ViewSonic VA702-1 Service Manual page 39

DC output voltage is unstable
3.
Output Voltage Unstable
Check Vbe of
Q801 below 0.3V
Check reference
voltage
Check feedback
circuit
END
ViewSonic Corporation
Check circuit if
short
Check Q801, Q802
Check pinR
of IC801
Check R810, R811
Check Vpin3-4 of
IC801 about 6V
Check Vpin1-2 of
1V
IC801 about
Check R809,
R814
Confidential - Do Not Copy
36
Check ZD801, ZD802,
ZD803, D803, D805
Check R809, R814,
IC801, R818
Check C815, D806,
R812
VA702-1_VA702b-1