LG CM9730 - System Part

3-30
ELECTRICAL TROUBLESHOOTING GUIDE
2. SYSTEM PART
Power on.
FRONT board OK.
Check 17p FFC cable.
Check SMPS board.
Check FFC cable.
Check MAIN board.
Check SMPS board.
Check MAIN board.
Replace DIG301.Q301, 303, 304 grid voltage OK?
Replace LED
(LD3V09 ~ LD3V24).
Check MAIN board.
“HELLO”
Display on FLD
OK?
Volume LED
(LD3V31 ~ LD3V40
LD3V42 ~ LD3V49)
Turn on?
When turn
the volume, count is
change?
NO
NO
NO
NO
NO
NO
NO
NO
NO
NO
CN301
cable connection
OK?
Q301,
Q303, Q304 grid voltage
OK?
CN3V01
Pin31, 32 signal
OK?
CN301
Pin9, 10, 11 data signal
OK?
CN301 pin1, 3, 5
power OK?
CN3V01
Pin8, 9 +12 V OK?
YES
YES
YES
YES
YES
YES
YES
YES
YES