Brother DCP-8070D Service Manual page 141

■ Dark
Step Cause
Drum unit
1
electrode dirty
Drum unit failure
2
Developing bias
3 malfunciton
HVPS PCB
4 failure
Main PCB failure Is the problem solved
5
<User Check>
- Check the machine's environment. High temperature and high
humidity conditions can cause this problem.
- Replace the drum unit with a new one.
- Replace the toner cartridge with a new one.
Check
Is the electrode of the
drum unit dirty?
Is the problem solved
after replacing the drum
unit?
Is the problem solved
after reseting the
developer roller counter?
Is the problem solved
after replacing the
HVPS PCB ASSY?
after replacing the main
PCB ASSY?
3-50
Result Remedy
Clean the electrode.
Yes
Replace the drum unit.
Yes
Reset the developer roller
Yes counter.
Replace the HVPS PCB
Yes ASSY.
Replace the main PCB
Yes ASSY.
Confidential