HP L1702

HP L1702
31
No Backlight
Check C201(+) =12V
Check the resonant wave of Pin
2&Pin5 for PT210/PT202
Check the Pin1 of U201 have
sawtooth wave
Check the output of PT201/PT202
Check ON/OFF signal
Check U201 Pin9=12V
Check adapter circuit
Check main board
OK
OK
NG
NG
Check Q201 or Q202 circuit
NG
NG
OK
Check D201/D202(-) have the output
of square wave at short time
Change U201/R204/C208
Check Q203/Q204/D201/D202
Check Q209/Q210/Q211/Q212/C213/C214
OK
OK
OK
NG
NG
Check connecter & lamp
Change PT201/PT202
OK
NG