After Replacing The Dc Controller Pcb; Checking The Surface Potential Control System - Canon GP605 Service Manual

5

After Replacing the DC Controller PCB

No particular work is needed in conjunction with the replacement of the DC controller PCB.
6

Checking the Surface Potential Control System

a. Outline
If an image fault occurs, it is important first to find out whether the cause is in the latent static
formation block (including the photosensitive drum and the potential control system) or the devel-
opment/transfer block, requiring a check on the surface potential, which may be checked in service
mode.
b. Disabling Auto Control
The auto control mechanism may be disabled as one way of finding out whether the corona
current control, lamp intensity control, or developing bias control mechanism is faulty ("non-auto
control mode" hereafter).
Non-auto control mode, further, may be used as an emergency measure in response to a fault in
any of the auto control mechanisms.
Keep in mind that each output in non-auto control will be fixed to its standard setting.
1. Steps
1) Select COPIER>OPTION>BODY>PO-CNT in service mode; then, enter '0', and press the
OK key.
2) Press the Reset key twice.
Caution:
In non-auto control mode, all settings for corona current control, light intensity control, and
developing bias control will automatically be set to the standard settings stored in the ROM.
2. Making Use of Non-Auto Control Mode
If an image fault occurs, use it to find out whether the cause is on the input side or the output
side of the microprocessor on the DC controller PCB.
If the images made in non-auto control mode are relatively better, the potential measurement
unit or the DC controller PCB may be faulty.
COPYRIGHT © 1999 CANON INC. CANON GP605/605V REV.0 JAN. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 13 TROUBLESHOOTING
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