Oki B4100, Maintenance Manual

Page: 313 / 637

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