEM DIAGRAM

PC78US-6 Serial No.: 5501 – 6500 a This drawing shows the PC78US-6 of blade specification.

50-23-1 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

GENERAL SYSTEM DIAGRAM

1. Battery 2. Battery relay 3. Fusible link 4. Starting switch 5. Fuse box 6. Controller 7. Emergency pump drive switch 8. Swing holding brake release switch 9. Resistor (For emergency pump drive) 10. Safety lock lever 11. PPC lock switch 12. Starting motor cut relay 13. Safety relay 14. One-touch deceleration switch 15. Fuel control motor relay (For accelerator) 16. Fuel control motor relay (For deceleration) 17. Fuel control dial 18. Fuel control motor 19. Monitor panel 20. Travel speed boost pedal (Blade specification) 21. Travel alarm 22. PPC lock solenoid valve 23. 2-stage travel speed selector solenoid valve 24. Swing holding brake solenoid valve 25. TVC-EPC valve 26. Right work equipment PPC valve 27. Travel PPC valve 28. Left work equipment PPC valve 29. Blade PPC valve (Blade specification) 30. Boom RAISE PPC oil pressure switch 31. Travel PPC oil pressure switch 32. Arm IN PPC oil pressure switch 33. Swing PPC oil pressure switch 34. Engine stop solenoid 35. Engine stop solenoid relay 36. Starting motor 37. Engine speed sensor 38. Coolant temperature sensor 39. Hydraulic pump 39a. Servo piston 39b. LS valve 39c. TVC valve 40. Control valve 40a. Pump merge-divider valve 41. Travel motor 42. Swing motor 43. Overload alarm actuation switch 44. Overload alarm pressure sensor

PC78US-6

50-23-2 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

GENERAL SYSTEM DIAGRAM

PC78US-6 Serial No.: 6501 and up a This drawing shows the PC78US-6 of blade specification.

50-23-3 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

GENERAL SYSTEM DIAGRAM

1. Battery 2. Battery relay 3. Fusible link 4. Starting switch 5. Fuse box 6. Controller 7. Emergency pump drive switch 8. Swing holding brake release switch 9. Resistor (For emergency pump drive) 10. Safety lock lever 11. PPC lock switch 12. Starting motor cut relay 13. Safety relay 14. One-touch deceleration switch 15. Fuel control motor relay (For accelerator) 16. Fuel control motor relay (For deceleration) 17. Fuel control dial 18. Fuel control motor 19. Monitor panel 20. Hydraulic pump pressure sensor 21. Travel alarm 22. PPC lock solenoid valve 23. 2-stage travel speed selector solenoid valve 24. Swing holding brake solenoid valve 25. TVC-EPC valve 26. Right work equipment PPC valve 27. Travel PPC valve 28. Left work equipment PPC valve 29. Blade PPC valve (Blade specification) 30. Boom RAISE PPC oil pressure switch 31. Travel PPC oil pressure switch 32. Arm IN PPC oil pressure switch 33. Swing PPC oil pressure switch 34. Engine stop solenoid 35. Engine stop solenoid relay 36. Starting motor 37. Engine speed sensor 38. Coolant temperature sensor 39. Hydraulic pump 39a. Servo piston 39b. LS valve 39c. TVC valve 40. Control valve 40a. Pump merge-divider valve 41. Travel motor 42. Swing motor 43. Travel alarm drive relay 44. Overload alarm actuation switch 45. Overload alarm pressure sensor

PC78US-6

50-23-4 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

OVERLOAD ALARM FUNCTION

OVERLOAD ALARM FUNCTION PC78US-6 Serial No.: 4809 – 6500

PC78US-6 Serial No.: 6501 and up

1. 2. 3. 4. 5. 6. 7. 8. 9.

Battery Battery relay Fusible link Starting switch Fuse box Controller Monitor panel Overload alarm actuation switch Overload alarm pressure sensor

Input/Output signals a. Power supply of controller b. Power supply of solenoids c. Power supply of monitor panel d. S-NET signal e. Overload alarm actuation signal f. Overload alarm pressure signal

Function • If the pressure in the boom cylinder bottom circuit rises above the set value, the caution lamp lights up and the buzzer sounds to notify the operator of possibility of tipping over of the machine by an overload.

50-24 (10)

PC78US-6

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

OVERLOAD ALARM PRESSURE SENSOR

OVERLOAD ALARM PRESSURE SENSOR

1. Plug 2. Sensor 3. Connector Function • One pressure sensor is installed to the boom cylinder bottom circuit to sense the hydraulic pressure on the boom cylinder bottom side.

PC78US-6

50-25 (10)

STRUCTURE, FUNCTION AND MAINTENANCE STANDARD

METER DISPLAY UNIT

METER DISPLAY UNIT

No.

Display type

1

Display item

Service meter

[*1] 2

Display

3a

Gauge

3b

Monitor

4a

Gauge

Coolant temperature

Fuel level 4b

Monitor

5

Display range

Display method

0-99999.9 h

Time is measured while engine is running (alternator is generating) (Lamp always lights up even if starting switch is at OFF position.)

3 alphanumerics

If electric control system has trouble, 3 alphanumerics (user code, service code) is displayed. In depth 0 set mode, depth from datum plane is displayed.

See above drawing. Above set temperature (99°C) See above drawing. Below set level (30 liters)

Preheating

During preheating

6

One-touch deceleration

When one-touch decelerator operates

7

Overload

Below set pressure (14.7 MPa {150 kg/cm2})

Charge level

When charging is defective (charge voltage < battery voltate)

Engine oil pressurre

Below set pressure (49 kPa {0.5 kg/cm2})

Pilot

8

Caution

9

Segment of corresponding level and all segments below it light up. [Monitor lamp blinks when 8th level lights up (above 99°C). Monitor lamp blinks and alarm buzzer sounds when 9th level lights up.] Segment of corresponding level and all segments below it light up. [Monitor lamp blinks and alarm buzzer sounds when 1st level lights up (below 30 liters).] Lamp lights up for about 30 seconds when starting switch is turned to HEAT position, then blinks (for about 10 seconds) to show that preheating is finished and then goes off.

Display color

Remarks

Blue

LCD

Red

LED

Blue

LCD

Red

LED

Green

Lamp lights up when one-touch decelerator operates. Lamp Lamp lights up when starting switch is turned to ON position and goes off after engine starts. Lamp is turned off when normal and on when abnormal. (If trouble occurs while engine is running, buzzer sounds.)

Red

*1: For the display method of the marked items, see ELECTRIC CONTROL SYSTEM.

50-26 (10)

PC78US-6

TROUBLESHOOTING

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING CONNECTOR TYPES AND MOUNTING LOCATIONS Serial No.: 4809 – 5500 a The addresses in the address column are used in the connector arrangement drawing (3-dimensional drawing). Connector No.

Type of Connector

No. of Pins

Address

Connector No.

Type of Connector

No. of Pins

D4

SWP

2

Diode (Engine stop solenoid)

G-1

K45

M

1

Radio ground

Q-3

D5

SWP

2

Diode (Starting switch BR ->Battery relay BR)

G-1

K51

AMP 090

20

M-7

SWP

2

Diode (Alternator R -> Battery relay BR)

Intermediate connector (Starting switch, light switch)

D6

G-1

K52

M

3

Light switch

N-8

D11

SWP

2

Diode (TVC solenoid)

R-5

K53

M

2

Buzzer cancel switch

O-8

D12

SWP

2

Diode (TVC solenoid)

R-5

K54

M

3

Beacon switch

P-8

2

Diode (Swing holding brake solenoid)

R-4

K55

SHINAGAWA

5

Additional working lamp relay

Q-8

2

Diode (Air conditioner compressor)

H-1

M1

L

2

Intermediate connector (Power supply, ground)

M-4

2

Overload warring cancel switch

R-4 M2

X

2

M-3

Beacon lamp

I-9

Intermediate connector (Power supply, glow plug)

Fuse

R-3

M3

DT

8

Intermediate connector (Fuel level sensor, hydraulic switch)

M-4

M4

DT

8

Intermediate connector (Washer, travel/swing alarm)

M-4

M5

DT

8

Intermediate connector (TVC, power supply, starting switch)

M-3

M6

DT

8

Intermediate connector (Pressure switch, air conditioner sensor)

M-3

D13 D22 E01 F02

SWP SWP M DT

2

FBI

Location

K1

S1

12

Intermediate connector (Monitor panel)

N-7

K2

S

16

Intermediate connector (Monitor panel)

M-7 O-2

Location

Address

K3

DT

2

2nd travel speed selection solenoid valve

K11

SWP

12

Auto A/C unit

N-2

K12

M

2

Resister

Q-8

M7

DT

8

For connection of boom bottom pressure sensor

M-3

K17

X

2

Optional power supply

P-2

M9

DT

2

Intermediate connector

I-2

K18

AMP 090

2

Decelerator switch

Q-2

M13

DT

2

PPC hydraulic lock

M-2

K19

PA

9

Radio

R-3

M14

DT

2

Swing holding brake

N-2

K20

M

8

Cab inlet

R-6

M15

DT

2

Travel speed selector

M-2

K21

S

8

Cab inlet

R-6

M16

DT

2

Engine speed sensor

J-3

K22

DT

2

Attachment selector wire

P-8

M17

X

1

Glow plug

K-9

K23

Relay

5

Starting motor cut relay (PPC lock)

R-7

M18

DT

2

Engine water temperature

L-9

K26

AMP 090

2

Horn switch

M-7

M19

X

1

Air conditioner compressor

L-8

K27

SWP

6

Fuel governor control motor

N-7

M20

DT

2

TVC solenoid

K-9

K28

M

3

PPC hydraulic lock switch

P-2

M21

X

2

Pressure switch (Boom RAISE)

G-9

K32

SHINAGAWA

5

Accelerator relay

O-8

M22

X

2

Pressure switch (Swing)

J-9

K33

SHINAGAWA

5

Decelerator relay

N-8

M23

X

2

Pressure switch (Swing)

G-9

K34

SHINAGAWA

5

Motor drive relay

O-8

M24

X

2

Pressure switch (Arm IN)

H-9

K42

SUMITOMO

16

Floor intermediate connector

P-8

M25

X

2

Pressure switch (Travel)

I-9

PC78US-6

50-101 (7)

TROUBLESHOOTING

CONNECTOR TYPES AND MOUNTING LOCATIONS

Connector No.

Type of Connector

No. of Pins

M26

L

2

M27

L

M28

Address

Connector No.

Type of Connector

No. of Pins

Fusible link

C-8

T31

Terminal

1

Safety relay B

K-3

2

Fusible link

B-7

T32

Terminal

1

Safety relay C

J-3

SWP

6

Intermediate connector (Working lamp)

J-9

T33

Terminal

1

Starting motor B

L-8

M30

X

2

Safety relay (S•R)

K-4

T34

Terminal

1

Starting motor C

L-7

M31

KES

2

Windshield washer

C-8

V2

DT

12

Intermediate connector

O-2

M32

DT

2

Travel/Swing alarm (Optional)

J-3

W04

M

6

Wiper motor

M-5

M33

DT

2

Air conditioner outside temperature sensor (Optional)

L-5

W19

2

Cigarette lighter

M-5

M40

YAZAKI 7222-1424

2

Working lamp (cab)

H-9

M41

YAZAKI 7222-1424

2

Working lamp (cab)

G-9

M42

YAZAKI 7222-1424

2

Working lamp (cab)

J-9

M45

SUMITOMO 61890443

Alternator

L-5

M75

DT

2

Working lamp

D-9

M76

DT

2

Working lamp (Boom)

E-9

M80

AMP 090

2

Horn

M-2

M92

DT

3

Boom bottom pressure sensor (Optional)

I-2

M95

DT

24

Controller

R-8

M96

DT

40

Controller

R-8

M97

DT

40

Controller

Q-8

P01

AMP 040

12

Monitor panel

M-6

P02

AMP 040

20

Monitor panel

M-6

P15

AMP 040

2

Sunlight sensor (Optional)

M-6

T1

Terminal

1

Revolving frame ground

I-2

T2

Terminal

1

Revolving frame ground

H-2

T3

Terminal

1

Revolving frame ground

H-1

T5

Terminal

1

Alternator B

L-6

T6

Terminal

1

Engine oil pressure switch

L-4

T7

Terminal

1

Engine stop solenoid (+)

K-9

T8

Terminal

1

Engine stop solenoid (-)

K-9

T9

Terminal

1

Battery relay E

A-4

T10

Terminal

1

Battery relay BR

A-3

T11

Terminal

1

Battery relay M

A-6

T12

Terminal

1

Battery relay B

A-5

50-102 (12)

Location

Location

Address

B

Terminal

1

Starting switch terminal B

M-9

BR

Terminal

1

Starting switch terminal BR

M-8

ACC

Terminal

1

Starting switch terminal ACC

M-8

C

Terminal

1

Starting switch terminal C

M-9

R1

Terminal

1

Starting switch terminal R1

N-8

R2

Terminal

1

Starting switch terminal R2

N-8

PC78US-6

TROUBLESHOOTING

CONNECTOR ARRANGEMENT DIAGRAM

CONNECTOR ARRANGEMENT DIAGRAM Serial No.: 4809 – 5500

50-104 (7)

PC78US-6

TROUBLESHOOTING

PC78US-6

CONNECTOR ARRANGEMENT DIAGRAM

50-105 (7)

TROUBLESHOOTING

50-106 (4)

CONNECTOR ARRANGEMENT DIAGRAM

PC78US-6

TROUBLESHOOTING

CONNECTOR TYPES AND MOUNTING LOCATIONS

Serial No.: 5501 – 6500 a The addresses in the address column are used in the connector arrangement drawing (3-dimensional drawing). Connector No.

