Table of Contents
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Step
Cause
10
Drum unit
High-voltage
cord, high-
voltage power
supply PCB,
DC controller
PCB
4
The copy has uneven density. (darker at front)
5
The copy has uneven density. (lighter at front)
Step
Cause
Scanner
Transfer
charging
assembly
Pre-exposure
lamp
Developing
assembly
Charging wire,
copy paper
COPYRIGHT © 1997 CANON INC.
Download Service Manual And Resetter Printer at http://printer1.blogspot.com
Checks
Replace the drum unit. Is the
problem corrected?
Checks
1
Clean the scanning lamp, reflect-
ing plate, side reflecting plate,
mirror, lens, and dust-proofing
glass. Is the problem corrected?
2
Perform the Image Adjustment
Basic Procedure. Is the problem
corrected?
3
Is the transfer charging assembly
set securely?
4
Is the charging wire of the transfer
charging assembly hooked
properly, and is its height normal?
5
Is the pre-exposure lamp on
during copying operation?
6
Is the coating of toner on the
developing cylinder even?
CANON NP6330 REV.0 MAY 1997 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 11 TROUBLESHOOTING
YES/NO
Action
YES
End.
NO
1. Check the high-
voltage cord for
electrical continuity.
2. Check the high-
voltage power supply
PCB and the DC
controller PCB
YES/NO
Action
YES
End.
YES
End.
NO
Set the charging
assembly securely.
NO
Re-string the charging
wire.
NO
See "The pre-exposure
lamp fails to turn on."
NO
• Check the edge of the
blade of the developing
assembly.
• Dry wipe the surface of
the developing cylinder.
YES
• Clean all charging
wires once again, and
check their position.
• Try replacing the copy
paper.
11-59
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Troubleshooting
