Trouble Shooting Chart; Panel Control Circuit Trouble Shooting - AOC PB20C Service Manual

5-1.Panel Control Circuit:

5. TROUBLE SHOOTING CHART

No Display
Check CN101 pin 42-45
is 5V and signal on pin
35,37,39,40,25-28,30-33,15-
18,20-23,5-8,10-13
NG
Check U300 Output to
CN101 relative circuit and
CN101 VCC at Q300,
Q301, L309 (5V)
NG
Check U300 crystal
X300 (12MHZ)
NG
Check 2.5V L301-L304
3.3V L305-L308
NG
Replace U300
OK
Replace panel or FFC
cable to panel
OK
Replace L118, C137
OK
Replace X300
OK
Replace components
if it has problem
13