Type of Connector

No. of Pins

Address

Connector No.

Type of Connector

No. of Pins

Location

Address

D4

SWP

2

Diode (Engine stop solenoid, HOLD)

H-1

K42

SUMITOMO

16

Floor intermediate connector

P-8

D5

SWP

2

Diode (Starting switch BR ->Battery relay BR)

G-1

K45

M

1

Radio ground

Q-3

D6

SWP

2

Diode (Alternator R -> Battery relay BR)

G-1

K51

AMP 090

20

Intermediate connector (Starting switch, light switch)

M-7

D11

SWP

2

Diode (TVC solenoid)

R-5 K52

M

3

Light switch

N-8

D12

SWP

2

Diode (TVC solenoid)

R-5 K53

M

2

Buzzer cancel switch

O-8

D13

SWP

2

Diode (Swing holding brake solenoid)

R-4 K54

M

3

Beacon switch

P-8

D22

SWP

2

Diode (Air conditioner compressor)

H-1 K55

5

Additional working lamp relay

Q-8

2

Diode (Engine stop solenoid PULL)

SHINAGAWA

G-1 M1

L

2

Intermediate connector (Power supply, ground)

M-4

2

Diode (Engine stop solenoid relay coil)

H-9 M2

X

2

M-3

R-4

Intermediate connector (Power supply, glow plug)

M3

DT (Gr)

8

Intermediate connector (Fuel level sensor, hydraulic switch)

M-4

M4

DT (G)

8

Intermediate connector (Washer, travel/swing alarm)

M-4

M5

DT (Gr)

8

Intermediate connector (TVC, power supply, starting switch)

M-3

M6

DT (B)

8

Intermediate connector (Pressure switch, air conditioner sensor)

M-3

D25 D26

SWP SWP

Location

EU1

M

2

Overload warring cancel switch

F02

DT

2

Beacon lamp

J-9

FBI

Terminal

Fuse box

R-3

Terminal

1

Engine stop solenoid (GND)

L-3 L-2

GND HOLD

Terminal

1

Engine stop solenoid (HOLD)

K1

S1

12

Intermediate connector (Monitor panel)

M-7

K2

S

16

Intermediate connector (Monitor panel)

N-7

M7

DT (G)

8

For connection of boom bottom pressure sensor

M-3

K3

DT

2

2nd travel speed selection solenoid valve

O-2

M9

DT

2

Intermediate connector

I-2

K11

SWP

12

Auto A/C unit

N-2

M13

DT

2

PPC hydraulic lock

M-2

K12

M

2

Resister

Q-8

M14

DT

2

Swing holding brake

N-2

K17

X

2

Optional power supply

P-2

M15

DT

2

Travel speed selector

M-2

K18

AMP 090

2

Decelerator switch

Q-2

M16

DT

2

Engine speed sensor

J-3

K19

PA

9

Radio

R-3

M17

X

1

Glow plug

K-9

K20

M

8

Cab inlet

R-6

M18

DT

2

Engine water temperature

L-9

K21

S

8

Cab inlet

R-6

M19

X

1

Air conditioner compressor

L-8

K22

DT

4

Attachment selector wire

P-8

M20

DT

2

TVC solenoid

K-9

K23

Relay

5

Starting motor cut relay (PPC lock)

R-7

M21

X

2

Pressure switch (Boom RAISE)

G-9

K26

AMP 090

2

Horn switch

M-7

M22

X

2

Pressure switch (Swing)

I-9

K27

SWP

6

Fuel governor control motor

N-7

M23

X

2

Pressure switch (Swing)

G-9

K28

M

3

PPC hydraulic lock switch

P-2

M24

X

2

Pressure switch (Arm IN)

H-9

K32

SHINAGAWA

5

Accelerator relay

O-8

M25

X

2

Pressure switch (Travel)

I-9

K33

SHINAGAWA

5

Decelerator relay

N-8

M26

L

2

Fusible link

C-8

PC78US-6

50-107 (12)

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

Connector No.

Type of Connector

No. of Pins

M27

L

2

Fusible link

B-7

2

Intermediate connector (Working lamp)

I-9

M28

DT

Location

Address

Connector No.

Type of Connector

No. of Pins

T16

Terminal

1

Terminal: Engine stop solenoid relay (Contact 1)

K-3

T17

Terminal

1

Terminal: Engine stop solenoid relay (Contact 2)

K-3

Location

Address

M30

X

2

Safety relay (S•R)

J-3

M31

KES

2

Windshield washer

C-8

T31

Terminal

1

Safety relay B

K-4

M32

DT

2

Travel/Swing alarm (Optional)

J-2

T32

Terminal

1

Safety relay C

L-5

M33

DT

2

Air conditioner outside temperature sensor (Optional)

L-6

T33

Terminal

1

Starting motor B

L-8

Terminal

1

Starting motor C

L-7

L

2

Intermediate connector (Starting motor C)

T34

M35

K-1 DT

12

Intermediate connector

O-2

DT

2

Engine stop solenoid relay (Coil)

V2

M36

J-2

YAZAKI 7222-1424

W04

M

6

Wiper motor

M-5

M40

2

Working lamp (cab)

H-9 2

Cigarette lighter

M-5

M41

YAZAKI 7222-1424

2

Working lamp (cab)

H-9

M42

YAZAKI 7222-1424

2

Working lamp (cab)

J-9

M45

SUMITOMO 61890443

3

Alternator

L-5

M75

DT

2

Working lamp

D-9

M76

DT

2

Working lamp (Boom)

E-9

M80

AMP 090

2

Horn

M-2

M92

DT

3

Boom bottom pressure sensor

I-2

M95

DT

24

Controller

R-8

M96

DT

40

Controller

R-8

M97

DT

40

Controller

Q-8

P01

AMP 070

12

Monitor panel

M-6

P02

AMP 040

20

Monitor panel

M-6

P15

AMP 040

2

Sunlight sensor (Optional)

M-6

PULL

Terminal

1

Engine stop solenoid (PULL)

L-3

T1

Terminal

1

Revolving frame ground

I-2

T2

Terminal

1

Revolving frame ground

H-2

T3

Terminal

1

Revolving frame ground

H-1

T5

Terminal

1

Alternator B

L-5

T6

Terminal

1

Engine oil pressure switch

L-6

T9

Terminal

1

Battery relay E

A-4

T10

Terminal

1

Battery relay BR

A-3

T11

Terminal

1

Battery relay M

A-6

T12

Terminal

1

Battery relay B

A-5

W19

50-107-1 (12)

B

Terminal

1

Starting switch terminal B

M-9

BR

Terminal

1

Starting switch terminal BR

M-8

ACC

Terminal

1

Starting switch terminal ACC

M-8

C

Terminal

1

Starting switch terminal C

M-9

R1

Terminal

1

Starting switch terminal R1

N-8

R2

Terminal

1

Starting switch terminal R2

N-8

PC78US-6

TROUBLESHOOTING

CONNECTOR ARRANGEMENT DIAGRAM

Serial No.: 5501 – 6500

50-107-3 (12)

PC78US-6

TROUBLESHOOTING

PC78US-6

CONNECTOR ARRANGEMENT DIAGRAM

50-107-4 (7)

TROUBLESHOOTING

50-107-5 (7)

CONNECTOR ARRANGEMENT DIAGRAM

PC78US-6

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

Serial No.: 6501 and up a The addresses in the address column are used in the connector arrangement drawing (3-dimensional drawing). Connector No.

Type of Connector

No. of Pins

Location

Address

D4

SWP

8

Diode (Assembled-type diode)

H-1

2

Diode (Starting switch BR ->Battery relay BR)

G-1 G-1

D5

SWP

D6

SWP

2

Diode (Alternator R -> Battery relay BR)

EU1

M

2

Overload warring cancel switch

R-4

F02

DT

2

Beacon lamp

J-9

FBI

Terminal

Fuse box

R-3

GND

Terminal

1

Engine stop solenoid (GND)

L-3

1

Engine stop solenoid (HOLD)

L-2

12

Intermediate connector (Monitor panel)

M-7

16

Intermediate connector (Monitor panel)

N-7

HOLD K1 K2

Terminal S1 S

K11

SWP

12

Auto A/C unit

N-2

K12

M

2

Resister

Q-8

K17 K18 K19 K20 K21

X AMP 090 PA M S

2 2 9 8

Optional power supply Decelerator switch Radio Cab inlet

No. of Pins

Location

Address

M3

DT (Gr)

8

Intermediate connector (Fuel level sensor, hydraulic switch)

M-4

M7

DT (G)

8

For connection of boom bottom pressure sensor

M-3

M9

X

2

Fuel level sensor

M13

DT

2

PPC hydraulic lock

M-2

M14

DT

2

Swing holding brake

N-2

M15

DT

2

Travel speed selector

M-2

M16

DT

2

Engine speed sensor

J-3

M17

X

1

Glow plug

K-9

M18

DT

2

Engine water temperature

L-9

M19

X

1

Air conditioner compressor

L-8

M20

DT

2

TVC solenoid

K-9

M21

X

2

Pressure switch (Boom RAISE)

G-9

M22

X

2

Pressure switch (Swing)

I-9

M23

X

2

Pressure switch (Swing)

G-9

M24

X

2

Pressure switch (Arm IN)

H-9

M25

X

2

Pressure switch (Travel)

I-9

M26

L

2

Fusible link

C-8

M27

L

2

Fusible link

B-7

M28

DT

2

Intermediate connector (Working lamp)

I-9

M30

X

2

Safety relay (S•R)

J-3

M31

KES

2

Windshield washer

C-8

M32

DT

2

Travel/Swing alarm (Optional)

J-2

M35

L

2

Intermediate connector (Starting motor C)

K-1

M36

DT

2

Engine stop solenoid relay (Coil)

J-2

M40

YAZAKI 7222-1424

2

Working lamp (cab)

H-9

Q-2 R-3 R-6

8

Cab inlet

R-6 R-7 M-7

K23

Relay

5

K26

AMP 090

2

Horn switch

P-2

K28

M

3

PPC hydraulic lock switch

K32

SHINAGAWA

5

Accelerator relay

O-8

K33

SHINAGAWA

5

Decelerator relay

N-8

SUMITOMO

16

M

1

K45

Type of Connector

P-2

Starting motor cut relay (PPC lock)

K42

Connector No.

Floor intermediate connector

P-8

Radio ground

Q-3

K51

AMP 090

20

Intermediate connector (Starting switch, light switch)

K52

M

3

Light switch

N-8

M41

YAZAKI 7222-1424

2

Working lamp (cab)

H-9

K53

M

2

Buzzer cancel switch

O-8

M42

YAZAKI 7222-1424

2

Working lamp (cab)

J-9

K54

M

3

Beacon switch

P-8

M45

SUMITOMO 61890443

3

Alternator

L-5

K55

SHINAGAWA

5

Additional working lamp relay

Q-8 M75

DT

2

Working lamp

D-9

2

Intermediate connector (Power supply, ground)

M-4

M76

DT

2

Working lamp (Boom)

E-9

2

Intermediate connector (Power supply, glow plug)

M-3

M80

AMP 090

2

Horn

M-2

M1 M2

PC78US-6

L X

M-7

50-107-6 (12)

CONNECTOR TYPES AND MOUNTING LOCATIONS

TROUBLESHOOTING

Connector No.

