All One Color; Dirt On The Back Of Paper - Brother HL-4040CN Service Manual

All one color

Step Cause
1 Corona wire
failure
2
3 Transfer HVPS
PCB failure
4 Charge HVPS
PCB failure
5 Main PCB failure
6 Engine PCB
failure
7 Laser unit failure

Dirt on the back of paper

Step Cause
1 Fuser unit dirty
2 Dirt in the paper
feed system
3 Belt unit dirty
Check
Are the electrodes on the
drum unit of the
appropriate color and
machine body dirty?
Is the corona wire
damaged?
Is the problem solved
after replacing the
transfer HVPS PCB
ASSY?
Is the problem solved
after replacing the charge
HVPS PCB ASSY?
Is the problem solved
after replacing the main
PCB ASSY?
Is the problem solved
after replacing the engine
PCB ASSY?
Is the problem solved
after replacing the laser
unit?
User Check
- If there is dirt on the back of the paper in duplex printing, the
back of the paper tray may be dirty. Clean the back of the
paper tray.
Check
Is the pressure roller
ASSY dirty? Is any other
area in the machine dirty?
Is the paper tray or feed
system on the drum unit
dirty with toner?
Is the problem solved by
replacing the belt unit?
1-46
Remedy
Result
Yes Clean both electrodes.
Yes Replace the drum unit.
Yes Replace the transfer
HVPS PCB ASSY.
Yes Replace the charge
HVPS PCB ASSY.
Yes Replace the main PCB
ASSY.
Yes Replace the engine PCB
ASSY.
Yes Replace the laser unit.
Remedy
Result
Yes Print approximate 10
pages.
No Replace the fuser unit.
Yes Wipe dirt off.
Yes Replace the belt unit.
Confidential