Tech Troubleshooting – LED LCD TCON and panel Troubleshooting

Model: LCD, LED

Symptom: There are vertical lines in the top right part of the screen.

Solution: The LVDS cable can cause this symptom if it is not seated correctly. Check the position of the LVDS cable and the contacts. If it is seated correctly and you still see vertical lines, replace the LVDS cable.

Model: LCD, LED
Symptom: There are two RED vertical bars and RED smears around objects.

Solution: The LVDS cable can cause this if it is not seated correctly. Check the position of the LVDS cable and the contacts. If it is seated correctly and you still see red bars and smears, replace the LVDS cable.

Model: LCD,LED
Symptom: There are horizontal black and white bars across the screen in RF ONLY

Solution: As you can see, the OSD is not affected. That tells you that the panel is OK. Replace the main board.

Model: UN55C8000XFXZA
Symptom: The right side of the screen is darker than the left.

Solution: Bring up the Test Picture. If the symptom affects the Test Picture, replace the panel.

Model: LCD, LED
Symptom: There are vertical lines in the picture.

Solution: The LVDS cable can cause this symptom if it is not seated correctly. Check the position of the LVDS cable and the contacts. If it is seated correctly and you still see vertical lines, replace the LVDS cable.

Model: PN42C430A1DXZA
Symptom: The picture has blemishes.

Solution: If the symptom affects the Test Picture, replace the panel.

Model: LNT5271
Symptom: The right side of the screen has horizontal lines.

Solution: In the example above, the line distortion is affecting the menu. Bring up the OSD menu. If the symptom affects the menu, replace the T-Con board.

Model: UN46D6500VFXZA
Symptom: Ghosting image (Double Image)

Solution: Replace the T-Con and LVDS.

Model: LN55C650
Symptom: Colored Vertical lines

Solution: Bring up the “Picture Test”. If the lines appear in the Picture Test, the cause is a bad panel. If the lines do not appear, disconnect all signal sources and check again. If the lines are still in the Picture Test, change the main board. If the lines are gone, then a signal 
source is causing the problem.

Sony LCD Projection television KDF-55WF655 - KDF-60WF655 – Diagnostic indication – Led blinking and causes – Lamp hour reset – Power supply circuit

Diagnostic Test Indicators
When an error occurs, the POWER/STANDBY or LAMP LED will flash a set number of times to indicate the possible cause of the problem. If there is more than one error, the LED will identify the first of the problem areas. If the errors occur simultaneously, the one that corresponds to the fewest flashes is identified first.
Results for all of the following diagnostic items are displayed on screen. No error has occurred if the screen displays a “0”.

Diagnostic Item Description	Number of times STANDBY or LAMP LED lamp flashes	Probable Cause	Detected Symptoms
Lamp cover error	3 times	- Lamp cover is not fastened securely	- No picture/No sound
Fan error	4 times	- Fan1-4 Power is not supplied.(G2 board) - Fan connector is not seated securely - Fan caught wires or harnesses	- No picture/No sound
Temp error	4 times	- Internal temperature is too high - IIC-E line connector is not seated properly (WE:H3 board, WF/XS:H4 board)	- No picture/No sound
Lamp driver error	5 times	- Lamp driver defect	- No picture/No sound
Low B error	6 times	-No "DD 6V " output (G1 board)	- No picture/No sound
Audio error	7 times	- Short-circuit of Audio power supply line (KD board, G1 board) - Blowout of a fuse (F4702,F4703,F4704 on KD board) - IC failure (IC4703,IC4708,IC4710 on KD board)	- No picture/No sound
D-OVP error	8 times	- Overvoltage of +3.3V or +2.5V (A board, B board)	- No picture/No sound
ATSC-OVP error	10 times	-No "DTL MODULE 5V " output (G1 board, G2 board)	- No picture/No sound
Lamp error	LAMP-LED is ON.	- Lamp is dead	- No picture/No sound