Type of Connector

No. of Pins

Location

Address

Connector No.

Type of Connector

No. of Pins

M92

DT

3

Boom bottom pressure sensor

I-2

M13

M

2

Speaker (Right)

M95

DT

24

Controller

R-8

M71

M

2

Room light

P01

AMP 070

12

Monitor panel

M-6

M73

M

2

Speaker (Left)

P02

AMP 040

20

Monitor panel

M-6

M87

S

12

Air conditioner unit junction

P15

AMP 040

2

Sunlight sensor (Optional)

M-6

M88

YAZAKI 2

10

Air conditioner foot area air outlet servo

PULL

Terminal

1

Engine stop solenoid (PULL)

L-3

S1

M

3

Fuel control dial

T1

Terminal

1

Revolving frame ground

I-2

S2

SWP

6

Fuel governor control motor

T2

Terminal

1

Revolving frame ground

H-2

S3

DT

3

Main pump pressure sensor

T3

Terminal

1

Revolving frame ground

H-1 S4

SHINAGAWA

5

Travel/Swing alarm relay (If equipped)

V3

SHINAGAWA

5

Starting motor cutout relay

W03

X

2

Window limit switch

T5

Terminal

1

Alternator B

L-5 L-6

T6

Terminal

1

Engine oil pressure switch

T9

Terminal

1

Battery relay E

A-4

T10

Terminal

1

Battery relay BR

A-3

T11

Terminal

1

Battery relay M

A-6

T12

Terminal

1

Battery relay B

A-5

T16

Terminal

1

Terminal: Engine stop solenoid relay (Contact 1)

K-3

T17

Terminal

1

Terminal: Engine stop solenoid relay (Contact 2)

K-3

T31

Terminal

1

Safety relay B

K-4

T32

Terminal

1

Safety relay C

L-5

T33

Terminal

1

Starting motor B

L-8

T34

Terminal

1

Starting motor C

L-7

V2

SWP

12

Intermediate connector

O-2

W04

M

6

Wiper motor

M-5

W19

Terminal

2

Cigarette lighter

M-5

B

Terminal

1

Starting switch terminal B

M-9

BR

Terminal

1

Starting switch terminal BR

M-8

ACC

Terminal

1

Starting switch terminal ACC

M-8

C

Terminal

1

Starting switch terminal C

M-9

R1

Terminal

1

Starting switch terminal R1

N-8

R2

Terminal

1

Starting switch terminal R2

N-8

J1

SUMITOMO 2

20

Junction connector

J2

SUMITOMO 2

20

Junction connector

50-107-7 (12)

Location

Address

PC78US-6

TROUBLESHOOTING

CONNECTOR ARRANGEMENT DIAGRAM

Serial No.: 6501 and up

50-107-9 (12)

PC78US-6

TROUBLESHOOTING

PC78US-6

CONNECTOR ARRANGEMENT DIAGRAM

50-107-10 (12)

TROUBLESHOOTING

50-107-11 (12)

CONNECTOR ARRANGEMENT DIAGRAM

PC78US-6

TROUBLESHOOTING

EXPLANATION OF FUNCTIONS OF ELECTRIC SYSTEM CONTROL MECHANISM

EXPLANATION OF FUNCTIONS OF ELECTRIC SYSTEM CONTROL MECHANISM Serial No.: 4809 – 6500 The control mechanism of the electric system consists of the monitor panel, governor, and pump controller. Those components receive signals necessary to them. The governor and pump controller output or input the necessary signal according to the signals selected by the monitor panel to control the absorption torque, engine output, etc. Network information 1) 2) 3) 4) 5)

Working mode (Standard, E) information One-touch slow-down (ON/OFF) signal Travel Hi/Lo signal Coolant temperature (Water temperature) information Service code (Failure code) information

50-108 (12)

(Monitor panel o Controller) (Monitor panel i Controller) (Monitor panel i Controller) (Monitor panel o Controller) (Controller o Monitor panel)

PC78US-6

TROUBLESHOOTING

EXPLANATION OF FUNCTIONS OF ELECTRIC SYSTEM CONTROL MECHANISM

Serial No.: 6501 and up The control mechanism of the electric system consists of the monitor panel, governor, and pump controller. Those components receive signals necessary to them. The governor and pump controller output or input the necessary signal according to the signals selected by the monitor panel to control the absorption torque, engine output, etc. Network information 1) 2) 3) 4) 5)

Working mode (Standard, E) information One-touch slow-down (ON/OFF) signal Travel Hi/Lo signal Coolant temperature (Water temperature) information Service code (Failure code) information

PC78US-6

(Monitor panel o Controller) (Monitor panel i Controller) (Monitor panel i Controller) (Monitor panel o Controller) (Controller o Monitor panel)

50-108-1 (12)

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL 1. Diagnostic function of lamps, gauges, and buzzer If the starting switch is turned ON, all the lamps and gauges light up for about 3 seconds and the buzzer sounds for about 1 second to check the monitor panel, then the monitor panel displays normally (A lamp which does not light up at this time is broken). 2. Function of displaying "user code" All trouble information items of the controller are sent to the monitor panel. An emergent information item among them is displayed as a "user code" automatically on the display (1) of the monitor panel to urge the operator to take proper actions. ★ The lamps other than display (1), service meter unit (2), and lighting parts (solid parts in the following illustration) are turned OFF. 1) Display of User Code (1) Display (2) Service meter unit (3) Mode selector switch (UP) (4) Mode selector switch (DOWN) (5) Set switch (6) Travel speed selector switch (7) Working mode selector switch (8) Buzzer cancel switch Note) Since the switches "3, 4, and 5" are not indicated on the panel of model US, operate the same parts as the panel of model UU.

Example) User code "E02" is displayed.

2)

User Codes List User Code

PC78US-6

Troubled System

E02

TVC-EPC system

E03

Swing holding brake system

E05

Governor control system

50-109

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

3. Function of displaying "service code" All trouble information items of the controller are sent to the monitor panel. All of the information items which must display "user codes" and those which do not need display "user codes" are saved as "service codes" in the monitor panel. If the following operation is executed, the service code is displayed on the display of the monitor panel and the letter "E" to indicate that the trouble is happening currently and the lapse time (service meter reading) are displayed on the service meter unit. 1) Method of displaying and deleting service code i) The service code is displayed by the following procedure: a. Push and hold the "Buzzer cancel switch (8)" and "Working mode selector switch (7)" for 2.5 seconds. b. Push the "Buzzer cancel switch (8)" and "Mode selector switch (UP) (3)" [or Mode selector switch (DOWN) (4)] and set "01" to the 2nd and 3rd columns from the left on service meter unit (2).

(1) Display (2) Service meter unit (3) Mode selector switch (UP) (4) Mode selector switch (DOWN)

(5) Set switch (6) Travel speed switch (7) Working mode selector switch (8) Buzzer cancel switch

c. Push the "Set switch (5)".

* Since the switches "3, 4, and 5" are not indicated on the panel of model US, operate the same parts as the panel of model UU. Example 1) "01" is displayed on service meter unit (2).

Example 2) "E213" happened 6 hours ago. ★ If "E213" is still happening, the letter "E" is displayed in the 2nd column of service meter unit (2). If "E213" has been repaired, "E" is not displayed. ★ The lapse time is displayed in the 3 columns from the right of service meter unit (2).

50-110

PC78US-6

TROUBLESHOOTING

ii)

iii)

iv)

v)

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

Example 3) If any service code is not saved, "-" is displayed in every column of display (1) and service meter unit (2). To see the next displayed service code, push the "Buzzer cancel switch (8)" and "Mode selector switch (UP)" (3). To see the previous displayed service code, push the "Buzzer cancel switch (8)" and "Mode selector switch (DOWN) (4)". To stop display of the service code, push the "Buzzer cancel switch (8)" and "Working mode selector switch (7)". To delete the saved service codes, press the "Buzzer cancel switch (8)" and turn OFF the "starting switch" simultaneously, then turn ON the "starting switch" again and push and hold the "Buzzer cancel switch (8)" for 5 seconds. a If the number of service codes exceeds 20, they are deleted one by one from the oldest one.

2) Service codes lit Error Code

Troubled System

User Code

E101

Error history data are abnormal

–

E108

Engine coolant temperature is 105°C

–

E112

Short circuit in forward system of wiper motor drive

–

E113

Short circuit in reverse system of wiper motor drive

–

E114

Short circuit in windshield washer drive system

–

E115

Wiper does not start wiping in 10 seconds

–

E116

Wiper is not start retracted in 10 seconds

–

E203

Short circuit or short circuit with chassis ground in swing holding brake solenoid system

E03

E206

Short circuit or short circuit with chassis ground in 2nd travel speed selection solenoid system

E03

E213

Disconnection in swing holding brake solenoid system

–

E216

Disconnection in 2nd travel speed selection solenoid system

–

E218

Defective communication between monitor panel and controller

–

E227

Short circuit or disconnection in engine speed sensor system

E232

Short circuit or short circuit with chassis ground in TVC-EPC solenoid system

E02

–

E233

Disconnection in TVC-EPC solenoid system

E02

E251

Short circuit with chassis ground or disconnection on boom bottom pressure sensor (overload sensor) signal side or (+) side or disconnection on (-) side.

–

E258

Short circuit with chassis ground on all angle sensor power supply side

–

E304 (*2)

Short circuit or short circuit with chassis ground in engine stop solenoid relay system

–

E314 (*2)

Disconnection in engine stop solenoid relay system

–

E306 (*3)

Governor feedback potentiometer

–

E308 (*3)

Trouble in fuel control dial system

E05

E321 (*1)

Short circuit with chassis ground in governor control motor drive relay system

E05

E323

Short circuit with chassis ground in governor control accelerator relay system

E05

E325

Short circuit with chassis ground in governor control decelerator relay system

E05

E328

Stall of governor conveyor motor

E05

*1. Serial No.: 4809 – 5500 *2. Serial No.: 5501 – 6500 *3. Serial No.: 6501 and up

PC78US-6

50-111 (12)

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

4. Function of displaying "monitoring code" The input signals from the sensors to each component and the output signals to drive the solenoids can be checked in real time with the monitoring codes. If the following operation is executed, the monitoring code No. is displayed in the 3rd column through the 5th column from the left on service meter unit (2) of the monitor panel and the monitoring information is displayed on display (1).

1) Method of displaying monitoring code i) The monitoring code is displayed by the following procedure: a. Push and hold the "Buzzer cancel switch (8)" and "Working switch (7)" for 2.5 seconds. b. Push the "Buzzer cancel switch (8)" and "Mode selector switch (UP) (3)" [or Mode selector switch (DOWN) (4)] and set "02" to the 2nd and 3rd columns from the left on display (2). c. Push the "Set switch (5)". * Since the switches "3, 4, and 5" are not indicated on the panel of model US, operate the same parts as the panel of model UU.

(1) Display (2) Service meter unit (3) Mode selector switch (UP) (4) Mode selector switch (DOWN)

(5) Set switch (6) Travel speed switch (7) Working mode selector switch (8) Buzzer cancel switch

Example 1) A numerical monitoring code (Engine speed: 2,050 rpm) is displayed.

Example 2) A bit pattern monitoring code 1020 (ON/OFF input state (1)) is displayed.

50-112 (4)

PC78US-6

TROUBLESHOOTING

CONNECTOR TYPES AND MOUNTING LOCATIONS

ii)

To see the next displayed monitoring code, push the "Buzzer cancel switch (8)" and "Mode selector switch (UP) (3)". iii) To see the previous displayed monitoring code, push the "Buzzer cancel switch (8)" and "Mode selector switch (DOWN) (4)". iv) To stop display of the monitoring code, push and hold the "Buzzer cancel switch (8)" and "Working mode selector switch (5)" for 2.5 seconds. 2) Monitoring codes list a For details of a code marked with "(6 bit)" in the Unit column, see the bit patterns table. Code No.

Item

Unit

Component Name

0001

Monitor model code

–

Controller

0008

S-NET connection state

(6 bit)

Controller

0041

Water temperature sensor voltage

10 mA

Controller

0042

Fuel level sensor voltage

10 mA

Controller

0043

Charge voltage

100 mA

Controller

0045

Sensor input 1

(6 bit)

Controller

0046

Sensor input 2

(6 bit)

Controller

0047

Output state

(6 bit)

Controller

0048

Wiper state

(6 bit)

0049

Spare

Controller

0200

Software version No. (Monitor)

Controller

1000

Software version No. (Controller)

If 1.0 is displayed, version No. of controller is 1.0.

