Poor Fixing - Brother HL-2440 Service Manual

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Poor fixing

Step Cause
High pressure of
1 pressure roller in
the fuser unit
Fuser unit failure
2
Low-voltage
3 power supply
PCB failure
HVPS PCB
4 failure
Main PCB failure Is the problem solved
5
■ Completely blank
Step Cause
Developing bias
voltage
1
conduction
failure
Scanner harness
of the laser unit
2
connection
failure
Laser unit failure
3
HVPS PCB
4 failure
Main PCB failure Is the problem solved
5
User Check
• Replace the drum unit with a new one.
• Replace the toner cartridge with a new one.
Check
Is the problem solved by
changing the position of
the pressure roller?
Is the problem solved
after replacing the fuser
unit?
Is the problem solved
after replacing the PS
PCB unit?
Is the problem solved
after replacing the
HVPS PCB ASSY?
after replacing the main
PCB ASSY?
User Check
• Replace the drum unit with a new one.
• Replace the toner cartridge with a new one.
Check
Are the electrodes on
the drum unit and
machine body dirty?
Is the scanner harness
of the laser unit
connected securely?
Is the problem solved
after replacing the laser
unit?
Is the problem solved
after replacing the
HVPS PCB ASSY?
after replacing the main
PCB ASSY?
1-25
Result Remedy
Change the position of the
Yes pressure roller.
(Refer to Fig. 1-5.)
Replace the fuser unit.
Yes
Replace the PS PCB unit.
Yes
Replace the HVPS PCB
Yes ASSY.
Replace the main PCB
Yes ASSY.
Result Remedy
Clean both electrodes.
(Refer to Fig. 1-2, Fig.
Yes
Reconnect the scanner
harness of the laser unit.
No
Replace the laser unit.
Yes
Replace the HVPS PCB
Yes ASSY.
Replace the main PCB
Yes ASSY.
1-3.)
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