Panasonic GPH10DU, TH-42PX75U, TH-50PX75U, TH-42PX77U, TH-50PX77U Service Manual

Technical Guide

Plasma

(GPH10DU Chassis)

Troubleshooting Handbook

Model : TH--

Model : TH

TH--

Panasonic Services Company

42PX75U

50PX75U

42PX77U

50PX77U

National Training

Prepared by

Panasonic Service and Technology Company

National Training

Warning

This service information is designed for experienced repair technicians only and is not designed for use by the general public. It does not contain warnings or cautions to advise non-technical individuals of potential dangers in attempting to service a product. 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.

Table of Contents

Subject Page

Troubleshooting Shutdown Problems 5 Power LED’s Response to Shutdown Operation 6 LED blinks 1 time 7 LED blinks 2 times 8 LED blinks 3 times 9 LED blinks 4 times 10 LED blinks 5 times (Quick Troubleshooting) 11 LED blinks 5 times 12 LED blinks 6 times 13-14 LED blinks 7 times 15 LED blinks 8 times 16 LED blinks 9 times 17 LED blinks 10 times before pressing the power button 18 LED blinks 10 times after pressing the power button 19

LED blinks 12 times Dead part I Dead part II

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

20 21 22 23

Subject

No Picture\No OSD No Sound (TH-42PX600U) Troubleshooting for Picture Problems Diagnostic Method for Troubleshooting PDP

Television Diagnosis by Test Pattern When OSD is Available

Diagnosis by Removing the D5 Connector Troubleshooting for Picture Trouble Diagnosis for Picture Problem (All Over the Screen) Diagnosis of Vertical Line Problem Picture Trouble at Upper or Lower half Picture Trouble at Right or Left half (50 Inch) Picture Trouble at Right or Left half (42/37 Inch) Picture Trouble in 50 Inch Models Picture Trouble all Over the Screen Examples of Symptoms and Remedies Reset and Self-check Procedure Driver Setup Adjustment Board Layout and Part Numbers

Page

24 25 27 28

29 30 31 32~35 36 37 38 39 40 41 42~48 49 51~52 53~56

Introduction

1. Basic concept of how to determine the defective board

1) 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.

2) 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”.

2. Troubleshooting Video and Audio problems

3. Examples of video problems

4. Adjustment after PCB exchange

1) After exchanging the following boards, voltage adjustment is required.

P board, SC board, SS board => Please refer to the “Service Manual”.

Troubleshooting Shutdown Problems

Power LED’s Response to Shutdown Operation

LED

Blinking

times

1 2 3 4

6 7

3.0sec (interval)

Contents Check Point

STB5V sense time out 15V line abnormality

3.3V line abnormality Power Supply abnormality

5V line abnormality Scan Driver (1)

abnormality/DRV_RST Scan Driver (2) abnormality

Light No Light

A Board D Board (15V SOS) D Board (3.3V SOS) P Board (Power SOS)

D Board (5V SOS) SC,SU,SD Board (SC Energy recovery circuit) C and D Boards Connections SC,SU,SD Board (SC Floating voltage area)

8 9

10 12

Sustain Driver abnormality Panel Status abnormality

REG. voltage abnormality

Voltage for sound abnormality

SS Board (SS Energy recovery circuit)/Panel D Board (Panel Status DET)

A Board (A SOS, Tuner SOS)/SC/SS A Board (Sound SOS), C boards connections

LED blinks 1 time

Trouble Mode

Communication Error

Defective Board

A Board

Warning: Disconnect AC Power prior to

making any disconnection or

connection.

The A board is defective. 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.

A5, A6, and A7

location

Note: CN = Connector

LED blinks 2 times

Trouble Mode

15V down SOS

Defective Board (Possibility)

P, D, A, SC, SS Board (P > A, D, SC, SS)

Warning: 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:

Unplug the TV, reconnect CN A5, A6, and A7 and disconnect CN SC20 and SC2. To isolate the SC board.

Turn the unit on.

Does the power LED

stay on?