Controller

1001

Attachment selection

00: 01: 02: 03:

Controller

1010

Engine speed

10 rpm

Controller

1020

ON/OFF input 1

(6 bit)

Controller

1021

ON/OFF input 2

(6 bit)

Controller

1022

ON/OFF input 3

(6 bit)

Controller

1023

ON/OFF input 4

(6 bit)

Controller

1024

ON/OFF input/output

(6 bit)

Controller

1025

ON/OFF input/output

(6 bit)

Controller

1026

ON/OFF input/output

(6 bit)

Controller

1060

ON/OFF output

(6 bit)

Controller

PC78US-6

Standard arm Long arm Slide arm Multi-changer

Controller

50-113 (12)

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

3) Bit patterns list (Bits of corresponding Nos. light up) a [1] – [6] on digital display unit (1) are bit Nos. a The monitoring code No. (4 digits) is displayed in the 2nd column through 5th column from the left on service meter display unit (2).

Code No.

0008

0045

Item

S-NET connection state

Sensor input 1

Bit

Details (State When Bit Lights Up)

(1)

ID2 is connected.

(2)

ID3 is connected.

(3)

ID4 is connected.

(4)

ID5 is connected.

(5)

ID6 is connected.

(6)

ID7 is connected.

(1)

Starting switch is at "ON"

(2)

Starting switch is at "START"

(3)

Starting switch is at "PREHEAT"

(4)

Light switch is at "ON"

(2)

Constant bit Engine oil pressure

0046

Sensor input 2

(3) (6)

Charge level is low (Engine is stopped)

0047

State of output

(1)

Buzzer output

(2)

Washer output (Washer switch is turned ON)

(3)

Wiper output 1

(4)

Wiper output 2

(5)

Wiper output 3

0048

0049

1020

1021

1022

State of wiper

Spare

ON/OFF input 1 For detail of model selection, see Table 1. For detail of ATT selection, see Table 2.

* *

ON/OFF input 2

ON/OFF input 3

(6)

Wiper output 4

(2)

Buzzer cancel switch

(3)

Window limit switch (ON)

(4)

W contact (Wiper is operated)

(5)

P contact (Wiper is operated)

(1)

ATT selection 2 (GND is connected)

(2)

ATT selection 1 (GND is connected)

(3)

Model selection 1 (GND is connected)

(4)

ATT selection 3 (GND is connected)

(5)

UU/US selection (GND is connected)

(6)

Model selection 2 (GND is connected)

(3)

Compressor signal

(4)

Arm crane is installed (Power supply is connected)

(5)

a Tier 2 selection signal (Power supply is connected)

(1)

2nd travel speed selection switch (Panel)

(2)

Working mode selector switch

(3)

Backup light

(4)

SET/CLEAR switch

(5)

Mode selector (

) switch

(6)

Mode selector (

) switch

(a) Serial No.: 5501 and up

50-114 (7)

PC78US-6

TROUBLESHOOTING

Code No.

CONNECTOR TYPES AND MOUNTING LOCATIONS

Item

Bit (3)

1023

1024

1025

1026

1060

ON/OFF input 4

ON/OFF input/output

ON/OFF input/output

ON/OFF input/output

ON/OFF input/output

Details (State When Bit Lights Up) Travel pressure switch

(4)

Swing pressure switch

(5)

Arm IN pressure switch

(6)

Boom RAISE pressure switch

(1)

Deceleration signal

(2)

Acceleration signal

(3)

Motor drive power supply

(4)

Auto deceleration signal

(5)

Motor relay (-)

(6)

Motor relay (+)

(1)

Crane mode switch (Monitor)

(2)

Display selector switch (Monitor)

(3)

Arm ground angle alarm cancel switch

(6)

Bucket dump prohibition solenoid + Rotary lamp

(1)

Deceleration switch

(2)

Overload warning cancel switch "OFF"

(3)

Emergency work equipment operation switch

(4)

2nd travel speed selection switch (Pedal)

(5)

Slide arm limit switch

(1)

Swing holding brake switch (Brake is released)

(2)

PPC main pressure lock (Main pressure lock is reset)

(4)

2nd travel speed is selected (Machine travels at 2nd gear speed)

(5)

Travel/Swing alarm (Alarm is output)

Table 1 Model selection table Model Selection 1

Model Selection 2

Selection Signal

Tire 2 signal

PC78US-6

GND

OPEN

GND

OPEN

PC78US-6 Tire 2 (a)

GND

OPEN

GND

Power supply is connected

(a) Serial No.: 5501 and up

Table 2 * 1: Connection of the attachment selection wires is shown. (The bits of GND are displayed during normal operation.) Connection table of attachment selection wires Attachment

Attachment Selection (1)

Attachment Selection (2)

Attachment Selection (3)

GND

OPEN

OPEN OPEN

Standard specification Standard arm Long arm

OPEN

GND

Slide arm

GND

GND

OPEN

OPEN

OPEN

OPEN

Multi-changer

PC78US-6

50-115 (12)

TROUBLESHOOTING

DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL

Procedure for correcting angle sensor, preventing interference, and setting depth display to 0 Back mode (When SP monitor is used) Table 1 Method of selecting back mode and ordinary display

Mode Code (Note 3)

Back Mode 02 These modes are set to 2 levels (Note 8) Error Memory Next Previous item Monitoring Display item (Note 6) (Note 6) 01

Emergency Trouble (Note 4)

–

PC78US-6 B

Buzzer cancel

a

Working mode selection

b

Travel

c

SET/CLEAR

d e

Error Memory Deletion

–

Model selection ( ) Model selection ( ) Wiper selection Washer Continuous operation time (SEC)

2.5

5 (Note 1)

Note 1) Note 3) Note 4) Note 6) Note 8)

Limited to 5 seconds after the power is turned ON. Displayed on the service meter unit. A flag from the controller is a trigger. Used to save monitoring error. Select with Buzzer cancel + Working mode selection. Select next or previous items with Buzzer cancel + / . Enter each mode with the SET/CLEAR switch. * Since the switches "c, d, and e" are not indicated on the panel of model US, operate the same parts as the panel of model UU.

50-116 (4)

PC78US-6

TROUBLESHOOTING FOR CONTROLLER PUMP CONTROL SYSTEM (C MODE) Precautions for troubleshooting for controller (pump control system) ......................................................... 50-118 Action taken by controller when trouble occurs and problems on machine ................................................ 50-120 Judgement table for controller (pump control system) and hydraulic equipment ........................................ 50-122 Electric circuit diagram of C Mode system .................................................................................................. 50-124 C- 1 [E232] Trouble in TVC-EPC solenoid system ................................................................................. 50-125 C- 2 [E233] Trouble in TVC-EPC solenoid system ................................................................................. 50-125 C- 3 [E203] Trouble in swing holding brake solenoid system ................................................................. 50-127 C- 4 [E213] Trouble in swing holding brake solenoid system ................................................................. 50-127 C- 5 [E206] Trouble in 2nd travel speed selection solenoid system ....................................................... 50-129 C- 6 [E216] Trouble in 2nd travel speed selection solenoid system ....................................................... 50-129 C- 7 [E251] Trouble in boom pressure sensor (overload sensor) system............................................... 50-131 C- 8 [E258] Short circuit in 5 V system of sensor power supply ........................................................50-132- 1 C- 9 Work equipment still moves after work equipment lock lever is set to LOCK ............................50-132- 4 C-10 Machine does not swing.............................................................................................................50-132- 7 C-11 Travel speed does not rise .........................................................................................................50-132- 9 C-12 Gear speed does not change automatically...............................................................................50-132-10 C-13 Trouble in controller power supply (LED of controller is turned OFF) ........................................50-132-10

PC78US-6

50-117 (12)

TROUBLESHOOTING

PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (PUMP CONTROL SYSTEM)

PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (PUMP CONTROL SYSTEM) 1. Precautions to be taken when trouble is repaired by itself 1) When a trouble is repaired by itself or 2) When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the Tadapter is removed and the connector is returned, if the service code is not displayed or the monitor displays normally, the same trouble will occur again probably. Accordingly, follow up the condition of the machine sufficiently. 3) After finishing troubleshooting, be sure to delete the saved service code. 2. Handling of function of saving service code When displaying a saved service code for troubleshooting, "take the notes of the all displayed items and delete those items", then reproduce the trouble and start the troubleshooting according to the service code displayed at this time. (Troubles caused by wrong operation, disconnection of a connector, etc. May be saved in the memory. In this case, you can avoid unnecessary work by performing the above operation.)

50-118 (4)

PC78US-6

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

TROUBLESHOOTING

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE Serial No.: 4809 – 6500 Application

User Code

Service Code

Troubled System

Contents of Trouble

Short circuit in TVC-EPC solenoid system (When emergency pump drive switch is turned ON)

1. Short circuit in wiring harness between M97 pin 16 – M20 pin 1 2. Short circuit in EPC solenoid 3. (Wrong operation of switch)

E233

Disconnection in TVC-EPC solenoid system

1. Disconnection in wiring harness between M97 pin 16 – M20 pin 1 2. Disconnection in EPC solenoid 3. Disconnection in wiring harness between M20 pin 2 – M97 pin 23

E203

Short circuit in swing holding brake solenoid system

1. Short circuit in wiring harness between M97 pin 7 – M14 pin 2 2. Short circuit in solenoid

E213

Disconnection in swing holding brake solenoid system (When emergency swing holding brake reset switch is turned ON)

1. Disconnection in wiring harness between M97 pin 7 – M14 pin 2 2. Disconnection in solenoid 3. Disconnection in wiring harness between M14 pin 1 – M97 pin 3 4. (Wrong operation of switch)

E206

Short circuit in 2nd travel speed selection solenoid system

1. Short circuit in wiring harness between M97 pin 27 – M15 pin 2 2. Short circuit in solenoid

E216

Disconnection in 2nd travel speed selection solenoid system

1. Disconnection in wiring harness between M97 pin 27 – M15 pin 2 2. Disconnection in solenoid 3. Disconnection in wiring harness between M15 pin 1 – M97 pin 3

E232

E02

E03

--

--

--

E227

Trouble in engine speed sensor

1. Disconnection in wiring harness between M96 pin 40 – M16 pin 1 2. Disconnection in sensor 3. Disconnection in wiring harness between M16 pin 2 – M96 pin 39

--

E258

Short circuit in 5 V system of sensor power supply

1. Short circuit in wiring harness between M95 pin 22 – M92 pin B.

Trouble in boom bottom pressure sensor (overload sensor) system

1. Disconnection in wiring harness between M95 pin 22 – M92 pin B 2. Short circuit or disconnection in wiring harness between M95 pin 2 – M92 pin C 3. Disconnection in wiring harness between M95 pin 21 – M92 pin A

--

50-120 (12)

E251

PC78US-6

TROUBLESHOOTING

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

Action Taken by Controller When Trouble Occurs

Problems on Machine

When trouble is detected, TVC-EPC solenoid output is stopped.

Current does not flow in TVCEPC solenoid. Accordingly, if load is large, engine speed may lower to stall.

When trouble is detected, swing holding brake reset solenoid output is stopped.

Since motor brake is not released, machine does not swing.

When trouble is detected, 2nd travel speed selection solenoid output is stopped.

When speed selector switch pedal is operated, travel speed does not change. (It is kept at 1st gear.)

Resistance between M96 pin 40 – M16 pin 1: Max. 1 z Resistance of M16 sensor: 500 – 1,000 z Resistance between M16 pin 2 – M96 pin 39: Max. 1 z

When trouble is detected, constant current flows in TVC-EPC solenoid (600 mA). Working mode cannot be changed. Engine governor control is limited to operation of fuel control dial.

Since constant current (600 mA) is output to TVC-EPC solenoid, work equipment speed and travel speed are low. If engine speed is low, engine may stall.

Resistance between M95 pin 22, M92 pin B – chassis ground: Min. 1 Mz

Overload alarm is turned ON. • Buzzer sounds. • Caution lamp flashes.

Overload alarm is turned ON. • Buzzer sounds. • Caution lamp flashes.

Resistance between M95 pin 22 – M92 pin B: Max. 1 z Resistance between M95 pin 22, M92 pin B – chassis ground: Min. 1 Mz Resistance between M95 pin 2 – M92 pin C: Max. 1 z Resistance between M95 pin 2, M92 pin C – chassis ground: Min. 1 Mz Resistance between M95 pin 21 – M92 pin A: Max. 1z

Overload alarm is turned ON. • Buzzer sounds. • Caution lamp flashes.

