Troubleshooting Guide - Multiplexing Faults

TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults

Table of Contents Table of Contents ............................................................................................................................................ 1 Introduction ..................................................................................................................................................... 1 Locomotives Affected:.................................................................................................................................... 1 Documents Referenced: .................................................................................................................................. 1 Theory of Operation ........................................................................................................................................ 2 Multiplex Cycle ........................................................................................................................................... 2 Multiplex Circuit ......................................................................................................................................... 4 Standard Operating Description ...................................................................................................................... 6 Fault Code Troubleshooting ........................................................................................................................... 8 Troubleshooting Tips: .................................................................................................................................. 8 Troubleshooting Steps: .............................................................................................................................. 10 Help Desk Troubleshooting .......................................................................................................................... 14 Appendix A: Inspection Procedure for Grounds .......................................................................................... 15 Low Voltage Grounds: ............................................................................................................................... 15 AC Grounds: .............................................................................................................................................. 16 NOTE: The troubleshooting procedures contained in this guide are intended as general instructions. If any specific step within this guide causes a violation of railroad or local safety rules, do not perform that specific step and contact your local EMD rep for troubleshooting guidance. Changes in revision A of this Troubleshooting Guide are indicated by the box (A) in the margin of the affected text Introduction This Troubleshooting Guide (TSG) is issued to provide an overview and troubleshooting guidelines for locomotive digital Multiplex system. Locomotives Affected: Any EM2000 equipped locomotive. Documents Referenced:  Service Advisory 05-050: Troubleshooting APC Low Voltage Grounds

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TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults

Theory of Operation Multiplexing is a process through which several inputs can be monitored with the use of only one input channel. Selective monitoring makes this possible. Not all inputs to the computer need to be monitored constantly, just periodically. The inputs are gathered in groups of 5; the CPM looks at the first group for 10 milliseconds, the next group for 10 milliseconds, and so on until it has seen inputs from all five groups. A sixth group of channels is used for verification of the multiplexing circuit. Six DIO module output channels are used for completing paths to negative through the multiplexed input channels. During each 10-millisecond portion of the cycle, a different output channel is energized thereby allowing monitoring of the different sets of input channels. Multiplex Cycle The CPM completes the Multiplex cycle in 100 milliseconds. Each multiplex cycle consists of 10 portions, each of which is monitored for a duration of 10 milliseconds. The first five portions are for reading system feedbacks, which consist mainly of contactor interlock feedbacks (P1, B, SGC, MB, etc.) and switch feedbacks (isolation, engine run, horn, etc.). During each of the first five portions, the CPM energizes a different DIO output channel and thereby monitors a different set of feedbacks. Based on the operating conditions of the locomotive, the CPM knows whether a specific feedback interlock should be active. When the multiplexed output channel containing that specific feedback is energized, the computer is expecting to see a specific result. For example, when under power, the computer expects to see the P1 interlock feedback closed. If during the multiplexing cycle, the P1 feedback interlock circuit is not completed, the computer will log a “Failed To Pick Up” fault. The opposite is also true, whereby if the computer sees a channel active that should not be, it will log a “Failed To Drop Out” fault.

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TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults

Figure 1: Multiplex Cycle

The 6th and 7th portions are Multiplex system diagnostic checks. During the 6th portion of the cycle, all channels are turned ON to verify the circuit is completed on all channels. During the 7th portion of the cycle, all channels are turned OFF to ensure none of the channels remain energized when they shouldn’t be. The remaining three portions of the Multiplex cycle serve no purpose. If during the 6th portion, all MUXON channels do not turn on, or during the 7th portion, all the MUXOFF channels do not turn off, the computer will log one of the DIGITAL INPUT SYSTEM FAILURE faults show in the Fault Code Troubleshooting Section. Figure 1 illustrates the full 100-millisecond Multiplex cycle.

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TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults

Multiplex Circuit Figure 2 illustrates a simplified multiplex circuit. The illustration uses only two output channels and three input channels. The locomotive multiplex circuit has six output channels and up to 144 input channels. It can be seen by tracing the circuit how energizing different output channels allows the computer to monitor different feedbacks.

