Brother DCP-8070D Service Manual page 144

■ All black
Step Cause
Corona wire
1 failure
2
Scanner harness
of the laser unit
3
connection
failure
FG harness
ASSY connection
4
failure
HVPS PCB
5 failure
Main PCB failure Is the problem solved
6
Laser unit failure
7
Check
Are the electrodes on
the drum unit and
machine body dirty?
Is the corona wire
damaged?
Is the scanner harness
of the laser unit
connected securely?
Is the FG harness ASSY
between the laser unit
and main PCB ASSY
connected securely?
Is the problem solved
after replacing the
HVPS PCB ASSY?
after replacing the main
PCB ASSY?
Is the problem solved
after replacing the laser
unit?
3-53
Result Remedy
Clean both electrodes.
Yes (Refer to Fig. 3-2, Fig.
Replace the drum unit.
Yes
Reconnect the scanner
harness of the laser unit.
No
Reconnect the FG harness
ASSY between the laser
No
unit and main PCB ASSY
securely.
Replace the HVPS PCB
Yes ASSY.
Replace the main PCB
Yes ASSY.
Replace the laser unit.
Yes
3-3.)
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