System Part - LG BD390 Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

3. SYSTEM PART

POWER on
"HELLO
PLEASE WAIT"
Display on VFD
OK?
YES
"READING"
Display on VFD
OK?
YES
System part OK
CN901,
NO
Pin6; +5.3V, Pin21; -30V,
Pin7; -27V, Pin11;
-24V?
X901 10MHz
OK?
R916
About 625kHz serial
Clock OK?
R923
about 500kHz
OK?
DIG901 change
CN701,
Pin5; 12V, Pin7; 5V,
Pin2; 3.3V, Pin11;
5V?
CA726; 5V
CA723; 1.2V
CA725; 1.8V
X504
54.000MHz
OK?
Check IC201
3-41
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
Check SMPS
X901 Change
IC901 Change
IC902 Change
Timer Board
Check SMPS
IC701, IC702 Change,
IC703 Change,
IC705 Change,
IC706 Change,
IC704 Change.
X504 Change
Main Board