Figure 2: Example Two Channel Multiplex Circuit

When the DIO-1 (OUT) CH 23 turns ON for (10 ms) the DIO-1 (IN) CH 2, DIO-2 (IN) CH 6 and DIO-2 (IN) CH 8 provide an ON = (1) or OFF= (0) sample back to the CPM. The ON or OFF state of the device is then compared to an internal lookup table compiled in the CPM’s software logic in order to determine if the input should be active or not. For example DIO-1 (IN) CH 2 is sampling GFC interlock while DIO-2 (IN) CH 6 is providing a sample of FCF1 interlock. The exception is DIO-2 (IN) CH 8. This input is connected directly to the DIO OUTPUT channels 21 through 25 with a solid wire connection. This DIO Page 4 Copyright  Electro-Motive Diesel, Inc.. All rights reserved. Neither this document, nor any part thereof, may be reproduced or reprinted without the prior written consent of the Electro-Motive Diesel, Inc.. Contact EMD SDO office.

TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults (IN) is used exclusively to test the ON state of the OUTPUTS. When DIO-1 (OUT) CH 23 is ON the DIO2 (IN) CH 8 will convey an ON state to the CPM, or what is called the MUXSEL-3 value. The MUXSEL input provides a feedback to the CPM as to the turn ON state of each OUTPUT device that is used to sample switches or interlocks. The feedback can be observed on the EM2000 fire screen as the MUXSEL values 1 through 5. The MUXSEL 1 is testing the DIO-1 (OUT) CH 21, then MUXSEL 2 DIO-1 (OUT) CH 22 and so on through CH 25. The DIO-1 (OUT) CH 26 does not have a MUXSEL test. Continuing, when the DIO-1(OUT) CH 24 turns ON for (10 ms), all the inputs DIO-1 (IN) CH 2, DIO-2 (IN) CH 6 & DIO-2 (IN) CH 8 provide a sample back to the CPM (CPU) to the state of the contact that are in circuit. During this next sampling period of (10ms) the same inputs previously used are now sampling the contacts or switches of different components. DIO-1 (IN) CH2 is checking GFD interlock while DIO-2 (IN) CH 6 is checking FCF2 interlock. DIO-2 (IN) CH 8 is now sampling the turn ON state of DIO-1 (OUT) CH 24 or MUXSEL-4 value which should be ON. Below each INPUT channel is a CMU Plug. All Multiplexed inputs, contacts, interlocks and switches are connected to the CMU Plug. The CMU base plug, to which the CMU Plug connects, acts as a shorting connector so that up to Five (5) individual interlock of switches can be connected to One (1) input Channel. Above each OUTPUT channel is a Diode Input Panel (DIP). The DIP panel diode assembly provides a gated path for current to travel through the respective INPUTS and SWITCHES to the OUTPUT that is active (ON). Having these DIP devices in circuit discrimination of the switches or contacts being sampled is then possible. No cross channeling occurs with these diodes in the circuit, allowing the system to provide accurate data back to the CPM regardless of the switch position.

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TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults

Standard Operating Description Refer to Table 1 for standard normal operating of the Mulitplex system. The signals listed below can be located in the Data Meters section of the EM2000 remote session. Table 1: Multiplex Diagnostic Circuits

Signal MxOf01< MxOf02< MxOf03< MxOf04< MxOf05< MxOf06< MxOf07< MxOf08< MxOf09< MxOf10< MxOf11< MxOf12< MxOf13< MxOf14< MxOf15< MxOf16< MxOf17< MxOf18< MxOf19< MxOf20< MxOn01< MxOn02< MxOn03< MxOn04< MxOn05< MxOn06< MxOn07< MxOn08< MxOn09< MxOn10< MxOn11< MxOn12<

Description

Normal Operation OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF OFF ON ON ON ON ON ON ON ON ON ON ON ON

