Trouble Shooting Flow Chart - ViewSonic va520 Service Manual

6. Trouble Shooting Flow Chart

(VA521/VE510s-2/VE510b-2)
6.1.
NO POWER or BACKLIGHT
Check main board
backlight_on signal
Check Q903,D906
Check R925,F901
broken or not
Check Q905.
Check I901,I902,
R904,R905
ViewSonic Corporation
NO POWER
Yes
3.3V on P801
pin5,6 to GND
12V on P802
pin3 to GND
Yes
NO BACKLIGHT.
No
Check P802 pin2 with
3.3V or not
Yes
No
Check 5V on I901 pin6
Yes
Check I901 pin1 voltage
No
>1.0volts,<3.0volts
while inverter turn on
Yes
Check
Q901,Q902,D903,D904
With power
but power saving mode more
than 1 Watts
CHECK C805
No
with voltage more than
150volts or not
Yes
Check R813~R815 broken or
not
No
Check Q802,D813 failed or not
If there had Sawtooth
waveform on DC output
No
Check I802,I803
If there had Sawtooth
waveform on DC output
No
Check D809,D811.
If there had Sawtooth
waveform on DC outputr
Confidential - Do Not Copy
17
Check Q903,I804
without connecting main board,
Yes
with main board more than
1Watts
check main board.
CHECK
No
D801~D804 failed or not,
F801 broken or not,
R802 failed or not
Check Q801 D & S short
Yes
not,I801 failed,
R807 broken or not
VA521
VE510b/s-2
or