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Technical Guide
Preliminary
Plasma Display Television
GP8DU Chassis
Panel Replacement Procedure
Panasonic Services Company
National Training Center
Prepared by
Jean Magloire
Panasonic Services 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
Equipment List: .....................................................................................................1
Panel Handling Precautions..................................................................................1
Preparation of the new Panel................................................................................2
Removal of the Defective Chassis PC Boards ......................................................4
Rear Cabinet Removal ......................................................................................4
Board Description..............................................................................................5
Disassembly and Reassembly Procedure ............................................................5
Removal of the fans ..........................................................................................5
Removal of the metal frame ..............................................................................6
Removal of the power supply board (P board) ..................................................6
Removal of the PB board and metal frame .......................................................7
Removal of the D board ....................................................................................7
Transferring the SU-Board ................................................................................8
Transferring the SD-Board ................................................................................8
Transferring the SC-Board (37, 42inch) ............................................................9
Transferring the SS2-Board ............................................................................10
Transferring the SS3-Board ............................................................................10
Transferring the SS-Board ..............................................................................11
Transferring the AC Inlet .................................................................................12
Installation of the power supply board (P board) .............................................12
Transferring the C1 and C2 Boards flexible ribbon cable assembly ................13
Removal of the C3 and C4 Boards flexible ribbon cable (HD Models Only)....13
Removal of the front cabinet from the plasma display panel ...........................14
Removal of the Panel from the stand ..............................................................16
Removal of the stand brackets ........................................................................16
Installation of the D board ...............................................................................17
Installation of the PB board and metal frame ..................................................17
Installation of the metal frame .........................................................................17
Installation of the front escutcheon..................................................................18
Installation of the fans .....................................................................................20
Lead Dressing.....................................................................................................20
Connector Connection:....................................................................................21
Lead Dressing 2 ..............................................................................................22
Additional Information for 37 and 50-inch Models ...............................................23
Adjustments ........................................................................................................24
Driver Set-up ...................................................................................................24
Initialization Pulse Adjustment.........................................................................25
Drive Waveform ...........................................................................................25
Adjustment Volume Locations .........................................................................26
Test Point Locations........................................................................................27
Serviceman Mode and Adjustment procedure of the new panel .........................28
Serviceman mode (Electronic Controls)..............................................................29
CAT (computer aided test) Mode ....................................................................30
CAT mode menu..........................................................................................30
How to access the CAT Mode .........................................................................30
I2C Mode .........................................................................................................31
I2C Menu Structure..........................................................................................32
Alignment Procedures.........................................................................................33
Pedestal Setting ..............................................................................................33
NTSC White Balance Adjustment....................................................................34
HD Panel White Balance Adjustment ..............................................................35
Sub Brightness Setting....................................................................................36
Examples of Defective Panels ............................................................................37
Service Contact Information................................................................................40
Objective
This disassembly procedure assists the technician in disassembling a defective
Plasma Display television. It shows a complete service procedure broken down
into three steps:
1. Complete removal of the printed circuit boards and the defective plasma
panel from the chassis assembly.
2. Lead dressing
3. Adjustment of critical voltages and picture settings
The example unit shown in the guide is a TH-42PX50U but the procedures listed
here are similar for other models of the GP8DU and GP8HDU chassis.
Equipment List:
1. Electric Screwdriver (Part # EY6220B or equivalent)
2. Digital Volt Ohmmeter
3. Oscilloscope
4. Anti-static 5 foot by 4 foot foam cushioning
5. Plasma Stand
6. Screw storage bin
7. Large flat work area
8. Isolation Transformer
9. Colorimeter for white balance adjustment (Sencore CP5000 or equivalent)
10. A Video Signal Generator capable of providing NTSC, 480i, 480p, 720p,
1080i and PC with adjustable brightness levels. (Sencore VP300 or
equivalent)
Panel Handling Precautions
Plasma Display Panels use a high voltage power supply, disconnect the AC from
the unit and wait one minute for the voltage to dissipate.
