Oki B 4100 Maintenance Manual page 313

ACTION Item:
No.
9 Probable cause 1:
Check item 1:
Probable cause 2:
Check item 2:
Probable cause 3:
Check item 3:
10 Probable cause 1:
Check item 1:
Check item 2:
11 Probable cause 1:
Check item 1:
Probable cause 2:
Check item 2:
Check item 3:
12 Probable cause 1:
Check item 1:
Probable cause 2:
Check item 2:
Probable cause 3:
13 Probable cause 1:
Check item 1:
14 Probable cause 1:
Check item 1:
Check item 2:
Check item 3:
15 Probable cause 1:
Check item 1:
Probable cause 2:
Check item 2:
40055101TH Rev.4
D85 is defective.
Replace D85.
The load is larger than the normal value.
Check if the load current is 2 A or less.
D52 is defective.
Check if D52 is iZ300 class Y or Z (class X is not acceptable).
Q11 and Q12 are malfunctioning.
Check the PWM waveform of DB output (cycle: 142 s, ON time: 36 s).
Check Q11 and Q12. Check the base voltage of Q21, Q22 and Q23 (3.7V or more
to 3.9V or more).
Current set resistor R115 is defective.
Check R115 (tolerance error: +/-1%)
The reference voltage is incorrect.
Check if the voltage at CN3-B10 pin is 2.5V.
Check the PWM waveform of TR1 (cycle: 142Ms, ON time: 36 s).
CC (Constant Current) mode is not set.
Check if TR SEL2 is "H".
T2 is defective.
Replace T2. Check T2.
Check (3) of ACTION 11.
The voltage memory circuit is malfunctioning.
Check if the average value of the VSEN voltage in the CC mode is equal to that in
the CV (Current Voltage) mode.
Check if the voltage across C230 remains unchanged in the CV mode (for 15
seconds or more).
D65 or D66 is defective.
Check if these diodes are 1ZB390.
Check the PWM waveform of TR2 output (cycle: 146 s, ON time: 36 s).
Check if TR1 is "L" or TR2 is "H" (if TR1 is "H", TR1 output appears).
The class of D76 or D82 is incorrect.
Check if both D76 and D82 are of EB-2 class.
The load current is lower than the specified value.
The load current shall be 6 to 8 A. (Namely, the load current shall not be more than
or less than this limit range.)
ACTION
313 /