Brother MFC-9320CW Service Manual page 149

■ Dirt on the back of paper
Step Cause
1 Fuser unit dirty
2 Dirt in the paper
feed system
3 Waste toner
sensor failure
4 HVPS control PCB
failure
5 High-voltage power
supply PCB failure
<User Check>
- Replace the waste toner box with a new one.
- Replace the belt unit with a new one.
Check
Is the pressure roller
dirty?
Is the fuser unit dirty?
Is the paper tray or feed
system on the drum unit
dirty with toner?
Is the waste toner box
full of toner?
Is the problem solved
after replacing the HVPS
control PCB ASSY?
Is the problem solved
after replacing the
high-voltage power
supply PCB ASSY?
3-68
Remedy
Result
Yes Print approximate 10
pages.
No Replace the fuser unit.
Yes Wipe dirt off.
Yes Replace the waste toner
sensor.
Yes Replace the HVPS
control PCB ASSY.
Yes Replace the
high-voltage power
supply PCB ASSY.
Confidential