2019 Led Lcd T-1

schematic4you.blogspot.com

casalaptopguide.blogspot.com

schematic4you.blogspot.com

LED/LCD TV T-CON & Screen Panel Repair Guide

You CANNOT give this E-book away for free. You do not have the rights to redistribute or sharing this E-book in internet or no matter where it is.

schematic4you.blogspot.com Copyright @ All Rights Reserved Warning! No part of this E-book/guide may be reproduced or transmitted in any form whatsoever, electronic, or mechanical, including photocopying, printing, recording, or transmitting by any informational storage or retrieval system without expressed written, dated and signed permission from the author. You cannot alter, change, or repackage this document in any manner.

Disclaimer And/ Or Legal Notices The reader is expressly warned to consider and adopt all safety precaution that might be indicated by the activities herein and to avoid all potential hazards. This E-Book is for INFORMATIONAL PURPOSES only and the author do not accept any responsibilities or liabilities resulting from the use of this information. While every attempt has been made to verify the information provided here, the author cannot assume any responsibility for any loss, injury, errors, inaccuracies, omissions or inconvenience sustained by anyone resulting from this information. Most of the repair tips and solution given should only be carried out by suitable qualified electronics engineers/technicians. Please be careful as all electrical equipment is potentially dangerous when dismantled. Any perceived slights of policy, specific people or organizations are unintentional.

http://www.lcdrepairguide.com/tcon-panel/

2

LED/LCD TV T-CON & Screen Panel Repair Guide

Limit of Liability/ Disclaimer of Warranty: The author and publisher of this E-book and the accompanying materials have used their best efforts in preparing this program. The authors and publisher make no representation or warranties with respect to the accuracy, applicability, fitness, or completeness of the contents of this program. They disclaim any warranties (expressed or implied), merchantability, or fitness for any particular purpose. The reader is expressly warned to consider and adapt all safety precautions that might be indicated by the activities here in and to avoid all potential hazards. By following the instructions contained herein, the reader willingly assumes all risks in connection with such instructions. The authors and publisher shall in no event be held liable for any loss or other damages, including but not limited to special, incidental, consequential, or other damages. As always, the advice of a competent legal, tax, accounting or other professional should be sought. No this parts of this E-book/Guide/Manual shall be reproduced or transmitted by any means, electronic, mechanical, photocopying, printing and recording or otherwise . Any unauthorized use of this material is prohibited. All product illustration, product names and logo are trademark of their respective manufacturers.

If you have any information regarding the illegal reselling or duplication of the E-book, please report it to [email protected] for your reward.

If you want to buy the Test Equipment, Tools and Spare Parts please visit to the page here: http://www.LCDRepairGuide.com/tools

All these tools and equipments will help you in troubleshooting and repairing the electronics devices. http://www.lcdrepairguide.com/tcon-panel/

3

LED/LCD TV T-CON & Screen Panel Repair Guide

Table of Contents How to Use This Repair Guide ........................................................................ 14

Part-1: Basic Theory of How an LCD/LED Screen Work .......... 15 How LCD/LED TV Works? ............................................................................ 17 How an LCD Display Work ............................................................................. 19 What are LCD Screen and LCD Panel? ........................................................ 22 T-con Board Part Number ............................................................................... 23 TAB/COF IC Part Number ............................................................................. 23 LCD Panel Part or Model Number ................................................................. 24

schematic4you.blogspot.com Part-2: How an LCD/LED Screen Panel Works ............................ 25 Types of LCD Panel and Their Structure ...................................................... 26 The TFT LCD Structure .................................................................................. 27 Learn About LCD TV and TFT LCD Displays ............................................. 28 History of TFT LCD ......................................................................................... 28 What is TFT LCD? .......................................................................................... 28 TFT LCD - Electronic Aspects of LCD TVs and LCD Monitors ................ 29 Passive and Active Matrix LCDs ..................................................................... 30 Structure of Color TFT LCD TVs and LCD Monitors ................................. 32 Driving Circuit Unit .......................................................................................... 33 How TFT LCD Pixels Work ........................................................................... 34 Generating Colors ............................................................................................. 37 http://www.lcdrepairguide.com/tcon-panel/

4

LED/LCD TV T-CON & Screen Panel Repair Guide The TFT LCD Pixel .......................................................................................... 38 The Resolution of an LCD Panel with TAB/COF.......................................... 40 A Block Diagram of Driving an LCD Panel ................................................... 41 Gate Driver Signals & Supply Lines ............................................................... 41 Typical Waveform of Gate Driver Control Signals ....................................... 42 Timing Control (TCON) IC CM2681A-KQ Diagram................................... 47 Various of T-CON Board DC-DC Diagrams & their Output Voltages ...... 48 How a CPT CLAA320WB02 LCD Panel Work ............................................ 50 Terminology of the T-CON Board and LCD/LED Panel PCB .................... 51 All About the T-CON Board ............................................................................ 57 What is T-CON Board? ................................................................................... 58 How the T-CON Board Work? ....................................................................... 59 Where the T-CON Board Output Supplies & Signal Lines Go? ................ 60 Top 5 Voltages in LCD T-CON Board............................................................ 61 The Importance of Checking GAMMA & Vcom Voltages in T-CON Board ............................................................................................................................. 63 How the GAMMA Channels Voltages & VCOM Voltage Generated? ...... 63 What will Happen When VCOM (Common Voltage) Voltage Missing? ... 67 How to Know the GAMMA Channels Voltages Normal or Abnormal? .... 67 If These Supply Voltages & Control Signals Missing What will Happen in LCD Panel? .................................................................................................. 69 Various of T-CON Board Good Voltage Testing Points & Their Symptom When Voltage Fail to Appear .......................................................................... 70 Case Study to Learn LCD/LED TV T-CON Board Repair.......................... 85

http://www.lcdrepairguide.com/tcon-panel/

5

LED/LCD TV T-CON & Screen Panel Repair Guide

Part-3: How to Troubleshooting & Repairing LCD/LED TCON & Panel ................................................................................................. 92 Types of LCD/LED TV Display Problem ....................................................... 93 Tools and Equipment for LCD Screen Panel Repair .................................... 95 How to Use the LCD/LED Panel Tester Correctly? ..................................... 98 How to Isolate Display Problem from Mainboard, T-con Board or LCD Panel? .............................................................................................................. 101 You Must Know Why Repair LED/LCD TV Panel Unsuccessfully? ....... 106 Is T-CON Board Can Do Their Self Test Like Power Supply Self Test? . 108 What is TAB Bypass Modification? ............................................................. 110 What is LCD Panel Cut Off Modification? ................................................. 113 TAB Bonding Machine ................................................................................... 117 Laser Repair System ....................................................................................... 119

Part-4: LCD/LED Screen Panel Repair Case Histories ............. 121 Procedure to Repair Samsung LCD/LED Panel without External Gate COF .................................................................................................................. 122 About Samsung Panels ......................................................................... 122 General Considerate Regarding Samsung Panel by Disconnecting Gate Drivers Signals ....................................................................................... 126 Steps You Have To Do When Repairing a Samsung Panel .............. 129 Samsung Panel Screen Repair Case ................................................... 130 (4.1) Panel Screen: LTA260AP02 T-CON: 260AP02C2LV0.2 Level Shifter IC: IC8-AG32AE2 .................................... 130

http://www.lcdrepairguide.com/tcon-panel/

6

LED/LCD TV T-CON & Screen Panel Repair Guide (4.2) Panel Screen: LTA320AB02 and LTF320AB01 T-CON: 320AB02CP2LV0.3 Level Shifter IC: 2x AG16BG ......................................... 133 (4.3) Panel Screen: LTJ400HM03 B T-CON: S100FAPC2LV0.3 ............................................. 134 (4.4) Panel Screen: LTF320AP11 T-CON: S100FAPC2LV0.3 Processor: BD8193MWV, Gamma MAX9694E ........... 136 (4.5) Panel Screen: LTJ400HM07 T-CON: S100FAPC2L v0.3 (BN41-01687A) ................. 138 (4.6) Panel Screen: LTF400HM03 T-CON: S100FAPC2L v0.3 ............................................. 140 (4.7) Panel Screen: LSF320HJ01 T-CON: 2013_TCON_FOX_FT1 (BN41-01939) .......... 142 (4.8) Panel Screen: LTY320AP04 and LTZ320AP04 TCON: 320AP04S4LV1.5 and 320AP04S4LV1.7 ......... 145 (4.9) Panel Screen: LTA400HW03 J TCON: SH120PMB45V0.3.............................................. 147 (4.10) Panel Screen: LSY320AN02 TCON: 320KSB_S2LV0.2 ............................................... 150 (4.11) Panel Screen: LTJ400HM05 T-CON: 400HR42S4LV0A, 400HR42S4LV0B ............. 154 (4.12) Panel Screen: LTF320HM01, LTA320HM03 T-CON: LJ94- 03256H (F 60M B4C2LV0. 6) .............. 159

http://www.lcdrepairguide.com/tcon-panel/

7

LED/LCD TV T-CON & Screen Panel Repair Guide (4.13) Panel Screen: LTJ400HV01-J T-CON: SH120PMB4SV0.3 ............................................ 162 How to Repair Double Images Problem on Samsung LCD Screen ........... 165 Samsung LTA320AP Series LCD Panel with Double Images Problem Solved ............................................................................................................... 180 Samsung LCD Panel with Display Problem Causing by Gate Driver Sides ........................................................................................................................... 183 How to Solve LG LCD Panel Display Upside Down Problem .................... 186 How to Solve BOE HV320WXC-200 Panel Upside Down Problem .......... 190 How to Solve Display Upside Down Problem in Universal LCD/LED TV Mainboard ....................................................................................................... 192 Display Left Right Reverse Problem Solved ................................................ 195 White Screen Problem on V315B3-C04 T-con Board ................................. 197 No Display or Grey Screen - Common Fault on LG 370WX4-SLA1 (6870C-0158A) ................................................................................................ 199 LG 470WU5-SLA1(6870C-0140B) No Display Problem Solved ................ 200 AUO T460HB01 V0 (46T12-C01) T-con Board with Randomly No Display Problem ............................................................................................................ 202 How to Solve Samsung LCD TV Oil Painting Display Problem ................ 203 Samsung Display Distortion (Oily Painting Display) Repair Solution ...... 207 How to Solve Display Distortion (Oily Painting Display) Problem in Universal LCD/LED TV Mainboard ............................................................ 212 How to Repair LCD TV Symptom with Blue Screen and Vertical Bars .. 214 How to Repair the Display Washed Out Screen Problem .......................... 216 Why After Replaced the AS15-G IC to AS15-HG the TV Still Has Problem? ......................................................................................................... 219

http://www.lcdrepairguide.com/tcon-panel/

8

LED/LCD TV T-CON & Screen Panel Repair Guide How to Easily Remove AS-15F or AS-15HF IC without 3 Minutes .......... 221 This LCD Panel Display Problem is Beyond Repair ................................... 224 Troubleshooting & Repairing Hisense RSAG7.820.5129 T-CON Board.. 226 LCD/LED TV Display Problem & T-CON Board Repair Tips ................. 241 • • • • • • • • • •

CHANGHONG ..................................................................................... 241 CHIMEI ................................................................................................. 254 HAIER ................................................................................................... 255 HISENSE ............................................................................................... 259 KONKA ................................................................................................. 270 LG ........................................................................................................... 273 SAMSUNG ............................................................................................ 278 SHARP ................................................................................................... 290 SKYWORTH ........................................................................................ 293 SONY ..................................................................................................... 295

Part-5: All Good LCD/LED TV T-CON & Screen Panel Repairing Information .................................................................... 298 TAB/COF Bypass Modification Repair Case Histories .............................. 299 LCD/LED Panel COF Equivalent List ......................................................... 304 COF BoardView List ...................................................................................... 311 T-CON Board P-GAMMA IC & DC-DC IC Programming Method ........ 352 How to Login to the Universal LCD/LED TV Mainboard Factory Setting ............................................................................................................... 367

http://www.lcdrepairguide.com/tcon-panel/

9

LED/LCD TV T-CON & Screen Panel Repair Guide

BONUS-A: Collection of Various Brand TV Schematic Diagrams of T-CON Board & Timing Control (Built-in PCB or Mainboard). This Bonus info was inside this ebook. ......................................................... 374 AUO B140XW02_V0_01_PCB with T-CON Schematic ............................. 376 AUO B156XW02-V2 T-CON Schematic ...................................................... 381 AUO T260XW02-VS-BN07-00638A-T-CON ............................................... 388 AUO T315HW02-V2-BN07-00640A-T-CON ............................................... 399 AUO T315HW02-V3-BN07-00641A-MEMC-T-Con .................................. 403 AUO T315XW02-VV-BN07-00639A-T-CON............................................... 413 AUO T370HW02-VC-BN07-00643A-T-CON .............................................. 424 AUO T370HW02-VE-BN07-00644A-Memc-T-CON .................................. 428 AUO T370XW02 V5_CA1-H0453-02_1........................................................ 438 AUO T370XW02-VF-BN07-00642A-T-CON ............................................... 444 AUO T400HW02-V3-BN07-00645A-T-CON ............................................... 448 AUO T400XW01-V7-BN07-00650A-T-CON ............................................... 452 AUO T420XW01_CA1-H0509-61_1 ............................................................. 456 AUO T460HW03-V4-BN07-00647A-T-CON ............................................... 461 AUO T520HW01-V0-BN07-00650A ............................................................. 465 AUO T546HF02-VO-CB_T-con_Schematic................................................. 472 CMO_Chimei V260B1-C03_LG 26LG7R .................................................... 508 CMO V315B3-L01-C_Same as TLM32V68 (1453) Built-In V315B3LN1_T-CON Schematic.................................................................................. 510 CMO_Chimei V315B3-L01T-CON Schematic ............................................ 513 Hisense LED42K16X3D (4736) LED TV Built-In TCON Schematic ........ 516 http://www.lcdrepairguide.com/tcon-panel/

10

LED/LCD TV T-CON & Screen Panel Repair Guide Hisense RSAG7.820.5129 T-con Board Schematic ...................................... 521 Hisense RSAG7-820-4159 T-con Schematic Diagram ................................. 529 LG LC320WXN-SAC1-731_6870C-0195A................................................... 534 LG LC370WX4-SLA1-F11_6870C-0158A ................................................... 538 LG LC420WUD-SAC1-G31-LC37WU_LC420WU_LC470WU_6870C0202B ................................................................................................................ 544 LG LC420WX7-SLA1-731(EN) T-con Schematic ....................................... 557 LG LC470WUN-SAA2-731_6870C-4200C................................................... 562 LG-Philips LC470WX1-SLA_6870C-0143B T-CON .................................. 568 Samsung ESP_C4LV0.4- LJ94-03842E T-Con ............................................ 574 Samsung LJ94-16057D_S100FAPC2LV0.0_T-con Schematic Diagram... 579 Samsung LTA320AP02 Panel_320AP03-C2LV0.1 T-con Schematic ........ 584 Sharp RUNTK0093FVZx_LC60UD20KN_4K2K 120Hz T-con ................ 587 Skyworth 5800-TCON6-0P10 TCON Board Schematic ............................. 598

BONUS-B (This bonus is NOT listed in this Ebook, it’s on the Download Page)

* Collection of LG LCD/LED TV Interconnect Diagrams * Collection of LG T-CON Board Testing Points & Voltages Values * LG 2012 Understanding T-CON Troubleshooting & Training Guide * Collection of T-CON Board Repairing Information * LG TFT-LCD Production Process Explained

http://www.lcdrepairguide.com/tcon-panel/

11

LED/LCD TV T-CON & Screen Panel Repair Guide * Collection of T-CON Board EEPROM Data/Firmware * Collection of P-GAMMA IC & DC-DC Firmware *EC5575-AS15 Series GAMMA IC Datasheet

All these Bonuses are inside the BONUS-B section:

http://www.lcdrepairguide.com/tcon-panel/

12

LED/LCD TV T-CON & Screen Panel Repair Guide Highly recommended another great related repair information for you: With all these great repair information, it will help you in troubleshooting and repairing electronic and the other display devices: (Please click on the ebook cover to get more details) 1) Flat Screen TV Troubleshooting & Repairing Ebooks:

http://www.LCDRepairGuide.com http://www.LCD-Television-Repair.com

schematic4you.blogspot.com http://www.lcdrepairguide.com/tcon-panel/

13

LED/LCD TV T-CON & Screen Panel Repair Guide

How to Use This Repair Guide 1) Yes, this repair guide not only can save you time and money, it also can earn more profit from repairing LED or LCD TV Screen/Panel. Because of LCD/LED TV has lots of the market now. And many of them are starting occur the problem. If we can repair it, so the profit is quite high to earn.

