System Part - LG CM9750 Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

2. SYSTEM PART

Power on.
"HELLO"
Display on MLD
OK?
YES
Top LED
(LD311, LD313),
(LD301, LD303)
Turn on?
YES
When turn
the volume, count is
change?
YES
System part OK.
CN605
NO
cable connection
OK?
CN605
pin14, 15, 16, 24 power
OK?
CN605
pin8, 9, 10 data signal
OK?
FL+/- & VKK voltage OK?
CN605 pin24
NO
+12 V OK?
Replace LED
(LD311, LD313),
(LD301, LD303)
Check
NO
CN605 pin5, 6
I2C data OK?
Check MAIN board.
3-28
NO
YES
NO
YES
NO
YES
NO
NO
YES
NO
YES
Check FFC cable.
Check SMPS board.
Check MAIN board.
Replace VFD301.
Check SMPS board.
Check FFC cable.