Multiplexer Off 1 (DIO 1, Channel 1) Multiplexer Off 2 (DIO 1, Channel 2 ) Multiplexer Off 3 (DIO 1, Channel 3) Multiplexer Off 4 (DIO 1, Channel 4 ) Multiplexer Off 5 (DIO 1, Channel 5 ) Multiplexer Off 6 (DIO 1, Channel 6 ) Multiplexer Off 7 (DIO 1, Channel 7 ) Multiplexer Off 8 (DIO 1, Channel 8 ) Multiplexer Off 9 (DIO 2, Channel 1 ) Multiplexer Off 10 (DIO 2, Channel 2 ) Multiplexer Off 11 (DIO 2, Channel 3 ) Multiplexer Off 12 (DIO 2, Channel 4 ) Multiplexer Off 13 (DIO 2, Channel 5 ) Multiplexer Off 14 (DIO 2, Channel 6 ) Multiplexer Off 15 (DIO 1, Channel 7 ) Multiplexer Off 16 (DIO 2, Channel 8 ) Multiplexer Off 17 (DIO 3, Channel 1 ) Multiplexer Off 18 (DIO 3, Channel 2 ) Multiplexer Off 19 (DIO 3, Channel 3 ) Multiplexer Off 20 (DIO 3, Channel 4) Multiplexer On 1 (DIO 1, Channel 1 ) Multiplexer On 2 (DIO 1, Channel 2 ) Multiplexer On 3 (DIO 1, Channel 3 ) Multiplexer On 4 (DIO 1, Channel 4 ) Multiplexer On 5 (DIO 1, Channel 5 ) Multiplexer On 6 (DIO 1, Channel 6 ) Multiplexer On 7 (DIO 1, Channel 7 ) Multiplexer On 8 (DIO 1, Channel 8 ) Multiplexer On 9 (DIO 2, Channel 1 ) Multiplexer On 10 (DIO 2, Channel 2 ) Multiplexer On 11 (DIO 2, Channel 3 ) Multiplexer On 12 (DIO 2, Channel 4 ) Page 6

Copyright  Electro-Motive Diesel, Inc.. All rights reserved. Neither this document, nor any part thereof, may be reproduced or reprinted without the prior written consent of the Electro-Motive Diesel, Inc.. Contact EMD SDO office.

TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults Signal MxOn13< MxOn14< MxOn15< MxOn16< MxOn17< MxOn18< MxOn19< MxOn20< MxSel1< MxSel2< MxSel3< MxSel4< MxSel5<

Description

Normal Operation

Multiplexer On 13 (DIO 2, Channel 5 ) Multiplexer On 14 (DIO 2, Channel 6 ) Multiplexer On 15 (DIO 2, Channel 7 ) Multiplexer On 16 (DIO 2 Channel 8 ) Multiplexer On 17 (DIO 3, Channel 1 ) Multiplexer On 18 (DIO 3, Channel 2 ) Multiplexer On 19 (DIO 3, Channel 3 ) Multiplexer On20 (DIO 3, Channel 4) Multiplexer 1 Feedback Multiplexer 2 Feedback Multiplexer 3 Feedback Multiplexer 4 Feedback Multiplexer 5 Feedback

ON ON ON ON ON ON ON ON ON ON ON ON ON

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TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults

Fault Code Troubleshooting The fault codes listed in Table 2 are addressed by the troubleshooting steps in Table 3. Table 2: Fault Codes

Fault Code 2955 3164 3479 3937 4264 4533

Description DIGITAL INPUT SYSTEM FAILURE (CHECK MUX CIRCUIT) DIGITAL INPUT SYSTEM FAILURE (CHECK MUX CIRCUIT) NO START DIGITAL INPUT SYSTEM FAILURE AUTOMATIC ENGINE SHUTDOWN DELAYED ACTIVE MUX FAULT NO LOAD - DIGITAL INPUT SYSTEM FAILURE CHECK MUX CIRCUIT OR BATTERY VOLTAGE NO LOAD - DIGITAL INPUT SYSTEM FAILURE BATTERY VOLTAGE TOO LOW

CAUTION: Before following the procedure below, make sure the locomotive is properly locked out and flagged per your local procedures. Ensure the proper job briefing, safety procedures and Personal Protective Equipment required for the task were discussed. Troubleshooting Tips: Prior to troubleshooting a Multiplex Fault, read through the following tips and keep them in mind as the troubleshooting steps in Table 3 are performed. Fault Commonality  Determine the operating condition of the locomotive at the time of fault. Doing so can help narrow down the events occurring at the time of the fault and allow you to replicate the conditions at the time of fault. Determining the operating state of the locomotive is especially useful if the MUX faults are no longer active. o Is the unit in power, dynamic brake, or transitioning from power to DB, etc.?  Are P contactors picked up, B contactors picked up, etc. o The specific contactors or relays logging faults can be an indicator of the operating conditions at the time of fault. Attempt to replicate these conditions while troubleshooting.

