Panasonic TC-P50UT50, TC-P50ST50 Service Manual
2012 Plasma TV Troubleshooting Guide
2012-Plasma FHD TV – ST Series (15
Applies to models:
TC-P50ST50
TC-P50UT50
th
Generation)
National Training Department
Panasonic Consumer Marketing
Company Of North America
TTG120313CP120417
Important Information
• To avoid the unnecessary replacement of multiple PC boards, please read this before
beginning to repair this unit.
• Do not use any service documentation oth er than the one designed for this particular model.
• Techniques used on previous models may not necessarily apply to the model you are
working on.
• For accurate diagnosis during troubleshooting, do not skip or alter the order of steps on the
guide.
Slide 2
SOS Precautions
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 3
Power LED Error Code Definition (1 of 2)
POWER LED
ERROR
CODE
1 BLINK
2 BLINKS P15V form the P board
3 BLINKS
4 BLINKS
6 BLINKS SC Energy Recovery Circuit
7 BLINKS
8 BLINKS
CIRCUIT MONITORED
Panel Information SOS
Incomplete or interrupted
Boot Program execution of
PEAKS IC (IC8000).
Power Supply output
voltages
Scan Drive Circuit and
Connection between the SC
board and the SC board.
Sustain Drive Circuit and
Connection between the SS
board and the Panel.
CONDITIONS TRIGGERING
THE SHUTDOWN
Communication problem A
Missing P15V
P15V is not been generated by the P board.
Wrong diagnostic by the A board
Shorted P15V
Missing F15V
Wrong diagnostic by the A board
Vsus Over Voltage Condition.
P15V Shorted while in operation.
Wrong diagnostic by the A board
An increase or reduction of the Energy Recovery Circuit
output (MID).
Shorted SUB5V.
Wrong diagnostic by the A board.
Missing or shorted 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
SC board (SC41, SC42, SC46).
Open or loose connection between connectors SC2/P2
Wrong diagnostic by the A board
Defective panel
Abnormality of the sustain drive circuit.
Open or loose connection between the SS/SS2 Boards.
and FPCs from the panel (SS52 – SS54 – SS55 – SS57).
Open or loose connection between connectors C10/C20 or
C26/C36.
Wrong diagnostic by the A board
LIST OF BOARDS POSSIBLY CASUSING THE FAILURE
#1 Suspect #2 # 3 Occasionally
P A
A P
P A
SC A C
SU/SD SC SS A/Panel
SS A C3 Panel
Not Often
#4
Slide 4
Power LED Error Code Definition (2 of 2)
POWER LED
ERROR
CODE
9 BLINKS
10 BLINKS SUB3.3V_Sense (OVP)
12 BLINKS Audio Amp. Circuit
13 BLINKS
CIRCUIT MONITORED
Discharge Control Circuit
DDC (IC9300)
IC8000 Internal
Communication
CONDITIONS TRIGGERING
THE SHUTDOWN
Failure of IC9300
Wrong diagnostic by the A board
Over Voltage Condition of SUB5V or SUB3.3V
Wrong diagnostic by the A board.
Defective Speaker/Subwoofer
Pinched Speaker Wire
Wrong diagnostic by the A board
Defective A board A
LIST OF BOARDS POSSIBLY CASUSING THE FAILURE
#1 Suspect #2 # 3 Occasionally
A
A
A
Speakers/
Subwoofer
Not Often
#4
Slide 5
Protection Circuit Block Diagram 1 of 2 (TC-P50ST50)
P15V
SUB3.3V
A20
SC_SOS6
3
SC
SS
FFC_OFF_DET(6)
SC
SC_SOS7
6
A33
SS_SOS8
5
SOS_DCC_S (9)
A20
SC_UHZ
Missing 2 Blinks
Shorted 3 Blinks
Missing 3 Blinks
Shorted
At plug-in
IC5000
REG
(STB3.3V)
RESET
9
11
12
10
8
7
1314
(If no signal,
Discharge Reset
6/8 blinks)
:
179
18
P15V
Det. Circuit
P15V
Q9201
(Analog output)
6 – 9 blinks
Normal : all input = “L”
(output = “L” )
DRVRST
D_UHZ
C24
M28
T4
IC9300
W3
N2
AG3
W28
P3.3V
Q9201
N
2 blinks
SOS
PANEL_SOS
(If no 3.3V in C1/C2-PCB,
Discharge Reset
6/8 blinks)
:
3.3V_DET
A31
55
A32
1
PDP_DRVRST
SOS
C
TC-P**ST50/UT50
AE20
IC8000-1
AD15
Peaks
LD4
AD16
Standby
uCOM
System
uCOM
AF16
(TNPH0989**)
2 Blinks
if P15 is
missing
SUB3.3V
Det. Circuit
SUB3.3V
3 blinks
3 Fast
Blinks
At plug-in
if SUB3.3
is missing
Slide 6
Blink Code/Voltage Condition (TC-P50ST50 - TC-P50UT50)
No. of Blinks
Voltage Condition
TC-P50UT50 TC-P50ST50
Missing 2 Blinks 2 Blinks
P15V
SUB3.3V
SUB5V
No power. The LED turns o n
Shorted
Missing 3 Fast Blinks at Plug-in 3 Fast Blinks a t Plug-in
Shorted 3 Fast Blinks at Plug-in 3 Fast Bli nks at Plug -in
Over Voltage
Missing 3 Fast Blinks at Plug-in 3 Fast Blinks a t Plug-in
Shorted 6 Blinks After 11sec. 6 Blinks After 11sec.
