Led Blinks 12 Times - Panasonic TH-42PX75U Technical Manual

<Trouble Mode and Defective Board>
Trouble Mode
Sound SOS
<How to find the defective boards>
Disconnect the connectors A5, A6,
and A7 on the P board.
Yes
Does the
TV turn on by itself
with a white screen.
Yes
Reconnect A5, A6, and
A7 and disconnect the
speakers. Turn the power
on. Does the TV stay on?
Check the speakers.
(*1) = To avoid potential shock from the VSUS voltage, discharge the
connectors SC2 or SS11 before reconnecting them into their respective socket.

LED blinks 12 times

Defective Board (Possibility)
Speakers, A Board
Warning: Disconnect AC Power
prior to making any disconnection
or connection.
No
Reconnect CN A5, A6, and
A7. Disconnect CN SC2(*1),
and SC20 of the SC board.
Turn the unit on.
No
A Board
(*2) = Remove the jumper at CN SS34 and
install it across pin 8 and 10 of connector P12.
(*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
Disconnect CN SS11(*1),
SS12 (*2) and SS23 (*3)
of the SS board. Turn the
No
unit on.
Does the power
LED stay on?
Does
Yes the power LED stay
SC Board
SS Board
20
Do pins 1
No
and 2 of CN P25
output 15V before
on?
the unit shuts
down?
Yes
P Board
Yes
No
D Board