HP L1706 - No Backlight Troubleshooting

17" LCD Color Monitor HP L1706
37
2. W/LED No Backlight
Check C811 (+) =12V
Check Q801/Q802/Q803
Check ON/OFF signal
Check Interface board
Check IC801 pin5=12V voltage
Check R826/D802/R826
Check the pin1/15 of IC801 if have waveforms
Short Q806 S D ,if the picture normal
Change IC801
Connect PIN4 /PIN7of IC801 and check Q806 collector waveforms
Check feedback circuit
Change Q806/PT802
Check connecter & lamp
OK
OK
OK
OK
NG
NG
NG
NG
NG
OK
NG
NG