Brother MFC-8710DW - Black Spots

2-83
Confidential
 Black spots
 Downward fogging of solid color
<User Check>
- When the black spots appear at intervals of 45.3 mm, replace the
toner cartridge with a new one.
- Refer to the User's Guide to remove the dirt from the exposure drum
using a cotton applicator.
- When the black spots appear at intervals of 94.2 mm, replace the
drum unit with a new one.
Step Cause Remedy
1
Dirt on electrodes of the drum unit
and those of the machine
Clean the electrodes of the drum unit and
those of the machine. (Refer to Fig. 2-10 or
Fig. 2-11.)
2
Dirt on electrodes of the toner
cartridge and those of the machine
Clean the electrodes of the toner cartridge
and those of the machine. (Refer to Fig. 2-
10 or Fig. 2-11.)
3
Scratches or dirt on the heat unit
(horizontal stripes at intervals of
104 mm), or dirt on the pressure
roller
Replace the fuser unit.
4
High-voltage power supply PCB
failure
Replace the high-voltage power supply PCB
ASSY.
5 Main PCB failure Replace the main PCB ASSY.
<User Check>
- Replace the toner cartridge with a new one.
Step Cause Remedy
1
High-voltage power supply PCB
failure
Replace the high-voltage power supply PCB
ASSY.
2 Main PCB failure Replace the main PCB ASSY.