Releasing the POWER/STANDBY LED Flash
Unplug the power cord from the outlet to temporarily stop the POWER/STANDBY lamp from flashing.
Self-Diagnosis Screen Display
For failures that are difficult to reproduce, or accompany occasional power off and/or picture mute, the Self-Diagnosis screen display is useful to specify the cause.
To Bring Up Screen Test
In standby mode, press the buttons on the Remote Commander sequentially, in rapid succession, as shown below:
1. Display  > Channel 5 > Sound Volume - > Power ON

Clearing the Result Display
To clear the result display to “0”, press the buttons on the Remote Commander sequentially when the diagnostic screen is displayed, as shown below:
1. If the screen is already displayed, proceed to step 3. If not, Power off (Set to Standby model).
2. Press Display > Channel 5 > Sound Volume - > Power ON
3. Press Channel 8 > ENTER
Clearing the Self-Diagnostic Screen
The self diagnosis screen display is cleared by turning off the set using the Remote Commander or the power switch.

Self-Diagnosis Function Operation

Blinking	Causes	Description
3	Lamp cover	The rib at the back of the lamp cover closes the SW on the T board to ground pin 3 of CN8001. It is monitored by the DE-micro (pin 94 of IC6902) and turns off the lamp when it is opened.
4	Fan	Fan rotation is detected by "FAN-PROT" and the DE-micro (pin 92 of IC6902) turns off the lamp when it is "high".
4	Temp	When the temperature sensor on the H3 board (WE models) or H4 board (WF/XS models) detects high temperature, or IIC-E line connector (CN6022:G2 board, CN44:H3board/H4board) is not seated securely, the DE-micro turns off the lamp.
5	Lamp driver	When the "LAMP-PROT" (pin 95) is low, the lamp is not turned on. If the "LAMP-HV-DET" (pin 96) is low at the same time, it is classified as no high voltage of the lamp driver.
6	Low B error	When no "DD 6V " is detected, pin 129 of TV-micro is low and it turns off the main power.
7	Audio	When DC voltage is detected at the speaker or woofer outputs, pin 128 of TV-micro is low and it turns off the main power.
8	D-OVP	When overvoltage of "+3.3V" or "+2.5V" is detected, pin 126 of TV-micro is low and it turns off the main power.
10	ATSC-OVP	When no "Digital Module 5V" is detected, pin 127 of TV-micro is low and it turns off the main power.
LAMP	Lamp	When the "LAMP-PROT" (pin 95) is low, the lamp is not turned on. If the "LAMP-HV-DET" (pin96) is high at the same time, it is classified as no lamp or a dead lamp.

Reading and Resetting Lamp and Panel time
Use the following to determine the lamp and panel time of a set.
Screen Display Method
In standby mode, press the buttons on the Remote Commander sequentially, in rapid succession, as shown below:
1. Press Display > Channel 5 > Sound Volume + > Power ON
2. To enter the DE-micro service menu, press Jump 3 times.
3. To display the Lamp time, press Channel [2] 9 times.

To reset the lamp time press Channel 3 > Mute > Enter .
WRI-EXE(Character color is Red) is momentarily displayed and LampTM is reset to “0”.

Exiting Service Mode
After completing the changes exit service mode by turning off the set using the Remote Commander or the power switch.

POWER SUPPLY CIRCUIT 

CLICK ON THE IMAGE TO ZOOM IN 

SONY KDL- 48R550C - KDL-48R555C – Service mode – Power LED blinking code – firmware update procedure

SELF DIAGNOSIS FUNCTION

If an error symptom cannot be reproduced, the remote commander can be used to review the failure occurrence data stored in memory to reveal past problems and how often these problems occur.

DIAGNOSTIC TEST INDICATORS
When an error occurs, the STANDBY LED will flash a set number of times to
indicate the possible cause of the problem.
If there is more than one error, the LED will identify the first of the problem areas.
Result for all of the diagnostic items are displayed on screen.
If the screen displays a “0”, no error has occurred .