Unplug the TV, reconnect SC20 and SC2 and disconnect CN P12, SS11, and SS23 (*1) to isolate the SS board. Remove the jumper at CN SS34 and install it across pin 8 and 10 of connector P12.

Turn the unit on.

Does the power LED

stay on?

Yes

Disconnect CN A5, A6,

and A7 on the A board. Does

the TV turn on by itself with

SC Board

SS Board

a white screen?

Yes

TH-42PX75U = SS23 TH-42PX77U = SS23 TH-50PX75U = SS33

A Board

Unplug the TV,

Reconnect CN P12, SS11,

And SS23 (*1). Turn the unit on.

Is there 15V output at

CN P25 pin 1 or 2

before the TV shuts down ?

Yes

D Board

TH-50PX77U = SS33

D Board

Unplug the TV.

Disconnect CN P25. Is pin 1

or 2 of the CN P25 shorted to

GND?

Yes

Note: CN = Connector

P Board

LED blinks 3 times

Trouble Mode

3.3V down SOS

Defective Board

D Board

The D board is defective.

Warning: Disconnect AC Power prior to

making any disconnection or

connection.

Note: CN = Connector

LED blinks 4 times

Trouble Mode

Power Supply SOS

Primarily P board or possible D board

Defective Board

Warning: Disconnect AC Power prior to

making any disconnection or

connection.

Turn the unit on.

Is pin 12 of CN P25 of

the P board high

before shutdown?

Yes

P Board

D Board

Note: CN = Connector

LED blinks 5 times (Quick Troubleshooting)

Trouble Mode

5V SOS

D, P, C, SC, SS board or Panel (DDIC)*1

Defective Board

Disconnect CN P12

of the power supply board. Measure the

resistance of pin 1 of the lead cable to ground.

Warning: Disconnect AC Power prior to

making any disconnection or

connection.

(*1) = Data Driver IC

Note: CN = Connector

Is there a short to ground?

Yes

Panel

Proceed to more extensive troubleshooting of

the pages that follow.

LED blinks 5 times

Trouble Mode

5V SOS

D, P, C, SC, SS board or Panel

Yes

CN SC20 on the SC board. Turn on the unit. Does the power LED

SC Board

Disconnect

stay on?

Defective Board

CN SS23 (*1) on the SS board.

Turn on the unit. Does the power

Connect

CN SC20. Disconnect

LED

Stay on?

Yes

SS Board

Warning: 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

Connect SS23 (*1).

Disconnect CN D31and D32

on the D board. Is pin 5of CN P25

shorted

to GND?

Yes

P Board

Disconnect

CN P25. Is pin 5 of the

socket P25 shorted

to GND?

Note: CN = Connector

D Board

Connect D31

and leave D32 disconnected.

Is pin 5 of CN P25 shorted

to GND?

Yes

Disconnect CB1-CB4.

Is pin 5 of CN P25 shorted

to GND?

Yes

C1 Board

Panel

Disconnect D31.

Connect D32.

Is pin 5 CN P25 shorted

to GND?

Yes

Disconnect CB5-CB8.

Is pin 5 of CN P25 shorted

to GND?

Yes

C2 Board

P Board

Panel

LED blinks 6 times

Trouble Mode

SC Energy Recovery SOS

Defective Board (Possibility)

SC, SS, D, P Board (SC > SS, D, P )

Warning: Disconnect AC Power prior to

making any disconnection or

connection.

Connect

SC2 and

Disconnect

connectors SC2, and

SC20 from the SC board. Turn the TV on. Does the TV power up

and

stay on?

Yes

SC Board

(*3) = 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

and SS11, SS34, and SS23 (*3) from

the SS board. Place the jumper from

Yes

D Board

Note: CN = Connector

SC20. Disconnect

CN P12(*2) from the P board

SS34 between pins 8 and 10 of

P12. Turn the TV on. Does

The TV power up

and stay on?

Yes

SS Board

Does the P board

output 15V at pin 7 of

P7 and Vsus at pin 1

of P2 before the TV

shuts down?

