ViewSonic P90F - Troubleshooting Flow Chart; Troubleshooting Section 1

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YES
NO
NO
YES
YES
YES
NO
NO
NO
NO
NO
YES
10.
TROUBLESHOOTING FLOW CHART
SECTION 1
Q811
o
n, Q812
o
ff
LED light up ?
LED color is Amber ?
C825 = 190V approx. ?
Q811 on
pin 2 of I803 > 2.5V
Check D815,D804, D816,
D817
,
D818
,
D819 short ?
OVP, D826 short? or Check
Q807
,
Q808 short ?
Load of secondary side
short ?
Fuse open ?
Check R807,R831
Q801
Check
D801
,
D802
,
D803
,
D800?
NO
Check pin 23 of IA01
(
> 3.3V
)
Check pin 41,42 of
IA01
YES
Check I807,I808,Q814 D827,
I804
YES
If D815, D850 are defective,
check Q402, Q433
Check if Q433, Q402,
short ?
Check if Q121, Q124
short ?
If disconnect P902 of
video board(PWB-0237) is
OK
then check I903 I901
ViewSonic Corporation
Confidential – Do Not Copy
P90f-1