PANASONIC TC-L37U22 SERVICE MODE - LED BLINKING AND SOLUTION - VCOM ADJUSTMENT

PANASONIC TC-L37U22 SERVICE MODE - LED BLINKING AND SOLUTION - VCOM ADJUSTMENT

PANASONIC TC-L37U22 

SERVICE MODE - LED BLINKING AND SOLUTION 

V COM ADJUSTMENT 

How to enter to Service Mode
While pressing [VOLUME ( - )] button of the main unit, press [INFO] button of the remote control three times within 2 seconds.

Key command
[1] button...Main items Selection in forward direction
[2] button...Main items Selection in reverse direction
[3] button...Sub items Selection in forward direction
[4] button...Sub items Selection in reverse direction
[VOL] button...Value of sub items change in forward direction ( + ), in reverse direction ( - )

How to exit
Switch off the power with the [POWER] button on the main unit or the [POWER] button on the remote control.

Display of SOS History
SOS History (Number of LED blinking) indication. From left side; Last SOS, before Last, three occurrence before, 2nd occurrence after shipment, 1st occurrence after shipment.
This indication except 2nd and 1st occurrence after shipment will be cleared by [Self-check indication and forced to factory shipment setting].
POWER ON TIME/COUNT
Note : To display TIME/COUNT menu, highlight position, then press MUTE for 3sec.
Time : Cumulative power on time, indicated hour : minute by decimal
Count : Number of ON times by decimal
Note : This indication will not be cleared by either of the self-checks or any other command.
Exit
1. Disconnect the AC cord from wall outlet.

Hotel mode
1. Purpose
Restrict a function for hotels.
2. Access command to the Hotel mode setup menu In order to display the Hotel mode setup menu, please enter the following command (within 2 second). [TV] : Vol. [Down] + [REMOTE] : INPUT (3 times)

Data Copy by SD Card
Purpose
(a) Board replacement (Copy the data when exchanging A-board):
When exchanging A-board, the data in original A-board can be copied to SD card and then copy to new A-board.

(b) Hotel (Copy the data when installing a number of units in hotel or any facility):
When installing a number of units in hotel or any facility, the data in master TV can be copied to SD card and then copy to other TVs.

Preparation
Make pwd file as startup file for (a) or (b) in a empty SD card.
1. Insert a empty SD card to your PC.
2. Right-click a blank area in a SD card window, point to New, and then click text document. A new file is created by default (New Text Document.txt).
3. Right-click the new text document that you just created and select rename, and then change the name and extension of the file to the following file name for (a) or (b) and press ENTER.
File name:
(a) For Board replacement : boardreplace.pwd
(b) For Hotel : hotel.pwd
Note: Please make only one file to prevent the operation error.
No any other file should not be in SD card.

Data copy from TV set to SD Card
1. Turn on the TV set.
2. Insert SD card with a startup file (pwd file) to SD slot.
On-screen Display will be appeared according to the startup file automatically.
3. Input a following password for (a) or (b) by using remote control.
(a) For Board replacement : 2770
(b) For Hotel : 4850
Data will be copied from TV set to SD card.
It takes around 2 to 6 minutes maximum for copying.
4. After the completion of copying to SD card, remove SD card from TV set.
5. Turn off the TV set.
Note: Following new folder will be created in SD card for data from TV set.
(a) For Board replacement : user_setup
(b) For Hotel : hotel

Data copy from to SD Card to TV set
1. Turn on the TV set.
2. Insert SD card with Data to SD slot.
On-screen Display will be appeared according to the Data folder automatically.
3. Input a following password for (a) or (b) by using remote control.
(a) For Board replacement : 2771
(b) For Hotel : 4851
Data will be copied from SD card to TV set.
4. After the completion of copying to SD card, remove SD card from TV set.
(a) For Board replacement : Data will be deleted after copying (Limited one copy).
(b) For Hotel : Data will not be deleted and can be used for other TVs.
5. Turn off the TV set.
Note:
1. Depending on the failure of boards, function of Data copy for board replacement does not work.
2. This function can be effective among the same model numbers.

Check of the IIC bus lines
How to access
Self-check indication only:
Produce TV reception screen, and while pressing [VOLUME ( - )] button on the main unit, press [OK] button on the remote control for more than 3 seconds.
Self-check indication and forced to factory shipment setting:
Produce TV reception screen, and while pressing [VOLUME ( - )] button on the main unit, press [MENU] button on the remote control for more than 3 seconds.

Exit
Disconnect the AC cord from wall outlet.

SELF DIAGNOSTICS

When an abnormality is detected, the protection circuit resets the unit to the standby mode. The (A) board microprocessor causes the power LED to blink a number of times. The number of blinks points to the board where the abnormality is detected.