Use extreme care when servicing the Plasma Display Panel. The glass used in
the plasma panel is thin, and its structure is extremely susceptible to impact.
Rough handling of the unit can crack the glass or cause pixel defect errors. Be
sure to transport the Panel in the upright position, the unit is designed to absorb
force vertically not horizontally.
Numerous flexible printed leads with extremely soft structure are used around the
panel. Be very careful during handling not to damage these by pulling, bending or
subjecting them to excessive force. When inserting a ribbon cable into a socket,
verify that the cable is straight; angled insertion can create an electrical short
circuit.
Anti-static measures should be applied, especially when connecting and
disconnecting the ribbon cables.
A protective sheet is attached to the back of the replacement panel to prevent
scratches and accumulation of debris. Be sure to remove the protective sheet
and wipe the surface with a soft cloth before installation.
A low torque setting is recommended when installing screws in the panel
assembly.
1
Preparation of the new Panel
1. The replacement panel is shipped in
a special shipping crate; retain this
crate to return the defective panel.
Figure 1. Panel Shipping Crate
2. Carefully remove the top of the crate,
remember you will have to reuse the
crate to return ship the defective
panel. Slide the panel out the opened
end.
Figure 2. Removal of Panel from crate
2
3. The replacement panel is
packed in an escutcheon
frame and a cardboard panel.
Protective cushioning
surrounds the panel. These
items must be saved and
used to return the defective
panel.
Figure 3. Packing of the Panel
Caution: Use extreme care when handling the Plasma Display Panel. The
glass used in the plasma panel is thin, and its structure is extremely
susceptible to impact. Therefore it is recommended that two individuals
handle the Plasma Display Panel to avoid accidental damage.
4. Remove the four screws that secure the protective cardboard on the new
panel. Place the protective cardboard aside.
Figure 4. Panel on Table Figure 5. Cardboard Removal
5. Unwrap the protective packaging from
the new panel.
Important Note:
The new panel comes with the C1 - C4
boards preinstalled. However, the lead
cables that connect C1 to C2 and C3 to
C4 might be missing. Check for board
jumpers. If missing, remove and transfer
to the new panel. Figure 6. Unwrapping the
Panel
3
Removal of the Defective Chassis PC Boards
Rear Cabinet Removal
Remove the 43 screws
as indicated in Figure 7,
and then pull away the
rear cover. Place it in a
secure location.
Figure 7. Back Cover Screws
Figure 8. Board Layout
4
Board Description
Note: The boards are listed in sequential order for quick removal.
Board Board
Function Function
Name Name
1 P Power Supply 6 SD Scan out (Down)
2 Audio Power, Fan 7
PB SC Scan Drive
Control
3 Format Converter, 8 Sustain Connector (Up)
D SS2
Plasma AI Processor (42 inches only)
4 DC-DC Converter, 9 Sustain Connector (Down)
PA SS3
Power SOS (42 inches only)
4 AV Terminal, AV 10
H SS Sustain Drive
Switch
4 DT ATSC Interface 11 C1 Data Driver (Up Left)
4 DV HDMI Interface 14 C4 Data Driver (Down Left)
4 Digital Signal
DG K Remote receiver, Keyscan
Processor
4 Speaker out, Audio
Z S Power Switch
AMP
5 SU Scan out (Up)
Table 1. Board Description
Disassembly and Reassembly Procedure
Caution: Wait 1 minute for the electrolytic capacitors to discharge before
removing any PCB from the unit.
Removal of the fans
1. Unlock the cable clampers of the fans to free the cables.
2. Disconnect the
connectors
PB31, PB33,
and PB34 from
the PB board.
3. Remove the
three screws that
secure each of Figure 9. Fans Location
the three fans.
4. Place the fans in a secure location
5
Removal of the metal frame
1. Unlock the cable clampers to
free the cable.
