LG L1718S-BN - - 17" LCD Monitor Service Manual page 17

Output Voltage Unstable
Check Vbe of
Q801 below 0.3V
Check reference
voltage
Check feedback
circuit
END
3. DC output voltage is unstable
Check circuit if
short
Check Q801, Q802
Check Pin R of
IC803
about 2.5V
Check R810, R811
Check Vpin3-4 of
IC801 about 6V
Check Vpin1-2 of
IC801 about 1V
Check R809,
R814
17
voltage
Check ZD801,
ZD802, ZD803,
D803, D805
Check R809,
R814, IC801,
R818
Check C815,
D806, R812