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TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults



 

o Review the event recorder download in order to determine if there is an event (e.g. bell, horn, etc.) that coincides with the faults. Any event that coincides is a clue to possible grounds on the locomotive and helps narrow down the problem circuit. Examine the quantity and duration of the faults logged in the archive. o A “failed to drop out” fault that is active once for a significant length of time is most likely a hard ground. o A “failed to drop out” fault that is logged a quantity of times for a shorter duration may be a spike or short time event  For example if the fault is logged 60 times and shows a duration of 10 minutes, you should be looking for an event that has a duration of 10 seconds.  Failed suppression diodes on magnet valves (horn, bell, sanding, radar blow down, radiator shutters, etc.) can cause spikes into the circuit. Active all of these type of valves during testing. Usually a number of “failed to drop out” faults are logged together. Look for commonality across the faults o Investigate the circuits these faults all share In addition to commonality across faults, look for an “odd man out” when it comes to a specific channel. For example: o Most P-contactors share the same channel. Is there one P-contactor that didn’t log a fault? Investigate this contactor. o Is there one fan that didn’t log a fault when a number of the others did? Investigate this contactor and circuit.

Low Voltage Ground Investigation  When investigating low voltage grounds, is the test light steady on or flashing/pulsing? o A pulsing light indicates a ground in the MUX circuitry o A steady light indicates a standard 74v circuit low voltage ground  When isolating low voltage grounds, it is possible to isolate specific circuits by disconnect the plugs from the DIP panel and even removing pins from the plugs in the DIP panels.  A MUX fault always requires at least two paths to ground in order to create the fault. Be sure to locate both grounded paths. 1. A ground in a circuit to provide current 2. A ground in the MUX circuit to allow that current into the MUX circuitry o Correcting only 1 ground only fixes half of the problem AC Ground Investigation  Always run all self-tests (blower, cooling fan, excitation, etc.) and check for AC grounds during the operation of the self-test.

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TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults

A

EMPATH Multiplex Self Test  If the unit has EMPATH then the Multiplex self-testis available. This test allows the user to activate specific DIO output channels thereby allowing current flow through that entire MUX circuit. In effect it is freezing the Multiplex Cycle (Figure 1) on a specific channel. This test is particularly useful when troubleshooting “failed to pick up” faults or faults where the “MuxOn” or “MuxSel” has failed and is showing off. DIO Swapping  Use caution when swapping DIO’s to cure a Multiplexing problem. Swapping DIO modules can appear to cure a problem when it really has not. o The input voltage required to “turn on” a channel can vary slightly between DIO’s. A 35v ground may be enough voltage to activate a channel on one DIO, but may not be enough voltage to activate a different DIO.

Troubleshooting Steps: Table 3: Troubleshooting Steps

Step 1

Action Examine the EM2000 fault archive and look for multiple faults of different relays and/or contactors that failed to drop out or pick up, plus the existence of any of the above listed Multiplex faults.

Results/Notes If there are Multiplex faults and repetitive relay/contactor faults for failing to drop out go to step 2. If there are repetitive relay/contactor faults for failing to pick up go to step 5. If there are only faults for one individual contactor, troubleshoot that circuit specifically.

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TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults Step 2

Action Relay or contactor faults that indicate failed to drop out are usually caused by grounds on the locomotive. NOTE: Review the Fault Commonality section of the Troubleshooting Tips listed above in order to attempt to narrow down the operating conditions of the locomotive at the time of fault. Any event that coincides is a clue to possible grounds on the locomotive and helps narrow down the problem circuit.

3

4

Examine the Muliplexing screen in the EM2000 Data Meters Menu. To locate this screen, select the Locomotive Data button on the engineer’s display screen. This will display the EM2000 remote session box. Now select “Data Meters” and then “Mulitplexing”. You may be required to push the “Next” button to scroll to the second page of the “Data Meters” menu.

Results/Notes Use a 15-watt test light to check for DC and AC grounds as described in Appendix A: Inspection Procedure for Grounds in order to narrow down the problem area. If the 15-watt test light does not light, it is acceptable to check with a lower wattage test light (6-watt). Clear any and all grounds and retest.