Overload alarm is turned ON. • Buzzer sounds. • Caution lamp flashes.

Normal Condition Between M97 pin 16 – chassis ground: Min. 1 Mz Between M20 pin 1 – solenoid body: Min. 1 Mz Resistance of M20 EPC solenoid (With switch directed down): 3 – 15 z Resistance between M97 pin 16 – M20 pin 1: Max. 1 Mz Resistance of M20 EPC solenoid: 3 – 15 z Resistance between M20 pin 2 – M97 pin 23: Max. 1 z Between M97 pin 7 – chassis ground: Min. 1 Mz Between M14 pin 2 – solenoid body: Min. 1 Mz Resistance of M14 solenoid: 35 - 80 z Resistance between M97 pin 7 – M14 pin 2: Max. 1 z Resistance of M14 solenoid: 35 – 80 z Resistance between M14 pin 1 – M97 pin 3 (With switch directed down): Max. 1 z Between M97 pin 27 – chassis ground: Min. 1 Mz Between M15 pin 2 – solenoid body: Min. 1 Mz Resistance of M15 solenoid: 35 - 80 z Resistance between M97 pin 27 – M15 pin 2: Max. 1 Mz Resistance of M15 solenoid: 35 – 80 z Resistance between M15 pin 1 – M97 pin 3: Max. 1 z

PC78US-6

50-121 (12)

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

TROUBLESHOOTING

Serial No.: 6501 and up Application

User Code

Service Code

Troubled System

Contents of Trouble

Short circuit in TVC-EPC solenoid system (When emergency pump drive switch is turned ON)

1. Short circuit in wiring harness between M95 pin 9 – M20 pin 1 2. Short circuit in EPC solenoid 3. (Wrong operation of switch)

E233

Disconnection in TVC-EPC solenoid system

1. Disconnection in wiring harness between M95 pin 9 – M20 pin 1 2. Disconnection in EPC solenoid 3. Disconnection in wiring harness between M20 pin 2 – M95 pin 40

E203

Short circuit in swing holding brake solenoid system

1. Short circuit in wiring harness between M95 pin 19 – M14 pin 2 2. Short circuit in solenoid

E213

Disconnection in swing holding brake solenoid system (When emergency swing holding brake reset switch is turned ON)

1. Disconnection in wiring harness between M95 pin 19 – M14 pin 2 2. Disconnection in solenoid 3. Disconnection in wiring harness between M14 pin 1 – M95 pin 40 4. (Wrong operation of switch)

E206

Short circuit in 2nd travel speed selection solenoid system

1. Short circuit in wiring harness between M95 pin 10 – M15 pin 2 2. Short circuit in solenoid

E216

Disconnection in 2nd travel speed selection solenoid system

1. Disconnection in wiring harness between M95 pin 10 – M15 pin 2 2. Disconnection in solenoid 3. Disconnection in wiring harness between M15 pin 1 – M95 pin 40

E232 E02

E03

--

--

--

--

--

--

50-121-1 (12)

E224

–

1. Disconnection, defective contact, short circuit, or grounding fault in pressure sensor 2. Disconnection or defective contact in wiring harness between controller M95 pin 22 – pressure sensor S3 pin B (power supply side) or between M95 pin 32 – S3 pin A (negative side) 3. Disconnection or defective contact in wiring harness between controller M95 pin 24 – pressure sensor S3 pin C (SIG side) 4. Defective controller

E227

Trouble in engine speed sensor

1. Disconnection in wiring harness between M95 pin 6 – M16 pin 1 2. Disconnection in sensor 3. Disconnection in wiring harness between M16 pin 2 – M95 pin 32

E258

Short circuit in 5 V system of sensor power supply

1. Short circuit in wiring harness between M95 pin 22 – M92 pin B M95 pin 22 – S1 pin 1 M95 pin 22 – S3 pin B M95 pin 22 – S2 pin 1

E251

Trouble in boom bottom pressure sensor (overload sensor) system

1. Disconnection in wiring harness between M95 pin 22 – M92 pin B 2. Short circuit or disconnection in wiring harness between M95 pin 33 – M92 pin C 3. Disconnection in wiring harness between M95 pin 32 – M92 pin A

PC78US-6

TROUBLESHOOTING

ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE

Action Taken by Controller When Trouble Occurs

Problems on Machine

When trouble is detected, TVC-EPC solenoid output is stopped.

Current does not flow in TVCEPC solenoid. Accordingly, if load is large, engine speed may lower to stall.

When trouble is detected, swing holding brake reset solenoid output is stopped.

Since motor brake is not released, machine does not swing.

When trouble is detected, 2nd travel speed selection solenoid output is stopped.

When speed selector switch pedal is operated, travel speed does not change. (It is kept at 1st gear.)

Between M95 pin 22 – pin 32: 4.5 – 5.5 V Between M95 pin 24 – S3 pin C: 0.5 – 4.5 V Resistance between M95 pin 24 – pin 32, between pin 24 – chassis ground: Min. 1 Mz (Disconnect M95 and S3)

Controller assumes pump pressure to be 0 Pa {0 kg/cm2} for operation.

Gear speed does not change automatically.

Resistance between M95 pin 6 – M16 pin 1: Max. 1 z Resistance of M16 sensor: 500 – 1,000 z Resistance between M16 pin 2 – M95 pin 32: Max. 1 z

When trouble is detected, constant current flows in TVC-EPC solenoid (600 mA). Working mode cannot be changed. Engine governor control is limited to operation of fuel control dial.

Since constant current (600 mA) is output to TVC-EPC solenoid, work equipment speed and travel speed are low. If engine speed is low, engine may stall.

Resistance between M95 pin 22 – M92 pin B, S2 pin 1, S3 pin B, S1 pin 1 – chassis ground: Min. 1 Mz

Overload alarm is turned ON. • Buzzer sounds. • Caution lamp flashes.

Overload alarm is turned ON. • Buzzer sounds. • Caution lamp flashes.

Resistance between M95 pin 22 – M92 pin B: Max. 1 z Resistance between M95 pin 22, M92 pin B – chassis ground: Min. 1 Mz Resistance between M95 pin 33 – M92 pin C: Max. 1 z Resistance between M95 pin 2, M92 pin C – chassis ground: Min. 1 Mz Resistance between M95 pin 32 – M92 pin A: Max. 1z

Overload alarm is turned ON. • Buzzer sounds. • Caution lamp flashes.

Overload alarm is turned ON. • Buzzer sounds. • Caution lamp flashes.

Normal Condition Between M95 pin 9 – chassis ground: Min. 1 Mz Between M20 pin 1 – solenoid body: Min. 1 Mz Resistance of M20 EPC solenoid (With switch directed down): 3 – 15 z Resistance between M95 pin 9 – M20 pin 1: Max. 1 Mz Resistance of M20 EPC solenoid: 3 – 15 z Resistance between M20 pin 2 – M95 pin 40: Max. 1 z Between M95 pin 19 – chassis ground: Min. 1 Mz Between M14 pin 2 – solenoid body: Min. 1 Mz Resistance of M14 solenoid: 35 – 80 z Resistance between M95 pin 19 – M14 pin 2: Max. 1 z Resistance of M14 solenoid: 35 – 80 z Resistance between M14 pin 1 – M95 pin 40 (With switch directed down): Max. 1 z Between M95 pin 10 – chassis ground: Min. 1 Mz Between M15 pin 2 – solenoid body: Min. 1 Mz Resistance of M15 solenoid: 35 – 80 z Resistance between M95 pin 10 – M15 pin 2: Max. 1 Mz Resistance of M15 solenoid: 35 – 80 z Resistance between M15 pin 1 – M95 pin 40: Max. 1 z

PC78US-6

50-121-2 (12)

JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT

TROUBLESHOOTING

JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT Serial No.: 4809 – 6500

Machine Model

PC78US-6

–

–

Monitoring Code

216

227

251

258

1023

Q

Q

Q

–

Q

–

232

233

203

213

Q

Q

Q

Q

206

Q

Boom RAISE (6)

–

Disconnection in 2nd travel speed selection solenoid system

Short circuit in 2nd travel speed selection solenoid system

Disconnection in swing holding brake solenoid system

Short circuit in swing holding brake solenoid system

Short circuit in 5 V system of sensor power supply

Service Code

E03

Trouble in boom bottom pressure sensor (overload sensor) system

Failure Mode

E02

Trouble in engine speed sensor system

User Code

Disconnection in TVC-EPC solenoid system

Self-diagnosis Display By Controller

Short circuit in TVC-EPC solenoid system

Part Which May Cause Trouble

Machine cannot move work equipment, travel, or move blade.

q

Machine cannot raise boom, move arm in. Work equipment, travel, swing, blade

Speed or power of 2 or more systems of work equipment, travel, swing, and blade is low.

q

q

q

Engine speed lowers extremely or engine stalls.

q

q

q

2 or more systems of work equipment, travel, swing, and blade do not move.

Work equipment

Travel

Speed or power is low.

(*1)

Boom Arm

Work equipment does Boom not move. Arm Travel speed or power is low.

q

q q

Travel speed does not change.

q

Swing speed or power is low. Swing

Machine does not swing.

q

q

Hydraulic drift is large.

q

q

Mode selection

Work equipment exceeds or stops before set height.

Overload warning

Alarm does not start sounding.

q

Alarm does not stop sounding.

After work equipment lock lever is set to LOCK, work equipment still moves Diagnosis code displayed when service code is displayed Diagnosis code displayed when trouble is detected by monitoring

C-1

C-2

C-3

C-4

–

–

–

–

C-5 –

C-6

E-6

C-7

C-8

–

–

–

–

–

F-3

q : Items corresponding to service codes. Q : Items checked by monitoring or with machine monitor. *1 : For the diagnosis codes E and F, see Section 20 *2 : Items checked by monitoring

50-122 (12)

PC78US-6

JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT

TROUBLESHOOTING

Items checked by monitoring

Emergency work equipment operation switch input (3)

Engine speed input

TVC-EPC current output

Overload warning cancel signal input (2)

Boom bottom pressure

ATT selection

Model selection and UU/US selection code

2nd travel speed selection (4)

Swing holding brake (1)

Travel speed selector pedal switch input (4)

Deceleration switch signal input (1)

Air compressor signal input (3)

Swing (4)

Travel (3)

Arm IN (5)

PPC main pressure (3)

State of solenoid

Hydraulic switch

1026

1010

1050

1026

1040

Q

Q

Q

Q

Q

Diagnosis code displayed when trouble is not detected by monitoring

Monitoring Code 1023

Q

Q

1021

Q

Q

1026

Q

1060

Q

Q

Q

1020

Q

(*2)

(*2)

Q

Q

(*2)

–

(*2)

–

(*2)

(*2)

(*2)

H-1

(*2)

(*2)

(*2)

H-2

(*2)

H-3 H-7

(*2)

H-8 H-10 H-11 (*2)

H-23 (*2)

(*2)

C-11, H-25 H-30

(*2)

(*2)

C-10, H-31

(*2)

(*2)

H-36 – (*2)

(*2)

–

(*2)

(*2)

– H-8

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

F-4

F-2

F-1

F-7

F-5

F-6

–

–

–

–

–

F-8

–

–

–

–

PC78US-6

50-123 (12)

JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT

TROUBLESHOOTING

Serial No.: 6501 and up

Failure Mode

Service Code

Machine Model

PC78US-6

Short circuit in 5 V system of sensor power supply

Boom RAISE (6)

–

Trouble in boom bottom pressure sensor (overload sensor) system

E03

Trouble in engine speed sensor system

Disconnection in 2nd travel speed selection solenoid system

Short circuit in 2nd travel speed selection solenoid system

Disconnection in swing holding brake solenoid system

Short circuit in swing holding brake solenoid system

E02

Trouble in pump pressure sensor system

User Code

Disconnection in TVC-EPC solenoid system

Self-diagnosis Display By Controller

Short circuit in TVC-EPC solenoid system

Part Which May Cause Trouble

–

–

–

–

Monitoring Code

232

233

203

213

206

216

224

227

251

258

1023

Q

Q

Q

Q

Q

Q

Q

Q

Q

–

Q

Machine cannot move work equipment, travel, or move blade.

q

Machine cannot raise boom, move arm in. Work equipment, travel, swing, blade

Speed or power of 2 or more systems of work equipment, travel, swing, and blade is low.

q

q

q

Engine speed lowers extremely or engine stalls.

q

q

q

2 or more systems of work equipment, travel, swing, and blade do not move.

Work equipment

Travel

Speed or power is low.

