Brother MFC-7450

1-34
Confidential
■ All black
Step Cause Check Result Remedy
1
Corona wire
failure
Are the electrodes on
the drum unit and
machine body dirty?
Ye s
Clean both electrodes.
(Refer to Fig. 1-1, Fig. 1-2.)
2
Is the corona wire
damaged?
Ye s
Replace the drum unit.
3
Under FG wire
not assembled
correctly
Is the under FG wire
connected securely? No
Re-assemble the under FG
wire.
4
Scanner harness
of the laser unit
connection
failure
Is the scanner harness
of the laser unit
connected securely?
No
Reconnect the scanner
harness of the laser unit.
5
FG harness
ASSY connection
failure
Is the FG harness ASSY
between the laser unit
and main PCB ASSY
connected securely?
No
Reconnect the FG harness
ASSY between the laser
unit and main PCB ASSY
securely.
6
HVPS PCB
failure
Is the problem solved
after replacing the
HVPS PCB ASSY?
Ye s
Replace the HVPS PCB
ASSY.
7
Main PCB failure Is the problem solved
after replacing the main
PCB ASSY?
Ye s
Replace the main PCB
ASSY.
8
Laser unit failure Is the problem solved
after replacing the laser
unit?
Ye s
Replace the laser unit.