Sony XBR-55X850D Service Manual page 22

FLOW
1-1. NO POWER
Case: BM1 + DPS structure
with G* board
No Power
Check STBY 3.3V
NG
C484
near CN401
on DPS board
OK
Check STBY 3.3V
NG
C9006
near CN9000
on BM1 board
OK
B* Board
XBR-55X850D/857D, 65X850D/855D/857D, 75X850D
Replace
NG
Between G* Board to G* Board
DPS Board Harness
OK
Harness
Replace DPS Board /
NG
Between DPS Board to R407, R408
BM1 Board Harness on DPS Board
OK
Harness
u-Com Failure
DDCON/LDO
Main Device Failure
TROUBLE SHOOTING
22