Brother MFC-P2000 - B/W Laser Printer Service Manual page 76

I-2 Dark
<Scanning>
Possible cause Step
Main PCB
failure
Laser unit failure
<Printing>
Possible cause Step
Corona failure
(soiled wire)
Corona failure
(contact failure)
Drum unit failure
High-voltage
power supply
PCB
Main PCB
Panel sensor
PCB
Check
1 Is the problem solved after the
main PCB is replaced?
2 Is the problem solved after the
laser unit is replaced?
Check
1 Is the corona wire dirty?
2 Are the corona electrodes
between the printer body and
drum unit dirty?
3 Is the problem solved when the
drum unit is replaced?
4 Are there any disconnected
connectors?
5 Are there any disconnected
connectors?
6 Are there any disconnected
connectors?
Result
Yes
Yes
Result
Yes
No
Yes
No
No
No
IV-7
Remedy
Replace the main PCB.
Replace the laser unit.
Remedy
Clean the corona wire
by using the wire
cleaner.
Clean both electrodes.
Replace the drum
unit with a new one.
Replace the high-
voltage power supply
PCB.
Replace the main
PCB.
Replace the panel
sensor PCB.
GND
contacts
(Fig.4-5)