(*1)

Boom Arm

Work equipment does Boom not move. Arm Travel speed or power is low.

q

q q

Travel speed does not change.

q

q

Swing speed or power is low. Swing

Machine does not swing.

q

q

Hydraulic drift is large.

q

q

Mode selection

Work equipment exceeds or stops before set height.

Overload warning

Alarm does not stop sounding.

q

Alarm does not start sounding.

After work equipment lock lever is set to LOCK, work equipment still moves Diagnosis code displayed when service code is displayed Diagnosis code displayed when trouble is detected by monitoring

C-1

C-2

C-3

C-4

–

–

–

–

C-5 –

C-6

–

E-6

C-7

C-8

–

–

–

–

–

–

F-3

q : Items corresponding to service codes. Q : Items checked by monitoring or with machine monitor. *1 : For the diagnosis codes E and F, see Section 20 *2 : Items checked by monitoring

50-123-1 (12)

PC78US-6

JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT

TROUBLESHOOTING

Items checked by monitoring

Engine speed input

TVC-EPC current output

Overload warning cancel signal input (2)

Boom bottom pressure

Fuel control dial voltage input

Governor feedback voltage input

Pump pressure

1026

1010

1050

1026

1040

1034

1035

1042

Q

Q

Q

Q

Q

Q

Q

Q

Emergency work equipment operation switch input (3)

2nd travel speed selection (4)

Swing holding brake (1)

Deceleration switch signal input (1)

Air compressor signal input (3)

Swing (4)

Travel (3)

Arm IN (5)

PPC main pressure (2)

State of solenoid

Hydraulic switch

Diagnosis code displayed when trouble is not detected by monitoring

Monitoring Code 1023

Q

Q

Q

1021

1026

Q

Q

1060

Q

Q

Q

(*2)

– – (*2)

(*2)

H-1

(*2)

(*2)

H-2

(*2)

H-3 H-7

(*2)

H-8 H-10 H-11 (*2)

H-23 (*2)

(*2)

(*2)

(*2)

(*2)

C-11, H-25 H-30

(*2)

(*2)

C-10, H-31

(*2)

(*2)

H-36 – (*2)

(*2)

–

(*2)

(*2)

– H-8

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

–

F-4

F-2

F-1

F-7

F-5

–

–

–

F-8

–

–

–

–

–

–

–

PC78US-6

50-123-2 (12)

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM Serial No.: 4809 – 5500

50-124 (7)

PC78US-6

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

Serial No.: 5501 – 6500

PC78US-6

50-124-1 (12)

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM

Serial No.: 6501 and up

50-124-2 (12)

PC78US-6

C-1, C-2

TROUBLESHOOTING

C-1 [E232], C-2 [E233] Trouble in TVC-EPC solenoid system Serial No.: 4809 – 6500 a Since this error is displayed when the emergency pump drive switch is turned ON (RAISE), check that this switch is turned OFF (LOWER). Cause • Disconnect M20 • 3 – 15 z • Resistance between solenoid and chassis ground: Min.1 Mz

Remedy

1 Is resistance of EPC solenoid normal and is EPC solenoid insulated from chassis?

NO

Defective TVC-EPC solenoid (internal short circuit, disconnection)

Replace

Disconnection or defective contact in wiring harness between M97 (Female) (16), (23) – M20 (Female) (1), (2)

Repair or replace

Short circuit with chassis ground or negative (–) wire in wiring harness between M97 (Female) (16) – M20 (Female) (1)

Repair or replace

Defective controller

Replace

YES

2 • Disconnect M97 • Resistance: 3 – 15 z

NO

Is resistance between M97 (Female) (16) – (23) normal?

YES

3 • Disconnect M97 • Resistance: Min. 1 Mz

Is resistance between M97 (Female) NO (16) – chassis ground normal?

YES

C-1, C-2 Electrical circuit diagram of each system

PC78US-6

50-125 (12)

C-1, C-2

TROUBLESHOOTING

Serial No.: 6501 and up a Since this error is displayed when the emergency pump drive switch is turned ON (RAISE), check that this switch is turned OFF (LOWER).

Cause • Disconnect M20 • 3 – 15 z • Resistance between solenoid and chassis ground: Min.1 Mz

Remedy

1 Is resistance of EPC solenoid normal and is EPC solenoid insulated from chassis?

NO

Defective TVC-EPC solenoid (internal short circuit, disconnection)

Replace

Disconnection or defective contact in wiring harness between M95 (Female) (9), (40) – M20 (Female) (1), (2)

Repair or replace

Short circuit with chassis ground or negative (–) wire in wiring harness between M95 (Female) (9) – M20 (Female) (1)

Repair or replace

Defective controller

Replace

YES

2 • Disconnect M95 • Resistance: 3 – 15 z

NO

Is resistance between M95 (Female) (9) – (40) normal?

YES

3 • Disconnect M95 • Resistance: Min. 1 Mz

Is resistance between M95 (Female) NO (16) – chassis ground normal?

YES

C-1, C-2 Electrical circuit diagram of each system

50-126 (12)

PC78US-6

C-3, C-4

TROUBLESHOOTING

C-3 [E203], C-4 [E213] Trouble in swing holding brake solenoid system Serial No.: 4809 – 6500 a Since this error is displayed when the emergency swing holding brake release switch is turned ON (RAISE), check that this switch is turned OFF (LOWER). Cause • Disconnect M14 • 35 – 80 z • Resistance between solenoid and chassis ground: Min. 1 Mz

Remedy

1 Is resistance of solenoid normal and is solenoid insulated from chassis?

NO

Defective swing holding brake solenoid Replace (internal short circuit, disconnection)

YES

2 • Disconnect M97 • Resistance: 35 – 80 z

NO

Is resistance between M97 (Female) (7) – (3) normal?

Disconnection or defective contact in wiring harness between M97 (Female) (7), (3) – M14 (Female) (2), (1)

Repair or replace

Short circuit with chassis ground or negative (–) wire in wiring harness between M97 (Female) (7) – M14 (Female) (2)

Repair or replace

Defective controller

Replace

YES

3 • Disconnect M97 • Resistance: Min. 1 Mz

Is resistance between M97 (Female) (7) – chassis ground normal?

YES

NO

C-3, C-4 Electrical circuit diagram of each system

PC78US-6

50-127 (12)

C-3, C-4

TROUBLESHOOTING

Serial No.: 6501 and up a Since this error is displayed when the emergency swing holding brake release switch is turned ON (RAISE), check that this switch is turned OFF (LOWER).

Cause • Disconnect M14 • 35 – 80 z • Resistance between solenoid and chassis ground: Min. 1 Mz

Remedy

1 Is resistance of solenoid normal and is solenoid insulated from chassis?

NO

Defective swing holding brake solenoid Replace (internal short circuit, disconnection)

YES

2 • Disconnect M95 • Resistance: 35 – 80 z

NO

Is resistance between M95 (Female) (19) – (40) normal?

Disconnection or defective contact in wiring harness between M95 (Female) (19), (40) – M14 (Female) (2), (1)

Repair or replace

Short circuit with chassis ground or negative (–) wire in wiring harness between M95 (Female) (19) – M14 (Female) (2)

Repair or replace

Defective controller

Replace

YES

3 • Disconnect M95 • Resistance: Min. 1 Mz

Is resistance between M95 (Female) (19) – chassis ground normal?

YES

NO

C-3, C-4 Electrical circuit diagram of each system

50-128 (12)

PC78US-6

C-5, C-6

TROUBLESHOOTING

C-5 [E206], C-6 [E216] Trouble in 2nd travel speed selection solenoid system Serial No.: 4809 – 6500

Cause • Disconnect M14 • 35 – 80 z • Resistance between solenoid – chassis ground: Min. 1 Mz

Remedy

1 Is resistance of solenoid normal and is solenoid insulated from chassis?

NO

Defective 2nd travel speed selection solenoid (internal short circuit, disconnection)

Replace

Disconnection or defective contact in wiring harness between M97 (Female) (27), (3) – M15 (Female) (2), (1)

Repair or replace

Short circuit with chassis ground or negative (–) wire in wiring harness between M97 (Female) (27) – M15 (Female) (2)

Repair or replace

Defective controller

Replace

YES

2 • Disconnect M97 • Resistance: 35 – 80 z

NO

Is resistance between M97 (Female) (27) – (3) normal?

YES

3 • Disconnect M97 • Resistance: Min. 1 Mz

Is resistance between M97 (Female) (27) – chassis ground normal?

YES

NO

C-5, C-6 Electrical circuit diagram of each system

PC78US-6

50-129 (12)

C-5, C-6

TROUBLESHOOTING

Serial No.: 6501 and up

Cause • Disconnect M14 • 35 – 80 z • Resistance between solenoid – chassis ground: Min. 1 Mz

Remedy

1 Is resistance of solenoid normal and is solenoid insulated from chassis?

NO

Defective 2nd travel speed selection solenoid (internal short circuit, disconnection)

Replace

Disconnection or defective contact in wiring harness between M95 (Female) (10), (40) – M15 (Female) (2), (1)

Repair or replace

Short circuit with chassis ground or negative (–) wire in wiring harness between M95 (Female) (10) – M15 (Female) (2)

Repair or replace

Defective controller

Replace

YES

2 • Disconnect M95 • Resistance: 35 – 80 z

NO

Is resistance between M95 (Female) (10) – (40) normal?

YES

3 • Disconnect M95 • Resistance: Min. 1 Mz

Is resistance between M95 (Female) (10) – chassis ground normal?

YES

NO

C-5, C-6 Electrical circuit diagram of each system

50-130 (12)

PC78US-6

C-7

TROUBLESHOOTING

C-7 [E251] Trouble in boom bottom pressure sensor (overload sensor) system Serial No.: 4809 – 6500 a Check that fuse 10 is not broken. Cause

Remedy

1 When normal: There is a bit. When reset: There is not a bit. (Monitoring code 1026 (2))

NO

Is signal input of overload alarm reset switch normal?

Disconnection in wiring harness between M97 (20) – fuse box (10) or defective switch

Repair or replace

Defective controller

Replace

Disconnection or short circuit in wiring harness between M95 (2) – M92 (C), M95 (21) – M92 (A), or M95 (22) – M92 (B)

Repair or replace

Defective pressure sensor

Replace

YES • 0 – 26.5 MPa (If boom circuit is relieved at RAISE end, pressure changes.) (Monitoring code 1040)

2 Is boom cylinder bottom pressure NO sensor signal normal?

YES

3

• Disconnect M95 and M92.

Is resistance between M95 (2) and M92 (C), between M95 (21) and M92 (A), and between M95 (22) and M92 (B) below 1 z? Is resistance between M95 (2), (22), M92 (C), (B) and chassis ground above 1 Mz?

NO

YES

C-7 Electrical circuit diagram of each system

PC78US-6

50-131 (12)

C-7

TROUBLESHOOTING

Serial No.: 6501 and up Cause

Remedy

1 When normal: There is a bit. When reset: There is not a bit. (Monitoring code 1026 (2))

NO

Is signal input of overload alarm reset switch normal?

Disconnection in wiring harness between M95 (Famale) (5) – EU1 (Famale) (2) or defective switch

Repair or replace

Defective controller

Replace

Disconnection or short circuit in wiring harness between M95 (22) – M92 (B), M95 (32) – M92 (A), or M95 (33) – M92 (C)

Repair or replace

Defective pressure sensor

Replace

YES • 0 – 26.5 MPa (If boom circuit is relieved at RAISE end, pressure changes.) (Monitoring code 1040)

2 Is boom cylinder bottom pressure NO sensor signal normal?

YES

3

• Disconnect M95 and M92.

Is resistance between M95 (22) and M92 (B), between M95 (32) and M92 (A), and between M95 (33) and M92 (C) below 1 z? Is resistance between M95 (22), (33), M92 (B), (C) and chassis ground above 1 Mz?

NO

YES

C-7 Electrical circuit diagram of each system

50-132 (12)

PC78US-6

C-8

TROUBLESHOOTING

C-8 [E258] short circuit in 5 V system of sensor power supply Serial No.: 4809 – 6500 a Check that fuse 10 is not broken. Cause

Remedy

1 When normal: There is a bit. When reset: There is not a bit. (Monitoring code 1026 (2))

NO

Is signal input of overload alarm reset switch normal?

