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
D
o
Not
Copy
VA702/b
ViewSonic
Corporation
Co
nfidential
Summary of Contents for VA702B - 17" LCD Monitor
Page 51: ...9 PCB Layout Main board Top layout 48 Do Not Copy VA702 b ViewSonic Corporation Confidential ...
Page 52: ...Main board bottom Layout 49 Do Not Copy VA702 b ViewSonic Corporation Confidential ...
Page 53: ...POWER board 50 Do Not Copy VA702 b ViewSonic Corporation Confidential ...
Page 54: ...51 Do Not Copy VA702 b ViewSonic Corporation Confidential ...
