3.
Checking the Potential System
11-47
Short J127-1 and -2 on the DC
controller PCB with a jumper wire.
Disconnect J103.
Select non-potential mode. (
*
4
*
;
'PO.CONT' '1')
Turn off the power switch.
Remove the jumper wire used to
short J127-1 and -2 on the DC
controller PCB. Connect J103.
Check to make sure that power is
on the potential measurement PCB,
and replace the potential
measurement unit.
Turn off the power switch.
Turn on the power switch.
Select non-potential control mode.
(
*
4
*
.CONT' '1')
Measure the voltage during
copying between J114A-6 (+) and
A-13 (-) on the DC controller PCB.
Check the transfer charging
assembly for leakage. Try changing
the setting of 'FUZZY' in service
mode (
*
5
*
). Try replacing copy
paper.
Replace the DC controller PCB.
Select the activation voltage limiter
of the scanning lamp(
*
1
*
; 'LIMT').
Select potential control mode.
(
*
4
*
; 'PO.CONT' '0')
Turn on the power switch.
Clean the standard white plate,
mirror, lens, and dust-proofing
glass; then, turn off and on the
power switch.
Select non-potential control.
(
*
4
*
; 'PO.CONT' '1')
START
NO
YES
NO
YES
NO
YES
NO
YES
NO
YES
NO
(transfer output)
(zero-level check)
End.
Turn on the power switch.
Start service
mode (
*
4
*
). Is the indication
of address P023 during initial
rotation between
'0003' and
'001B'?
Is the
actual measurement of
step A and the reading of 'TC' in
service mode ±10%?
NO
<Transfer Output>
<Scanning Lamp Output>
Has the image improved?
Is the
toner image on the
photosensitive drum before
transfer normal?
A
Replace the
high-voltage transformer.
Is the problem corrected?
Is 'LIMT' '1'?
Is 'LIMT' '1'?
YES
YES
Measure the voltage during copying
between J111B-7 (+) and B-8 (-) on
the DC controller PCB.
B
Start service mode (
*
1
*
), and
select 'TC' (transfer charging
assembly current). Convert the
reading (unit: µA) into its control
voltage as shown in 4 "Potential
Control Conversion Table."
Replace the DC controller PCB.