If any of the “MUXOFF” channels show “ON”, or are flickering from “OFF” to “ON”, this is an indication of a ground. Note that it takes more than one DC ground to cause mux problems. Therefore, when checking for DC grounds, look for multiple grounds on the locomotive. Check for DC and AC grounds as described in Appendix A: Inspection Procedure for Grounds. Clear any and all grounds and retest.

Examine the “MUXOFF” screens. All of the “MUXOFF” must be off. Look for any channels flickering “ON” and “OFF”, or staying “ON” constantly. Using the information gained in the step above Replace this DIO module. and the electrical schematic for the locomotive, determine which DIO input channel is giving the A quick check can be made by swapping the bad MUXOFF of “ON”. DIO with an adjacent DIO module, and the problem should move with the bad module. If the problem does clear, replace the offending DIO in the original spot to ensure the problem re-occurs in order to verify the module was truly at fault.

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TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults Step 5

6

Action Multiple relay/contactor problems that indicate failed to pick up are usually caused by intermittent connections.

View the “Multiplexing” screen as described in step 3. Normally all “MUXON” should be ON and all “MUXSEL” must be ON.

Results/Notes Use the electrical schematic to determine which circuit has the problem. Inspect all plugs, pins, sockets, fastons and wires within that circuit for loose connections or damage. Correct any defects and retest. If you isolated a multiplexer with problem, go to the next step. Otherwise go to step 9.

In EMPATH, select the “Simulate [F3]” tab and use the multiplexer self-test. The test enables you to lock open a DIO output channel, so the mux inputs associated with that multiplexer will be active while other inputs will not. Lock each of the six multiplexer in order to isolate the multiplexer with problem. Note: Make sure you select “Normal Operation” after completing the test.

7

Similar test can also be run using the EM2000 script in Crosstalk. If there is only one MUXON showing “OFF”, the input channel or the connections to and from it are failed. Use the locomotive schematic to determine the input channel that may be failed and swap out that DIO to test.

If the problem is fixed, replace the bad DIO module otherwise the fault is in the wiring connections. Check for wiring problems in the plugs and wires between the following points: 1. Between the Power Distribution plug and the plug in the back of EM2000 chassis 2. Between the plug in the back of EM2000 chassis and CMU plug 3. Between the CMU plug and DIP panel 4. Verify positive voltage is present at the PA wire for that input channel. This wire is shown at the very top of the schematic on the Multiplex pages. 5. Replace the computer chassis as a last resort.

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TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults Step 8

Action Multiple MUXON or MUXSEL channels showing “OFF” could be due to the loss of a “shared feed”.

9

Individual MUXSEL channel is reading “OFF” when they should all be reading “ON”. There is a wiring connection problem. An open circuit exists in the offending MUXSEL circuit. In EMPATH, select the “Simulate [F3]” tab and use the multiplexer self-test. The test enables you to lock open a DIO output channel, so the mux inputs associated with that multiplexer will be active while other inputs will not. Active the MUX output channel containing the offending MUXSEL signal. This will provide a continuous path to negative in order to troubleshoot the MUXSEL wiring.

Results/Notes 1. Verify positive voltage is present at the “PA” wire for that input channel. This wire is shown at the very top of the schematic on the Multiplex pages. 2. Verify continuity to negative of the “NA” wire at the bottom of the Multiplex circuit. 3. Replace the computer chassis as a last resort. An open circuit exists in the offending MUXSEL circuit. Therefore, qualify all the connections and wiring in the circuit. Make sure you trace the entire path from the Power Distribution panel to the DIO output cannel. Inspect all the connections, pins and wires. Replace the computer chassis as a last resort if an open patch is not found in the entire MUXSEL circuit.

Similar test can also be run using the EM2000 script in Crosstalk.

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TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults

Help Desk Troubleshooting Table 4: Help Desk Troubleshooting Steps

Step 1

2

Action Results/Notes Swap the DIO modules. It is recommended to swap the modules individually with the far right module. Open any unnecessary circuit breakers. It is If neither of these steps fix the problem, it will possible one of these circuits could be grounded. be necessary to shop the locomotive. Please make a note of any troubleshooting performed in the failure incident.

