Tuesday, 10 November 2020

How to troubleshoot Panasonic Plasma (GPH10DU Chassis) PDP 2007 10th generation TVs – Models TH42PX75U, TH50PX75U, TH42PX77U, TH50PX77U - Part-1

 

Products powered by electricity should be serviced or repaired only by experienced professional technicians. Any attempt to service or repair the product or products dealt with in this service information by anyone else could result in serious injury or death.

How to determine the defective board.

Verification of voltages

Normally, when there is a power problem, shutdown occurs immediately.  So, to resolve a power problem, voltage checks are necessary before shutdown.

Check if the power comes up after disconnecting the suspected board.  If power comes up  after disconnecting a board, the board is defective.   “Power comes up” equals “no shutdown”.

After exchanging the following boards, voltage adjustment is required.

P board, SC board, SS board,

Defective Board - A Board.

To confirm this, unplug the TV and disconnect connectors A5, A6, and A7 from the A board.

The TV should turn on automatically and display a white screen.

Warning: Disconnect AC Power prior to making any disconnection or connection.


Defective Board (Possibility)- P, D, A, SC, SS Board (P > A, D, SC, SS)

[Always Disconnect AC Power prior to making any disconnection or connection.]

(*1) = The reference number of the sustain data connector is different in some of the models:

TH-42PX75U = SS23

TH-42PX77U = SS23

TH-50PX75U = SS33

TH-50PX77U = SS33

Defective Board-D Board:  Trouble Mode-3.3V down SOS

LED Blinking codes detail

LED blinks 4 times

Defective Board-Primarily P board or possible D board:  Trouble Mode-Power Supply SOS

Turn the unit on.  Is pin 12 of CN P25 of the P board high before shutdown?

If no, D board is defective.

If yes, P board is defective.

LED blinks 5 times (Quick Troubleshooting)

Defective Board-D, P, C, SC, SS board or Panel (DDIC)*1:  Trouble Mode-5V SOS

(*1) = Data Driver IC

LED blinks 5 times

LED blinks 5 times-D, P, C, SC, SS board or Panel:  Trouble Mode-5V SOS

How to find defective board.

LED blinks 6 times- Defective Board (Possibility)- SC, SS, D, P Board (SC > SS, D, P )

Trouble Mode-SC Energy Recovery SOS

How to find defective board.

LED blinks 6 times-Defective Board (Possibility)- SC, SS, D, P Board (SC > SS, D, P ):  Trouble Mode-SC Energy Recovery SOS

LED blinks 7 times-Defective Board (possibility):  Trouble Mode-SC Floating voltage SOS

How to find the defective board.

LED blinks 8 times-Defective Board (possibility):  SS, SC, D, P board (SS>SC,D,P)/PDP: Trouble Mode-SS Energy recovery SOS/Panel

LED blinks 10 times before pressing the power button-Defective Board-P, A Board:  Trouble Mode-SUB 5V SOS, Main 3.3V SOS DTV 9V SOS, Tuner Power SOS

How to find the defective board.



LED blinks 12 times-Defective Board (Possibility)- Speakers, A Board:  Trouble Mode-Sound SOS

No Power/Dead Unit-troubleshooting

No Picture from one or all inputs (OSD and Sound OK)- All models

No Picture / No OSD-All Models

No Sound

There are two kinds of picture problem.  1) Abnormal picture. 2) No picture.

Basic concept of determining the defective board.

1) Which area is the symptom displayed on the screen?

A. Part of the screen

B. All over the screen

Adjustment after PCB exchange.

After exchanging the following boards, voltage adjustment is required. P board, SC board, SS board.

Diagnosis by Test Pattern When OSD is Available.

Picture problem such as “Picture Noise and or Vertical Line” displayed all over the screen is mainly caused by a defective D or A board. The “internal Test Pattern Generator” can help determine whether to replace the D or A board. The test patterns are created by the D board. Follow the steps below to confirm the operation of the D or A boards.

Diagnosis by Removing the A5 Connector.

Symptom such as “No picture, No OSD, Sound OK” is mainly caused by a defective A or D board. The internal pattern generator cannot be accessed due to the loss of OSD. This method makes it possible to determine whether the A board or the D (SC,SS) is defective.


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