Disconnection in wiring harness between M97 (20) – fuse box (10) or defective switch

Repair or replace

Defective controller

Replace

Disconnection or short circuit in wiring harness between M95 (2) – M92 (C), M95 (21) – M92 (A), or M95 (22) – M92 (B)

Repair or replace

Defective pressure sensor

Replace

YES • 0 – 26.5 MPa (If boom circuit is relieved at RAISE end, pressure changes.) (Monitoring code 1040)

2 Is boom cylinder bottom pressure NO sensor signal normal?

YES

3

• Disconnect M95 and M92.

Is resistance between M95 (2) and M92 (C), between M95 (21) and M92 (A), and between M95 (22) and M92 (B) below 1 z? Is resistance between M95 (2), (22), M92 (C), (B) and chassis ground above 1 Mz?

NO

YES

C-8 Electrical circuit diagram of each system

PC78US-6

50-132-1 (12)

C-8

TROUBLESHOOTING

Serial No.: 6501 and up a If E258 is displayed, E40 is also displayed.

Cause 1 • Disconnect M95. • Min. 1 Mz

Remedy

Grounding fault in wiring harness between M95 (female) (22) – chassis ground (Grounding fault in sensor power supply)

Repair or replace

NO

Defective fuel control dial potentiometer (Internal short circuit)

Replace

NO

Defective pump pressure sensor (Internal short circuit)

Replace

NO

Defective governor motor feedback potentiometer (Internal short circuit)

Replace

NO

Defective boom bottom pressure sensor (Internal short circuit)

Replace

Defective controller

Replace

Is resistance between M95 NO (female) (22) and chassis ground normal?

YES

2 • Operate fuel control dial. • 0.7 – 4.8 V

Is voltage of fuel control dial normal? (Monitoring code: 1034)

YES

3 • Turn starting switch ON: 0 {0} • When relieved: 26.5 ± 1.0 MPa {270 ± 10 kg/cm2}

Is monitored value of pump pressure sensor normal? (Monitoring code: 1042)

• Start engine. • Operate fuel control dial. • 2.7 – 4.7 V

Is voltage of governor feedback potentiometer normal? (Monitoring code: 1035)

YES

4

YES • Turn starting switch ON: 0 {0} • When relieved by raising boom: 26.5 ± 1.0 MPa {270 ± 10 kg/cm2}

50-132-2 (12)

5 Is monitored value of boom bottom pressure sensor normal? (Monitoring code: 1040)

YES

PC78US-6

C-8

TROUBLESHOOTING

C-8 Electrical circuit diagram of each system

PC78US-6

50-132-3 (12)

C-9

TROUBLESHOOTING

C-9 Work equipment still moves after work equipment lock lever is set to LOCK Serial No.: 4809 – 5500 Cause

Remedy

1

• When pushed, (1) – (2) are connected to each other. • When released, (1) – (2) are connected to each other (Test on switch unit)

Is PPC hydraulic lock switch normal?

• When locked: 0 V • When released: 20 – 29 V

Is voltage between M13 (2) – chassis ground normal?

NO

Defective hydraulic lock switch

Replace

Short circuit with positive (+) wire in wiring harness between K28 (2) – M13 (2)

Repair or replace wiring harness

Defective controller

Replace

YES

2 NO

YES

C-9 Electrical circuit diagram of each system

50-132-4 (12)

PC78US-6

C-9

TROUBLESHOOTING

Serial No.: 5501 – 6500 Cause

Remedy

1

• When pushed, (1) – (3) are connected to each other. • When released, (1) – (2) are connected to each other (Test on switch unit)

Is PPC hydraulic lock switch normal?

• When locked: 0 V • When released: 20 – 29 V

Is voltage between M13 (2) – chassis ground normal?

NO

Defective hydraulic lock switch

Replace

Short circuit with positive (+) wire in wiring harness between K28 (2) – M13 (2)

Repair or replace wiring harness

Defective PPC lock solenoid valve

Replace

YES

2 NO

YES

C-9 Electrical circuit diagram of each system

PC78US-6

50-132-5 (12)

C-9

TROUBLESHOOTING

Serial No.: 6501 and up Cause

Remedy

1

• When pushed, (1) – (3) are connected to each other. • When released, (1) – (2) are connected to each other (Test on switch unit)

Is PPC hydraulic lock switch normal?

• When locked: 0 V • When released: 20 – 29 V

Is voltage between M13 (2) – chassis ground normal?

NO

Defective hydraulic lock switch

Replace

Short circuit with positive (+) wire in wiring harness between K28 (2) – M13 (2)

Repair or replace wiring harness

Defective PPC lock solenoid valve

Replace

YES

2 NO

YES

C-9 Electrical circuit diagram of each system

50-132-6 (12)

PC78US-6

C-10

TROUBLESHOOTING

C-10 Machine does not swing Serial No.: 4809 – 6500 a Carry out the following troubleshooting when [E-203] and [E-213] are not displayed.

Cause

Remedy

1 • Check swing control lever

Is bit pattern 1023 – (4) displayed?

NO

Go to F-1 (See Section 20.)

–

Go to H-31 (See Section 20.)

–

YES

C-10 Electrical circuit diagram of each system

PC78US-6

50-132-7 (12)

C-10

TROUBLESHOOTING

Serial No.: 6501 and up a Carry out the following troubleshooting when [E-203] and [E-213] are not displayed.

Cause

Remedy

1 • Check swing control lever

Is bit pattern 1023 – (4) displayed?

NO

Go to F-1 (See Section 20.)

–

Go to H-31 (See Section 20.)

–

YES

C-10 Electrical circuit diagram of each system

50-132-8 (12)

PC78US-6

C-11

TROUBLESHOOTING

C-11 Travel speed does not rise Serial No.: 4809 – 6500 a Carry out the following troubleshooting when [E-206] and [E-216] are not displayed. Cause

Remedy

1 • 20 – 29 V • Turn starting switch ON • Disconnect K3

NO

Is voltage between K3 (Female) (2) – chassis ground normal?

YES • In 1-spool mode: Max. 1 Mz • In 2-spool mode: Max. 1 Mz • Turn starting switch OFF • Disconnect K3

2 NO

Is resistance between K3 (Male) (2) – (1) normal?

YES

Defective 2nd travel speed selection switch

Replace

Disconnection or defective contact in wiring harness between K3 (Female) (1) – M12 – chassis ground

Repair or replace

Defective controller

Replace

Disconnection or defective contact in wiring harness between M95 (Female) (5) – K3 (Female) (2)

Repair or replace

3 • 20 – 29 V • Turn starting switch ON. • Disconnect K3

Is voltage between M95 (5) – chassis ground normal?

YES

NO

C-11 Electrical circuit diagram of each system

PC78US-6

50-132-9 (12)

C-12, C-13

TROUBLESHOOTING

C-12 Gear speed does not change automatically Serial No.: 6501 and up a When [E-206], [E-216], [E-224], or [E-227] is not displayed. Cause

Remedy

1

• Monitoring FULL: 197 – 207 SLOW: 113 – 118 • Turn starting switch ON.

Is monitored value of engine speed normal? (Monitoring code: 1010)

• Monitoring relieved: 25.5 – 27.5 MPa {260.3 – 280.4 kg/cm2}

Is monitored value of pump pressure normal? (Monitoring code: 1042)

NO

Defective engine speed sensor

Replace

Defective pump pressure sensor

Replace

Defective controller

Replace

YES

2 NO

YES

C-13 Trouble in controller power supply (LED of controller is turned OFF) a See E-1. (See Section 20.)

50-132-10 (12)

PC78US-6

TROUBLESHOOTING FOR MACHINE MONITOR SYSTEM (M MODE) Action taken by controller when trouble occurs and problems on machine ........................................................... Electric circuit diagram of M mode system ...................................................................................................... 134 M- 1 [E101] (Error history data are abnormal) is displayed ............................................................................... M- 2 [E108] (Engine coolant temperature is 105°C) is displayed ...................................................................... M- 3 [E112] (Wiper forward output is shorted) is displayed................................................................................ M- 4 [E113] (Wiper reverse output is shorted) is displayed................................................................................ M- 5 [E114] (Contact with washer output of 24 V) is displayed.......................................................................... M- 6 [E115] (Wiper does not start wiping in 10 seconds) is displayed ............................................................... M- 7 [E116] (Wiper is not retracted in 10 seconds) is displayed ........................................................................ M- 8 When starting switch is turned to ON position, monitor panel segments do not light up for 3 seconds ............................................................................................................................................. a) Monitor panel segments do not light up at all ........................................................................................ b) Some monitor panel segments do not light up ...................................................................................... M- 9 When starting switch is set to ON position, all monitor panel segments light up but do not go off ............................................................................................................................................... M-10 While preheating is not executed, "Preheater monitor" lights up ............................................................... M-11 When starting switch is set to ON position and engine is started, basic check items flash ............ 50-136 a) Alternator system........................................................................................................................ 50-136 b) Engine oil pressure system ........................................................................................................ 50-137 M-12 When starting switch is set to ON position (but engine is stopped), caution items and emergency stop items (excluding battery and engine oil) flash ......................... 50-138 a) Alternator system........................................................................................................................ 50-138 b) Engine oil pressure sensor system............................................................................................. 50-139 M-13 When starting switch is set to ON position and engine is started, caution items and emergency stop items flash (When there is not abnormality in inspection items and engine before troubleshooting) .................................................................................................................. a) "Engine oil" flashes ................................................................................................................................ b) "Charge level" flashes ........................................................................................................................... c) "Coolant temperature" flashes ............................................................................................................... d) "Fuel level" flashes ................................................................................................................................ M-14 When starting switch is set to ON position (but engine is stopped), buzzer does not sound for 1 second While caution item is flashing, buzzer does not sound .............................................................................. M-15 Monitor planel lamp for nighttime is not turned on (LC display is normal) ................................................. M-16 Coolant temperature gauge does not rise ................................................................................................. M-17 Coolant temperature gauge is not displayed (Gauge does not rise to 1st line during operation) .............. M-18 Fuel level gauge always displays full......................................................................................................... M-19 Fuel level gauge is not displayed............................................................................................................... M-20 While engine is running, service meter does not advance ........................................................................ M-21 Trouble in fuel level sensor ........................................................................................................................ M-22 Trouble in coolant temperature sensor ...................................................................................................... M-23 Wiper does not operate or operates while wiper switch is turned off......................................................... a) Wiper does not operate ......................................................................................................................... b) Wiper operates while wiper switch is turned off..................................................................................... M-24 Washer motor does not operate or operate while washer switch is turned off .......................................... a) Washer motor does not operate ............................................................................................................ b) Washer operates while wiper switch is turned off .................................................................................. a For items marked with , see page 20-501. a When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the service code "E" is not displayed, the condition has returned to normal. a If the starting switch was turned off after the trouble occurred, turn the starting switch ON and check that the service code displays "E" at the head. (If "E" is not displayed, the condition has returned to normal.) a Before carrying out the troubleshooting, check that all the related connectors are properly inserted. a Always connect any disconnected connectors before going on to the next step. PC78US-6

50-133 (7)

TESTING AND ADJUSTING

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM Serial No.: 4809 – 5500

50-134 (7)

PC78US-6

TROUBLESHOOTING

PC78US-6

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

50-135 (4)

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

Serial No.: 5501 – 6500

50-135-1 (12)

PC78US-6

TROUBLESHOOTING

PC78US-6

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

50-135-2 (7)

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

Serial No.: 6501 and up

50-135-3 (12)

PC78US-6

TROUBLESHOOTING

ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM

Light • NORWAY: STD • EU: 2 = STD

PC78US-6

1 = OPT

50-135-4 (12)

TROUBLESHOOTING

M-11

M-11 When starting switch is set to ON position and engine is started, basic check items flash a Inspect both alternator system and engine hydraulic system. a) Alternator system Serial No.: 4809 – 6500 a Check monitoring code "0043". If it is 100 or larger while the engine speed is above the medium level, the monitor panel is defective.

Cause

Remedy

1

• Disconnect M45 • Run engine above medium speed level • 20 – 30 V

Is voltage between M45 (Male) (3) – chassis ground normal?

• Run engine above medium speed level • 20 – 30 V

Is voltage between P02 (11) – chassis ground normal?

NO

Defective alternator

Replace

Disconnection or defective contact in wiring harness between M45 (Female) (3) – P02 (Female) (11)

Repair or replace

Defective monitor panel

Replace

YES

2 NO

YES

M-11 a) Electrical circuit diagram of each system

50-136 (12)

PC78US-6

TROUBLESHOOTING

M-11

a) Alternator system Serial No.: 6501 and up a Check monitoring code "0043". If it is 100 or larger while the engine speed is above the medium level, the monitor panel is defective.