2) Inside this repair guide, I will NOT or I will seldom to provide the repair case about the failure of “Bulged” or “Bad ESR” values of Electrolytic Capacitor/s. As a TV repairer it is a very first step to see and measure the PCB boards inside the TV. Because it is a very basic things as a repairer need to know or know how to measure it. I highly recommend using the Blue ESR tester to testing electrolytic capacitor.

3) You can choose the chapter you’re interesting to read. For example, you want to know the COF pins info, you can directly go to that chapter and reading it.

4) Actually, all the LED/LCD TV their structure is nearly same. So, we can learn the LED/LCD TV repairing information from different brands & models of TV.

6) All the Programmer mention or using in this ebook is using the RT809F or RT809H Universal Programmer. For NAND/eMMC Flash it is using the RT809H Universal Programmer.

7) After you finished reading this ebook, I believe that you can improve yourself and confident in repairing the LED/LCD TV Screen Panel without guessing it. ☺

http://www.lcdrepairguide.com/tcon-panel/

14

LED/LCD TV T-CON & Screen Panel Repair Guide

Part-1 Basic Theory of How do LCD/LED Screen Work

schematic4you.blogspot.com

http://www.lcdrepairguide.com/tcon-panel/

15

LED/LCD TV T-CON & Screen Panel Repair Guide Nowadays, lots of the LCD & LED TV is in the market now. And this is the “peak season” these LCD & LED TV need to repair. But I found that, lots of the LCD TV or even LED TV I can found it in the recycling centers or factory! All these TV will be send to scrap and disposal as reuse their material only. So it is not only cause the money waste but it also increases the electronic waste on the earth. Finally found the answer is because of these scrap LCD/LED TV problem can’t be repair or not worth to repair it. Most of the symptom is because of “Display Problem”! The TV repairer told customer that this “Display Problem” is because of the Panel issue and no spare part to replace/repair or the repair cost is very expensive. But I can say their answer is not 100% true! Because I had tried before to repair these scrap LCD/LED TV, if the TV not crack screen, leakage their liquid crystal in the panel or Samsung Panel without Gate/Y- TAB, their success rate to repair these scrap TV is about 60~70%! ! So the actual the answer is because lots of the TV repairer they don’t know how to repair the LCD/LED Screen Panel. That’s why I created this ebook to help TV repairer to increase their troubleshooting & repairing knowledge in LCD screen panel repair. And the highest profit to repairing TV is repair the TV screen/panel problem. ☺

http://www.lcdrepairguide.com/tcon-panel/

16

LED/LCD TV T-CON & Screen Panel Repair Guide

How LCD/LED TV Works? Before we repair the LCD/LED TV, we must know how it works. So when we repair the LCD/LED screen or panel, we need to know how it works too.

1) Power Supply Unit (PSU) When the power supply input AC voltage and received a signal to power on, it will generate and output several types DC voltages to Mainboard and Inverter board (if that is LED TV, it is a LED Driver board).

2) Inverter Board/ LED Driver Board * For LCD TV, the inverter board receives 24V (normally) from PSU and received a backlight on signal from Mainboard, it will generate and output the AC voltages to start-up the CCFL lamps. So the backlight unit (BLU) can working properly and supplies the light to Panel. * For LED TV, the LED Driver board receives 24V (but different design will have different voltages. Please refer to their appropriate LED Driver board specification) from PSU and received a backlight on signal from Mainboard, it will step-up the DC voltage and output the DC voltage to start-up the LED Strip.

http://www.lcdrepairguide.com/tcon-panel/

17

LED/LCD TV T-CON & Screen Panel Repair Guide So the LED backlight can working properly and supplies the LED white light to Panel.

3) Mainboard Board The TV Mainboard received the video & audio signals from Tv channel (Tuner), AV, HDMI and etc, after that convert the audio signals, amplifier it and send to speakers to generate the sound. At the same time, Mainboard also convert the video signals to LVDS signals and send to T-con board through LVDS cable/s. Mainboard also control whole Tv to on/off, Power Supply on or cutoff and Backlight on or cutoff.

4) T-con Board When T-con board received the voltage supplies and LVDS signals from Mainboard, the T-con board will start working. The T-con Board converts the LVDS signal to TTL signals and through Timing Control circuit. After that generate the Data signals send to Source Driver Board. T-con board also generates the DC-DC voltages, Gamma circuit and control signals to control the Panel Glass working. For more details on how T-con board work, please read on chapter-2, How T-con Board works.

5) LCD Screen When the LCD Screen received the voltage supply and LVDS signals from Mainboard, it can show the display on the screen. But we also need the backlight to supply the light to Panel, so that we can see the picture or movie on the screen. If no backlight, it looks like no display but using a torch light shot to the screen, we can see the images on the screen. So LCD Screen is use to convert the videos/digital signals to images and the images can see by our eyes.

http://www.lcdrepairguide.com/tcon-panel/

18

LED/LCD TV T-CON & Screen Panel Repair Guide

How an LCD Display Work Liquid Crystals In school you learned that matter has three distinct states; solid, liquid, and gas. However, there are states of matter that may fall between these states, like liquid crystals. Basically they are crystals that hold their orientation (shape) but can flow similar to liquids. Their molecules point in same direction with respect to each other like in a solid, but they are free to change position like in a liquid. Think of a handful of pencils. They collectively hold their shape at rest, but change shape when you squeeze or let go of them.

There are different phases and types of liquid crystals that perform differently. Small amounts of pressure, heat, and/or electricity can cause liquid crystals to change in some way. For LCDs we are interested in the electricity aspect, but pressure and heat are side effects that have to be dealt with. This is why LCDs have a limited operating range and distort when you press on the screen. Liquid Crystal Display A Liquid Crystal Display is composed of a light source (backlight), a Liquid Crystal Panel, and a driving circuit. We start with a light source at the back of the panel composed of thin fluorescent bulbs (CCFLs - Cold Cathode Fluorescent Lamps). This light passes through filters to help create a uniform light source. Then the light passes through the Liquid Crystal Panel which is composed of thousands of pixels that control the flow of light through the panel to make images.

http://www.lcdrepairguide.com/tcon-panel/

19

LED/LCD TV T-CON & Screen Panel Repair Guide

http://www.lcdrepairguide.com/tcon-panel/

20

LED/LCD TV T-CON & Screen Panel Repair Guide Liquid Crystal Panel Below (on the left) is a cross section of a liquid crystal panel. The key to an LCD's operation is the polarizer. The polarizers only allow a certain wavelength of light to pass through. These two polarizers are mounted at a 90 degree angle with respect to each other, which prevents light from passing through. The liquid crystals are used to twist the light beam 90 degrees and allow light to pass through that cell. Color comes from a simple light filter.

Each sub-pixel or cell (a red, green, and blue sub-pixel equal’s one pixel) is controlled by a Thin Film Transistor (TFT). This provides accurate control of each cell and makes for an accurate picture. Some methods used in the past that didn't involve a switch and current could leak to surrounding cells resulting in a blurred image. A TFT is a semiconductor (bottom-right picture), it behaves like a relay switch.

http://www.lcdrepairguide.com/tcon-panel/

21

LED/LCD TV T-CON & Screen Panel Repair Guide

What are LCD Screen and LCD Panel? The words of LCD or LED screen or LCD or LED panel, actually both are different things. The LCD screen is meaning whole screen included Backlight, Metal Box (hold the backlight), T-con board and Panel Glass. Some LCD Screen also included the inverter board together and it is call as LCD Module. The LCD Panel is meaning the Panel Glass only. Sometime it also included the T-con board or Timing control section in their Source Driver board.

Different Sizes LCD Screens

LCD Panel http://www.lcdrepairguide.com/tcon-panel/

22

LED/LCD TV T-CON & Screen Panel Repair Guide

T-con Board Part Number The location of T-con Part Number:

TAB/COF IC Part Number The TAB part number is not on the center one but it is on the TAB file edges there as photo below:

http://www.lcdrepairguide.com/tcon-panel/

23

LED/LCD TV T-CON & Screen Panel Repair Guide

LCD Panel Part or Model Number LCD Panel part number sticker location:

http://www.lcdrepairguide.com/tcon-panel/

24

LED/LCD TV T-CON & Screen Panel Repair Guide

Part-2 How an LCD/LED Screen Panel Works

http://www.lcdrepairguide.com/tcon-panel/

25

LED/LCD TV T-CON & Screen Panel Repair Guide

Types of LCD Panel and Their Structure

The above picture is to show different types of LCD Panel. Type (1) & (2) is the old technology of LCD Panel used. The latest technology is using the (3) and (4) types design now. One more LCD Panel design is without the external Gate Driver COF/TAB on both sides.

schematic4you.blogspot.com

http://www.lcdrepairguide.com/tcon-panel/

26

LED/LCD TV T-CON & Screen Panel Repair Guide

The TFT LCD Structure

http://www.lcdrepairguide.com/tcon-panel/

27

LED/LCD TV T-CON & Screen Panel Repair Guide

Learn About LCD TV and TFT LCD Displays *This title information is from http://serdis.dis.ulpgc.es/ and contributes by Samsung Electronics.

History of TFT LCD Liquid crystal was discovered by the Austrian botanist Fredreich Rheinizer in 1888. "Liquid crystal" is neither solid nor liquid (an example is soapy water). In the mid-1960s, scientists showed that liquid crystals when stimulated by an external electrical charge could change the properties of light passing through the crystals. The early prototypes (late 1960s) were too unstable for mass production. But all of that changed when a British researcher proposed a stable, liquid crystal material (biphenyl). Today's color LCD TVs and LCD Monitors have a sandwich-like structure (see figure below).

What is TFT LCD? TFT LCD (Thin Film Transistor Liquid Crystal Display) has a sandwich-like structure with liquid crystal filled between two glass plates.

http://www.lcdrepairguide.com/tcon-panel/

28

LED/LCD TV T-CON & Screen Panel Repair Guide

TFT Glass has as many TFTs as the number of pixels displayed, while a Color Filter Glass has color filter which generates color. Liquid crystals move according to the difference in voltage between the Color Filter Glass and the TFT Glass. The amount of light supplied by Back Light is determined by the amount of movement of the liquid crystals in such a way as to generate color.

TFT LCD - Electronic Aspects of LCD TVs and LCD Monitors Electronic Aspects of AMLCDs The most common liquid-crystal displays (LCDs) in use today rely on picture elements, or pixels, formed by liquid-crystal (LC) cells that change the polarization direction of light passing through them in response to an electrical voltage. As the polarization direction changes, more or less of the light is able to pass through a polarizing layer on the face of the display. Change the voltage, and the amount of light is changed. There are two ways to produce a liquid-crystal image with such cells: the segment driving method and the matrix driving method. The segment driving method displays characters and pictures with cells defined by patterned electrodes. The matrix driving method displays characters and pictures in sets of dots. Direct vs. multiplex driving of LCD TVs.

http://www.lcdrepairguide.com/tcon-panel/

29

LED/LCD TV T-CON & Screen Panel Repair Guide

The segment drive method is used for simple displays, such as those in calculators, while the dot-matrix drive method is used for high-resolution displays, such as those in portable computers and TFT monitors. Two types of drive method are used for matrix displays. In the static, or direct, drive method, each pixel is individually wired to a driver. This is a simple driving method, but, as the number of pixels is increased, the wiring becomes very complex. An alternative method is the multiplex drive method, in which the pixels are arranged and wired in a matrix format. To drive the pixels of a dot-matrix LCD, a voltage can be applied at the intersections of specific vertical signal electrodes and specific horizontal scanning electrodes. This method involves driving several pixels at the same time by time-division in a pulse drive. Therefore, it is also called a multiplex, or dynamic, drive method.

Passive and Active Matrix LCDs There are two types of dot-matrix LCDs. Passive-matrix vs. active-matrix driving of LCD Monitors.

http://www.lcdrepairguide.com/tcon-panel/

30

LED/LCD TV T-CON & Screen Panel Repair Guide In passive-matrix LCDs (PMLCDs) there are no switching devices, and each pixel is addressed for more than one frame time. The effective voltage applied to the LC must average the signal voltage pulses over several frame times, which results in a slow response time of greater than 150 msec and a reduction of the maximum contrast ratio. The addressing of a PMLCD also produces a kind of crosstalk that produces blurred images because non-selected pixels are driven through a secondary signal-voltage path. In active-matrix LCDs (AMLCDs), on the other hand, a switching device and a storage capacitor are integrated at the each cross point of the electrodes. The active addressing removes the multiplexing limitations by incorporating an active switching element. In contrast to passive-matrix LCDs, AMLCDs have no inherent limitation in the number of scan lines, and they present fewer crosstalk issues. There are many kinds of AMLCD. For their integrated switching devices most use transistors made of deposited thin films, which are therefore called thin-film transistors (TFTs). The most common semiconducting layer is made of amorphous silicon (a-Si). a-Si TFTs are amenable to large-area fabrication using glass substrates in a lowtemperature (300°C to 400°C) process. An alternative TFT technology, polycrystalline silicon - or polysilicon or p-Si-is costly to produce and especially difficult to fabricate when manufacturing largearea displays. Nearly all TFT LCDs are made from a-Si because of the technology's economy and maturity, but the electron mobility of a p-Si TFT is one or two orders of magnitude greater than that of an a-Si TFT. This makes the p-Si TFT a good candidate for an TFT array containing integrated drivers, which is likely to be an attractive choice for small, high definition displays such as view finders and projection displays.

http://www.lcdrepairguide.com/tcon-panel/

31

LED/LCD TV T-CON & Screen Panel Repair Guide

Structure of Color TFT LCD TVs and LCD Monitors A TFT LCD module consists of a TFT panel, driving-circuit unit, backlight system, and assembly unit. Structure of a color TFT LCD Panel:

1. LCD Panel - TFT-Array Substrate - Color Filter Substrate 2. Driving Circuit Unit - LCD Driver IC (LDI) Chips - Multi-layer PCBs - Driving Circuits 3. Backlight & Chassis Unit - Backlight Unit - Chassis Assembly It is commonly used to display characters and graphic images when connected a host system. The TFT LCD panel consists of a TFT-array substrate and a color-filter substrate.

http://www.lcdrepairguide.com/tcon-panel/

32

LED/LCD TV T-CON & Screen Panel Repair Guide The vertical structure of a color TFT LCD panel.

The TFT-array substrate contains the TFTs, storage capacitors, pixel electrodes, and interconnect wiring. The color filter contains the black matrix and resin film containing three primary-color - red, green, and blue - dyes or pigments. The two glass substrates are assembled with a sealant, the gap between them is maintained by spacers, and LC material is injected into the gap between the substrates. Two sheets of polarizer film are attached to the outer faces of the sandwich formed by the glass substrates. A set of bonding pads are fabricated on each end of the gate and data-signal bus-lines to attach LCD Driver IC (LDI) chips

Driving Circuit Unit Driving an a-Si TFT LCD requires a driving circuit unit consisting of a set of LCD driving IC (LDI) chips and printed-circuit-boards (PCBs). The assembly of LCD driving circuits.

http://www.lcdrepairguide.com/tcon-panel/

33

LED/LCD TV T-CON & Screen Panel Repair Guide A block diagram showing the driving of an LCD panel.

To reduce the footprint of the LCD module, the drive circuit unit can be placed on the backside of the LCD module by using bent Tape Carrier Packages (TCPs) and a tapered light-guide panel (LGP).

How TFT LCD Pixels Work A TFT LCD panel contains a specific number of unit pixels often called subpixels. Each unit pixel has a TFT, a pixel electrode (IT0), and a storage capacitor (Cs). For example, an SVGA color TFT LCD panel has total of 800x3x600, or 1,440,000, unit pixels. Each unit pixel is connected to one of the gate bus-lines and one of the data bus-lines in a 3mxn matrix format. The matrix is 2400x600 for SVGA. Structure of a color TFT LCD panel.

http://www.lcdrepairguide.com/tcon-panel/

34

LED/LCD TV T-CON & Screen Panel Repair Guide Because each unit pixel is connected through the matrix, each is individually addressable from the bonding pads at the ends of the rows and columns. The performance of the TFT LCD is related to the design parameters of the unit pixel, i.e., the channel width W and the channel length L of the TFT, the overlap between TFT electrodes, the sizes of the storage capacitor and pixel electrode, and the space between these elements. The design parameters associated with the black matrix, the bus-lines, and the routing of the bus lines also set very important performance limits on the LCD. In a TFT LCD's unit pixel, the liquid crystal layer on the ITO pixel electrode forms a capacitor whose counter electrode is the common electrode on the color-filter substrate.

