Sony FPF55C17196UA Service Manual page 29

4.6 PROBLEM ANALYSIS PROCEDURE
4.6.1. "The entire screen does not light (Main power is turned off)" Problem analysis procedure
The entire screen does not light.
Remove the following power connectors
(Main power is turned off.)
PC for analysis
Connected?
N
Remove CN9 (LOGIC)
Turn on AC power.
PSU board
Vpr2 (3.3V)
Y
Turn off AC power.
Connect CN 9 (LOGIC).
Turn on AC power
PSU board
Vpr2 (3.3V) exists?
Y
Turn off the AC power.
(4 locations):
CN 21 (X-SUS）
CN 31 (Y-SUS)
CN 4-5 (ABUS-U4)
CN 24 (ABUS-D4)
(1)
Y
Analysis using PC
Chapter 4.7
N
PSU board is
defective.
STANDBY power
supply has defect
N
LOGIC board is
defective.
STANDBY power supply
(MPU power supply) system
has short-circuited.
-25-
Turn off the AC
power.
End of analysis