HP L1940T - Page 22

19" LCD Color Monitor HP L1940T
22
2. W/LED No Backlight
Measure C811 (+) =12V
NG
OK
Check power board part
Check ON/OFF si
g
nal
Check main board
ON/OFF circuit
NG
OK
Check U801 pin 2=12V?
OK
Replace Q873 or Q874
Check U801 Pin1/pin15 export wave
NG
OK
Check U801 pin 5/pin6
NG
OK
Replace U801
Check Q821/Q841 pin5/pin8 = 12V?
NG
Check PT801/PT802
Pin7/pin8 = 650V?
Disconnect Q821/Q841 with IC
,
check C811
(
+
)
=12V?
OK
NG
Disconnect the lamps
Check PT801/PT802 pin7/pin8 = 650V?
OK
NG
Replace lamp
Replace PT801/PT802
OK
NG
NG
Replace Q805
Check Q873 or
Q874
OK