3.
DC output voltage is unstable
Output Voltage Unstable
Check Vbe of
Q801 below
0.3V
Check circuit if
short
Check ZD801, ZD802,
ZD803, D803, D805
Check Q801, Q802
Check reference
voltage
Check pinR
of IC801
Check R809, R814,
IC801, R818
Check R810, R811
Check feedback
circuit
Check Vpin3-4 of
IC801 about 6V
Check Vpin1-2 of
IC801 about
1V
Check C815, D806,
R812
Check R809,
R814
END
26
ViewSonic Corporation
Co
nfidential
-
Do
Not
Copy
VA902/b
Summary of Contents for VA902B - 19" LCD Monitor
Page 32: ...6 Black Screen and backlight turn on 29 ViewSonic Corporation Confidential Do Not Copy VA902 b...
Page 49: ...46 ViewSonic Corporation Confidential Do Not Copy VA902 b 9 PCB Layout Main board Top layout...
Page 50: ...47 ViewSonic Corporation Confidential Do Not Copy VA902 b POWER board...