Vertical structure of a unit pixel and its equivalent circuit

A storage capacitor (Cs) and liquid-crystal capacitor (CLC) are connected as a load on the TFT. Applying a positive pulse of about 20V peak-to-peak to a gate electrode through a gate bus-line turns the TFT on. Clc and Cs are charged and the voltage level on the pixel electrode rises to the signal voltage level (+8 V) applied to the data bus-line. The voltage on the pixel electrode is subjected to a level shift of DV resulting from a parasitic capacitance between the gate and drain electrodes when the gate voltage turns from the ON to OFF state. After the level shift, this charged state can be maintained as the gate voltage goes to -5 V, at which time the TFT turns off. The main function of the Cs is to maintain the voltage on the pixel electrode until the next signal voltage is applied. Liquid crystal must be driven with an alternating current to prevent any deterioration of image quality resulting from dc stress. This is usually implemented with a frame-reversal drive method, in which the http://www.lcdrepairguide.com/tcon-panel/

35

LED/LCD TV T-CON & Screen Panel Repair Guide voltage applied to each pixel varies from frame to frame. If the LC voltage changes unevenly between frames, the result would be a 30-Hz flicker. (One frame period is normally 1/60 of a second.) Other drive methods are available that prevent this flicker problem. Polarity-inversion driving methods.

In an active-matrix panel, the gate and source electrodes are used on a shared basis, but each unit pixel is individually addressable by selecting the appropriate two contact pads at the ends of the rows and columns. Active addressing of a 3x3 matrix

By scanning the gate bus-lines sequentially, and by applying signal voltages to all source bus-lines in a specified sequence, we can address all pixels. One result of all this is that the addressing of an AMLCD is done line by line. Virtually all AMLCDs are designed to produce gray levels - intermediate brightness levels between the brightest white and the darkest black a unit pixel

http://www.lcdrepairguide.com/tcon-panel/

36

LED/LCD TV T-CON & Screen Panel Repair Guide can generate. There can be either a discrete numbers of levels - such as 8, 16, 64, or 256 - or a continuous gradation of levels, depending on the LDI. The optical transmittance of a TN-mode LC changes continuously as a function of the applied voltage. An analog LDI is capable of producing a continuous voltage signal so that a continuous range of gray levels can be displayed. The digital LDI produces discrete voltage amplitudes, which permits on a discrete numbers of shades to be displayed. The number of gray levels is determined by the number of data bits produced by the digital driver.

Generating Colors The color filter of a TFT LCD TV consists of three primary colors - red (R), green (G), and blue (B) - which are included on the color-filter substrate. How an LCD Panel produces colors.

The elements of this color filter line up one-to-one with the unit pixels on the TFT-array substrate. Each pixel in a color LCD is subdivided into three subpixels, where one set of RGB subpixels is equal to one pixel. (Each subpixel consists of what we've been calling a unit pixel up to this point.) Because the subpixels are too small to distinguish independently, the RGB elements appear to the human eye as a mixture of the three colors. Any color, with some qualifications, can be produced by mixing these three primary colors. The total number of display colors using an n-bit LDI is given by 23n, because each subpixel can generate 2n different transmittance levels..

http://www.lcdrepairguide.com/tcon-panel/

37

LED/LCD TV T-CON & Screen Panel Repair Guide

The TFT LCD Pixel

A Sub-Pixel:

A Pixel (Dot):

schematic4you.blogspot.com

http://www.lcdrepairguide.com/tcon-panel/

38

LED/LCD TV T-CON & Screen Panel Repair Guide

http://www.lcdrepairguide.com/tcon-panel/

39

LED/LCD TV T-CON & Screen Panel Repair Guide

The Resolution of an LCD Panel with TAB/COF

http://www.lcdrepairguide.com/tcon-panel/

40

LED/LCD TV T-CON & Screen Panel Repair Guide

A Block Diagram of Driving an LCD Panel

Gate Driver Signals & Supply Lines: DIO1, DIO2, SCLK, R/L, XON, OE1, OE2, OE3, VGG, VEE, VDD, VSS. (This Gate Drive Signals & Supply lines information is use for the LCD Panel Cut Off Modification use)

http://www.lcdrepairguide.com/tcon-panel/

41

LED/LCD TV T-CON & Screen Panel Repair Guide

Typical Waveform of Gate Driver Control Signals These signals waveform is a refer purpose only. Because with different design and manufacture it will has different result of waveforms. (A)

http://www.lcdrepairguide.com/tcon-panel/

42

LED/LCD TV T-CON & Screen Panel Repair Guide

http://www.lcdrepairguide.com/tcon-panel/

43

LED/LCD TV T-CON & Screen Panel Repair Guide

(B)

http://www.lcdrepairguide.com/tcon-panel/

44

LED/LCD TV T-CON & Screen Panel Repair Guide

http://www.lcdrepairguide.com/tcon-panel/

45

LED/LCD TV T-CON & Screen Panel Repair Guide

http://www.lcdrepairguide.com/tcon-panel/

46

LED/LCD TV T-CON & Screen Panel Repair Guide

Timing Control (TCON) IC CM2681A-KQ Diagram

http://www.lcdrepairguide.com/tcon-panel/

47

LED/LCD TV T-CON & Screen Panel Repair Guide

Various of T-CON Board DC-DC Diagrams and Their Output Voltages

http://www.lcdrepairguide.com/tcon-panel/

48

LED/LCD TV T-CON & Screen Panel Repair Guide

http://www.lcdrepairguide.com/tcon-panel/

49

LED/LCD TV T-CON & Screen Panel Repair Guide

How a CPT CLAA320WB02 LCD Panel Work

http://www.lcdrepairguide.com/tcon-panel/

50

LED/LCD TV T-CON & Screen Panel Repair Guide

51

Terminology of the T-CON Board and LCD/LED Panel PCB No.

1.

2.

3.

4.

Marking Code VON, VGH, VGON, VDDG

VOFF, VGL, VGOFF, VEEG

Description

Remark (Typically)

Gate-On Supply. VON is the positive supply voltage for the CKV_, CKVB_, and STVP high-voltage driver outputs. Bypass to GND with a minimum 1uF ceramic capacitor.

20V~ 35V

This VGH (VGate High) voltage was generated by DC-DC circuits. And their voltage is about 20V ~30V but it will depends on the T-con board design. The feature of VGH voltage is to supply to the Gate Driver Board as a “Switch ON” feature. It can switch on the TFT cells in LCD Panel and display shows. Gate-Off Supply. VOFF is the negative supply voltage for the CKV_, CKVB_, and STVP high-voltage driver outputs. Bypass to GND with a minimum 1uF ceramic capacitor. The VGL (VGateLow) voltage was generated by the DC-DC section too. Some T-con board will use a higher voltage as 15V or a lower voltage as -1V. So it will depend on the Tcon design and it’s not much on the market. Typically is 5V~ -7V. This negative voltage is supply to Gate Driver Board. The VGL voltage is as “Switch Off” feature. When VGL negative voltage is supply, the VGH voltage on TFT cells will “Clear” by VGL voltage, so that the next data can shows on that TFT cells.

VDD, Vlogic, Vddd, Dvdd

Supply Input. VDD is the logic supply input for the scan driver. Bypass to GND through a minimum 0.1uF capacitor.

VDA, Avdd, Vdda, Vsource

This VDA voltage is about 14V ~20V and it will depends on their T-con board design. The VDA voltage is generated by DC-DC Converter circuits. It is use to supply to the GAMMA circuits and reaching to the Source Driver Board

-5V~ -12V (Commonly is -5V ~ -8V)

3.3V

This VDD voltage is output from the DC-DC IC or using an external Voltage Regulator IC to generate. It is 3.3V and other voltages like 2.5V (VDD25) and 1.8V (VDD18) was using the VDD 3.3V voltage to convert. After VDD voltage generate it is supply to Timing Control section, Source Driver Board and Gate Driver Board.

http://www.lcdrepairguide.com/tcon-panel/

13V~ 25V

LED/LCD TV T-CON & Screen Panel Repair Guide

5.

AGND

Common Voltage. Normally their voltage is nearly half of the VDD voltages. (if VDD is 16V, then VCOM is about 7V) Ground

6.

BGND

Amplifier Ground

7.

GND

Ground/ Logic Ground

8.

PGND

Power Ground. Source connection of the internal step-up regulator power switch.

9.

STV

Vertical Sync Input. The rising edge of STV begins a frame of data. The STV input is used to generate the high-voltage STVP output.

VCOM

10. STVP

High-Voltage Scan-Drive Output. STVP is connected to VOFF when STV is low and is connected to VON when STV is high and CPV1 is low. When both STV and CPV1 are high, STVP is high impedance.

11. CPV1

CPV (Clock Pulse Vertical) -Vertical Clock Pulse Input. CPV1 controls the timing of the CKV1 and CKVB1 outputs, which change state (by first sharing charge) on its falling edge.

12. CPV2

Vertical Clock Pulse Input. CPV2 controls the timing of the CKV2 and CKVB2 outputs, which change state (by first sharing charge) on its falling edge.

13. CPV3

Vertical Clock Pulse Input. CPV3 controls the timing of the CKV3 and CKVB3 outputs, which change state (by first sharing charge) on its falling edge.

14. CKV1

CKV( Clock Signal)- High-Voltage Scan-Drive Output. When enabled, CKV1 toggles between its high state (connected to VON) and its low state (connected to VOFF) on each falling edge of the CPV1 input. Further, CKV1 is high impedance whenever CPV1 and STV are both low.

15. CKV2

High-Voltage Scan-Drive Output. When enabled, CKV2 toggles between its high state (connected to VON) and its low state (connected to VOFF) on each falling edge of the CPV2 input. Further, CKV2 is high impedance whenever CPV2 and STV are both low.

16. CKV3

High-Voltage Scan-Drive Output. When enabled, CKV3 toggles between its high state (connected to VON) and its low state (connected to VOFF) on each falling edge of the CPV3 input. Further, CKV3 is high impedance whenever CPV3 and STV are both low.

http://www.lcdrepairguide.com/tcon-panel/

52

LED/LCD TV T-CON & Screen Panel Repair Guide

17. CKVB1

CKVB (Inverted Clock Signal)- High-Voltage Scan-Drive Output. CKVB1 is the inverse of CKV1 during active states and is high impedance whenever CKV1 is high impedance.

18. CKVB2

High-Voltage Scan-Drive Output. CKVB2 is the inverse of CKV2 during active states and is high impedance whenever CKV2 is high impedance.

19. CKVB3

High-Voltage Scan-Drive Output. CKVB3 is the inverse of CKV3 during active states and is high impedance whenever CKV3 is high impedance.

20. CKVCS1

CKV1 Charge Sharing Connection. CKVCS1 connects to CKVBCS1 whenever CPV1 and STV are both low (to make CKV1 and CKVB1 high impedance) to allow CKVB1 to connect to CKV1, sharing charge between the capacitive loads on these two outputs.

21. CKVCS2

CKV2 Charge-Sharing Connection. CKVCS2 connects to CKVBCS2 whenever CPV2 and STV are both low (to make CKV2 and CKVB2 high impedance) to allow CKVB2 to connect to CKV2, sharing charge between the capacitive loads on these two outputs.

22. CKVCS3

CKV3 Charge-Sharing Connection. CKVCS3 connects to CKVBCS3 whenever CPV3 and STV are both low (to make CKV3 and CKVB3 high impedance) to allow CKVB3 to connect to CKV3, sharing charge between the capacitive loads on these two outputs.

23. CKVBCS1

CKVB1 Charge-Sharing Connection. CKVBCS1 connects to CKVCS1 whenever CPV1 and STV are both low (to make CKV1 and CKVB1 high impedance) to allow CKV1 to connect to CKVB1, sharing charge between the capacitive loads on these two outputs.

24. CKVBCS2

CKVB2 Charge-Sharing Connection. CKVBCS2 connects to CKVCS2 whenever CPV2 and STV are both low (to make CKV2 and CKVB2 high impedance) to allow CKV2 to connect to CKVB2, sharing charge between the capacitive loads on these two outputs.

25. CKVBCS3

CKVB3 Charge-Sharing Connection. CKVBCS3 connects to CKVCS3 whenever CPV3 and STV are both low (to make CKV3 and CKVB3 high impedance) to allow CKV3 to connect to CKVB3, sharing charge between the capacitive loads on these two outputs.

26. BOOST

Operational Amplifier Supply Input. Connect to VMAIN

http://www.lcdrepairguide.com/tcon-panel/

53

LED/LCD TV T-CON & Screen Panel Repair Guide

27. COMP

(Figure 2) and bypass to BGND with a 1μF or greater ceramic capacitor. Compensation Input for Error Amplifier. Connect a series RC from COMP to AGND. Typical values are 180k and 470pF.

28. DISH

VOFF Discharge Connection. Pulling DISH below ground activates an internal connection between VOFF and GND, rapidly discharging the VOFF supply. Typically, DISH is capacitively connected to VDD, so that when VDD falls, VOFF is discharged.

29. DLY

Startup Delay Setting. Connect a capacitor to adjust the delay.

30. EN

Enables the Scan IC. Drive EN high to start up the Scan IC after a delay time, which is set by a capacitor at DLY.

31. FB

Feedback Input. Reference voltage is 1.24V nominal. Connect external resistor-divider midpoint here and minimize trace area. Set VOUT according to: VOUT = 1.24V (1 + R1/R2).

32. GOFF

Gate-Off Supply. GOFF is the negative supply voltage for the CKV_, CKVB_, and STVP_ high-voltage driver outputs. Bypass to AGND with a minimum of 1µF ceramic capacitor.

33. GON

Gate-On Supply. GON is the positive supply voltage for the CKV_, CKVB_, and STVP_ high-voltage driver outputs. Bypass to AGND with a minimum of 1µF ceramic capacitor.

34. IN

Step-Up Regulator Supply Input. Bypass IN to AGND (pin 34) with a 1μF or greater ceramic capacitor.

35. LX

Switching Node. Connect inductor/catch diode here and minimize trace area for lowest EMI.

36. NEG

Operational Amplifier Inverting Input

37. OE

Active-High Gate-Pulse Output Enable. CKV_ and CKVB_ leave the floating charge-sharing state on the rising edge of OE.

38. OECON

Active-Low Output-Enable Timing Input. OECON is driven by an RC-filtered version of the OE input signal. If OE remains high long enough for the resistor to charge the capacitor up to the OECON threshold, the OE signal is masked until OE goes low and the capacitor is discharged below the threshold through the resistor.

http://www.lcdrepairguide.com/tcon-panel/

54

LED/LCD TV T-CON & Screen Panel Repair Guide

schematic4you.blogspot.com 39. OUT

Adjustable Sink-Current Output. OUT connects to the resistive voltage-divider at the op amp input POS (between BOOST and GND) that determines the VCOM output voltage. IOUT lowers the divider voltage by a programmable amount.

40. POS

Operational Amplifier Non-inverting Input

41. SET

Full-Scale, Sink-Current Adjustment Input. Connect a resistor, RSET, from SET to GND to set the full scale adjustable sink current that is VBOOST / (20 x RSET). IOUT is equal to the current through RSET.

42. VCOM

Operational Amplifier Output

43. VL

3.3V On-Chip Regulator Output. This regulator powers internal analog circuitry for the step-up regulator, op amp, and VCOM calibrator. External loads up to 10mA can be powered. Bypass VL to GND with a 0.22μF or greater ceramic capacitor.

44. WPN

Active-Low, Write-Protect Input. When WPN is low, I2C commands are ignored and the VCOM calibrator settings cannot be modified. Write-Protect Output. WPP is the inverse of WPN. It can be used to control active-high, write-protect inputs on other devices.

45. WPP

46. XAO

In order to solve the problem of image-retention effect of TFT-LCD, the technique of XAO function (power off control) is mostly used at present. XAO function means that XAO is set to low level when the display is turned off. For example, the logic low level is set to 0˜3.3 v, and thus all outputs of the gate driver will be shifted to high level at the same time and all TFT will be turned on. The charge stored on the CS can thus be discharged and the imageretention effect can be eliminated. However, the common method of using XAO function is to send XAO signal into logic control circuit and to convert low level to high level output through level shifter. After the display is turned off, much charge on the capacitor will be discharged since the voltage of power supply is maintained only by the capacitor and all TFT at low level will function at the same time. Therefore, when the pulse of XAO reaches, the gate voltage of all TFT are all shifted to VGH, and thus a large current is produced at the moment in which the gate of TFT on gate driver circuit is activated. This large current may cause the trace on gate driver circuit to burn. Furthermore, VDD voltage will also decrease rapidly and

http://www.lcdrepairguide.com/tcon-panel/

55

LED/LCD TV T-CON & Screen Panel Repair Guide

47. GSC

thus causes the conversion of the level shifter to fail and the XAO function to lose efficacy. Gate Shift Clock- Two clock signals GSC of a gate driver IC occur in a horizontal synchronous interval, and a GSC gate pulse is generated with each clock signal GSC of the gate driver IC. The gate start pulse has to occur so as to operate the gates

48. GOE

Gate Operation Enable- A timing controller supplying a gate operation enable (GOE) signal to the gate driver. a reset circuit supplying a reset signal to the timing controller, the reset signal enabling the GOE signal; and a filtering circuit connected to the reset circuit, the filtering circuit permitting a GOE mask time of the GOE signal to be longer than about 16 msec and reducing an impulse of the clock signal.

