Panasonic TH-L55WT50M, Service Manual, Page: 19 / 84

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7.2. Power LED Blinking timing chart
1. Subject
Information of LED Flashing timing chart.
2. Contents
When an abnormality has occurred the unit, the protection circuit operates and reset to the stand by mode. At this time, the
defective block can be identified by the number of blinks of the Power LED on the front panel of the unit.
7.3. LCD Panel test mode
Purpose:
To find the possible failure point where in LCD Panel or Printed Circuit Board when the abnormal picture is displayed.
How to Enter:
While pressing [VOLUME ( - )] button of the main unit, press [OPTION] button of the remote control three times within 2
seconds.
How to Exit:
Disconnect AC plug from wall outlet.
How to confirm:
If the abnormal picture is displayed, go into LCD Panel test mode to display the several test patterns.
And then, judge by the following method.
Still abnormal picture is displayed: The cause must be in LCD Panel.
Normal picture is displayed: The cause must be in A board.
Remarks:
The test pattern is created by the circuit in LCD Panel.
In LCD Panel test mode, this test pattern is displayed unaffected by signal processing for RF or input signal.
If the normal picture is displayed, LCD Panel must be okay and the cause of failure must be in A board.
Blinking Times Contents Check point
1 BACK LIGHT SOS LCD PANEL
P-Board
3 STM IROM BOOT PROGRAM SOS A-Board
P-Board
7 SUB 3.3V SENSE SOS A-Board
8 SOS (T-CON power) A-Board
9 SOUND SOS A-Board
Speaker
10 ZWEI/FRC SOS A-Board
12 BE SOS A-Board
13 EMERGENCY SOS A-Board
20 2nd BOOT PROGRAM SOS
(Watchdog timer over flow) A-Board
21 2nd BOOT PROGRAM SOS
(System error) A-Board
22 2nd BOOT PROGRAM SOS
(Main system bus freeze) A-Board
23 2nd BOOT PROGRAM SOS
(Accidental interrupt signal) A-Board
24 2nd BOOT PROGRAM SOS
(NAND Flash memory data transfer error finish) A-Board
25 2nd BOOT PROGRAM SOS
(Unsupported NAND Flash memory) A-Board