Panasonic TH-103PF9UK Technical Manual page 21

Dead - Power LED does not Light (2/2)
Power LED Status
OFF AC Power Cord or P Board
F
F F
1 8
AC
1 1
3 4
F
9
1
4
Continued from page 1/2
Is there STB 5V
output at pin 10 of CN P25 on the
P(SS) Board after turning the
power SW on?
Yes
Is there
STB 5V output
No
at pin 10 of PC201
after turning the
power SW
on?
Yes
Is there
STB 5V output at pin 12 of
CN D3 after turning the power
SW on?
Yes
Defective Block
D1603
D1604
P(SS)
P
D1703
9
D501
STB5V
1
3
D1603
P(SC)
D1604
P
9
D1703
STB5V
D501
1 Tr
3
MPU
Power
S
SW
No
P(SS) Board
Remove AC power.
Disconnect CN P25.
No
Is there a short
at pin 10 of socket P25
and GND.
Yes
P(SS) Board
No
D Board
DN Board
How to find the defective board
Power Supply / Protect Circuit
PC
D
P PC PC D
25 202 201 25
10 10 10 10
P PC
25 203
10 10
Disconnect
CN PC201.
No
Is there a
Short at pin 10 of
Socket PC201 and
GND?
Yes
PC Board
Is there a
short at pin 18 of
socket DS3 and
GND?
Yes
DS Board
21
DN
D DN
3 2
12 12
IC9011 IC4308
STB3.3V STB3.3V
MPU
Disconnect
CN D3.
No
Is there a
short at pin 12 of
a short at pin 18 of
socket D3 and
GND?
Yes
D Board
Disconnect
CN DS3.
No
P(SC) Board
DS
DN DS
3 3
18 18
30 30
MPU
Disconnect
CN DN3.
No
Is there
socket DN3 and
GND?
Yes (DN short)
DN Board