49. GSP

Gate Start Pulse

50. POL

Polarity Reverse

51. SSC

Source Sampling Clock

52. SOE

Source Output Enable

53. SSP

Source Start Pulse

http://www.lcdrepairguide.com/tcon-panel/

56

LED/LCD TV T-CON & Screen Panel Repair Guide

All About The T-CON Board Nowadays, the LCD LED Panel Timing Control section is not only in the TCON board, but it also built-in the LCD Panel and the Main board. The Timing Control section and their DC-DC circuit have higher repair rate in LCD LED TV. If the T-CON was built-in the LCD/LED Panel, then lots of TV repairer will direct return the TV to customer and told them this TV is beyond repair or not worth to repair it, because it is the LCD Panel problem.

The T-CON Board

The Timing Control Section & DC-DC Circuit Built-In the LCD Panel

http://www.lcdrepairguide.com/tcon-panel/

57

LED/LCD TV T-CON & Screen Panel Repair Guide

The Timing Control Section and DC-DC Circuit are Built-in the Main Board So if you have enough knowledge on how the Timing Control and their DC-DC circuit works, then it is no problem to troubleshooting and repairing it. Actually the small sizes LCD/LED Panel, their Timing Control and the DC-DC circuit were built-in the Panel long time ago. And we call this board as LCD Controller Board. But they are same thing, just the name is different. For more basic knowledge of T-Con Board, please refer to the V3.0 ebook for more details. If we know how the T-con board work and also know how to troubleshoot it, then it will help us to repair the T-con board or LCD Panel easily. Another problem to repair the T-con board/section is their spare parts. So we can search the parts online or find the part in the junk T-con boards.

What is T-CON Board? T-CON board is stand for Timing Controller board. Some LCD Panel manufacturer call is as LCD Controller Board. The features of T-CON board are converts LVDS signals to RSDS data and send to LCD Panel. The T-CON board has a individual power management call DC-DC Converter. The DC-DC section can generate the various voltages to drive the LCD Panel work.

http://www.lcdrepairguide.com/tcon-panel/

58

LED/LCD TV T-CON & Screen Panel Repair Guide

How the T-CON Board Work? The T-CON board are built by three main sections. They are Timing Control, DC-DC Converter and GAMMA circuits. When TV power on, mainboard MCU/CPU will send a Panel_ON signal to Q009 (as picture below), so that the 12V (or 5V) supply will go through I021 and reaching to the PVDD. Through LVDS cable the Vcc input supply was reached on T-con board as VIN.

After that the VDD voltage will send to Timing Control section and its’ start working. Timing Control IC will send an ON signal to DC-DC Converter section to switch on DC-DC circuits and generates other voltages like VDA, VGH & VGL. At the same time, LVDS signal will reach on Timing Control section and converts to RSDS signals and send to Source & Gate Driver Boards and reached to LCD Panel. When the VDA voltages generated, it will send to GAMMA Correction (Greyscale Generator) circuits and generates the VCOM voltages and reached to Source Driver Board, driver IC COF & TFT cells LCD Panel. Finally the LCD TV display appears on the screen.

http://www.lcdrepairguide.com/tcon-panel/

59

LED/LCD TV T-CON & Screen Panel Repair Guide

Where the T-CON Board Output Supplies & Signal Lines Go?

http://www.lcdrepairguide.com/tcon-panel/

60

LED/LCD TV T-CON & Screen Panel Repair Guide From the above picture, you will know how the signals and voltages are using in T-con Board, Source Driver Board, Gate Driver Board and LCD panel. Some big sizes lcd panel, they are using left Source & Gate Driver Board and right Source & Gate Driver Board. But their signals and voltages are same as the above picture. After the RSDS data and various type of voltages sent to LCD Panel, screen will show the display with backlight provided, we can seen the display perfectly. Notes: COF = Chip On Flim/Flex CIG = Chip IN Glass (Most of the Samsung LCD Panel using this type of Gate IC). COG = Chip ON Glass LVDS = Low Voltage Differential Signal RSDS = Reduce Swing Differential Signal

Top 5 Voltages in LCD T-CON Board VIN (VCC): (Typically is 12V or 5V) This voltage input also calls it as Vcc supply for T-CON board. Most of the LCD TV Panel are using 12V and 5V, but a little bit LCD panel design is using 3.3V (like Sharp TX38D21 lcd panel and other 15 inches lcd panel are using the 3.3V). IMPORTANT: Please make sure voltage supply to T-con Vcc is correct, if not it will damage the T-con or LCD Panel. Because some of the OEM LCD/LED TV mainboard, they are design to supply two type of voltages to Tcon Vcc (Panel_Vcc), one is 5V and another is 12V. It is set by a jumper or solder 0 ohm SMD resistor in the right position to select different voltages on mainboard. This voltage input to the T-con board and then supply to DC-DC section and the voltage regulator IC (depends on T-con board design).

http://www.lcdrepairguide.com/tcon-panel/

61

LED/LCD TV T-CON & Screen Panel Repair Guide VDD (Vlogic, VDDD): (Typically is 3.3V) This VDD voltage is output from the DC-DC IC or using an external Voltage Regulator IC to generate. It is 3.3V and other voltages like 2.5V (VDD25) and 1.8V (VDD18) was using the VDD 3.3V voltage to convert. After VDD voltage generate it is supply to Timing Control section, Source Driver Board and Gate Driver Board.

VDA (Vs, Vsource, VDDA, AVDD): (Typically is 14V~ 20V) This VDA voltage is about 14V ~20V and it will depends on their T-con board design. The VDA voltage is generated by DC-DC Converter circuits. It is use to supply to the GAMMA circuits and reaching to the Source Driver Board.

VGH (VGON, VoN, VDDG): (Typically is 20V~30V) This VGH (VGate High) voltage was generated by DC-DC circuits. And their voltage is about 20V ~30V but it will depends on the T-con board design. The feature of VGH voltage is to supply to the Gate Driver Board as a “Switch ON” feature. It can switch on the TFT cells in LCD Panel and display shows.

VGL (VGOFF, VoFF, VEEG): (Typically is -5V~ -7V) The VGL (VGateLow) voltage was generated by the DC-DC section too. Some Tcon board will use a higher voltage as -15V or a lower voltage as -1V. So it will depend on the T-con design and it’s not much on the market. Typically is -5V~ -7V. This negative voltage is supply to Gate Driver Board. The VGL voltage is as “Switch Off” feature. When VGL negative voltage is supply, the VGH voltage on TFT cells will “Clear” by VGL voltage, so that the next data can shows on that TFT cells.

Notes: Some old design T-con board they had different voltages for the DC-DC section. For example, the ChiMei LC-TM3008A LCD Panel is using V296W1-C1 X7 http://www.lcdrepairguide.com/tcon-panel/

62

LED/LCD TV T-CON & Screen Panel Repair Guide T-con board. This T-con board using FA3629 DC-DC IC and their voltage outputs are: 3.3V, 5V (both voltages using external voltage regulator IC to generate), 15V, -15V & 45V. So must refer to their original T-con board design and output voltages.

The Importance of Checking GAMMA & Vcom Voltages in T-CON Board If you’re repair LCD or LED TV, or even the LCD/LED Monitor, the Timing Control section is important and we must figure out how it work and how to troubleshoot it. Some repairer will say the T-CON board is cheap to replace, so no need to learn more about it. But the problem is not all LCD/LED TV and Monitor are using the T-CON board, especially the LCD/LED Monitor and Laptop LCD/LED Panel their Timing Control section are built inside the Panel or call it as LCD Controller. I found that lots of the LCD/LED Monitor and Laptop Panel/Screen problem can be repair but lots of the repairers just throw away it into the rubbish. And then replace a new Panel or just return back the Monitor to customer and say beyond repair or not worth to repair. So we must learn how the T-CON work and the method to troubleshoot it. No wonder the Timing Control section is design inside the Panel, T-CON Board or Main Board, so that we know how it works and where to checking their circuit.

How the GAMMA Channels Voltages and VCOM Voltage Generated? When the T-CON board (for example V315B3-C01 T-con board) DC-DC circuit generated the VDA voltage, this voltage is use to generate the GAMMA and VCOM voltages through U6 (HX8915A). This HX8915A is a 14+1 channels buffer IC, the ‘14’ is for 14 x GAMMA channels and another ‘1’ is for 1 x VCM channel use. http://www.lcdrepairguide.com/tcon-panel/

63

LED/LCD TV T-CON & Screen Panel Repair Guide This VDA voltage will go to:

1) VDA voltage go through the R335 resistor to generate the VDA_OP voltage for GAMMA IC U6 (HX8915-A, similar with the AS15 series IC) Vcc input use.

2) The VDA voltage also goes to D1 & D4 to generate the VREF (Voltage Reference) voltage and send it to their voltage divider resistor circuits.

Normally the VREF circuit just uses the D1 (KA431 type component) to generated VREF voltage only. This VREF voltage normally is about 12.5V. But different design it has a bit different on it.

3) For this T-CON board V315B3-C01, the VDA voltage also sends to U2 to generate the VSCM voltage and then send to U6 to generate the VCM (Vcom)

http://www.lcdrepairguide.com/tcon-panel/

64

LED/LCD TV T-CON & Screen Panel Repair Guide voltage. Normally this VCM voltage is generated by the VREF circuit. The VREF output line go through two resistors as voltage divider resistor circuit and get the VSCM voltage, and then send it to U6 (HX8915A) to output the VCM (Vcom) voltage. This Vcom voltage will send to the LCD Panel glass.

Note: The Vcom (VCM, Common Voltage) voltage is about half of the VREF voltage. Remember this rules, the VCM voltage is about half of the VREF voltage. If the Vcom voltage not stable or their voltage is out from the original values, the TV display will abnormal or their brightness problem.

After the VREF voltage was generated, it will send to 2 groups of resistors voltage dividing circuits. These 2 groups of resistors voltage divider resistor circuits will divided the VREF voltage to 14 channels different voltages call it as VS1~VS14 GAMMA voltages. But these voltages can’t direct send to the LCD Panel use, they need to send it to the buffer IC U6 (HX8915A or AS15 IC), and then it will output the GAMMA voltages GM1~GM14. These GAMMA voltages will send to the LCD Panel Source Driver board.

schematic4you.blogspot.com

http://www.lcdrepairguide.com/tcon-panel/

65

LED/LCD TV T-CON & Screen Panel Repair Guide

Finally the GAMMA voltages and the Vcom (VCM) voltages were generated through the circuit below:

http://www.lcdrepairguide.com/tcon-panel/

66

LED/LCD TV T-CON & Screen Panel Repair Guide

What will happen when Vcom (Common Voltage) voltage missing? When the Vcom (VCM) voltage is missing, the Panel display will become white and it is looks like the negative picture. If this is happen to your TV, you need to check their output voltage at the T-CON board. Normally their marking code at PCB board is “Vcom”, “VCM” or etc. If you’re not sure what voltage values is normal for the Vcom, never mind, do you remember the Vcom voltage is about half of the VREF voltage. So you can find the VREF voltage to measure it and then you can roughly know what the voltage values for the Vcom voltage are.

How to know the GAMMA channels voltages normal or abnormal? As you know that the GAMMA channels voltages when different T-con board or Panel, it has different channels in it. Normally is about 14 channels, 18 channels or above 20 channels. But all these GAMMA channels voltages has one important rules, that is “ The GAMMA Channels Voltage their voltages order is from high to low or low to high”! For example good GAMMA Voltages from high to low (V315B3-C01T-CON): CM1- 15.17V

CM8- 6.27V

CM2- 14.16V

CM9- 5.99V http://www.lcdrepairguide.com/tcon-panel/

67

LED/LCD TV T-CON & Screen Panel Repair Guide CM3- 11.99V

CM10- 5.20V

CM4- 11.40V

CM11- 4.26V

CM5-10.67V

CM12- 3.36V

CM6- 9.88V

CM13- 1.35V

CM7- 8.21V

CM14- 0.73V

Their voltages order high to low will looks like this: 15.17V, 14.16V, 11.99V, 11.40V, 10.67V, 9.88V, 8.21V, 6.27V, 5.99V, 5.20V, 4.26V, 3.36V, 1.35V, 0.73V If you found the GAMMA Channel Voltages like these, that’s mean the GAMMA circuit is failure and you need to check it. If not find any components failure, just try to replace their buffer IC like AS15, HX8915A & etc. The Example of Bad GAMMA Voltages: 1) 11.5V, 10V, 8V, 3V, 7.06V, 6.75V, 6.03V, 5.73V, 4.88V, 4.02V, 3.66V, 2.81V, 1.35V, 0.53V 2) 0.78V, 1.45V, 2.28V, 3.88V, 4.34V, 5.02V, 5.78V, 6.67V, 9.23V, 8.95V, 8.55V, 9.46V, 10.78V, 12.3V 3) 15.02V, 14.52V, 11.38V, 10.01V, 9.47V, 8.95V, 8.03V, 7.55V, 6.68V, 5.62V, 4.03V, 2.76V, 5.13V, 0.68V You can check the GAMMA voltages on the T-CON board and their marking code is GM, CM, PGM or etc.

http://www.lcdrepairguide.com/tcon-panel/

68

LED/LCD TV T-CON & Screen Panel Repair Guide Besides the DC-DC circuit has higher failure rate in T-Con board, the second is the GAMMA circuit. So if the GAMMA voltages abnormal, it will cause the TV display color abnormal, display noise in the display background or etc.

If These Supply Voltages & Control Signals Missing What will Happen in LCD Panel? (A) If missing or abnormal supply voltages of: 1.VGH (VON): Display will slow motion, white screen, display darkness or display blank. 2. VGL (Voff): Ghosting display, washed out display with vertical lines/bars. 3. VDA (Avdd): Display fully of vertical color lines/bars. 4. VDD (Vlogic): No display.

(B) If missing or abnormal of the gate control signals: The display symptom is involved on horizontal area. Like double images, jittering or jumping display, thin horizontal lines (a 1/3, 2/3 or full screen. It is not one horizontal line/bar only) and so on.

http://www.lcdrepairguide.com/tcon-panel/

69

LED/LCD TV T-CON & Screen Panel Repair Guide

Various of T-CON Board Good Voltage Testing Points and Their Symptom When Voltage Fail to Appear This chapter will provide the T-CON Board/Section of components part number and their good testing point voltage values. 1) T-CON Board P/N: CMO V315B1-C01 (V315B1-L01)

D1= 431W N6= 3.3V (LDO) N7= 2.5V (LDO) Q2= 4422 U1 & U2 = EM636165TS U3= CM2681A U5= 24LC128 U6= AS15-G http://www.lcdrepairguide.com/tcon-panel/

70

LED/LCD TV T-CON & Screen Panel Repair Guide UP1= AT1380AP (pin1= 0.5V, pin2= 0, pin3= 5V, pin4= 0V, pin5= 2.6V, pin6= GND, pin7= 0.36V, pin8= 0.19V) VCM= 5.9V, VREF= 12V, VDD= 3.3V, VGH= 19V, VDA= 13.5V, VGHP= 24V, VGL= -5.6V When U6 (AS15-G) fail, the TV will occur symptom like: display distortion, no display, TV auto shutdown & etc. The AS15 IC can use HX8915-A as a replacement at V315B1-L01, V315B3-L01, V315B1-L08 and V315B3-L04 TCON Board. The D1 (431W) pin1 (C)=12V, pin2 (R)= 2.4V and pin3 (A)= GND. When D1 damage, U6 (AS15-G) will no VREF voltage output and causing the TV no display symptom. Note: 431W and M431A is not same pin position, their pin1 & pin2 are opposite. So be careful when using the M431A as a replacement. But we can direct replace it with the “N1B” marking code 431 component on the inverter board.