TC-L37U22 Power LED blinking Codes

Blinking times	Contents	BOARD
1	BACK LIGHT_SOS	P BOARD LCD Panel
3	PANEL POWER_SOS	A BOARD
4	DTV12V_SOS	P/A BOARD
7	SUB 3.3V_SENSE	A BOARD
9	SOUND SOS	A BOARD
13	EMERGENCY_SOS	A BOARD

Protection circuits are incorporated in the unit to prevent the failure of a single circuit or component from creating catastrophic damage. A shutdown condition occurs when a there is an over voltage, a short or a drop in any of the voltage lines.

1 BLINKS

When the power button is pushed , IC8001 outputs the TVSUB ON command to turn on the main power supply and output the power_on voltages. Upon confirmation of the output voltages of the power supply, IC8001 sends the Inverter_ON command to P board. On the power supply board, the Inverter_On command enters IC7800, the inverter control IC. IC7800 then outputs the trigger that turns on the oscillator IC7801. The sine wave output of the oscillator is provided to the switching transistors connected to T7801 to generate a magnetic field. The AC output at the secondary of T7801 is provided to the LCD panel via the connectors P5, P6, P7 and P8 to power the backlights.
When the inverter is operating properly, the inverter SOS input of the micro is pulled low. If a malfunction occurs, a detection circuit located within IC7800 sends out a SOS command to alert the inverter control IC, IC7800. IC7800 conveys the SOS message to the main micro IC8001 by keeping the inverter SOS input high. The TV shuts down and the power LED blinks 1 time

3 AND 7 BLINKS

The A Board is responsible for the regulation, distribution and dissemination of all secondary voltages derived from the DTV12V output of the P Board. When the unit is powered, the 12V output of the P board biases the transistor Q5613 into operation, causing its collector to become “low”. As a result the transistors Q5612 turns off. The high at the collector of Q5612 causes IC5606, IC5608, IC5610, and D5670 to operate and provide the SUB5V, 1.8V, 1.2V, and SUB3.3V output.
If a malfunction occurs and the SUB5V, 1.8V, and 1.2V are not present, IC4700 detects the loss of voltage and provides an output to IC8001 to shut the unit down. The power LED blinks 3 times. The SUB3.3V is monitored directly by the CPU, IC8001. If it is shorted or missing, the unit shuts down and the power LED blinks 7 times. IC8001 turns off the AC power by disabling the SUB_ON command that turns on the AC relay.

4 BLINKS

When the unit is turned on, the DTV source of the P board is provided to the A board for conversion into other voltages. A zener diode at the base of transistor Q5613 protects against over-current condition. When the DTV12V source drops to a predetermined level, the zener diode turns off causing Q5613 to turn off and Q5612 to turn on. The input to IC8001 goes low resulting in the shutdown of the unit and 4 blinks of the power LED.

9 BLINKS

On the A board, the MPU (IC8001) monitors the operation of the audio power amplifier IC2106. If IC2106 or one of the speakers develops a short circuit, a high is output to IC8001 to trigger a shutdown and 9 blinks of the power LED. When a 9 blinks shutdown occurs, disconnect the speakers one at a time and turn the unit on. If the problem remains, replace the A board. If it goes away, the disconnected speaker is the problem

In the event the unit shuts down and the power LED blinks nine times, check for an improper connection of connector A21/TC05. The shutdown occurs due to no communication between the TC-Board and A-Board. A defective TCON board may also be the cause for the blink code.

VCOM Adjustment (Flicker Adjustment)
General information:
After replacing the LCD panel, TC board (T-CON) or both, the [VCOM] Adjustment has to be done.
Data for VCOM Adjustment is different depending on the LCD panel and the data stored in the TC board.
Adjustment procedures are as follows.
1. Enter the service mode
While pressing the [ VOLUME ( - ) ] button of the main unit, press the [ INFO ] button of the remote
control three times within 2 seconds.
2. Go into VCOM value indication
Press the [1] button on the remote control to select [ADJUST].
Press the [3] button on the remote control to select [VCOM]
The adjustment value of [VCOM] is displayed.
3. Flicker Confirmation
Press the [5] button on the remote control to display the flicker adjustment screen.
Confirm if flicker can be seen.
No flicker --- Exit from the Service mode.
Flicker --- Adjustment has to be done.
4. VCOM Adjustment (Flicker Adjustment)
This procedure writes into the EEPROM the correct data so the panel does not flicker.
Press the remote control [+/ -] button to delete or minimize the flicker.

Press the [ OK ] button to automatically write the data into the EEPROM (IC9206).
Caution:The data can be written into the EEPROM only 15 times. Don’t press the [ OK ] button many times.
If the data cannot be written, replace the TC board or IC9206 with a new one.
5. Exit from Service mode
Press the [ POWER ] button on the main unit or the [ POWER ] button on the remote control.