P Board

Connect CN P12, SS11, SS34, and SS23(*3). Remove the A

board block assembly to gain access to the D and C boards.

(Remove 4 screws and 7 connectors)

Ground the base of Q302 (Fig. 1 next pg) on the D board and turn the power on

Does the TV stay on?

Yes

Reseat the ribbon cables between

the D and the C boards. Also reseat

the cables between the C boards.

(See figure 2 on the next page

(*1) VSUS about 180V (Accurate voltage is provided on the Panel Label)

CAUTION: Before connecting P2 or P11, discharge is necessary to prevent potential shock caused by VSUS.

(*2) Place a jumper across pin 8 and 10 of connector P12. The unit will not enter the standby mode without the jumper.

LED blinks 6 times

Trouble Mode

SC Energy Recovery SOS

Defective Board (Possibility)

SC, SS, D, P Board (SC > SS, D, P )

Warning: Disconnect AC Power prior to

making any disconnection or

connection.

Figure 1

Figure 2

LED blinks 7 times

Trouble Mode

SC Floating voltage SOS

Defective Board (possibility)

SC, SU, SD, P board (SC,SU,SD>D,P)

Warning: Disconnect AC Power prior to

Make sure the connectors P2/SC2, SC20/D20 are not loose and seated properly.

Disconnect

the connectors SC2, and SC20 from the SC board. Turn the TV on. Does the TV power up

and

stay on?

Yes

Turn the TV on.

Does 15Vdc appear

at pin 1 of CN P25 on the

P board before the unit

shuts down?

Yes

P Board

voltage appear at pin 1 of

making any disconnection or

connection.

Turn the TV on. Does VSUS(*1)

CN P2 of the P board

before shutdown?

Yes

SS Board

P Board

Connect

the connectors SC2(*2),

and SC20 to the SC board.

Remove the SU board.

Turn the TV on. Does the

TV power up

and stay on?

Yes

SU Board

Note: CN = Connector

Install

the SU board and

Remove the SD board.

Turn the TV on. Does

it power up

and stay on?

Yes

SD Board

SC Board.

NOTE: If the SC board does not fix the problem, replace the D board.

(*1) VSUS about 180V (Accurate voltage is provided on the Panel

Label) (*2) CAUTION:

Before connecting P2/SC2 or P11/SS11, discharge is necessary to prevent potential shock caused by VSUS.

LED blinks 8 times

Trouble Mode

SS Energy recovery SOS/Panel

Disconnect

CN SS11 and SS23 (*2)

from the SS board and

CN P12 (*1) from the P

board. Turn the TV on. Does the TV power up

and stay on?

Yes

Defective Board (possibility)

SS, SC, D, P board (SS>SC,D,P)/PDP

Turn the TV on.

Is the VSUS(*3) input at

pin 1 of CN P11 present

before Shutdown?

Yes

D Board

Warning: Disconnect AC Power prior to

making any disconnection or

connection.

(*2) = The reference

number of the sustain

Disconnect

CN SC2, and SC20

from the SC board.

Turn the TV on. Does

the TV power up and

stay on?

Yes

SC Board

P Board

data connector is different in some of the

models: TH-42PX75U = SS23 TH-42PX77U = SS23 TH-50PX75U = SS33 TH-50PX77U = SS33

Panel

Is the collector of Q251 or the

anode of D255 on the SS board

high.

Q551 and D255 Location.

SS34

SS Board

Yes

SS34

SS Board

(*4)

(*1) Place a jumper across pin 8 and 10 of connector P12. The unit will not enter the standby

mode without the jumper.

(*3) VSUS about 180V (Accurate voltage is written on the Panel Label of the chassis)

CAUTION : To avoid potential shock from the VSUS voltage, discharge the connectors SC2 or SS11 before reconnecting them into their respective

socket.

(*4) If the power LED continues to blink after replacing the SS board, change the D board.

LED blinks 9 times

Trouble Mode

Panel Status

Defective Board

D Board

In this case, only the D board is defective.

Warning: Disconnect AC Power prior to

making any disconnection or

connection.

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