Brother HL-7050 Service Manual page 257

I-16 Black spots
User Check
(1) If the problem is not solved after printing a few pages, the drum unit may have
glue from label stock on the photosensitive drum surface. Refer to Step 1 in the
table below and
(2) The drum unit may be damaged. Install a new drum unit.
Possible cause Step
Drum unit 1
Drum 2
connection
failure
Fixing unit 3
High-voltage 4
power supply
PCB failure
NOTE in the previous page.
Check
Are the spots at 94mm
intervals?
(The problem is not solved
after printing a few pages.)
Is the contact between the
drum unit and printer body
connected correctly?
Are the spots at 108mm
intervals?
(The problem is not solved
after printing a few pages.)
Is the problem solved after
replacing the high-voltage
power supply PCB?
6-47
Result Remedy
Yes 1) If toner or glue
remains stuck, wipe it
off gently with a
cotton swab. (Refer
to NOTE in the
previous page.)
2) If the photosensitive
drum is scratched or
deteriorated
(exposed), replace
the drum unit.
No Clean contact electrode
both on the drum unit
and in the printer body.
Yes 1) Check and clean the
heat roller with a cloth
dampened with
alcohol.
2) Replace the fixing
unit.
Yes Replace the high-voltage
power supply PCB.
HL-7050 SERVICE MANUAL
Ground
contacts
(8)