ViewSonic P90F - Troubleshooting Section 5

32
SECTION 5
DC at Source o
f
Q402 =
190Vapprox.
Display is Vertical. Line
(No Horizontal output)
Check SMPS DC output
(SECTION 1)
REPLACE I301
NO
Is waveform at
Drain of Q402 Proper ?
Is output of Q400,Q421
proper ?
YES
NO
NO
Is output at Pin 28 o
f
I301 proper ?
NO
YES
Check Q433
short?, and is Q433
out
p
ut
p
ro
p
er ?
NO
NO
Is Q404 output
proper ?
Is output at Pin 26of
I301 proper ?
NO
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P90f-1