Brother MFC-9010CN - Page 176

3-84
Confidential
■ Unstable color density
<User Check>
- Make a print on a different type of paper.
- Replace the belt unit with a new one.
- Replace the drum unit with a new one.
- Replace the waste toner box with a new one.
- Replace the toner cartridge with a new one.
Step Cause Check
Result
Remedy
1 Drum unit
conduction failure
Are the electrodes on
the drum unit and
machine body dirty?
Yes
Clean both electrodes.
(Refer to
Fig. 3-3 (P3-33)
and Fig. 3-6 (P3-34)
)
2 Toner cartridge
conduction failure
Are the electrodes on
the toner cartridge and
machine body dirty?
Yes Clean both electrodes.
(Refer to
Fig. 3-3 (P3-33)
and
Fig. 3-6 (P3-34) )
3 Dirt on belt unit
electrode
Are the electrodes on
the belt unit and
machine body dirty?
Yes Clean both electrodes.
(Refer to
Fig. 3-4 (P3-33)
and Fig. 3-6 (P3-34)
)
4 Engine PCB failure Is the problem solved
after replacing the
engine PCB ASSY?
Yes Replace the engine
PCB ASSY.
5 HVPS control PCB
failure
Is the problem solved
after replacing the HVPS
control PCB ASSY?
Yes Replace the HVPS
control PCB ASSY.
6 High-voltage power
supply PCB failure
Is the problem solved
after replacing the
high-voltage power
supply PCB ASSY?
Yes Replace the
high-voltage power
supply PCB ASSY.
7 LED head control
PCB failure
Is the problem solved
after replacing the LED
head control PCB ASSY?
Yes Replace the LED head
control PCB ASSY.
8 Main PCB failure Is the problem solved
after replacing the main
PCB ASSY?
Yes Replace the main PCB
ASSY.