Brother DCP-7090 Service Manual page 130

 Horizontal stripes
<User Check>
Step
Dirty charge electrodes
1
Dirt on the exposure drum
2
A ground wire or ground plate
installation failure (Grounding
3
is not performed correctly.)
Scratch or dirt on the fuser
4
unit
High-voltage power supply
5
PCB failure
 White vertical streaks on image
<User Check>
Step
Dirt on the exposure drum
1
2 Laser unit failure
• This problem may disappear after printing multiple sheets of paper.
• Refer to <How to clean the drum unit>
exposure drum using a cotton applicator.
• Replace the drum unit with a new one.
• Replace the toner cartridge with a new one.
Cause
• Check that there is no dust on the toner cartridge.
• Refer to <How to clean the drum unit>
exposure drum using a cotton applicator.
• Replace the drum unit with a new one.
• Replace the toner cartridge with a new one.
Cause
2-90
to remove the dirt from the
Remedy
Clean the electrodes of the drum unit and
those of the machine. (Refer to
56) and Fig. 2-12 (P2-56).)
Perform drum cleaning.
(Refer to "2.1 Drum Cleaning" in Chapter
Retighten the screws of each ground wire or
ground plate. Repair the bend of the tray
ground spring of the paper tray.
(Refer to Fig. 2-18 (P2-89).)
Replace the fuser unit.
Replace the high-voltage power supply PCB
ASSY.
to remove the dirt from the
Remedy
Perform drum cleaning.
(Refer to "2.1 Drum Cleaning" in Chapter
Replace the laser unit.
Fig. 2-13 (P2-
5.)
5.)
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