2) T-CON Board P/N: CMO V420H1-C07 (V420H1-L07)

D1= N1B (can replace with 431W) LP2= 3.3V U2= 24LC128, U3& U4= EM638325TS

http://www.lcdrepairguide.com/tcon-panel/

71

LED/LCD TV T-CON & Screen Panel Repair Guide U5= i7822 (pin1&2= VST 0.6V, pin3= 0.6V, pin4= GND, pin5= 5.8V, pin6&7VCOM= 5.5V, pin8-VDA= 13.7V) U7= i7868A, U16= CM2679B/C/D , UP1= TPS65161, UP8= 2.5V (LDO) VDD= 3.3V, VDA= 13.7V, VGH= 18V, VGL= -5.5V, VCOM= 5.5V, GVON= 0V, GVOFF= 2.6V, VAA= 13.7V, VGHP= 20V When U16 is using the CM2679D, the UP8 is use the 1.8V LDO. For the CM2679B &C is use the 2.5V LDO. The LVDS Input Resistors for CM2679B/C their good ohm values (between the resistor and GND) is about 400 ohm. If that is CM2679D is about 500 ohm. If the R149 ohm values increases, normally this is because of the U16 (CM2679) is defective. Another design of the V420H1-C07:

I7868A (same as i7868A) and AS19 IC can be interchangeable in CMO 37 inches and above LCD/LED Panel, like HX8919-A.

http://www.lcdrepairguide.com/tcon-panel/

72

LED/LCD TV T-CON & Screen Panel Repair Guide

If U1 (CM2679B) damage, or the voltage supply: 2.5V, 3.3V, 13.7V, 18V, 5.5V and 12V missing, the TV will no display, but the backlight is lit. If the TV screen is abnormal display, it could be their U1 (CM2679B) damage or dry joins, GAMMA Correction IC i7868 or the T-CON board voltage supply abnormal. When the VCOM= 5.5V voltage is missing, the TV display will change to white or looks like negative picture.

3) T-CON Board P/N: CMO V370H1-L0A (35-D013142 [FHD-CM])

C= CP28, DP7 or Q9 damage will causing the 23V no output and the TV will No Display symptom. D1= 431 LP2 (Coil)= 3.3V U1= 8902 (pin5 output VCOM= 5.5V)

http://www.lcdrepairguide.com/tcon-panel/

73

LED/LCD TV T-CON & Screen Panel Repair Guide U5= 24LC128 U6= CM2677B U8 & U11= EM638325 U14= AS19-G UP2= FPS138, UP3= MAX1858, UP8= 2.5V (LDO), UP9= 2.5V (LDO) VGHP= 23V, GVON= 0V, GVOFF= 2.6V, VGH= 21V, VGL= -5.5, VDA= 13.5V, VDDC= 3.3V, VREF=12V, VCOM=5.5V When the voltage supply 13.5V & 23V their filter capacitor is leakage or shorted, the TV will No Display. Also for the other voltage supply like VDDC3.3V, VREF-12V, VDA-13.5V, VGH-21V, VGL=-5.5V, UP8&9=2.5V if missing, the TV also No Display. If the U6 (CM2677B) dry joins or U14 (AS19-G) damage will causing the TV display distortion problem. When the U1 (8902) damage and causing the VCOM 5.5V missing, the TV display will become white screen.

4) T-CON Board P/N: Chung Hwa CPT370WA03C

IC101= VTII8872, IC102 & IC103= EM636165TS, IC105= 25F12, http://www.lcdrepairguide.com/tcon-panel/

74

LED/LCD TV T-CON & Screen Panel Repair Guide IC201= E3A (same as 431), IC202= ISL24003, IC501= ISL976, L502= 3.3V Q501= 576RE (pin1,2,5&6 is output, pin3 is a control pin, pin4= 13.7V input) VREF= 12V C= This 13.7V line filter capacitors always short circuit in this T-CON board. Looks like a common fault in this T-CON board. CNSR2 & CNSL2=> pin7 &8= -6.2V, pin9&10= 24V, pin11&12= 13.7V, pin 13&14= 6.5V, pin15&16= 3.3V, pin 17&18= 13.7V

5) T-CON Board P/N: Chung Hwa CPT320WA01C

D501= 3.3V IC101= VE606RL (FPDB7352CXAVV) IC104= IS42S32200 IC301= M431A IC302, IC303, IC304, IC305, IC306= 2904 U501= 8728E VREF= 12V C537= 24V http://www.lcdrepairguide.com/tcon-panel/

75

LED/LCD TV T-CON & Screen Panel Repair Guide R528= 13.7V R545= -6.2V CNSR2 & CNSL2= PIN7&8= -6.2, PIN9&10= 24V, PIN11&12= 13.7V, PIN13&14= 6.5V, PIN15&16= 3.3V, PIN17&18= 13.7V When one of these IC: IC302, IC303, IC304, IC305 or IC306 defective, the TV display will be darkness. This IC101 has higher damage rate in this T-Con board. For example, their symptom likes no display and display distortion.

6) T-CON Board P/N: HV365WXC-200 LCD Panel: ChangHong M370X12-E1-B LED Panel

Testing the working voltage with Changhong LED37B1000C LED TV and the screen is no display with blue screen only.

http://www.lcdrepairguide.com/tcon-panel/

76

LED/LCD TV T-CON & Screen Panel Repair Guide

http://www.lcdrepairguide.com/tcon-panel/

77

LED/LCD TV T-CON & Screen Panel Repair Guide 1) LCD Panel: LG LC320WUN series LCD Panel T-CON P/N: 6870C-0230A T-con Board

http://www.lcdrepairguide.com/tcon-panel/

78

LED/LCD TV T-CON & Screen Panel Repair Guide 2) LCD Panel: LG LC370WUD T-CON P/N: 6870C-0264A

http://www.lcdrepairguide.com/tcon-panel/

79

LED/LCD TV T-CON & Screen Panel Repair Guide 3) LCD Panel: LG LC320/420/470/550WU_120Hz Control T-CON P/N: 6870C-4000H T-con Board

http://www.lcdrepairguide.com/tcon-panel/

80

LED/LCD TV T-CON & Screen Panel Repair Guide 4) LCD Panel: LG V5 LC370/420WUD VER.6 Panel T-CON Board P/N: 6870C-0309D

http://www.lcdrepairguide.com/tcon-panel/

81

LED/LCD TV T-CON & Screen Panel Repair Guide 5) LCD Panel: LG LC260WXESBA1 LCD Panel T-CON P/N: 6870C-0250A T-CON board Good Voltage Test Points

Note: The purpose of T-CON board LED is to determine if the boot up sequence of the T-CON is OK. This LED will turn on shortly after power is applied then will go out in about 30 seconds. This assists the backlight in firing

Some of the T-con board design, if there’s an inverter-switching fault occur, the LED light will remain on. If the LED light off, that’s mean the inverter section is working fine.

http://www.lcdrepairguide.com/tcon-panel/

82

LED/LCD TV T-CON & Screen Panel Repair Guide 6) LCD Panel: Samsung LTA320W-L06 LCD Panel T-Con P/N: 320WTLF3C2L V0.3

7) LCD Panel: Sharp LK315T3LZ54 LCD Panel T-Con Board P/N: X3562TP-XF (TW10794V-0)

http://www.lcdrepairguide.com/tcon-panel/

83

LED/LCD TV T-CON & Screen Panel Repair Guide Note: This T-con is using THV3051 as a DC-DC IC and BD8139EFV to generate the GAMMA and VCOM voltages. Their good voltage testing points: VIN: 5V, VDD: 3.3V, VDA: 15.6V, VGH: 30.9V, VGL: -1.6V GAMMA, GM0~GM9 OUT= 15.5V ~ 8.5V (Decrement)

http://www.lcdrepairguide.com/tcon-panel/

84

LED/LCD TV T-CON & Screen Panel Repair Guide

Case Study to Learn LCD/LED TV T-CON Board Repair Use this T-CON Board P/N: CHIMEI V315B3-C01 as a reference case. It will let us easy understand when the T-con board voltages change and how it will cause the screen display symptom.

This T-con board is using CM1682A as Timing Control IC, TPS65161 as a DCDC Converter IC and HX8915 for generates the GAMMA voltages. Here are the T-con board good voltages testing points: Vin: 12V, VGH: GATE ON= 21V, VGL: GATE OFF= -5.6V, VDA= 15.9V, VDD33= 3.3V, VDD18= 1.8V If each of their voltages changes, it will make the display on screen change too. Here is the good example of the change of T-con board voltages:

http://www.lcdrepairguide.com/tcon-panel/

85

LED/LCD TV T-CON & Screen Panel Repair Guide 1) If the VGL line voltage drops to -1V it will looks like this:

2) If VGL is 0V, the screen display as below:

http://www.lcdrepairguide.com/tcon-panel/

86

LED/LCD TV T-CON & Screen Panel Repair Guide 3) If the VGH voltage drops to 6V, display will looks like the weakness CRT TV tube as picture below:

4) For the GAMMA and VCOM circuit, if these circuit voltage lines abnormal the display screen will change to white screen, negative display and so on. - If GAMMA/GM1-GM14 voltages are 0V or 12V, it could be their dividing resistor open circuits and causing white screen.

schematic4you.blogspot.com http://www.lcdrepairguide.com/tcon-panel/

87

LED/LCD TV T-CON & Screen Panel Repair Guide - If the GAMMA/GM1-GM14 1 group or more group’s voltage drops, it will because of their dividing resistors values change or the GAMMA IC damage, their LCD screen display will change to Negative display. Must check their GM1-GM14 with voltage decrement.

- If VCOM not output or it is 0V, it is causing by the IC damage, CN1 or CN2 FPC cable/s contacts problem, Soure (Scan) & Gate (Data) Driver IC damage also can occur the symptom like picture below:

http://www.lcdrepairguide.com/tcon-panel/

88

LED/LCD TV T-CON & Screen Panel Repair Guide 5) Repair Tips for V315B3-C01T-con Board: a) Symptom: TV No Display but Sound Ok and the backlight working. Check the T-con board and found that SMD fuse burnt. If this type of symptom doesn’t just put another fuse to power on the TV, it may damage seriously again. Repair/Solution: Since the SMD fuse burnt, must using the Multimeter checking Vcc input line with GND ohm values. The values show it is normal, continue checking the other voltages lines like VGL, VGH, VDA & etc. Finally found VDA line to GND was shorted and it was 0 ohm. Disconnect the both FPC cables, VDA line still remain shorted. Now checking their VDA line corresponding components and found the CP12 shorted. After remove CP12, VDA line ohm values back to normal and testing this CP12 was confirm it had shorted. After replace SMD fuse and CP12, the VDA output 15.9V and TV is working properly.

b) Symptom: No Display but Sound Ok and the backlight is working Repair/Solution: Check the Vin have 12V input and other voltages lines also normal except VDA line is 0V. Because of the T-con board DC-DC voltage control by the timing control, as follows: VDD25, VDD18 => VDA => VGL =>VGH, the VDA is control by TPS65161 pin 27 output logic high/low signal (voltage) to QP1 (P-ch MOSFET) pin 4, when signal logic low received the MOSFET is switch ON and the VDA voltage has output and reaching to the GAMMA correction IC. Test the QP1 MOSFET, pins 1, 2 & 3 have 15.9V. It had proved that the VDA voltage is present. Testing MOSFET pin 4 is logic low signal, but pins 5, 6, 7 & 8 no VDA output! Remove and testing the QP1 MOSFET and found it had opened circuit. After replace QP1, the VDA got 15.9V output and display back to normal. Note: If don’t have the QP1 on hand, temporary can just using a wire connect QP1 pins 1 and 8, so it will bypass the QP1 switch function and testing T-con board is ok or not. http://www.lcdrepairguide.com/tcon-panel/

89

LED/LCD TV T-CON & Screen Panel Repair Guide c) Symptom: Screen Shows Vertical Color Stripes. The stripes are slowly to increase.

Repair/Solution: The vertical color stripes is slowly increase till full screen of vertical color stripes. This symptom could be the VGH circuit abnormal. Check the VGHP has 21V but VGH is 0.3V only instead of 21V. Testing QP7 (2N7002) pin 2 is logic high, pin 6 has 21V. For testing purpose, try to using a wire connect QP7 pin 6 to pin 4. After connected the wire, the VGH has 21V output now and display show perfectly. After replace the QP7, display is working properly now.

d) Symptom: Screen Fully of Vertical Stripes and Sometime NO Display

Repair/Solution: From the above symptom, it could be one of the DC-DC circuits abnormal and causing this problem. Check the DC-DC circuits and found that VGH voltage not stable and it is about 4.6V only. After some time, the DC-DC circuits all voltages will no output (No Display) and need to power off and then

http://www.lcdrepairguide.com/tcon-panel/

90

LED/LCD TV T-CON & Screen Panel Repair Guide on it again the voltages will come. When the no voltages output, power off the TV, using the finger touch the IC and feeling their temperature is a bit high but not extremely hot. Suspect the FPC cables problem; remove both CN1 & 2 and measure the VGH voltage still not stable. So the problem is still in VGH circuit line. Check the VGH line corresponding components, by disconnecting the CP19, CP43 and found that when removed CP43, the VGH voltage line is back to 21V! Replace CP43 with 1uF/50V, the T-con problem solved.

http://www.lcdrepairguide.com/tcon-panel/

91

LED/LCD TV T-CON & Screen Panel Repair Guide

Part-3 How to Troubleshooting & Repairing LCD/LED T-CON & Panel

http://www.lcdrepairguide.com/tcon-panel/

92

LED/LCD TV T-CON & Screen Panel Repair Guide

Types of LCD/LED TV Display Problem 1) No Display (Grey Screen: you can feel that their backlight is lit) This type of screen problem, you need to see their backlight is lit or not. If the backlight lit but no display, then use the volt meter to check their T-con board VCC supplies input voltage. If the Vcc has 12V or a similar voltage, that’s mean the problem is on T-CON board or Panel. If the T-con VCC input voltage missing, you need to trace it back to mainboard. We can use the LCD/LED Panel Tester to checking their T-con + Panel are working or not. So to confirm the problem is on Mainboard or Panel. Also we can use the other two testers too. 2) Display Upside Down & Painting Display Problem Normally this type of problem is causing by their setting in between Mainboard and their T-con board. So the solution is to login to TV service mode (Mainboard) to change their Panel setting. Or you can modify their T-con like inside the LCD/LED Screen Panel Repair ebook. If cannot modify, then change the T-con board to solve this problem. 3) White Display Normally this type of problem is the T-con or Panel damage. If you use the LVDS convert to VGA Tester, the TV Mainboard can output a perfect display on its LCD screen there.

4) Display Slow Motion Normally this type of problem is the T-con or Panel damage. If you use the LVDS convert to VGA Tester, the TV Mainboard can output a perfect display on its LCD screen there. 5) Display Double Images/ Jittering or Jumping

http://www.lcdrepairguide.com/tcon-panel/

93

LED/LCD TV T-CON & Screen Panel Repair Guide Normally this type of problem is the T-con or Panel damage. If you use the LVDS convert to VGA Tester, the TV Mainboard can output a perfect display on its LCD screen there. 6) Whole Screen of Vertical Colors Lines (Static or Dynamic) Most of the time, this type of screen problem is causing by their T-con. If you’re not sure, you can call out their TV OSD Menu. It is also same problem too. If their OSD Menu can show a perfect image on the screen, that’s mean the problem is in the Mainboard there. Or just use the LCD Panel Tester to testing it, you will know the result directly. 7) Screen Display Divided to Several Section or Display Content Opposites This type of problem is causing be their T-con board EEPROM firmware abnormal. 8) One or Several Horizontal/Vertical Bar or Lines on Screen Normally this type of problem is causing by their TV Panel. 9) Abnormal Display (Not mention the above) This type of screen symptom, you can try call out their OSD Menu to see it is normal or not. If OSD Menu normal, that’s mean the problem is on the Mainboard. If still same problem, then you needs to use the LCD Panel Tester or another two testers to testing this TV.

Notes: If these voltage lines abnormal on T-CON Board, what will happen on TV Screen? a) Vin (12V), VDD (3.3V), VAA/VDA(~17V) If these voltage missing or abnormal, the screen will no display. b) VGH, VGL If these voltage missing or abnormal, the screen will become slow motion or abnormal display.

http://www.lcdrepairguide.com/tcon-panel/

94

LED/LCD TV T-CON & Screen Panel Repair Guide c) Vcom If this voltage missing or abnormal, the screen will flashing or display not sharp (like low level contrast screen).

