Power Supply Unit - Oki B 4100 Maintenance Manual

7.1.17 Power Supply Unit

(1) The main power supply is not turned ON.
C26 at 4.8 V or more?
40055101TH Rev.4
Start
Is the MPON
set to high?
Yes
No
Is the VCE voltage of
Q5 set to almost 0 V?
Yes
No
Is the voltage across
Yes
No
Is the triac side of
PC2 set to ON?
Yes
No
Is the voltage applied
across C6 at 140 V
or more?
Yes
End
No
Replacement
Replacement
To flowchart
(2) for no 5 V(S)
output.
Replacement
Replacement
1. Breakdown of Q5
by short circuit.
1. Breakdown of Q5
in open mode.
1. PC2 fault
2. R25, R26 open circuit
1. Short or open circuit
of D1 to D4
2. Open circuit of TH1
256 /