Brother 1240 Service Manual page 158

CHAPTER 6 TROUBLESHOOTING
I-16 Black spots
Possible cause
Drum unit
Fixing unit
High-voltage
power supply
PCB failure
I-17 Black band
Possible cause
Corona failure
Corona failure
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 NOTE
(2) The drum unit may be damaged. Install a new drum unit.
Step Check
1 Are the spots at 94mm
intervals?
(The problem is not solved
after printing a few pages.)
2 Are the spots at 79mm
intervals?
(The problem is not solved
after printing a few pages.)
3 Is the problem solved after
replacing the high-voltage
power supply PCB?
Step Check
1 Is the wire cleaner at its home
position?
2 Is the corona wire dirty?
in the previous page.
Result
Yes
Yes
Yes
Result
No
Yes
6-36
Remedy
1) If toner or glue remains
stuck, wipe it off gently with a
cotton swab. (Refer to
in the previous page.)
2) If the photosensitive drum is
scratched or deteriorated
(exposed), replace the drum
unit.
1) Check and clean the heat
roller with a cloth dampened
with alcohol.
2) Replace the fixing unit.
Replace the high-voltage power
supply PCB.
Remedy
Return the wire
cleaner to its home
position.
1) Clean the corona
wire.
2) If the problem still
appears after
cleaning, replace
the drum unit.
NOTE
Ground
contacts