Over Voltage
briefly and then it goes off
immediately
Dead. Power LED never
turns on
Dead. Power LED never
turns on
3 Fast Blinks
10 Blinks
10 Blinks
Slide 7
Protection Circuit Block Diagram 2 of 2 (TC-P50ST50)
SUB5V &
SUB3.3V
OV Det.
Circuit
SUB5V
SUB3.3V
IC4900
IC4901
Audio
AMP
Audio
AMP
22
22
SUB3.3V
Normal=“H”
Q8771
STB3.3V
Q8771
10 blinks
SOUND_SOS
12blinks
TC-P**ST50/UT50
(TNPH0989**)
10 Blinks if
SUB5V or
SUB3.3V is
too high
AA15
SOS
IC8000-2
Peaks
LD4
AD19
Standby
uCOM
SUB5V
Missing 3 Fast
Shorted 6 blinks
after 11 sec.
Over Voltage 10 blinks
Emergency : 13 blinks
IROM error : quickly 3 blinks
blinks at
plug-in
P
FAN_SOS
(11blinks)
A6
ALL_OFF(P_SOS4)
4
4 blinks
System
H6
uCOM
AE15
Slide 8
Troubleshooting 1 -9 -10 - 13 Blinks Failure
Blink
List of boards likely to cause this symptom
Code
No.1 No.2 No.3 No.4
1 A Board
9 Blinks A Board
10 Blinks A Board
13 Blinks A Board
When 1, 9, 10, or 13 blinks occur, replace the A board
Slide 9
Troubleshooting 2 Blinks Failure (TC-P50ST50)
Find information for TC-
P50UT50 on the next slide)
Start Here
Place the positive lead of a voltmeter at pin 13
of connector P6 while the black lead is
connected to ground (Chassis ground). Plug in
the TV and turn it on
Blink
List of boards likely to cause this
symptom.
Code
No.1 No.2 No.3 No.4
2 Blinks P A
Replace the A
board
Yes
Does 15V
appears
momentarily
on pin13 of
CN P6?
No
Replace the P
board
Slide 10
Troubleshooting 2 Blinks Failure (TC-P50UT50)
Blink
Code
List of boards likely to cause this
symptom.
No.1 No.2 No.3 No.4
2 Blinks P A Panel/C2
Place the positive lead of a voltmeter at
pin 13 of connector P6 while the black lead
is connected to ground (Chassis ground).
Plug in the TV and turn it on
Start Here
Find information for TC-
P50ST50 on the previous
slide)
Unplug the TV. Check the resistance between TP201 (P3.3V)
on the C2 board and chassis ground.
Yes
Does 15V appears
momentarily on
pin13 of CN P6?
Yes No
Defective
Panel and/or
C2 board
No
Replace the P
board
Is there a
short
circuit?
Replace the A
board
Slide 11
Troubleshooting 3 Fast Blinks Failure (TC-P50ST50)
List of boards likely to cause this symptom. Blink
Code
3 Blinks A P SS/SC
No.1 No.2 No.3 No.4 No.5
Bluetooth
Module
With the TV still disconnected, remove connector
A6 from the A board and perform the same
resistance check on pin 13 of connector P6.
Is there a short circuit
or a resistance lower
than 1 Kilo-ohm?
Yes
Reconnect SS33 and remove connector
A31 and A32 from the A board and
check for short circuit or low resistanc e
on pin 13 of connector P6.
Replace the P
board
No
than 1 Kilo-ohm?
Replace the SS
board
Yes
Is there a short
circuit or a
resistance lower
Start Here
Unplug the TV. Check for short circuit or low
Panel
resistance between pin 13 of connector P6
and ground (Chassis ground).
Is there a short
Yes
circuit or a
resistance
lower than 1
Kilo-ohm?
No
Reconnect SC20 and remove
connector SS33 from the SS board
and check for short circuit or low
resistance on pin 13 of connector P6.
Unplug the blue-
tooth module. If the
blinking stops,
change the blue-
tooth module
No
Reconnect A6 and remove connector SC20
from the SC board and check for short circuit
or low resistance on pin 13 of connector P6.
Yes
short circuit or
a resistance
lower than 1
Replace the A
board
Is there a
No
Kilo-ohm?
Replace the A
board
Yes
Is there a
short circuit or
a resistance
lower than 1
Kilo-ohm?
No
If no short
circuit is found
on any of the C
boards, change
the panel
Replace the SC
board
Slide 12
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