Tools and Equipment for LCD Screen Panel Repair Before starting repair LCD Panel, the first thing is we must have the right tools. Without the tools, we can’t do anything even you know how to repair it. The common tools like Multimeter, cutter, soldering iron, Oscilloscope (50MHz ~100Mhz, optional) and etc it is a common use tools. But I will list out some special tools to helps TV repairer to repair LCD Panel easily. 1) Magnifier: more than 60X is better. Also prepare a small magnifier in the pocket, when need to see a small thing or lines it will helps to you.

http://www.lcdrepairguide.com/tcon-panel/

95

LED/LCD TV T-CON & Screen Panel Repair Guide 2) A clean and big table: To suitable for big size LCD Panel repair. Like the photo above. Also put the fluorescent light below the table as a backlight of Panel. 3) Vacuum Pad: To let us easy to pick up the LCD Panel safely and easily.

http://www.lcdrepairguide.com/tcon-panel/

96

LED/LCD TV T-CON & Screen Panel Repair Guide 4) LCD/LED Panel Tester: This is a MUST have tool to let us easily diagnosis LCD Panel working or not, and no more guess game in LCD Panel repair. If you know how to setting TV Mainboard and programming their firmware through ISP Programmer, you can use the Universal TV Mainboard as a LCD Panel Tester. Because the Universal TV Mainboard can support more range of LCD Panel. It can support 15inches ~42 inches or 26 inches ~84inches LCD Panel.

With the above tools and equipment, it will increase your LCD Panel repairing speed and you will enjoy repairing LCD Panel.

http://www.lcdrepairguide.com/tcon-panel/

97

LED/LCD TV T-CON & Screen Panel Repair Guide

How to Use the LCD/LED Panel Tester Correctly? Nowadays, the LCD/LED Panel Tester is a must have tool to repair an LCD/LED TV. It is cheaper than the LVDS Convert to VGA & V-By-One Panel Testers. So lots of the TV repairer purchased this type of Panel Tester. Unfortunately, they bought the wrong package of this LCD/LED Panel Tester. Please look at the picture below:

The above LCD Panel Tester is a standard package only. The seller put their advertisement say this Tester can support LCD Panel from 10 inches until 55 or higher inches too! But from the above picture to see that, it is not user friendly for the TV repair!! When you bought the above LCD Panel Tester package, this tester will not help much in TV Panel repair. Because of the seller not put all type of the LVDS cables to standard package of LCD/LED Panel Tester. When you want to testing the 32, 37, 39, 40, 42, 47, 50, 55 inches TV panel with this tool, you will feel the lack of the LVDS cables to testing the above TV Panel. So I will recommend you when purchase this type of LCD/LED Panel, you must ask the seller to purchase extra LVDS cables like: 8-bits Single & Dual Channels types, and also for the 10-bits Single & Dual Channels LVDS cables. http://www.lcdrepairguide.com/tcon-panel/

98

LED/LCD TV T-CON & Screen Panel Repair Guide

Especially this type of connector LVDS cable:

http://www.lcdrepairguide.com/tcon-panel/

99

LED/LCD TV T-CON & Screen Panel Repair Guide How to Know Which LVDS Cable is Suitable to this TV Panel? That’s easy to just refer to back to their LCD Panel specification sheet, and then you will know what type of LVDS cable of this Panel (T-con board) use. Below is an example Panel datasheet of AUO T315XW02 VC. Inside the “”General Description” section there, it is shows their cable type already is 8-Bits and 1 Channel LVDS cable like picture below:

Important Note: 1) Make sure that the T-CON Vcc input voltage pins are connected correctly to LCD/LED Panel Tester. 2) Also choose the correct LCD Panel voltage values for the TV Panel need to test. If just wrong doing the above either one, it can damage and burn the LCD/LED TV Panel!!! So be careful on this part, if not, afterward you will regret. One more thing is make sure the TV backlight is working properly. If not you can’t see anything on TV screen.

http://www.lcdrepairguide.com/tcon-panel/

100

LED/LCD TV T-CON & Screen Panel Repair Guide

How to Isolate Display Problem from Mainboard, T-con Board or LCD Panel? This is an important subject to all TV repairers. Because every day the TV repairer will facing many TV display problem on their workbench. So they need to know the faster way to how to isolate TV display problem.

1) Mainboard or T-con board Problem? In this section, you have two methods to isolate the display problem from Mainboard and T-con board. a) First is call out the TV OSD Menu (just click on the remote control MENU button is ok). If the OSD Menu can show good display, that’s mean the problem is in the Mainboard or there LVDS cable/s there. But when the display problem still present on the OSD Menu there, that mean higher percentage is their T-con board or LCD Panel defective. But this method is not 100% accurate. b) So using the LCD Panel Tester to test the T-con board and we can know the result directly. Or we can also using the Universal TV Mainboard as an LCD Panel Tester. If you know how change their setting. Besides these LCD Panel testers, actually I also found other design LCD Panel tester in the market now. But compare with their price and performance, I think these two types LCD Panel Tester is ok to use. Unless you’re repair the 4K (or above) type LCD Panel.

http://www.lcdrepairguide.com/tcon-panel/

101

LED/LCD TV T-CON & Screen Panel Repair Guide c) Using the good tools can help us to isolate the TV Display problem made easy, for example: i) LCD/LED Panel Tester - A tester to test the T-con + Panel is working or not. So this tester can generate and send the Testing Color Bar to the Panel through T-con Board. The tester like picture below:

ii) LVDS convert to VGA Tester - This type of tester have two design, one is their tester build in the LCD screen and another one is need to connect to a monitor to see the video output is normal or not. Normally, this tester can test Mainboard output video signals LVDS to VGA and see the result on its own LCD screen or connect it to a monitor to see the display result. This tester is looks like the picture below:

http://www.lcdrepairguide.com/tcon-panel/

102

LED/LCD TV T-CON & Screen Panel Repair Guide iii) V-by-One converts to LVDS (also to VGA) for 4K TV Mainboard. - This type of tester is more expensive than the above two. Because of this tester can support to the latest 2K~4K TV Panel. It also same as the LVDS convert to VGA Tester, the display result can see on its own LCD screen or connect to a VGA monitor. Please see on the picture below:

The item (ii) & (iii) tester also use for TV mainboard repair. Because the mainboard just supply the voltage input and their LVDS output just connects to the Tester and you will know this Mainboard can output a good display or not.

schematic4you.blogspot.com d) Use an Oscilloscope (about 100MHz, higher is better but cost high) to measure the LVDS signals to determine mainboard have LVDS signals reaching the T-con board. So that you can confirm the mainboard is ok or not. But this method was not 100% accurate. If the display abnormal but the mainboard still have send the LVDS signals to T-con board. Or you have all the good waveform and values records on your own for that mainboard & T-con board. So that you can compare each other and know which signals waveform are good and bad. Below are the pictures of how T-con board Vcc input to T-con and the mainboard LVDS signals connect to T-con Board. http://www.lcdrepairguide.com/tcon-panel/

103

LED/LCD TV T-CON & Screen Panel Repair Guide

Picture troubleshooting with checking the LVDS signal:

LVDS with full field color bar input

http://www.lcdrepairguide.com/tcon-panel/

104

LED/LCD TV T-CON & Screen Panel Repair Guide The scope probe was placed on a random LVDS connector pin with a full field color bar input. Note: Both pictures look different due to the time/division settings. When full field color bar input signal has been removed, the scope will look like pictures below with different time/division:

This check will verify whether or not the LVDS signal is reaching to the T-con board.

2) T-con Board or LCD Panel? In this section, I will recommend to read on this ebook “Part-3: LCD Panel Cut Off Modification”. Actually this method not only can repair the display Double Images problem, it cans also diagnosis the LCD Panel at the same time. Even this method is not 100% accurate but it still acceptable. Compare to the TV repairer have buy the TAB Bonding Machine. Normally they are just directly replacing a working Tcon board to testing it. Even that T-con was built-in the Source PCB board. Their reason is this method will save time and increase the repairing speed. Because they need to repair over 200 pcs LCD panel per month. But the question is, when all these LCD Panel came in with different brands and models, so how can they prepare all these T-con board? It will stuck the cash flow for a company. So why not learn the troubleshooting & repairing skills to save money and even troubleshooting time if you know exactly how it work. http://www.lcdrepairguide.com/tcon-panel/

105

LED/LCD TV T-CON & Screen Panel Repair Guide

You Must Know Why Repair LED/LCD TV Panel Unsuccessfully Repair LCD/LED TV Panel is a challenging job. So we always need to find and learn the good & helpful TV Panel repairing information to improve our skills. When the skills improved, that’s mean repair the TV Panel successful rate will increase at the same time too! But I received several members email said they hard to successful repair the TV Panel. Finally, I found that they have a same mistake to learn the knowledge of repair TV Panel. For example: An LCD TV with display slow motion problem. Normally it is causing by their abnormal VGH voltage. So the member emails me about this problem and I told him to checking the VGH voltage. After next day, he replied my email and said all voltages on the T-CON board are normal. I asked him, did you check the VGH voltage until to the X-COF pin there? He said no. Then I asked him to check again. But I forgot to tell him that LCD Panel has 3 x external Gate COF and also need to check too. So next email, he told me that the VGH voltage normal even measure until the X-COF pins there. So he feels like this TV Panel is beyond repair and need to return back to customer. So I encourage him try again. Because he never finish check the VGH yet. Luckily, when he check the Gate COF-1 (COF BoardView or my previously call it as Bypass Modification) and found that VGH voltage missing! So he connects a wire from T-con board VGH point to the Gate COF-1 VGH point. Finally, his TV Panel problem solved! From the above story, we know that different people even learn from a same book, but get a different result! Hopefully, the entire TV repairers don’t do this mistake again.

http://www.lcdrepairguide.com/tcon-panel/

106

LED/LCD TV T-CON & Screen Panel Repair Guide A Good Workbench and Tools will Help to Increase Successful Repair Rate Yes, a good environment workbench with the entire necessary tools standby to use will help to increase the successful TV panel repair rate. These things and tools will helps to you: 1) 2) 3) 4) 5) 6) 7) 8)

A clean workbench with the proper lighting. Magnifier LCD/LED Panel Tester LCD & LED Backlight Tester Sharp & Fine tip Needle Soldering Iron Universal ISP Programmer Good sharp knife and etc accessories. TV Panel repairing information like: Panel datasheet specification info, Panel schematic diagram and my ebooks: V3, V4, LCD/LED Screen Panel Repair Guide (V1.0) and this ebook also.

http://www.lcdrepairguide.com/tcon-panel/

107

LED/LCD TV T-CON & Screen Panel Repair Guide

Is T-CON Board Can Do Their Self Test Like PSU Self Test? Yes it is. The latest design of T-con board they have built in the self test color patterns. But for some old design T-con board it is not available. To put the TCon board self test, you just need to provide their Vcc input (VIN) but must take off their LVDS cable/s. But some T-con board they have special method to do their self test, like the LG panel T-con board 6870C-0309D. I will shows you later. So using a wire solder on mainboard Panel_Vcc point and another side solder to T-con Vcc input. You MUST make sure the T-con board Vcc/Vin voltage first and then checking that mainboard Panel_Vcc voltage is same as your T-con Vin. After make sure their voltage is correct then solder them with a wire. If not it will damage your T-con board or LCD Panel! Other section like PSU, Inverter, and CCFL/EEFL Lamps just connected as it. Make sure WITHOUT connect the LVDS cable/s. After that power on the TV, you will see White, Red, Blue, Green and Black patterns show on screen. So that you can confirm the T-con Board, LCD Panel, CCFL/EEFL Lamps, PSU/IP Board are ok. Otherwise the T-con is defective. For example: if the TV having the display distortion problem, but you not sure is it the T-con board or mainboard problem. So you can use this method to testing the T-con board. If the T-con can show a good display (Color patterns) on the screen, so that problem is the mainboard or LVDS cable/s. Also don’t forget to check the T-con board LVDS cable connector socket for dry joins or pins problem.

For example, the LG 42LK520 LCD TV T-con Board Self Test Method: (LCD Panel: V5 LC370/420WUD Ver.6, T-CON: 6870C-0309D)

http://www.lcdrepairguide.com/tcon-panel/

108

LED/LCD TV T-CON & Screen Panel Repair Guide

http://www.lcdrepairguide.com/tcon-panel/

109

LED/LCD TV T-CON & Screen Panel Repair Guide

What is TAB Bypass Modification? This repairing method only can apply to the LCD Panel with external Gate Driver TAB/COF. If the LCD Panel Gate Driver COF built-in the LCD Panel glass, so this method will not work to this LCD Panel. The TAB Bypass Modification method is use to solve the LCD Panel Gate Driver control lines and supply voltage lines circuit break inside the glass! If your LCD Panel facing this problem, even you have the expensive TAB Bonding Machine also can’t help in this issue. How to do the TAB Bypass Modification? First we need to standby some tools and spare parts before starting to do the TAB Bypass Modification. 1) Multimeter 2) Magnifier- more than 60x is better 3) Thin copper wire (0.1mm)

4) TAB Bypass List (inside this ebook Part-5: TAB/COF Bypass List) * If you know where to connect from T-con board or Source PCB to TAB IC correct point, then no need to refer to this list. 5) Fine tip soldering iron For example, when a TV problem is Display Slow Motion symptom, normally it is because of their VGH voltage missing on the Gate Driver side. Using Multimeter to measure VGH voltage is present on the Source PCB or not. If yes, continue to checking the Y-TAB testing point. With the help of TAB Bypass List, we know that which point is the Y-TAB VGH voltage point. If no any VGH voltage here or the voltage drop a lot causing by supply line increasing http://www.lcdrepairguide.com/tcon-panel/

110

LED/LCD TV T-CON & Screen Panel Repair Guide resistance. Now we can use the thin copper wire to solder Y-TAB VGH voltage point. After that find the VGH point on Source PCB or T-con board there and solder that thin copper wire. That’s all. Sometime the circuit break inside the LCD Panel glass is not just one line only. Maybe 2 or more lines, especially their top corner side if broken a bit. It can be more than 10 lines too! If TAB part number not in the list or we don’t know which point is for which signal line, so how to solve this problem? Actually we can use the Magnifier over 60X to trace their lines from Source PCB to the Y-TAB there. If the LCD Panel top corner is broken, so we can use this method to repair the LCD Panel. Because when the Panel top corner side is broken, it will need to connect more than 5 or 10 lines! So it will hard to get the full TAB voltage point, unless you use this method to find it out. Below is a sample photos on how to do TAB Bypass Modification:

1. Check the voltage on Source PCB there.

http://www.lcdrepairguide.com/tcon-panel/

111

LED/LCD TV T-CON & Screen Panel Repair Guide 2. Checking the voltage values on Y-TAB to make sure that supply voltages or signals is reaching there. If not, that’s mean this line is circuit break inside the Panel glass.

3. Solder the appropriate TAB point, where their voltage or signal lines are open circuit from Source PCB.

4. Finally solder these wires to the correct points on the Source PCB.

http://www.lcdrepairguide.com/tcon-panel/

112

LED/LCD TV T-CON & Screen Panel Repair Guide

What is LCD Panel Cut Off Modification? This repairing method is for diagnosis LCD Panel when occur short circuit or leakage inside the Panel. Even this method is not 100% accurate, but it has higher rate as over 80% accuracy. From the theory of how is LCD Panel work, ‘most’ of the LCD/LED Panel has both sides of Gate Driver, especially for HD LCD Panel or above level Panel. That’s why, when the LCD Panel one of their Gate Driver side failure or short circuit, we can diagnosis and cut off their shorted line/s to save an expensive LCD Panel.

A) When to use this “LCD Panel Cut Off Modification Method”? 1) When LCD Panel symptom is Double Images or Jittering/Jumping display. 2) When the LCD Panel problem has unstable Horizontal Lines/Bars. 3) When suspect one of the Gate Driver side has short circuit in signal lines or voltage supply lines. 4) The LCD Panel has fully of horizontal thin lines on the screen. 5) The strange display problem occurs in LCD Panel. When facing this type of display problem, we can try to use this method to isolate the problem is occurs in Gate Driver side or not. Or which Gate Driver side is causing the problem occurs. 6) To isolate the display problem in LCD Panel or T-con board itself.

B) How to use this “LCD Panel Cut Off Modification Method”? We must know which are the Gate Driver control signal lines (included the clock lines) and voltage lines (VGH, VGL and so on). Normally these signal and voltage lines are going through the first X-TAB (X1) to right side Gate Driver and the last X-TAB (Xn) to left side of Gate Driver.

http://www.lcdrepairguide.com/tcon-panel/

113

LED/LCD TV T-CON & Screen Panel Repair Guide When a display problem occurs and suspects it is the T-con board or LCD Panel failure: 1) With T-con Board: If this LCD Panel has the T-con board, it is easy to do the Cut Off Modification testing. Just remove their FPC cables one by one. For example: a) First write down the Gate Driver control signals and supply voltage values on the paper. b) Power off TV, remove one side of FPC cable from T-con board. Now power on TV and see the display screen result. If half of the display normal and another half is blank (or no display) refer to the photo below, that’s mean, the problem was in the right side of Panel Gate Driver. And confirm this is a LCD Panel problem. Remember to write down their signals and supply voltage values.