2. Disconnect the speaker
connectors (SP-L and SP-R)
and the black connector that
couples the K board and the
DG board.
3. Disconnect the connectors
DG3 and DG5 of the DG
board, PB7 of the PB board
and PA10 of the PA board.
4. Remove the five screws that
hold the metal frame as Figure 10. Metal Frame
indicated in figure 10.
5. Remove the metal frame and
place it aside.
Note: The metal frame contains the Z, DT, H, DG, and PB boards.
Removal of the power supply board (P board)
1. Unlock the cable
clampers to free
the cables.
2. Disconnect the
couplers (P2, P5,
P9, P10, P11, P12,
P23, P25 and P30)
from the P board.
3. Remove the six
screws as
indicated in Figure
11.
4. Installation of the P
board will be
performed later.
Figure 11. P Board
6
Removal of the PB board and metal frame
1. Unlock all the cable clampers of
the PB board metal frame to free
the cables.
2. The connector PB7 is already
disconnected from the PB board.
The connectors (PB30, and PB5)
are already disconnected from the
P board.
3. Disconnect the connectors D20
and D25 from the D board. The Figure 12. PB Board Metal Frame
connectors D3 and D5 are already
disconnected from the DG board.
4. Remove the three screws as indicated in Figure 12 and remove the PB-
Board metal frame. The PB board remains attached to the metal frame.
5. Place the PB board and metal frame aside.
Removal of the D board
1. Disconnect the flexible cables
(D31, D32, D33 and D34).
2. Remove the four screws of the D
board as indicated in figure 13 and
place the D board aside.
Figure 13. D Board
7
Transferring the SU-Board
1. Remove the 2 screws of the SU
board as indicated in figure 14.
2. Disconnect the bridge connector
(SU45 or SC45) and slide the SU-
board to the left to disconnect the
coupler (SC41 -SU41) from the SC
board.
3. Remove the flexible cables (SU1,
SU2, SU3, SU4) and place the SU
board aside. Installation is
performed after the removal of the
SC board.
Transferring the SD-Board
1. Remove the two screws of the SD
board as indicated in figure 14.
2. Disconnect the bridge connector
(SD46 or SC46) and slide the SD
board to the left to disconnect from
the coupler (SC42 -SD42) on the
SC board.
3. Remove the flexible cables (SD1,
Figure 14. SU and SD boards
SD2, SD3, SD4) connected to the
SD-Board, and place the SD board
aside. Installation is performed after the removal of the SC board.
8
Transferring the SC-Board (37, 42inch)
1. Disconnect from adjoining boards
any cable that originates from the
SC board.
2. Remove the six screws that attach
the SC board to the panel. Place
the SC board aside.
3. Remove the rubber insulator
located underneath the SC board
and transfer it to the new panel.
(See figure 16.)
4. Transfer the SC-Board to the new
panel.
5. Connect the flexible cables (SU1,
SU2, SU3, SU4) to the SU board
and slide the SU board to the right
into the coupler (SC41) of the SC- Figure 15. SC Board
Board.
6. Connect the flexible cables
(SD1, SD2, SD3, SD4) to the
SD board and slide the SD
board to the right into the
coupler (SC42) of the SC-
Board.
7. Install the screws that secure
the SD and SU boards to the
new panel.
Figure 16. Rubber Insulator
9
Transferring the SS2-Board
1. Disconnect the coupler (SS23)
from the SS2 board.
2. Disconnect the flexible cable
(SS55). See figure 17 and 17B.
3. Remove the two screws that
attach the SS2-Board to the panel.
4. Place the SS2 board aside.
Installation is performed after the
removal of the SS board.
Transferring the SS3-Board
1. Disconnect the coupler (SS22)
from the SS3 board.
2. Disconnect the flexible cable
(SS56). See figure 17 and 17B.
3. Remove the two screws that
attach the SS3-Board to the panel.
4. Place the SS3 board. Installation
is performed after the removal of
the SS board.
