AOC e940Swa - No Picture Troubleshooting

18.5" LCD Color Monitor AOC e940Swa
39
No Picture
No picture
OK
OK
NG
NG
Measure U702 Vout=3.3V,
U704 Vout=1.8V
Replace U702, U704,
CN702
X401 oscillate waveforms are
normal
Replace X401
Check if the sync signal from
computer is output and video
cable is connected normally
Input the sync signal of
computer, or change
the cable
Replace U401
NG
OK