LED BLINKING CODES AND CAUSES 

The Number of Standby LED (RED blinking)	Error Detection	Error Location
2	Main Power Error	AC adapter Error
3	Audio Error	B board Error
4	Panel Power Error	B board Error
5	Panel I2C COMM Error	B or Source board Error
6	Backlight Error	B  board Error
7	Subwoofer Error	B board Error

SELF-DIAGNOSTIC SCREEN DISPLAY

For errors with symptoms such as “power sometimes shuts off” or “screen sometimes goes out” that cannot be confirmed, it is possible to bring up past occurrences of failure

for confirmation on the screen:

To Bring Up Screen Test
In standby mode, press buttons on the remote commander sequentially in rapid succession as shown below:

DISPLAY > CHANNEL 5 > VOLUME - > POWER ON

Since the diagnostic results displayed on the screen are not automatically cleared, always check the self-diagnostic screen.
After you have completed the repairs, clear the result display to “0”.
Clearing the Self Check Diagnostic List
1. Error history and Error count : Press the Channel 8 => Channel 0 .
2. Panel operation time : Press the Channel 7 => Channel 0 .
Exiting the Self-diagnostic screen
To exit the Self Diagnostic screen, turn off the power to the TV by pressing the POWER button on the remote or the POWER button on the TV.

HOW TO ENTERING SERVICE MODE
1) Turn on the main power switch to place this set in standby mode.
2) Press the buttons on the remote commander as follows, and entering service mode.

INFORMATION > CHANNEL 5 > VOLUME - > POWER ON

ACCESSING SERIAL NUMBER EDIT
1) Press RIGHT button on Remote to edit Serial Number.

2) Press UP or DOWN button to select number.
The font color of YES is change to black when it is selected.

3) Serial Number can be set ONLY ONCE

# After user input data , press <Enter>.
# Pop dialog will appear to inform user to confirm data.
# Press RIGHT or LEFT button to select YES or NO.
# Select YES if input data is correct.
# Select NO if input data is incorrect.
# Press <Enter> to save answer

4) If YES is selected, the input data is saved into EEPROM.

# SERIAL NUMBER EDIT is grayed out and the serial number that has been input is displayed.

# User will not able to edit anymore.

5) If NO is selected, the input data is not saved into EEPROM.

# The serial number that has been input is displayed.
# User can still edit the Serial Number.

ACCESSING MODEL NAME EDIT

1) Press button on Remote to edit Model Name.

2) Press UP or DOWN button on Remote to select character.

3) Model Name can be set ONLY ONCE.

# After user input data , press <Enter>.
# Pop dialog will appear to inform user to confirm data.
# Press UP or DOWN  button to select YES or NO.
# Select YES if input data is correct.
# Select NO if input data is incorrect.
# Press <Enter> to save answer.

4) If YES is selected, the input data is saved into EEPROM.

Model Name EDIT is grayed out and the model name that has been input is displayed.

User will not able to edit anymore

5) If NO is selected, the input data is not saved into EEPROM.

# The model name that has been input is displayed.
# User can still edit the Model Name.

How to update TV Software
1. Insert USB pen drive to USB port of TV with updated firmware version

2. Pull Out the AC plug and wait 10 second (considering the charge of AC adaptor).
3. Press and hold the side Power Key for 5 seconds and re-insert the AC plug at the same time.

4. After 20-30 seconds, the LED is turn to Amber and blink.

LED blinking indicates “Under SW Update”.
IMPORTANT NOTE: PLEASE DO NOT PULL OUT THE AC PLUG DURING THIS STATE.

5. After 1-2 minutes, LED blinking will finish. Please press <Power> key.
If “SONY” Logo displays the screen and LED is turn to GREEN, Software update is success!

6. Pull out the USB pen drive from TV.

7. TV on standby and Enter Service Mode. Press “i+ (info)”, “5”, “Volume +” then “TV power” on remote.

8. Select “Status Information” item and Press <Enter> key.

9. Confirm SW,NVM,Boot,Panel ID,PQ,AQ Version.

10. Press <Return> to back Service Mode Menu.

11. Select “UART Selection” by UP/DOWN  key, and select “No log” item by LEFT/RIGHT Key and press <Enter> key for Selection.