So find the failure Right side of Gate Driver control signals (if that is Double Images problem, Display Jumping, Horizontal bars/lines Jittering and so on), CKV1, 2, 3…, CKVB1, 2, 3…, STVP, VCST, OE and so on. For how to cut off the signal lines please refer to the Part-4: Double Images repair case histories. If the display problem is slow motion on the screen, you need to find their supply voltage lines like VGH (most of the time is this voltage failure), http://www.lcdrepairguide.com/tcon-panel/

114

LED/LCD TV T-CON & Screen Panel Repair Guide DVDD, VGL and so on to do the TAB Bypass Modification. If that LCD Panel is without the external Y-TABs, and the voltage values are normal, that’s mean this LCD Panel is beyond repair. Because the problem was inside the Gate Driver glass, so nothing we can do for this LCD Panel.

If the result is both side also show failure display on the screen and their voltages recorded were all normal, that’s mean this LCD Panel is NOT worth to repair it, if LCD Panel is no Y-TAB on both sides of Gate Driver. If one or both sides have the Y-TABs there, then you need to use the TAB Bonding Machine to replace their Y-TABs to save the LCD Panel. But some time with this situation, about 20% of LCD Panel with above symptom (both sides show bad display) can be repaired. But this LCD Panel is not last long. If the result is both side also show failure display on the screen and their voltages recorded for T-con board is abnormal, then we can suspect the problem is in the T-con board not the LCD Panel! From here we can isolate the problem is in the T-con or LCD Panel defective! For big inches LCD Panel with 4 FPC cables, it also uses the same method. Where left side is 2 FPC cables and right is another 2 FPC cables.

http://www.lcdrepairguide.com/tcon-panel/

115

LED/LCD TV T-CON & Screen Panel Repair Guide 2) Without T-con Board:

For the LCD Panel without T-con board and no any external Y-TABs it is hard to swap testing both sides of Gate Driver. But we still can cut off their Gate Driver supply voltages like VGH, VGL and DVDD (3.3v) for one side first. So the display will show half screen is ok, another half screen is blank/black. So their result will same as “With T-con” method. If the first half display can show a good images but another one is bad images, this LCD Panel can be repair. If both sides also showing bad images, that’s mean this LCD Panel is beyond repair. To learn how to cut off the signal lines please refer to the “Part-4: Double Images repair case histories” for more details.

http://www.lcdrepairguide.com/tcon-panel/

116

LED/LCD TV T-CON & Screen Panel Repair Guide

TAB Bonding Machine

The main purpose of TAB Bonding Machine is to use for bonding the TAB/COF on the LCD Panel only. Is the TAB Bonding Machine is a compulsory tool to repair LCD Panel? My answer is not really. Because it will depends on the repairing business. For example how many quantity of LCD Panel need to repair every month? If your answer is HUGE over 50 or 100 pcs above, I will highly recommend you buy a good TAB Bonding Machine to earn more profit from this field.

http://www.lcdrepairguide.com/tcon-panel/

117

LED/LCD TV T-CON & Screen Panel Repair Guide

The TAB Bonding Machine is not a cheap tool and their cost for the TAB & ACF cleaning chemical, ACF glue and so on is very high. So if your repairing business didn’t have this repairing volume on LCD Panel, I will not recommend buying it. But when you buy the TAB Bonding Machine, make sure you’re choose a good quality with a good support seller or manufacturer, if not it will waste your money and time!

If you’re interesting to buy the TAB Bonding Machine please contact me at: [email protected] or http://www.lcdrepairguide.com/tools/

http://www.lcdrepairguide.com/tcon-panel/

118

LED/LCD TV T-CON & Screen Panel Repair Guide

Laser Repair System

Latest LCD Panel repair equipment is Laser Repair System. This is a new repair machine for LCD Panel repair. The price for this machine is very expensive than TAB Bonding Machine. It is about 10X more expensive than the TAB Bonding Machine! This LCD Panel repair equipment is use by the LCD Panel manufacturer or the LCD Panel Repair manufacturer only. This laser repair system can repair: 1) LCD Panel bright dots on the screen - Actually they just use this laser system to “turn off” that bright dot only. Where this bright dot after laser machine repair, it will change to “black dot” only. So a one black dot will hard to see or scan by human eyes. 2) It can remove the circuit short (ITO) inside Panel. 3) And so on.

http://www.lcdrepairguide.com/tcon-panel/

119

LED/LCD TV T-CON & Screen Panel Repair Guide

All these troubleshooting & repairing methods will not write again in Part-4 repair case histories to save some pages and file size of this ebook. http://www.lcdrepairguide.com/tcon-panel/

120

LED/LCD TV T-CON & Screen Panel Repair Guide

Part-4

schematic4you.blogspot.com

LCD/LED Screen Panel Repair Case Histories

http://www.lcdrepairguide.com/tcon-panel/

121

LED/LCD TV T-CON & Screen Panel Repair Guide

Procedure to Repair Samsung LCD/LED Panel without External Gate COF This chapter will help you repair a Samsung 2008-2013 type panel screens that use gate circuits embodied in glass screen cell (chip on glass COG). But the knowledge you learn from this chapter, also can apply to other brands of panel repair. The procedure has a rate of success of 0-90%, but it will depend on your screen panel type, the tools you use and the knowledge you’ve learn from my previous ebook (Also included this chapter too). You have to accept that sometimes, even the screen panel will work but a thin line may appear randomly on screen. Also, sometimes, the screen will not respond to any procedure described here. In this file, I will refer only on repairing gate problems of fault in Samsung screen panels.

1. About Samsung Panels A display device includes multiple pairs of field generating electrodes and an electro-optical active layer interposed there between. Generally, one of the pair of field generating electrodes is connected to a switching element to receive an electric signal and the electro-optical active layer converts electric signal into an optical signal to display images. The display device typically includes a gate driver and a data driver. The gate driver applies to a gate line a gate signal that turns a pixel on and off, and the data driver converts image data into data voltages and then applies the converted data voltage to a data line.

http://www.lcdrepairguide.com/tcon-panel/

122

LED/LCD TV T-CON & Screen Panel Repair Guide

“We are interested only in gate signal circuit, this is the one that faults and need to be fixed” The gate signals are processed by the scan driver circuits and amplified by the level shifter to analog signals, which are outputted as the gate pulses for scanning the display panel. Gate driving circuits can be mounted - (TCP) tape carrier package or printed on glass - (COG) chip on glass. On Samsung panels, gate driving circuits were replaced since 2008-2009 with gate drivers on glass mounted transistors, using ASG technology (Amorphous Silicon Gate).

http://www.lcdrepairguide.com/tcon-panel/

123

LED/LCD TV T-CON & Screen Panel Repair Guide

Each gate line has a block circuit glass mounted transistors called SR, made using ASG technology. The gate driver receives clock signals CKV and CKVB and the start signal STVP, and sequentially apply on voltages to gate lines G1Gn.

The display area 300 is represented by the resistor Rp and the capacitor

http://www.lcdrepairguide.com/tcon-panel/

124

LED/LCD TV T-CON & Screen Panel Repair Guide Cp. As show below, the gate lines G1-Gn, and the liquid crystal capacitor CIc and storage capacitor Cst , respectively have the resistance and capacitance, and the sum thereof is represented by one resistor Rp and one capacitor Cp. The gate voltage output from each line block SR1-SRn is analog transmitted through the gate line corresponding. The SR blocks are connected between, with glass printed connections, and when a component of one SR block faults, owing to the fact that is on glass, the repair is impossible.

However, with some trickery made on command signals of gate driver’s blocks, you can partially or totally repair the faults. CKV and phase opposition CKVB signal, and start STVP signal, are synchronizing the gate outputs to screen lines. For a small screen, we will have only one set of signals: CKV, CKVB and STVP. For a bigger screen, we will have 2 gate drivers blocks and 2 sets of signals, CKV1, CKVB1, STVP1 and CKV2, CKVB2, STVP2, each of this signals sets will command a gate driver on down or upper side of the screen.

http://www.lcdrepairguide.com/tcon-panel/

125

LED/LCD TV T-CON & Screen Panel Repair Guide

The fault can be visible on whole screen, half of screen, so we need to cut in either signals sets, or one by one, depending on each situation. On large screen panels, starting with 32 inch, there are gate drivers on both sides of the screen, and we can have 2, 3 or 4 sets of signals. In this case, the command of 4 blocks gate drivers (CKV1.....CKV4, etc) are made in various ways, one way it is as below: - First gate signal will command upper side of screen odd lines, second gate signal - lower side of screen odd lines, third gate signal will command upper side of screen even lines, fourth gate signal lower side of screen even lines. A fault screen will display in many ways: - Doubled image on all screen, on vertical, or image stop. - Half of screen, upper or lower, doubled or static image, the other half will be correct displayed. - On whole screen are horizontal lines where image is reversed or static. - A part of the screen is darker and with lines. - Vertical flickering image on all screen or upper or lower half of the screen - In an area of the screen, the image has lines on it. - On area where image is not right, can also to have a certain color or fail of color.

2. General Considerate Regarding Samsung Panel by Disconnecting Gate Drivers Signals This method also called as “Cut-Off Modification” in my previous ebook “LCD/LED Screen Panel Repair Guide”. (2.1) The generating circuit for gate drivers, called LEVEL SHIFTER or SCAN DRIVER, can be mounted on T-CON drivers, on PCB (printed wire board) connected to screen, or in glass screen. (2.2) When level shifter is in glass cell, you cannot disconnect it, but you can try to disconnect the input signal – CPV, STV and OE. This signals will go on both sides of the screen, thru left and right PCB, you can disconnect one side first,

http://www.lcdrepairguide.com/tcon-panel/

126

LED/LCD TV T-CON & Screen Panel Repair Guide check if any improvement, and if not, disconnect other side and re-connect first one. (2.3) First of all you have to check is: where is the LEVER SHIFTER IC, by finding check points CKV CKVB and STVP. Usually the LEVER SHIFTER is on TCON board or on T-CON PCB attached to the screen glass cell. (2.4) When you cut CKV, CKVB and STVP signals on printed wire circuit, you have to be sure that the disconnection will be made to screen direction, there are several situations when connection with level shifter is between check points and screen, so cutting the printed wire circuit near this check points to be with no result. (2.5) The T-CON processor generates only low voltage gate signals, like CPV, STV and OE, the level shifter circuit is not integrated in t-con processor, is a separate IC. (2.6) Sometimes there are 2 or 3 LEVEL SHIFTER IC, like in picture below:

But latest t-con boards have the same IC for LEVEL SHIFTER and DC-DC source, especially on small size screens (15-32”).

http://www.lcdrepairguide.com/tcon-panel/

127

LED/LCD TV T-CON & Screen Panel Repair Guide (2.7) Generally, if screen configuration permits, you have to check the printed wire circuit from T-con to both left/right PCBs, in connection to panel for all signals CKV, CKVB and STVP. The best way to repair is to cut the signals near screen, on left/right PCB, or left/right connection to screen on PCB (if only one board attached to screen cell). (2.8) Sometimes, cutting some signals only from left or right will solve the image problems but cutting same signals from both right / left connection to screen to generate more errors. (2.9) If you have a T-con apart from screen cell, first step is to find which part of the screen is fault. Disconnect left FFC between T-con and left PCB and power the tv. If you have now on right part of the screen a normal image, means that you have a fault in left side of the cell. If still a fault image, re-connect the left FFC and disconnect right FFC between T-con and left PCB and power the tv. If you have now on left part of the screen a normal image, means that you have a fault in right side of the cell. (2.10) On some screens, Level Shifter IC have on outputs, some zero ohms resistors, so, you can first remove this resistors and check if any improvements. You should remove on signal groups, for example, when you remove output of CKV2, you have to remove also CKVB2 signal. (2.11) Sometimes, you have on left/right PCB, some zero ohms resistors that connect Level Shifter to right/left screen cell. In this case, just remove those resistors for groups that fault. In example below, RM1 connects to screen the STVP signal, RM2 connects to screen CKV1 signal, RM3-CKV2, RM4-CKV3, RM5-CKVB1, RM6-CKVB2, and RM7-CKVB3 .

http://www.lcdrepairguide.com/tcon-panel/

128

LED/LCD TV T-CON & Screen Panel Repair Guide (2.12) As I explained in previous presentation, the CKV, CKVB and STVP signals scan between positive voltage VONE and negative voltage VOFFE. Sometimes, a small raise of VOFFE negative voltage will remove faults of the screen.

3. Steps You Have To Do When Repairing A Samsung Panel (3.1) identify the Level Shifter generator, by finding the inputs CPV, OE and STV check points, or finding the outputs CKV1...CKVn, CKVB1...CKVBn, and STVP1...STVPn check points. (3.2) Check the VONE and VOFF voltages and note the values. (3.3) First, disconnect the CKV1, CKVB1 and STVP signals, after that CKV2, CKVB2, and so on. (3.4) Disconnections will be made so the wires from screen panel to be “on air” (3.5) when disconnect the printed wire board near screen entrance, by cutting the printed circuit, you have to be sure that you will be able to solder this wires, so the cut has to be made with some distance from data driver flexible circuit. (3.6) First disconnect, CKV1 and CKVB1- if image still have thin lines, just strap the wires coming from screen panel CKV1 and CKVB1 with a thin wire. (3.7) After connecting CKV1 and CKVB1 with a thin wire, try also to ground this 2 points, or try to connect to VOFF. (3.8) If no improvements, try to disconnect CKV2 and CKVB2 (with STVP disconnected) and make same steps as for CKV1 and CKVB1 (3,6 and 3.7). (3.9) If we have also CKV3, CKVB3 and CKV4 and CKVB4, make the same procedure as CKV1 and CKVB1, described on 3.6-3.7.

http://www.lcdrepairguide.com/tcon-panel/

129

LED/LCD TV T-CON & Screen Panel Repair Guide (3.10) If, for example, by disconnecting CKV3 and CKVB3 we have a normal screen display, re-connect the former signals to panel screen, one by one in pairs (CKV1 and CKVB1, and so on). (3.11) It is possible that, sometimes only by disconnecting pair 1 and 4 to have a normal screen, but by disconnecting all 4 pairs to have a fault image. (3.12) Sometimes, even the image is correct displayed, you'll have a thin line in the area where gain glass circuit is failure - this cannot be repairable. You have to advice the client about this, and ask him to put in balance the final result of this procedure against the cost of a new panel screen.

4. Samsung Panel Screen Repair Case (4.1) Panel Screen: LTA260AP02 T-CON: 260AP02C2LV0.2 Level Shifter IC: IC8-AG32AE2 Level shifter receives from processor this low voltage signals: OE, STV and CPV1, CPV2, and from DC-DC source, VON and VOFF voltages Output signals that controls 2 gate drivers are CKV1, CKVB1 and STVP1, respectively, CKV2, CKVB2 and STVP2.

http://www.lcdrepairguide.com/tcon-panel/

130

LED/LCD TV T-CON & Screen Panel Repair Guide

Clock signals are starting from T-con Board, and you don't have to open the screen panel. First, cut and disconnect on printed side, where indicated in picture, CKV1 and CKVB1, strap on the check point on component side only CKV1 and CKVB1

If still image fault, proceed identical with CKV2 and CKVB2. If there is no image, just rebuild the CKV1 and CKVB1 connections on printed side. Sometimes, you need to disconnect also STVP1 (2) signal. Be patience, and check all combinations possible to have a normal picture. If fault solved but after a while appears some vertical white lines in an area with a static image, like a channel logo, you have to connect strapped pair to VOFF, instead of GND, and raise a little the VOFF with minus 3-5v. You can do that by lowering the resistor connected between REF and FBN of bias power supply IC7. Have TPS65160 schematic below:

http://www.lcdrepairguide.com/tcon-panel/

131

LED/LCD TV T-CON & Screen Panel Repair Guide

Another fault, over all image there are vertical thin colored lines. All voltages are correct. SDRAM – IC4 EM638325TS-7G is fault. Change T-con or replace memory.

Another fault: Black screen, after a while will appear vertical colored lines. Check all voltages – AVDD, VCC, VON, VOFF. Usually there is a problem with Von voltage, bias power supply TPS65160 fault. Change T-con or replace IC.

http://www.lcdrepairguide.com/tcon-panel/

132

LED/LCD TV T-CON & Screen Panel Repair Guide (4.2) Panel Screen: LTA320AB02 and LTF320AB01 T-CON: 320AB02CP2LV0.3 Level Shifter IC: 2x AG16BG On this panel, we have 2 versions of repairing it. a) On T-con board: There are 2 gate drivers and clock signals are outputted by 2 level shifter IC's, ICS1 and ICS2, located on T-con board. First, cut the circuits between ICS1 - CKV1 and CKVB1, right near resistors, as shown in image below. If image still fault, try to strap CKV1 and CKVB1, connect to the ground, or connect with an wire to Voff. ATTENTION! Make sure the connection between check point and ICS1 is opened with diode instrument, before strapping CKV1 and CKVB1. If there is still connection to the level shifter IC, you can burn it by connecting to the ground or Voff. If image still faults, make a similar procedure with ICS2, by disconnecting CKV2 and CKVB2. Reconnect CKVB1 and CKVB2 to ICS1, and follow the same procedure.

