Oki B4100 - Manual (Page 260)

40055101TH Rev.4 260 /
(5) No –8 V output
Yes
Yes
Yes
No
No
No
Replacement
Replacement
Replacement
1. Q1 short circuit
2. Q3 short circuit
3. R9 open circuit
4. D8, D9 or D10 short circuit
1. D10 open circuit
2. R23 short circuit
1. IC2 fault
2. C20 short circuit
3. Short circuit on load side
Is there oscillation
waveform at VCE of Q1?
Start
Is the output voltage
of C20 at -8V.
End
Is the voltage across
C19 at 9 V or more?