12. Pull Out the AC plug and wait 10 second (considering the charge of AC adaptor).

13. Insert the AC plug.

14. Press <Power> Key to turn on the TV.

Tech troubleshooting – TCON board – Backlight Dimming through TCON board – Deference between TCON and 3D TCON board - Purpose of LED in TCON board

T-CONs Deliver P-DIM (Dimming Signals) to the Inverter
P-DIM (Called PWM-DIM which stands for Pulse Width Modulation Dimming) is a signal from the Main board that is generated by monitoring the Video content’s average brightness level. It is then sent to theBacklight driver IC to control the brightness of the backlights accordingly. The maximum brightness level isestablished by the customer through the Customer’s Menu in the Video selection under Backlights. Thissetting has a bar graph that can be set from 100% down to 0%.
The P-DIM signal will follow the percentile setting proportionately. The range of P-DIM is 3.3V to 0V. Sowhen the bar graph is set for 100% the P-DIM line will be 3.3V and the backlight brightness will be maximum.
Most often the P-DIM line is routed directly from the Main board to the Power Supply, it is routed through thePower Supply directly to the Inverter and then to the Backlight driver IC.
(If the Power Supply has an on-board Inverter, the Driver IC is on the Power Supply itself). However,on some sets, the P-DIM line is routed to the T-CON board.The T-CON then generates a control signal that is then routed to the Inverter and then to the Driver IC.

Here is the T-CON from a 42SL80. The connector in the bottom left goes to the Inverter and carries the P-DIM Control Signals. The P-DIM signal from the Main board is brought in on pin 8 of the left LVDS and is then routed to the large MCM IC. Then it is output through the 8 pin IC on the bottom left to the connector.

Troubleshooting the P-DIM Line when Routed Through the T-CON

When troubleshooting this type of P-DIM routing, you will still use the same procedure. Enter the Customer’s Menu and go to Video, then select Backlights. Place a DC voltage meter on the output from the T-CON CN3or the input to the Inverter CN2. You can check either of the two pins. While adjusting the Backlights from 100% down to 0% the P-DIM lines will vary accordingly from 2.4V at 100% down to 0.67V at 0%.

Pin	Label	Run	Diode Test
1	n/c	n/c	n/c
2	SCAN 1	0.67V>2.4V	Open
3	SCAN 2	0.67V>2.4V	Open
4	Gnd	Gnd	Gnd

Function of the Blue LED on Some T-CON Boards

On some of the LCD T-CONs there is a bright Blue LED that turns on for a brief moment during turn on and then it shuts off. These are only used in set with Florescent Bulbs as the Backlights. As in the example below (from 42LG60), it shows the Blue LED is on the lower right hand side.
The purpose of LD1 is to help excite the Selenium gas in one of the backlight bulbs. This helps the bulb to light when there’s little room light by pre-exciting the gas. With little room light, the gas in the florescent Bulbs tends to lie dormant, (Little movement). This LED help to get the Electrons moving just before the point of firing (turning on).  There is a small hole under LD1. This is how the light goes through the board to get to the Bulbs. (There is a hole in the back metal cover of the panel as well).

Differences between a T-CON and a 3D FRC T-CON

The typical T-CON’s basic responsibilities are to drive the TFT panel and to generate panel voltages.The video input through the LVDS cables is already formatted for usage by the T-CON board.

Typical T-CON

The 3D FRC T-CON basic responsible to; generate panel voltages. When not in 3D it generates the Tru-Motion, Motion Estimated Motion Compensated (MEMC) frames. When in 3D it unpacks 3D frame content. It generates 3D sync which is used by the 3D Shutter glasses. It formats the video for usage by the panel driver circuit and it drives the panel. The video input through the LVDS cables is 24 bit LVDS video.

3D FRC T-CON

Since the 3D FRC T-CON does so much more work than a standard T-CON, it has an additional 12V input via a two wire connector. The voltage is from the same source as a typical TCON board. It comes from the  power supply and switched on/off by the Main board.