Panasonic G20 Series User manual

Panasonic National Training
Panasonic Service and Technology Company
TC-P42G25
TC-P46G25
TC-P50G20
TC-P50G25
TC-P54G20
TC-P54G25
Applies to models:
TTG101013CP
Cover Page
2010 - FHD Plasma TV Troubleshooting Handbook
2010- Plasma FHD TV – (13th Generation)
G20 & G25 Series

Table of Content
Slide 2
Topic Page
Table of Content 2
SOS Detect (Shutdown) 3
Power LED Error Code Definition and the Failure-Causing-Boards 4
Power LED Error Code Definition 5
Boards Replacement by Blinking Code (G20/G25 Series) 6
Quick Procedure To Check For Short or Low Resistance Condition of the Vsus,
Vda, and P15V Lines 7
Quick Procedure To Check For Short or Low Resistance Condition of the Vsus,
Vda, and P15V Lines 8
Quick Procedure To Determine the Cause of the Problem if a short or Low
Resistance Reading is Found 9
Quick Procedure To Determine the Cause of the Problem if a short or Low
Resistance Reading is Found 10
Detailed Troubleshooting Procedure for Shorted Vsus 11
Detailed Troubleshooting Procedure for Shorted Vsus 12
Detailed Troubleshooting Procedure for Shorted P15 13
Detailed Troubleshooting Procedure for Shorted P15V 14
Detailed Troubleshooting Procedure for Shorted Vda 15
Detailed Troubleshooting Procedure for Shorted Vda 16
Troubleshooting 1 Blink Failure 17
Troubleshooting 1 Blink Failure 18
Troubleshooting 2 Blinks Failure 19
Troubleshooting 2 Blinks Failure (1 of 2) 20
Troubleshooting 2 Blinks Failure (2 of 2) 21
Troubleshooting 3 Blinks Failure 22
Troubleshooting 3 Blinks Failure (1 of 2) 23
Troubleshooting 3 Blinks Failure (2 of 2) 24
Troubleshooting 4 Blinks Failure 25
Troubleshooting a 4 Blinks Failure (1 of 2) 26
Troubleshooting a 4 Blinks Failure (2 of 2) 27
Troubleshooting 5 Blinks Failure 28
Troubleshooting 5 Blinks Failure (1 of 3) 29
Troubleshooting 5 Blinks Failure (2 of 3) 30
Troubleshooting 5 Blinks Failure (3 of 3) 31
Topic Page
Troubleshooting 6 Blinks Failure 32
Troubleshooting 6 Blinks Failure (1 of 2) 33
Troubleshooting 6 Blinks Failure (2 of 2) 34
Troubleshooting 7 Blinks Failure 35
Troubleshooting 7 Blinks Failure (1 o 2) 36
Troubleshooting 7 Blinks Failure (2 o 2) 37
SU-SD boards (Together) Isolation Procedure 38
SU-SD boards (Together) Isolation Procedure 39
SU Board Isolation Procedure 40
SD Board Isolation Procedure 41
Vfo, VSCN-F, & 5V_F Resistance Measurements (SU-SD boards) 42
Vfo, VSCN-F, & 5V_F Resistance Measurements (SU-SD boards) 43
Vfo, VSCN-F, & 5V_F Resistance Measurements (SU-SD boards) 44
Troubleshooting 8 Blinks Failure 45
Troubleshooting 8 Blinks Failure 46
Troubleshooting 8 Blinks Failure 47
Troubleshooting 9 Blinks Failure 48
Troubleshooting 9 Blinks Failure 49
Troubleshooting 10 Blinks Failure 50
Troubleshooting 10 Blinks Failure At Plug in 51
Troubleshooting 10 Blinks Failure 52
Troubleshooting 10 Blinks Failure After Power On 53
Troubleshooting 12 Blinks Failure 54
Troubleshooting 12 Blinks Failure 55
Troubleshooting 12 Blinks Failure 56
Troubleshooting No Power/Dead Unit 57
Troubleshooting No Power/Dead Unit 58
Troubleshooting No Power/Dead Unit 59
TV’s Behavior After Connectors Removal 60
TV’s Behavior After Connectors Removal 61
End 62

