Canon CP660 Service Manual page 297

1 The print is too light.
Cause Step
1
Black toner 2
cartridge
High-voltage 3
PCB 1 (inade-
quate black
developing bias
output)
Secondary pre- 4
transfer charg-
ing assembly
Intermediate 5
transfer drum
unit
High-voltage 6
PCB 2 (inade-
quate pre-
transfer charg-
ing bias output)
COPYRIGHT © 1999 CANON INC.
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Checks
Make a test print in service mode
(TEST>PG>TYPE=14), and find the
color that is light on the print.
Is the color on the test print?
Is the contact of the black toner car-
tridge (for black developing bias) or
the contact for black developing bias
of the printer unit soiled?
Open the front cover while black
toner is being developed on the
photosensitive drum (about 30 sec
after the start of test printing), and
take out the black toner cartridge.
Then, take out the black toner car-
tridge, and check the toner image
on the photosensitive drum. Is the
black toner image fully developed on
the surface of the photosensitive
drum?
Is the charging wire of the sec-
ondary pre-transfer charging assem-
bly inside the intermediate transfer
drum unit broken?
Is the contact of the intermediate
transfer drum unit (for secondary
pre-transfer charging bias) or the
contact for the secondary pre-trans-
fer charging bias of the printer unit
soiled?
Replace the high-voltage PCB. Is
the problem corrected?
CANON 660/2100 REV.0 FEB. 1999 PRINTED IN JAPAN (IMPRIME AU JAPON)
CHAPTER 10 TROUBLESHOOTING
Yes/No Action
YES If the problem is black
only, go to step 2.
If the problem is three
colors, go to step 7.
If the problem is all four
colors, go to step 9.
If the problem is one
color, go to step 7.
YES Clean the contact. If it
is deformed, replace
the problem part. Also,
check for a displaced
contact.
NO Replace the high-volt-
age PCB 1.
YES Replace the secondary
pre-transfer charging
assembly.
YES Clean the contact. If it
is soiled or damaged,
replace the problem
part. Also, check for a
displaced contact.
NO Replace the DC con-
troller PCB.
YES End.
10-15