The Copy Is Blank - Canon iR8500 Service Manual

3.3.21 The copy is blank

Developing assembly (engagement)
1) During printing operation, is the developing assembly locked to the
NO:
Developing assembly drive mechanism
2) During printing, is the developing assembly rotating?
NO:
Transfer charging assembly
3) Is the transfer charging assembly fitted fully?
NO:
4) Is leakage noted in the transfer charging assembly?
YES: Check the transfer charging assembly.
CCD unit, Relay PCB
5) Is the voltage supplied to the CCD unit as rated?
NO:
Laser unit, Image processor PCB, Drum unit
6) Is the laser output normal?
NO:
YES: Replace the drum unit.
7) Are the connector J1452 (found to the left of the controller box)
NO:
YES: Replace the drum unit
Developing bias connector
8) Is the connector (on the machine rear) for the developing bias con-
NO:
COPYRIGHT© 2001 CANON INC.
photosensitive drum?
Check the locking mechanism of the developing assembly.
Check the developing assembly drive mechanism.
Fit it fully.
Perform the following:
1. Check the relay PCB.
2. Check the power path between the CCD unit and the relay PCB;
if normal, replace the CCD unit.
Perform the following:
1. Replace the laser unit.
2. Replace the image processor PCB.
and the connector J1302 of the laser driver PCB firmly connected?
Fit them securely (so that they are locked in place).
nected?
Connect the connector.
2000 2000 2000 2000
CHAPTER 6 TROUBLESHOOTING
CANON iR8500/7200 REV.1 AUG. 2001
6-91