Samsung SF3000 Service Manual page 48

7-2-1. No +5 V
START
Y
DC 6 V
N
Check PCB Pattern
7-2-2. No -12 V
START
Y
-15 VDC
N
Check PCB Pattern
Samsung Electronics
N
Output Shorted ?
Y
Remove short
Y
Check U2 ?
N
Replace U2
N
output shorted ?
Y
Remove short
Y
U1 Output ?
N
Replace U4
N
D2 Open or
Shorted ?
Y
Replace D4
Check CON1
N
D3 Open or
Shorted ?
Y
Replace D3
Check CON1
Troubleshooting
Check U2 Input
voltage
END
Check U3 Input
voltage
END
7-3