Front Block - LG HB954TB Service Manual

ELECTRICAL TROUBLESHOOTING GUIDE

4. FRONT BLOCK

Power on
"WELCOME
PLEASE WAIT" Display
on VFD OK?
YES
Volume LED
Turn ON?
YES
When you turn
the volume knob, count
is change?
YES
FRONT Block OK
NO
CN303 cable
connection OK?
CN303 pin2,3,4,7
power OK?
CN303 pin10,11,12
data signal OK?
IC301
check OK?
Digitron(DIG301) OK?
NO
CN303 pin6
+12V OK?
Replace LED
NO
CN303 pin17,18
signal OK?
I/F Junction & MAIN
Block check
2-33
NO
YES
NO
YES
NO
YES
NO
YES
NO
NO
YES
NO
YES
20p FFC cable connect
After I/F Junction B/D's power
line check, SMPS Block check
After I/F Junction B/D's data
line check, MAIN Block check
Replace IC301
Replace DIG301
After I/F Junction B/D's check,
SMPS Block check
Replace VR301