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TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults Appendix A: Inspection Procedure for Grounds Low Voltage Grounds: 1. Verify the test 15-Watt light illuminates when connected across battery knife switch. 2. Make sure the locomotive is completely isolated and is not connect to any other locomotive via the MU cable. 3. Ensure all circuit breakers are closed, and turn on all the lights (cab lights, front and rear headlights, engine room lights, ground and step lights). 4. Apply one of the test light leads to the positive side of the battery knife switch and the other lead to anywhere convenient on the car body that is paint free and makes adequate contact. Note if the light illuminates. If it illuminates, go to step 6 otherwise go to step 10. 5. Now apply one of the test light lead to negative side of the battery knife switch and other lead to car body ground. Note if the light illuminates. If it illuminates, go to step 6 otherwise go to step 10. 6. If the light illuminates in step 4 or 5 above, it indicates that there is a low voltage ground present in either the negative side or the positive side. Note that a pulsating light bulb indicates a ground in the MUX circuit. If the light is steady and not pulsating, go to the next step otherwise go to step 11. 7. Now connect the test light to the side of the battery knife switch that lit the light above and the other lead to the car body ground. 8. Open one (1) circuit breaker at a time until the test light extinguishes. If the ground clears when a particular circuit breaker is opened, that circuit needs to be inspected in order to find and repair the ground. 9. If ground is still present after opening all the circuit breakers, check all the battery connections for problems. 10. With one lead connected to battery knife switch and the other to car body ground, perform each of the following tests in order to identify and narrow down the source of the possible grounds: a. Check the turbo lube pump circuit by shutting down the locomotive engine b. Operate the horn, bell, sanders, heated windshield etc. c. Perform the contactor/relay self test. During the test, keep an eye on the contactor/relay that causes the light to illuminate. d. Perform throttle 8 load test e. Perform all the other EM2000 self tests f. Perform throttle 1 stall test 11. View the MUXOFF data meter screens to determine which MUXOFF input is showing ON or flickering between OFF and ON. 12. In the locomotive electrical schematic, identify the circuits that are associated with the affected channel. 13. Once the circuits are identified, the ground can be isolated by disconnecting the D1 plug on the DIP panels one by one until the ground goes away. As you go through the process of disconnecting the D1 plugs that belongs to the affected channel, leave the plugs disconnected once the ground is Page 15 Copyright  Electro-Motive Diesel, Inc.. All rights reserved. Neither this document, nor any part thereof, may be reproduced or reprinted without the prior written consent of the Electro-Motive Diesel, Inc.. Contact EMD SDO office.

TSG#: 07-012 REVISION: A REVISION DATE: June 18, 2013 ISSUE DATE: July 26, 2007 AUTHOR: A. Ford APPROVED BY: C. Harkness Customer Engineering  Electro-Motive Diesel, Inc.  9301 W. 55th Street  LaGrange, IL 60525

TROUBLESHOOTING GUIDE - Multiplexing Faults isolated to a DIP panel. Leave that panel isolated and start reconnecting the removed plugs to ensure that there are not additional grounds on the mux circuit. 14. After identifying the affected DIP panel, plug the D1 connector back in, ensure the ground is still present. Follow the electrical schematic and start to isolate the ground by removing pins from the D2 and D3 plugs on the DIP panel that was isolated in step 13. 15. After determine what mux channel has the ground, start isolating the components until the failed component is identified.

AC Grounds: 1. Verify the 15-Watt test light illuminates when connected across battery knife switch. 2. Check for grounds with the test light connected between each of the six (1-6) Companion Alternator test points and car body ground under following conditions: a. Perform throttle 2 stall test b. Perform throttle 1-8 load test. Throttle out slowly and stop at a throttle position at which the light illuminates. c. Perform all the blower self tests d. Perform Cooling fan self test 3. On SD70ACe and SD70M-2 models, don’t use the test light to check for grounds on the APC winding of the companion alternator. APC winding test points are 7, 8 and 9. Follow Service Advisory 05-050: Troubleshooting APC Low Voltage Grounds to check for grounds across each of the test points 7-9 and car body ground with the use of a megger.

Page 16 Copyright  Electro-Motive Diesel, Inc.. All rights reserved. Neither this document, nor any part thereof, may be reproduced or reprinted without the prior written consent of the Electro-Motive Diesel, Inc.. Contact EMD SDO office.