Dell S1909WNf Service Manual page 32

Power (include IF +5Vand +3.3V) supply and display normal but LED Amber
Is Power LED Amber?
Do the Hsync. & Vsync. Signals exist
in CN102 #13& #14 separately when
select VGA mode by OSD?
Do the Hsync. & Vsync. Signals exist
in R133 & R134?
Do the Hsync. & Vsync. Signals exist
in U105#32& #33?
Is the Q108 work normal?
Is theLED control signal at #124 of
U105 high-low convertible when DC
on/off
YES
YES
YES
YES
YES
END
NO
Insert VGA Cable correctly
NO
Check R133 & R134
NO
Change R115 & R116
NO
Change Q108
Change U105
NO
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Service Manual