Brother DCP7010 Service Manual page 222

I-7 Black and blurred horizontal stripes
(1) The drum unit may be damaged. Install a new drum unit.
(2) Check the paper used meets the recommended paper specifications.
(3) Clean the printer interior and the corona wire in the drum unit.
Possible cause
Step
Scratch on the 1
drum
Toner stuck 2
on the
developer
roller
Scratch on the 3
heat roller
Corona 4
contact failure
High-voltage 5
power supply
PCB failure
I-8 Black vertical streaks (in a gray background)
Possible cause
Step
Translucent 1
stain on the
scanner
window
Corona failure 2
User Check
Check
Are the horizontal stripes
at 74mm (exposure drum)
intervals?
Are the horizontal stripes
at 37mm (developer roller)
intervals?
Are the horizontal stripes
at 79mm (heat roller)
intervals?
Are the charge electrodes
between the printer body
and the drum unit dirty?
Is the problem solved after
replacing the high-voltage
power supply PCB?
Check
Is there any dirt on the
scanner window?
Is the corona wire dirty?
9 -3 4
Remedy
Result
Yes The exposure drum was
scratched. Replace the
drum unit.
Yes
After printing several
pages, the problem will
disappear.
If not, replace the toner
cartridge.
Yes Replace the heat roller.
Yes Clean both electrodes.
Yes Replace the high-
voltage power supply
PCB.
Remedy
Result
Yes
1) Clean the scanner
window.
2) If it is not effective,
replace the laser
unit.
Yes Clean the corona wire
with the wire cleaner.
Ground
contacts
(3)
Ground
contacts
(2)
Confidential