If image is correct, but on still images there are some white vertical artifacts’, you have to connect strapped pair to VOFF, instead of GND. b) On PCB connected to glass screen panel Cut the connections CKV1, CKVB1, CKV2, CKVB2 and STVP1 (2) on side with gate block fault (left or right) . You can see where the fault is by checking left/right margin of the screen with a magnifier lens, or a microscope. You will see a burned glass circuit, in the area where screen faults.

http://www.lcdrepairguide.com/tcon-panel/

133

LED/LCD TV T-CON & Screen Panel Repair Guide

(4.3) Panel Screen: LTJ400HM03 B T-CON: S100FAPC2LV0.3 Screen is flickering and has a part/all the screen with doubled image.

First step is to find which part of the screen is fault. Disconnect left FFC between T-con and left PCB and power the tv. If you have now on right part of the screen a normal image, means that you have a fault in left side of the cell. If still a fault image, re-connect the left FFC and disconnect right FFC between Tcon and left PCB and power the TV. If you have now on left part of the screen a normal image, means that you have a fault in right side of the cell. On the right side (with problems) just remove the CKV1 and CKVB1 resistors RM2 and RM5 and see any improvements.

http://www.lcdrepairguide.com/tcon-panel/

134

LED/LCD TV T-CON & Screen Panel Repair Guide

If not, remove CKV2 and CKVB2 resistors RM2 and RM6, check if any improvements, and if not, remove CKV3 and CKVB3 resistors RM3 and RM7. If still no improvements, remove STVP resistor, RM1 see picture. You will have a normal picture now, but sometimes, you will have, on side with problems, a little ODD/EVEN lines distance. Strap with a wire, on check points, CKV1 with CKVB1, see if lines are now correct displayed. If not, strap with a wire, on check points, CKV2 with CKVB2, check, and repeat procedure with CKV3 with CKVB3. Now you will have a clean image. Sometimes, it will be better to put back the resistors for the blocks pair that have no problem. For example if only by disconnecting CKV3 and CKVB3 will solve image problem, that means pair 1 and 2 have no problems. Sometimes, if you have a bigger problem on cell circuit, the image will be correct but a/some thin line/s will be displayed sometimes on screen, noticeable on lighter/darker images. Try to connect the strapped pair that not works on GND or Voff. You can also raise Voff voltage with 3~5 volts to minus and the line will disappear. You can do that by changing the input resistors from FBN input of BiasPS/Level Shifter ICD1 – SM4109.

http://www.lcdrepairguide.com/tcon-panel/

135

LED/LCD TV T-CON & Screen Panel Repair Guide

(4.4) Panel Screen: LTF320AP11 T-CON: S100FAPC2LV0.3 Processor: BD8193MWV, Gamma MAX9694E Panel screen used in Samsung LE32D450G1W TV VONE = 28v, VOFFE= -11,5v Gain signals CKV1, CKVB1, CKV2, CKVB2 and STVP are outputted to screen cell thru 4 resistors, 0 ohms, as in image below:

http://www.lcdrepairguide.com/tcon-panel/

136

LED/LCD TV T-CON & Screen Panel Repair Guide When all image is colorless or with hue of green/red pale, the fault is from NVM EEPROM IC, 24C64WP. Replace it, with another one, need to use the Universal Programmer to write the good firmware into it before solder back to PCB. A very often fault found with this type of panel: Image is ok only on lower part of the screen, and upper side is discolored and full of visible horizontal lines, as in picture below:

The reason for this fault is a fried connection of a SR gate block, from left or right side of the screen (check after you remove the metal rim that covers the screen).

The repair procedure: The fault starts after a few minutes, when faulty SR gate run too hot, so you can add a thermal sponge pressed by metal rim, or you can cut the signals CKV1, CKVB1, CKV2, CKVB2 and STVP only on fault side.

http://www.lcdrepairguide.com/tcon-panel/

137

LED/LCD TV T-CON & Screen Panel Repair Guide

(4.5) Panel Screen: LTJ400HM07 T-CON: S100FAPC2L v0.3 (BN41-01687A) Fault: The thin horizontal stripes were at the top of the screen. Cause of the defect: burned SR block in the higher right/left corner of the panel.

schematic4you.blogspot.com http://www.lcdrepairguide.com/tcon-panel/

138

LED/LCD TV T-CON & Screen Panel Repair Guide Repair procedure: Disconnect left FFC between T-con and left PCB and power the tv. If you have now on right part of the screen a normal image, means that you have a fault in left side of the cell. If still a fault image, re-connect the left FFC and disconnect right FFC between T-con and left PCB and power on the tv. If you have now on left part of the screen a normal image, means that you have a fault in right side of the cell. The right side (with problems) resistors are RM2, RM3, RM4, RM5 RM6 and RM7. You will have a normal picture now, but sometimes, you will have, on side with problems, a little ODD/EVEN lines distance. Strap with a wire, on check points, CKV1 with CKVB1, see if lines are now correct displayed. If not, strap with a wire, on check points CKV2 with CKVB2, check, and repeat procedure with CKV3 with CKVB3. Now you will have a clean image. Sometimes, if you have a bigger problem on SR circuit, the image will be correct but a / some thin line (s) will be displayed sometimes on screen, noticeable on lighter/darker images. Check if any improvements if connect all pairs of check points on fault side on GND or Voff.

http://www.lcdrepairguide.com/tcon-panel/

139

LED/LCD TV T-CON & Screen Panel Repair Guide (4.6) Panel Screen: LTF400HM03 T-CON: S100FAPC2L v0.3 Fault: 15 - 30 minutes of good image, begins to trembling, double vertically. If you check on strips of glass with your fingers, you will find that hot broken drivers are on one of the left/right bar. Repair procedure: Disconnect left/right FFC cable between T-con and left/right PCB one by one, and check which part is fault. Remove on pairs (CKV1 and CKVB1 and so on), the 7 resistors from fault side RM1-RM7. If needed, strap pairs coming from screen, on check points (CKV1 with CKVB1, CKV2 and CKVB2, and so on). You can also try to strap pairs to GND or Voff and see if better picture. Left PCB:

http://www.lcdrepairguide.com/tcon-panel/

140

LED/LCD TV T-CON & Screen Panel Repair Guide Right PCB:

On example below, was enough to cut CKV1-CKVB1 pair on fault side, by removing corresponding resistors, and the image came back to normal.

Some thin lines can appear sometimes. Just Strap CKV1-CKVB1 pair, and connect it to GND or VSS, and the lines will disappear.

http://www.lcdrepairguide.com/tcon-panel/

141

LED/LCD TV T-CON & Screen Panel Repair Guide

(4.7) Panel Screen: LSF320HJ01 T-CON: 2013_TCON_FOX_FT1 (BN41-01939) Fault: Horizontal lines are partial or whole of the screen. Repair procedure: Disconnect one by one the left/right FFC cable between T-con and left/right PCB and start the tv, this way you can easy check which part is fault. Level shifter IC is connected to left/right gate blocks, thru some zero ohms resistors fitted on T-con, thru left/right FFC cable, thru left/right PCB and extreme left/right flexible data driver circuit.

http://www.lcdrepairguide.com/tcon-panel/

142

LED/LCD TV T-CON & Screen Panel Repair Guide The clock signal pairs CKV1-CKVB1, CKV2-CKVB2, CKV3-CKVB3 and start signal STVP have check points on each side, but they are covered with paint and are very close to PCB's through-holes, so cutting the circuits is an hard operation.

Right PCB:

Left PCB:

http://www.lcdrepairguide.com/tcon-panel/

143

LED/LCD TV T-CON & Screen Panel Repair Guide The easiest way to repair the panel is to cut all 7 signal connectors from FFC cable, only on the side with fault, on T-con side.

If any horizontal thin lines remains over normal displayed image, clean the paint from check points on PCB side with fault, and strap with a wire the pair check points CKV1- CKVB1, see if lines disappeared. If not, connect the strapped to GND or Voff. Repeat procedure with pairs CKV2-CKVB2, and CKV3-CKVB3 for best results.

http://www.lcdrepairguide.com/tcon-panel/

144

LED/LCD TV T-CON & Screen Panel Repair Guide (4.8) Panel Screen: LTY320AP04 and LTZ320AP04 TCON: 320AP04S4LV1.5 and 320AP04S4LV1.7 Fault: Image trembling, double vertically, horizontal lines are partial or whole of the screen.

T-CON board is not detachable, and signals to left/right gate blocks, is transmitted thru left/right flexible data driver circuits. So, it's almost impossible to check which gate is fault. Usually, the right part faults more often, so you can start to disconnect signals from there. You must cut the connections between PCB's through-holes and check points, so the check points to remain connected to panel, as in picture.

http://www.lcdrepairguide.com/tcon-panel/

145

LED/LCD TV T-CON & Screen Panel Repair Guide Disconnect first the pair CKV1-CKVB1 and STVP and power the tv and check if any improvement. If not, try to strap CKV1-CKVB1. Check again. Try to connect CKV1- CKVB1 to GND. Disconnect the pair CKV2-CKVB2 and power the tv and check if clear display. If not, try to strap CKV2-CKVB2. Try to connect CKV2-CKVB2 to GND. If CKV2-CKVB2 faults, try to rebuild connection for pair CKV1-CKVB1. Your goal is to have best image you can achieve. Sometimes a thin horizontal line will be displayed even you have a perfect image. You can not eliminate this failing. The line is not noticeable from normal view distance, but its position depends on the position of faulty SR gate block. On image below, the line is very close to lower part of the screen.

http://www.lcdrepairguide.com/tcon-panel/

146

LED/LCD TV T-CON & Screen Panel Repair Guide (4.9) Panel Screen: LTA400HW03 J TCON: SH120PMB45V0.3 Fault: Image trembling, double vertically, horizontal lines are partial or whole of the screen.

Repair procedure: Disconnect left FFC between T-con and left PCB and power the tv. If you have now on right part of the screen a normal image, means that you have a fault in left side of the cell. If still a fault image, re-connect the left FFC and disconnect right FFC between T-con and left PCB and power the tv. If you have now on left part of the screen a normal image, means that you have a fault in right side of the cell. On upper image, there is a problem in the right side gate screen driver.

http://www.lcdrepairguide.com/tcon-panel/

147

LED/LCD TV T-CON & Screen Panel Repair Guide

On the side with problems remove from PCB the resistors RM1-RM7, in this order: first remove the CKV1 and CKVB1 resistors RM2 and RM5 and see any improvements. If not, remove CKV2 and CKVB2 resistors RM2 and RM6, check if any improvements, and if not, remove CKV3 and CKVB3 resistors RM3 and RM7. If still no improvements, remove STVP resistor, RM1 see picture.

http://www.lcdrepairguide.com/tcon-panel/

148

LED/LCD TV T-CON & Screen Panel Repair Guide You will have a normal picture now, but sometimes, you will have, on side with problems, a little ODD/EVEN lines distance. Strap with a wire, on check points, CKV1 with CKVB1, see if lines are now correct displayed. If not, strap with a wire, on check points, CKV2 with CKVB2, check, and repeat procedure with CKV3 with CKVB3. In example bellow, the pair CKV3- CKVB3 was strapped Connect check points by pair, but only if corresponding resistors were removed, or else you can burn the LEVEL SHIFTER IC from T-CON.

Sometimes, it will be better to put back the resistors for the blocks pair that have no problem. For example if only by disconnecting CKV3 and CKVB3 will solve image problem, that means pair 1 and 2 have no problems. Sometimes, if you have a bigger problem on cell circuit, the image will be correct but a / some thin line (s) will be displayed sometimes on screen, noticeable on lighter/darker images. Try to connect the pair that not works on GND or Voff. You can also raise Voff voltage with 3~5 volts to minus and the line will disappear. You have to do this on T-con Board, by raising the value of the resistor connected between FBN input of BiasPS/Level Shifter ICD1 - RT9979 and VOFFE.

http://www.lcdrepairguide.com/tcon-panel/

149

LED/LCD TV T-CON & Screen Panel Repair Guide

(4.10) Panel Screen: LSY320AN02 TCON: 320KSB_S2LV0.2 Fault: Screen is flickering, have a part/whole of the screen with doubled image, white ghosting on part / whole screen. T-CON board is not detachable, and signals to left/right gate blocks, is transmitted thru extreme left/right flexible data driver circuit. It's only one data driver flexible circuit, so, it's almost impossible to check which gate is fault (left/right).

http://www.lcdrepairguide.com/tcon-panel/

schematic4you.blogspot.com

150

LED/LCD TV T-CON & Screen Panel Repair Guide

But sometimes, if you detach and reverse the cell glass, you will see burned circuits on glass, so you can now know which side is fault. There are several connections that you have to cut on fault side: CKV1-CKVB1, CKV2-CKVB2, Vss, Vcom and Vcst.

The LEVEL SHIFTER is integrated in DC-DC source drive IC2 - RT69068, or SM4151. The IC's have same configuration, the only difference is the Vreff voltage (pin18) 3,3V or 5v.

http://www.lcdrepairguide.com/tcon-panel/

151

LED/LCD TV T-CON & Screen Panel Repair Guide

The connections from LEVEL SHIFTER and left/right gate blocks are made thru some 10 ohms resistors, RD10, RD14, RD9, RD11, RD13, RD12 and RD40, as in picture. CKV1 and CKV2 have 2 outputs on each side to double the current and to avoid LEVEL SHIFTER overheating. Repair Procedure: On fault side, you must cut the connections to left/right side, between PCB's through-holes and panel, so the check points to remain connected to working side of the panel, as in picture. PCB's through-holes, connects the other side of the cell with gate signals, so cutting the connections between resistors and through-holes, will cut signals on both sides of the screen. If no burned circuits http://www.lcdrepairguide.com/tcon-panel/

152

LED/LCD TV T-CON & Screen Panel Repair Guide on reverse side of the cell, first try to find out which pair creates problems on screen. First, remove RD10, RD14 and RD13, and check if CKV1- CKVB1 pair creates problems. If not, solder back the resistors, and remove RD9, RD11 and RD 12, and see if CKV2-CKVB2 pair creates problems. Cut only pair with problems, as in picture:

Attention: It's a very difficult procedure. Do not try it, if you don't have the good tools like: a thin & sharp knife/cutter, microscope or a power magnifier lens! Now you will have a clean and almost perfect image like the picture below:

http://www.lcdrepairguide.com/tcon-panel/

153

LED/LCD TV T-CON & Screen Panel Repair Guide (4.11) Panel Screen: LTJ400HM05 T-CON: 400HR42S4LV0A, 400HR42S4LV0B Fault: Screen is flickering, have a part/whole the screen with doubled image, upper side is discoloured and have visible horizontal lines. First step is to find which part of the screen is fault. This operation is very hard and the t-con is attached to cell glass thru data drivers. We don't have resistors on CKV-CKVB left-right pair signals, so we have to make a big effort to find out where is the fault. If you have a point where fault starts, you can try to see if a burned SR block can be seen on fault side. You can detach and reverse the cell glass, so you will see burned circuits on glass and you can now know which side is fault. There are several connections that you have to cut on fault side: CKV1-CKVB1, CKV2-CKVB2, CKV3-CKVB3 and STVP.

This operation is very hard (the screen is 40 inches), so do not try this if you don't have 2 clean and large tables, covered with some bubble wrap or white paper. If you cannot see any burned blocks, even with a microscope or magnifier, follow this step: a) Remove resistors R2, R127, R5 and R131 (zero ohms) for pair CKV1CKVB1 that connects LEVEL SHIFTER IC with both left-right SR blocks. R2 and R127 are connected parallel for CKVB1 signal. R5 and R131 are in parallel connection for CKV1. You can find the resistors in the left side of level shifter IC - SM4109, as in image below:

http://www.lcdrepairguide.com/tcon-panel/

154

LED/LCD TV T-CON & Screen Panel Repair Guide

Power on the tv and check if any improvements on screen. If not, solder back the resistors from 1st pair and remove CKV2 and CKVB2 resistors R7+R132 and R8+R133, power up the tv and check if any improvements.

If still no change, solder back the resistors from 2nd pair and remove CKV3 and CKVB3 resistors R9+R134 and R11+R136.

http://www.lcdrepairguide.com/tcon-panel/

155