Cause • Disconnect M45 • Run engine above medium speed level • 20 – 30 V

Remedy

1 NO

Is voltage between M45 (Male) (3) – chassis ground normal?

Defective alternator

Replace

Disconnection or defective contact in wiring harness between M45 (Female) (3) – P02 (Female) (11)

Repair or replace

Defective monitor panel

Replace

YES

2 • Run engine above medium speed level • 20 – 30 V

Is voltage between P02 (11) – chassis ground normal?

NO

YES

M-11 a) Electrical circuit diagram of each system

PC78US-6

50-137 (12)

TROUBLESHOOTING

M-11

b) Engine oil pressure system Serial No.: 4809 – 6500 a Carry out the following troubleshooting when the engine oil pressure is normal. a Check bit (3) of monitoring code "0046". If it is lighting up, the monitor panel is defective.

Cause

Remedy

1 • Run engine at low speed

When engine speed is low, if oil pressure sensor terminal T6 is disconnected, does error disappear?

NO

YES

Defective oil pressure sensor (Low pressure)

Replace

Short circuit with chassis ground in wiring harness between P02 (Female) (7) – sensor terminal T6

Repair or replace

Defective monitor panel

Replace

2 • Turn starting switch OFF • Disconnect sensor wiring harness and P02

Is there continuity between P02 (7) – chassis ground normal?

NO

YES

M-11 b) Electrical circuit diagram of each system

50-137-1 (12)

PC78US-6

TROUBLESHOOTING

M-11

b) Engine oil pressure system Serial No.: 6501 and up a Carry out the following troubleshooting when the engine oil pressure is normal. a Check bit (3) of monitoring code "0046". If it is lighting up, the monitor panel is defective.

Cause

Remedy

1 • Run engine at low speed

When engine speed is low, if oil pressure sensor terminal T6 is disconnected, does error disappear?

NO

YES

Defective oil pressure sensor (Low pressure)

Replace

Short circuit with chassis ground in wiring harness between P02 (Female) (7) – sensor terminal T6

Repair or replace

Defective monitor panel

Replace

2 • Turn starting switch OFF • Disconnect sensor wiring harness and P02

Is there continuity between P02 (7) – chassis ground normal?

NO

YES

M-11 b) Electrical circuit diagram of each system

PC78US-6

50-137-2 (12)

TROUBLESHOOTING

M-12

M-12 When starting switch is set to ON position (but engine is stopped), caution items and emergency stop items (excluding battery and engine oil) flash a Inspect both alternator system and engine hydraulic system. a) Alternator system Serial No.: 4809 – 6500 a Check monitoring code "0043". If it is 100 or larger while the engine speed is above the medium level, the monitor panel is defective.

Cause

Remedy

1 • Disconnect M45 • Turn starting switch ON • Max. 1 V

NO

Is voltage between M45 (Male) (3) – chassis ground normal?

Defective alternator

Replace

Short circuit with power source in wiring harness between P02 (Female) (11) – M45 (Female) (3)

Repair or replace

Defective monitor panel

Replace

YES

2 • Disconnect P02 • Turn starting switch ON • Max. 1 V

Is voltage between P02 (Female) (11) – chassis ground normal?

NO

YES

M-12 a) Electrical circuit diagram of each system

50-138 (12)

PC78US-6

TROUBLESHOOTING

M-12

a) Alternator system Serial No.: 6501 and up a Check monitoring code "0043". If it is 100 or larger while the engine speed is above the medium level, the monitor panel is defective.

Cause

Remedy

1 • Disconnect M45 • Turn starting switch ON • Max. 1 V

NO

Is voltage between M45 (Male) (3) – chassis ground normal?

Defective alternator

Replace

Short circuit with power source in wiring harness between P02 (Female) (11) – M45 (Female) (3)

Repair or replace

Defective monitor panel

Replace

YES

2 • Disconnect P02 • Turn starting switch ON • Max. 1 V

Is voltage between P02 (Female) (11) – chassis ground normal?

NO

YES

M-12 a) Electrical circuit diagram of each system

PC78US-6

50-139 (12)

TROUBLESHOOTING

M-12

b) Engine oil pressure sensor system Serial No.: 4809 – 6500 a Carry out the following troubleshooting when the engine oil pressure is normal. a Check bit (3) of monitoring code "0046". If it is lighting up, the monitor panel is defective.

Cause

Remedy

1 • Turn starting switch OFF • Disconnect sensor terminal T6

Is there continuity between sensor terminal T6 – chassis ground?

NO

Defective oil pressure sensor

Replace

Disconnection or defective contact in wiring harness between P02 (Female) (7) – sensor terminal T6

Repair or replace

Defective monitor panel

Replace

YES

2 • Turn starting switch OFF • Disconnect P02 – sensor terminal T6

Is there continuity between P02 (Female) (7) – sensor terminal T6?

NO

YES

M-12 b) Electrical circuit diagram of each system

50-140 (12)

PC78US-6

TROUBLESHOOTING

M-12

b) Engine oil pressure sensor system Serial No.: 6501 and up a Carry out the following troubleshooting when the engine oil pressure is normal. a Check bit (3) of monitoring code "0046". If it is lighting up, the monitor panel is defective.

Cause

Remedy

1 • Turn starting switch OFF • Disconnect sensor terminal T6

Is there continuity between sensor terminal T6 – chassis ground?

NO

Defective oil pressure sensor

Replace

Disconnection or defective contact in wiring harness between P02 (Female) (7) – sensor terminal T6

Repair or replace

Defective monitor panel

Replace

YES

2 • Turn starting switch OFF • Disconnect P02 – sensor terminal T6

Is there continuity between P02 (Female) (7) – sensor terminal T6?

NO

YES

M-12 b) Electrical circuit diagram of each system

PC78US-6

50-141 (12)

90 OTHERS HYDRAULIC CIRCUIT DIAGRAM PC78US-6 Serial No.: 4001 – 6500 (Blade-less specification)........... 90- 3 PC78US-6 Serial No.: 6501 and up (Blade-less specification).......... 90-3-2 PC78US-6 (Additional attachment circuit)........................................... 90- 5 PC78US-6 Serial No.: 4001 – 6500 (Blade specification) .................. 90- 7 PC78US-6 Serial No.: 6501 and up (Blade specification) ................. 90-7-2 PC78US-6 Serial No.: 4809 – 6500 (Norway & EU specification) ..... 90-7-4 PC78US-6 Serial No.: 6501 and up (Norway & EU specification) ..... 90-7-6 PC78UU-6.......................................................................................... 90-7-8 ELECTRICAL CIRCUIT DIAGRAM PC78US-6 Serial No.: 4001 – 5500 (1/2)........................................... 90- 9 PC78US-6 Serial No.: 4001 – 5500 (2/2)............................................90-11 PC78US-6 Serial No.: 5501 – 6500 (1/2)........................................... 90-13 PC78US-6 Serial No.: 5501 – 6500 (2/2)........................................... 90-15 PC78US-6 Serial No.: 6501 and up (1/2)....................................... 90-15-2 PC78US-6 Serial No.: 6501 and up (2/2)....................................... 90-15-4 PC78US-6 Serial No.: 4809 – 5500 (Norway & EU specification) (1/2) ..................................................... 90-17 PC78US-6 Serial No.: 4809 – 5500 (Norway & EU specification) (2/2) ..................................................... 90-19 PC78US-6 Serial No.: 5501 – 6500 (Norway & EU specification) (1/2) ..................................................... 90-21 PC78US-6 Serial No.: 5501 – 6500 (Norway & EU specification) (2/2) ..................................................... 90-23 PC78US-6 Serial No.: 6501 and up (Norway & EU specification) (1/2) .................................................. 90-23-2 PC78US-6 Serial No.: 6501 and up (Norway & EU specification) (2/2) .................................................. 90-23-4 PC78UU-6 Serial No.: 22832 – 23500 (1/2)....................................... 90-25 PC78UU-6 Serial No.: 22832 – 23500 (2/2)....................................... 90-27 PC78UU-6 Serial No.: 23501 and up (1/2)......................................... 90-29 PC78UU-6 Serial No.: 23501 and up (2/2)......................................... 90-31

PC78US-6

90-1

HYDRAULIC CIRCUIT DIAGRAM PC78US-6 Serial No.: 4001 – 6500 (Blade-less specification)

PC78US-6

*1. Serial No.: 4001 – 4248 *2. Serial No.: 4249 and up

*3. Serial No.: 4001 – 5500 *4. Serial No.: 5501 and up

90-3 (10)

HYDRAULIC CIRCUIT DIAGRAM PC78US-6 (Additional attachment circuit)

PC78US-6

90-5

HYDRAULIC CIRCUIT DIAGRAM PC78US-6 Serial No.: 6501 and up (Blade-less specification)

PC78US-6

90-3-2 (10)

HYDRAULIC CIRCUIT DIAGRAM PC78US-6 Serial No.: 4001 – 6500 (Blade specification)

PC78US-6

*1. Serial No.: 4001 – 4248 *2. Serial No.: 4249 and up

*3. Serial No.: 4001 – 5500 *4. Serial No.: 5501 and up

90-7 (10)

HYDRAULIC CIRCUIT DIAGRAM PC78US-6 Serial No.: 6501 and up (Blade specification)

PC78US-6

90-7-2 (10)

HYDRAULIC CIRCUIT DIAGRAM PC78US-6 Serial No.: 4809 – 6500 (Norway & EU specification)

PC78US-6

*1. Serial No.: 4809 – 5500 *2. Serial No.: 5501 and up

90-7-4 (14)

HYDRAULIC CIRCUIT DIAGRAM PC78US-6 Serial No.: 6501 and up (Norway & EU specification)

PC78US-6

90-7-6 (14)

HYDRAULIC CIRCUIT DIAGRAM PC78UU-6

PC78US-6

*1. Serial No.: 22832 – 23500 *2. Serial No.: 23501 and up

90-7-8 (10)

ELECTRICAL CIRCUIT DIAGRAM PC78US-6 Serial No.: 4001 – 5500 (1/2)

PC78US-6

90-9

ELECTRICAL CIRCUIT DIAGRAM PC78US-6 Serial No.: 4001 – 5500 (2/2)

PC78US-6

90-11

ELECTRICAL CIRCUIT DIAGRAM PC78US-6 Serial No.: 5501 – 6500 (1/2)

PC78US-6

90-13 (10)

ELECTRICAL CIRCUIT DIAGRAM PC78US-6Serial No.: 5501 – 6500 (2/2)

PC78US-6

90-15 (10)

ELECTRICAL CIRCUIT DIAGRAM PC78US-6 Serial No.: 6501 and up (1/2)

PC78US-6

90-15-2 (10)

ELECTRICAL CIRCUIT DIAGRAM PC78US-6 Serial No.: 6501 and up (2/2)

PC78US-6

90-15-4 (10)

ELECTRICAL CIRCUIT DIAGRAM PC78US-6 Serial No.: 4809 – 5500 (Norway & EU specification) (1/2)

PC78US-6

90-17 (10)

ELECTRICAL CIRCUIT DIAGRAM PC78US-6 Serial No.: 4809 – 5500 (Norway & EU specification) (2/2)

PC78US-6

90-19 (10)

ELECTRICAL CIRCUIT DIAGRAM PC78US-6 Serial No.: 5501 – 6500 (Norway & EU specification) (1/2)

PC78US-6

90-21 (10)

ELECTRICAL CIRCUIT DIAGRAM PC78US-6 Serial No.: 5501 – 6500 (Norway & EU specification) (2/2)

PC78US-6

90-23 (10)

ELECTRICAL CIRCUIT DIAGRAM PC78US-6 Serial No.: 6501 and up (Norway & EU specification) (1/2)

PC78US-6

90-23-2 (10)

ELECTRICAL CIRCUIT DIAGRAM PC78US-6 Serial No.: 6501 and up (Norway & EU specification) (2/2)

PC78US-6

90-23-4 (10)

ELECTRICAL CIRCUIT DIAGRAM PC78UU-6 Serial No.: 22832 – 23500 (1/2)

PC78US-6

90-25

ELECTRICAL CIRCUIT DIAGRAM PC78UU-6 Serial No.: 22832 – 23500 (2/2)

PC78US-6

90-27

ELECTRICAL CIRCUIT DIAGRAM PC78UU-6 Serial No.: 23501 and up (1/2)

PC78US-6

90-29

ELECTRICAL CIRCUIT DIAGRAM PC78UU-6 Serial No.: 23501 and up (2/2)

PC78US-6

90-31