Figure 17. SS2 and SS3 boards
Figure 17B. SS Board Connector
10
Transferring the SS-Board
1. Disconnect the connector C24
from the C2 board.
2. Disconnect the connector C32
from the C3 board.
3. Disconnect the connector SS34
from the SS board.
4. Disconnect the flexible cables
(SS52, and SS53) from the SS
board.
5. Remove the six screws that
hold the SS board in place and
place the SS board aside.
Figure 18. SS Board
6. Remove the rubber insulator
located underneath the SS
board and transfer it to the
new panel. (See figure 19.)
7. Transfer the SS board to the
new panel.
8. Reinstall the SS2 and SS3
boards.
Figure 19. Rubber Insulator
11
Transferring the AC Inlet
1. Remove the two screws that attach
the AC inlet to the panel as
indicated in figure 20.
2. Transfer the AC inlet to the new
panel.
Figure 20. AC Inlet
Installation of the power supply board (P board)
5. Unlock the cable
clampers to free
the cables.
6. Connect the
couplers (P2, P5,
P9, P10, P11, P12,
P23, P25 and P30)
to the P board.
7. Mount the six
screws as
indicated in Figure
21.
Figure 21. P Board
12
Transferring the C1 and C2 Boards flexible ribbon cable assembly
1. Remove the three screws of
the cable bracket.
2. Unlock the sockets C11 and
C21 to disconnect the two
ribbon cables that attach the
D board to the C1 and C2
boards.
3. Install the flexible cables and
bracket to the new panel.
4. Remove the lead cable that is
connected between the
socket C12 and C22 of the C1
and C2 boards. Transfer the
cable to the new panel. Figure 22. Upper C Boards Flex Cables
Note: The new panel comes with preinstalled C boards.
Note: Reinstallation of the ribbon cables into a socket requires special care.
Verify that the cable is straight; angled insertion can create an electrical short
circuit.
Removal of the C3 and C4 Boards flexible ribbon cable (HD Models
Only)
1. Remove the three screws that
attach the angle bracket to the
panel.
2. Remove the two screws that
attach the metal plate to the
panel.
3. Unlock the sockets C41 and
C11 to disconnect the two
flexible cables that attach the
D board to the C3 and C4
boards.
4. Remove the lead cable that is
connected between the
sockets C33 and C43 of the
C3 and C4 boards. Transfer
the flexible cable, bracket,
and metal plate to the new
panel.
Note: Pay careful attention when
connecting the ribbon cables to the Figure 23. Lower C Boards Flex. Cables
13
D board and the C boards. Verify that the cable is straight; angled insertion can
create an electrical short circuit.
Removal of the front cabinet from the plasma display panel
1. Remove the 8
screws as
indicated in
figure 24.
Note: The
metal plate at
the bottom left
side of the
picture
automatically
falls off when
the screws are
removed.
Place it aside
for installation
into the new
panel.
Figure 24. Removal of Front Escutcheon
2. Remove the three screws of the
right stand bracket as indicated
in figure 25.
3. Disconnect the connector S1 of
the S board.
4. Free the cable from the retainers.
.
Figure 25. Right Stand Bracket
14
5. Remove the three screws of the
left stand bracket as indicated in
figure 26.
Figure 26. Left Stand Bracket
6. Make sure all the wiring connected to the
front panel is unattached.
7. With the help of an assistant, the Cabinet can
now be removed from the panel by tilting the
bottom out and lifting up slightly. Place it in a
secure location.
Figure 27.
Escutcheon Removal
15
Removal of the Panel from the stand
With the help of an assistant,
remove the plasma panel from
the servicing stand. Lay it, facing
down, on a flat surface such as a
table covered with a cushioned
anti-static mat, and a soft cloth to
avoid scratching the glass.
Removal of the stand Figure 28. Panel on Table
brackets
Note: Perform this task only after removing the plasma
television from the stand. The television should be placed
face down on a table equipped with a cushioned anti-static
mat and a soft cloth.