SOS Detect
(Shutdown)
When an abnormality occurs in the unit, the “SOS Detect” circuit is triggered and the TV shuts down.
The power LED on the front panel will flash a pattern indicating the circuit that has failed.
Cautions:
If the power LED continues to blink even after the TV is unplugged, press and hold the power switch
on the TV for a few seconds until the LED turns off.
Some steps require removal of connectors and sometimes PC boards removal. Do not allow the TV to
run for more than 30 seconds while connectors or boards are disconnected.
NOTE: When taking voltage reading, place your meter’s probe on the test point or pin indicated before
connecting the TV to the AC line. The voltage you intent to measure may only appear for a brief
moment.
Warning: The Vsus line has large capacitors that hold the charge for some time even after the TV has been turned off and
unplugged. When disconnecting P2/SC2 or P11/SS1, bleed the remaining charge of the Vsus before reconnecting the cable.
Use a 500 ohms/ 5W (At least) resistor to discharge the Vsus line before reconnecting P2/SC2 or P11/SS11.
Slide 58
Slide 3

Slide 4
Power LED Error Code Definition and the Failure-Causing-
Boards
LIST OF BOARDS POSSIBLY CASUSING THE FAILURE
POWER LED
ERROR
CODE CIRCUIT MONITORED CONDITIONS TRIGGERING
THE SHUTDOWN MOST
COMMON 2
ND
OCCASIONALLY RARELY
1 BLINLK Panel Information SOS
Panel Alarm SOS Communication problem between CPUs on A board. A
¤ ¤ ¤
2 BLINKS P15V form the P board
Missing P15V
•P15V is not been generated by the P board.
•P15V is been affected by one of the boards it is
connected to (A short circuit ofthe P15V).
Wrong diagnostic by the A board
SC P SS A
3 BLINKS P3.3V from the A board
Missing P3.3V
Reasons:
•The A board is not generating the 3.3V
•The 3.3V is been affected by one of the C boards
or the Panel (A short circuit of the P3.3V).
Wrong diagnostic by the A board
C1 or C2 A Panel
¤
4 BLINKS Power Supply output
voltages
Regulation issues with any of the voltages output from the
power supply.
Wrong diagnostic by the A board P A
¤ ¤
5 BLINKS P5V from the Aboard
Missing P5V
Reasons:
•The A board is not generating the 5V
•The 5V is been affected by the SC, SS, A, or C2
board (A short circuit of the P5V).
Wrong diagnostic by the A board
SC,SS C2 A
¤
6 BLINKS SC Energy Recovery Circuit
An increase or reduction of the Energy Recovery Circuit
output (MID).
Open connection between connector A33 on the Aboard
and SC20 on the SC board.
Open connection between any of the ribbon cables on the
C boards and the A board.
Open connection between the ribbon cable/cables
interconnecting the C boards.
Wrong diagnostic by the A board.
SC A
¤ C

Slide 5
Power LED Error Code Definition
LIST OF BOARDS POSSIBLY CASUSING THE FAILURE
POWER LED
ERROR
CODE CIRCUIT MONITORED CONDITIONS TRIGGERING
THE SHUTDOWN MOST
COMMON 2
ND
OCCASIONALLY RARELY
7 BLINKS
Scan Drive Circuit and
Connection between the SC
board and the SM(SU/SD)
board.
Missing Vsus.
Abnormality of the scan circuit output, the 15V_F, the
scn_pro, and Vscn circuit.
Loose or open Connection between the SC board and the
SM(SU/SD) board (SC41, SC42, SC46).
Open or loose connection between connectors SC2/P2
Wrong diagnostic by the A board
SC SM Panel+SC+SM A
8 BLINKS Sustain Drive Circuit and
Connection between the SS
board and the Panel.
Abnormality of the Sustain drive circuit.
Open or loose connection between the SS board and FPCs
from the panel (SS61, SS64, SS21, SS24 and SS58).
Open or loose connection between connectors C10/C20
Wrong diagnostic by the A board
SS Panel A C2
9 BLINKS Discharge Control Circuit
(IC9300) Failure of IC9300 A
¤ ¤ ¤
10 BLINKS
Abnormalities of the F+15V.
Reasons:
•The P board is not generating the F+15V
•SUB Voltages are affected by the K board or by
metal object present in the SD card slot..
Shorted Vsus (By the SS board or SC board).
Shorted Vda (By the panel, C1, or C2 board)
Wrong diagnostic by the A board.
SS SC A - P K
12 BLINKS AUDIO AMP Abnormalities of the Audio AMP A
¤ ¤ ¤

