Sony XR-55A75L Service Manual page 34

TROUBLESHOOTING
1.3 No Power DDCON/LDO (DDCON Check) – XR-83A80*
START
Check IC600 Vcc
no
Voltage C601
Is voltage >12V?
yes
Check Vcc voltage
no
C801 / CL819 / C628
Is voltage >4V?
yes
Check Enable
no
IC800 #pin1 / R803 /
IC608 #pin4 / R631
Is voltage >2.5V?
yes
Change DDCON
IC801 / IC802 / IC803 / IC603
Check Vcc voltage
no
C801 / CL819 / C628
Is voltage >3V?
yes
Check
no
D801 / D601
Is diode okay?
yes
1.2 No Power U-Com Failure
Or Change IC800 / IC608
Check no
D800 / 600
Is diode okay?
yes
Change D801 / D601
Check 5V_MAIN DDCON (IC600)
Please Refer page 31 for Ref Number.
Board
BM5S21
Change D800 / D600
Check 3.3V_STBY.
G* board
Operation IC Ref Voltage supply
DC/DC IC801 1.1V_M5_DDR
DC/DC IC802 0.9V_M5_STBY
DC/DC IC803 1.8V_STBY
DC/DC IC603 1.0V_TU_P
34
SYS SET