1. Remove the 4 screws securing the left stand bracket.
2. Repeat the procedure for the right stand bracket.
3. Transfer the stand brackets to the new panel.
Figure 29. Stand
Bracket
16
Installation of the D board
1. Install the D board to the new panel
and secure it with 4 screws.
2. Connect the flexible cables (D31,
D32, D33 and D34).
Note: Reinstallation of the ribbon
cables into a socket requires special
care. Verify that the cable is straight;
angled insertion can create an
electrical short circuit.
Figure 30. D Board
Installation of the PB board and metal frame
1. Install the PB-Board metal frame
and secure it with three screws as
indicated in Figure 31.
2. Connect the connector PB7 to the
PB board.
3. Connect the connectors (D3, D5,
D20, and D25) to the D board.
4. Route the lead cables through the
cable clampers. Lock the cable
clampers.
Figure 31. PB Board Metal Frame
Installation of the metal frame
1. Install the metal frame and
secure with it with 5 screws.
2. Connect the speaker
connectors (SP-L and SP-R)
and the black connector that
couples the K board and the
DG board.
3. Connect the connectors DG3
and DG5 of the DG board,
PB7 of the PB board and
PA10 of the PA board.
4. Route the cables through the Figure 32. Metal Frame
clampers. Fasten the
clampers.
17
Installation of the front escutcheon
1. Verify that the front Escutcheon cover and the
panel are free of dust and fingerprints.
2. Install the front escutcheon cover by tilting
the bottom away from the panel and then
pushing down from the top. Once the top is
secured, push the bottom in to lock it in place.
Caution: If the top is not tightly pushed down
from the top and held securely in place, pushing
the bottom in can cause the bottom edge to cut
the bottom ribbon cables.
3. Secure the escutcheon with two screws on
the left and right sides.
4. Connect the connector S1 to the S board.
Figure 33. Escutcheon
Install
18
5. Install the three screws of the
right stand bracket as indicated
in figure 34.
Figure 34. Right Stand Bracket
6. Install the three screws of the left
stand bracket as indicated in
figure 35.
Figure 35. Left Stand Bracket
19
Installation of the fans
1. Secure the three
fans using the
three mounting
screws with rubber
bushings.
2. Connect the
connectors PB31,
PB33, and PB34
from the PB board.
3. Route the lead Figure 36. Fans Location
cables through the
cable clampers. Fasten the clampers.
Note: Defective Panels are considered hazardous waste please follow the
disposal instructions included with the replacement panel.
Lead Dressing
TH-42PX50U
Figure 37. Lead Dressing Location
20
Connector Connection:
P2, P5, P9, P10, P11, P12, P23, P25, P30
D3, D5, D25
PB5, PB7, PB30
SC2, SC20, SC23,
SS11, SS12
DG3, DG5
C24, C32
Table 3. Lead Dressing
21
Lead Dressing 2
TH-42PX50U
Figure 38. Lead Dressing 2
Connector Connection:
PB31, PB33, PB34
Table 4. Lead Dressing 2
22
Figure 39. Example of Lead Dressing
Figure 39 shows an example of harness with a triple wound clamper.
Additional Information for 37 and 50-inch Models
Standard definition 37 and 42-inch screens as well as 50-inch high definition
screens have differences that require slightly different techniques in disassembly
and reassembly. Please refer to the appropriate service manual for lead dressing
instructions.
23
Adjustments Panel Label information
Driver Set-up
Item / Preparation
Input an APL 100 % white signal.
Set the picture controls to:
Picture mode = Normal
White Balance = Cool
Aspect = 16:9
Note: To perform the following adjustments, Figure 40. Panel Label
please refer to the panel information label
located on the heat sink of the panel. See Figure 40 for more information about
the panel label.
TH-42PX50U
Name Test point Voltage Volume
Vsus TPVSUS 188V