Boards Replacement by Blinking Code (G20/G25 Series)
Blink
Code List of boards likely to cause the symptom. (Based on Actual Reports and Circuit Operation)
Most
Common 2nd 3rd 4th 5th 6th 7th
1A
2SC PSS A
3SC C1 C2 C3 Panel A
4SC P A SS SD
5SD SC SS C2 A
6SC SD A C
7SC SU SM SD Panel A
8SS APanel C2
9A
10 SC ASD SS SU P K
11 Fan A
12 ASpeakers
This part can possibly cause this
error code, but so far there has
not been any report of this part
causing this symptom.
This part can possibly cause
this error code and it has
been confirmed to cause this
symptom.
Technically, this part is not likely
to cause this error code, but it
has been confirmed to cause this
symptom.
Slide 6

Quick Procedure To Check For Short or
Low Resistance Condition of the Vsus,
Vda, and P15V Lines
Slide 7

Slide 8
Quick Procedure To Check For Short or Low Resistance
Condition of the Vsus, Vda, and P15V Lines
1. Make sure the TV is disconnected.
2. Remove any residual charge from the Vsus and Vda
lines by momentarily grounding them through a 500
ohms resistor (At least 5Watts).
3. Measure the resistance between chassis ground and
the pins indicated on the table below. A dead short or
a reading lower than 1K indicates a shorted or
partially shorted line.
Note: Vsus is generated by the Power supply and is only used by the SS and SC boards
Vda is generated by the Power supply and is only used by the Panel (Panel Drive ICs)
P15V is generated by the Power supply and is used by the A, SS, and SC boards
Test points for the Vsus, Vda, and P15V can be easily found on
the P board. To check for short circuit or low resistance on
these lines, follow this procedure:
TC-P42G25
Preparation
Voltage Test Points
Connector/
Wire Color Pin Number Voltage
P11/White 1Vsus
P11/Brown 4P15V
P35/White 1Vda
TC-P46G25
TC-P50G20 TC-P50G25
TC-P54G20 TC-P54G25
Note: For a quick procedure to determine the cause of the problem
when a short or low resistance reading is found, see the next page.
For a detailed procedure, see pages 11~16

Quick Procedure To Determine the
Cause of the Problem if a short or Low
Resistance Reading is Found
Slide 9

Slide 10
Quick Procedure To Determine the Cause of the
Problem if a short or Low Resistance Reading is Found
If a short is found on the Vsus line, remove connectors P2/SC2 and P11/SS11 one at a time to determine if the SC
board or the SS board is defective.
P15V is generated by the
Power supply and is
used by the A, SS, and
SC boards
Shorted Vsus
Shorted Vda
If a short is found on the Vda line, is likely that the panel or one of the C boards is defective. To determine which is
defective, remove connector C10 between the C1 and C2 boards and the panel’s flex-cables connected to the
C boards one at a time.
Shorted P15V
If a short is found on the P15V
line, remove connectors P6,
P11, P25, and SC20 one at a
time to determine which board
is defective. A shorted P15 is
primarily caused by the
following boards in the order
presented; SC, P, A, and SS
boards.
Note: Even though is not
common, the P board can also
cause a shorted Vsus, Vda, or
P15V. Vsus, Vda, and P15V Distribution
Note: Vsus is generated by the Power supply and is only used by the SS and SC boards
Vda is generated by the Power supply and is only used by the Panel (Panel Drive ICs)
Note: For a detailed procedure, see pages 11~16
Note: For a detailed procedure, see pages 11~16

