Sony XR-55A75L Service Manual page 51

TROUBLESHOOTING
1.3 No Power DDCON/LDO (LDO Check)
START
yes
Check Vcc voltage
C815
Is voltage >3.2V?
yes
Check Enable pin
voltage
Is voltage >3V?
yes
Change LDO IC
Check 3.3V_DDC_OUT
DDCON
no
(IC607 on Main)
or
3.3V_STBY (G-board)
no
1.2 No Power U-Com Failure
or
Enable source
Please Refer page 30 for Ref Number.
Board Operation IC Ref
BM5STY LDO IC809
Voltage supply
3.3V_M5_STBY
51
SYS SET