Oki B 4100 Maintenance Manual page 258

(3) No 5 V output
Isn't fuse F1 blown?
Isn't fuse F2 blown?
Is the output wave-
form at VCE of Q1 as
shown in Fig. 1?
40055101TH Rev.4
Start
No
Yes
No
Yes
No
(page A3-49)
Yes
End
To flowchart (6)
no heater output.
1. D1 to D4 short circuit
Replacement
2. C6 short circuit
1. Q1 short circuit
2. Q3 short circuit
Replacement
3. R9 open circuit
4. Check the output line
and load if the overcurrent
protection circuit is operated.
5. ZD4 short circuit
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