Detailed Troubleshooting Procedure
for Shorted Vsus
Slide 11

Detailed Troubleshooting Procedure for Shorted Vsus
Start Here
Unplug connectors P2 and P11, on
the P board. Measure the
resistance between pin 1 of
connector P2 and ground (Chassis)
Measure the resistance between pin1
of connector SC2 on the SC board
and ground (Chassis).
Yes
No Is there a
short
circuit?
Replace the P
board
Yes
No Is there a
short
circuit?
Replace the SC
board
Replace the SS
board
Measure the resistance between pin1
of connector SS11 on the SS board
and ground (Chassis).
Yes
No Is there a
short
circuit?
Replace the SC
and SS boards
Slide 12
See the picture on page 10 for
connector’s location
Note: Perform firmware upgrade after replacing the SC or SS boards

Detailed Troubleshooting
Procedure for Shorted P15
Slide 13

Detailed Troubleshooting Procedure for Shorted P15V
Start Here
Unplug connectors P6 and P11, on
the P board. Measure the
resistance between pin 1 of
connector P6 and ground (Chassis)
Reconnect P11 and measure the
resistance between pin 1 of
connector P6 and ground (Chassis)
Yes
No Is there a
short
circuit?
Replace the P
board
Disconnect SC20 on the SC board and reconnect P6. Measure the
resistance between pin 1 of connector P6 and ground (Chassis)
Yes
No Is there a
short
circuit?
Replace the SS
board
Yes
No Is there a
short
circuit?
Replace the A
board
Replace the SC
board
Slide 14
See the picture on page 10 for
connector’s location
Note: Perform firmware upgrade after replacing the SC or SS boards

Detailed Troubleshooting
Procedure for Shorted Vda
Slide 15

Detailed Troubleshooting Procedure for Shorted Vda
Yes
Unplug the connector P35 on the P board and check the resistance between pin 1 of connector P35 on the P board and ground (Chassis).
No Replace the P
board
Is there a
short
circuit ?
Start Here
Reconnect the ribbon cable between the C2 and C3
boards and unplug the ribbon cable between the C1 and
C2 boards. Measure the resistance between pin 1 of
connector P35 on the P board and ground (Chassis)
Yes
No Is there a
short
circuit?
Yes No
Is there a
short
circuit?
The problem could be the C2
board or the panel. Proceed to
isolate the panel from the C2
board to determine which is bad.
The problem could be the C1
board or the panel. Proceed to
isolate the panel from the C1
board to determine which is bad.
TC-P50G20
TC-P50G25
TC-P42G25
TC-P46G25
TC-P54G20
TC-P54G25
Reconnect P35 and unplug the
ribbon cable between the C2 and
C3 boards. Measure the resistance
between pin 1 of connector P35 on
the P board and ground (Chassis)
Reconnect P35 and unplug the
ribbon cable between the C1 and
C2 boards. Measure the resistance
between pin 1 of connector P35 on
the P board and ground (Chassis)
Yes
No Is there a
short
circuit ?
The problem could be the C3
board or the panel. Proceed to
isolate the panel from the C3
board to determine which is bad.
Slide 16

Troubleshooting 1 Blink Failure
Slide 17

Troubleshooting 1 Blink Failure
If the TV shuts down and the power
LED blinks 1 time, replace the A
Slide 68
Slide 18

Troubleshooting 2 Blinks Failure
Slide 19

Troubleshooting 2 Blinks Failure (1 of 2)
Check connections between P6 on
the P board and A6 on the A board.
Cautions: Disconnect the AC Power prior to making any disconnection or connection.
If the power LED continues to blink even after the TV is unplugged, press and hold the power switch on the TV for a few
seconds until the LED turns off.
When taking voltage reading, place the voltmeter probe at the test point, component, or connector’s pin indicated before
connecting the TV to the AC line. This will ensure voltage reading accuracy before the TV shuts down. (Since the TV is
shutting down, expect the voltage to only come up a couple of seconds.)
Slide 20
P6/A6 connection
TC-P42G25 TC-P46G25
TC-P50G20 TC-P50G25
TC-P54G20 TC-P54G25