Brother MFC-7450

1-32
Confidential
■ Poor fixing
■ Completely blank
User Check
• Replace the drum unit with a new one.
• Replace the toner cartridge with a new one.
Step Cause Check
Result Remedy
1
Fuser unit
pressure is high
Is the problem solved
after replacing the
position of the pressure
roller?
Ye s
Replace the position of the
pressure roller.
(Refer to Fig. 1-4.)
2
Fuser unit failure Is the problem solved
after replacing the fuser
unit?
Ye s
Replace the fuser unit.
3
LVPS PCB failure Is the problem solved
after replacing the LVPS
PCB unit?
Ye s
Replace the LVPS PCB
unit.
4
HVPS PCB
failure
Is the problem solved
after replacing the
HVPS PCB ASSY?
Ye s
Replace the HVPS PCB
ASSY.
5
Main PCB failure Is the problem solved
after replacing the main
PCB ASSY?
Ye s
Replace the main PCB
ASSY.
User Check
• Replace the drum unit with a new one.
• Replace the toner cartridge with a new one.
Step Cause Check
Result Remedy
1
Developing bias
voltage
conduction
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
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.
3
Laser unit failure Is the problem solved
after replacing the laser
unit?
Ye s
Replace the laser unit.
4
HVPS PCB
failure
Is the problem solved
after replacing the
HVPS PCB ASSY?
Ye s
Replace the HVPS PCB
ASSY.
5
Main PCB failure Is the problem solved
after replacing the main
PCB ASSY?
Ye s
Replace the main PCB
ASSY.