LG MDT505 - Front Board Troubleshooting

3-4
ELECTRICAL TROUBLESHOOTING GUIDE
Power on.
FRONT board ok.
YES
YES
Check 36p FFC cable.
Check 5p FFC cable.
Check SMPS board.
Check MAIN board.
Replace IC301.
Replace DIG301.
YES
YES
YES
YES
YES
Digitron (DIG301) ok?
Check MAIN board.
Replace LED (LD301~LD315).
“WELCOME”
Display
on VFD ok?
When you turn
the volume knob, count
is change?
NO
NO
NO
NO
NO
NO
NO
NO
PN301 cable
connection ok?
PN301 Pin22, 26
signal ok?
PN301 Pin1,2,3,6
power ok?
PN301
Pin7, 8, 9, 10 data signal
ok?
IC301
check ok?
2. FRONT BOARD
YES
Check SMPS board.
Check Main board.
YES
YES
Volume LED
(LD301~LD315)
turn on?
NO
NO
NO
PN301 Pin21
+12 V ok?
Check
PN301 Pin11,13,29~36
data signal.