System Part - LG MCV1306 Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

2. SYSTEM PART

Power on.
"HELO"
Display on FLD
OK?
YES
Volume LED
(LD302~LD322)
Turn on?
YES
When turn
the volume, count is
change?
YES
FRONT board OK.
CN301
NO
cable connection
OK?
CN301
Pin27, 28, 29 power
OK?
CN301
Pin20, 21, 22 data signal
OK?
Q301, 303, 304
grid voltage OK?
NO
CN301 Pin18
+12 V OK?
CN301 Pin7, 9, 12
I2C data OK?
Replace LED
(LD302 ~ LD322).
NO
CN301 Pin13, 14
signal OK?
Check MAIN board.
3-33
NO
YES
NO
YES
NO
YES
NO
NO
YES
NO
YES
NO
YES
Check FFC cable (Pin29).
Check SMPS board.
Check MAIN board.
Replace DIG301.
Check SMPS board.
Check MAIN board.
Check FFC cable.