PANASONIC TX-LR42U20 SERVICE MODE AND STANDBY LED BLINKING CODE

PANASONIC TX-LR42U20 Service mode and standby led blinking code

Contents of this article 

• How to enter to service mode 
• How to access hotel mode
• Power light blinking and causes
• Voltages at different points   

PANASONIC TX-LR42U20  

FACTORY MODE AND POWER LED BLINKING AND CAUSES 

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

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

SRV-TOOL
How to access
1. Select [SRV-TOOL] in Service Mode.
2. Press [OK] button on the remote control.

How to 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.

Service Mode Adjustment
Set timer to 30min, press the ‘RECALL’ button on the remote control and press ‘-’ vol button on the LCD panel.
Press button R and G for adjustment.
Self Check Mode
1. Press the ‘MENU’ button (on the remote control) and the ‘DOWN’ button on the LCD panel.
2. Press ON/OFF button on the panel to Exit.
Hotel Mode Adjustment
1. Press the ‘VOLUME DOWN’ button on the TV panel and simultaneously press the AV button on the remote control 3 times to enter Hotel Mode.
2. Set Hotel mode ‘on/off’, then press ‘EXIT’ to come out.
Hotel Mode
Restrict a function for hotels.
In order to display the Hotel mode setup menu, please enter the following command (within 2 second). [TV] : Hold Vol [Down] + [Remote] : Press AV button 3 times.

Troubleshooting 
Use the self-check function to test the unit.
1. Checking the IIC bus lines
2. Power LED Blinking timing
How to Check 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.

Power LED Blinking and causes 

When an abnormality occurs, the protection circuit will operate and reset the unit to stand by mode. During this time, the defective block can be identified by the number of blinking times of the Power LED on the front panel of the unit as follow:

Blinking times	Contents	BOARD
1	Inverter_SOS	P BOARD
2	FAN_SOS	A BOARD
3	SOS	A BOARD
4	DTV_9V	P/A BOARD
5	MAIN_9V	A BOARD
6	SUB_5V	A BOARD
7	SUB_3.3V	A BOARD
8	MAIN_3.3V	A BOARD
9	SOUND_SOS	A BOARD
10	HQ1L_SOS / ZWEI_SOS	A BOARD
13	EMERGENCY SOS	A BOARD
14	Audio PWM SOS	A BOARD

Measurements and Adjustments
Voltages of A-board
Set A-Board to a dummy set and check the satisfaction with the specified voltage as following.

Power Supply Name	Measurement Point	Specification (V)
SUB1.8V	TP5601	1.74 - 1.90
SUB1.2V	TP5600	1.18 - 1.32
SUB3.3V	TP5602	3.19 - 3.46
SUB5V	TP5200	4.9 - 5.1
SUB9V	TP5220	8.82 - 9.18
STB5V	TP5400	4.9 - 5.1

Voltages of P-board
Set IP-Board to a dummy set and check the satisfaction with the specified voltage as following.

Power Supply Name	Measurement Point	Normal Condition
P24V	TP7503	24 ± 1.2 V
17V	TP7502	18 ± 2 V
DTV12V	TP7501	12 ± 0.6 V
TUNER6V	TP7601	6.1 ± 0.3 V
DC390V	TP7201	390 ± 10 V