Brother FAX-2840 Service Manual page 108

Black horizontal stripes
<User Check>
- Clean inside the machine and the corona wire of the drum unit.
- When the horizontal stripes appear at intervals of 94.2 mm, replace
- The paper tray earth spring on the machine side may be dirty. Clean
- Toner attached on the developer roller (horizontal stripes at intervals of 32.5 mm)
Step
Dirt on electrodes of the drum unit
1 and those of the machine
Bend of tray earth spring
2
Scratch or dirt on the heat roller
3
(horizontal stripes at intervals of 53.4 mm)
4 High voltage power supply PCB failure Replace the high voltage power supply PCB ASSY.
5 Main PCB failure
CAUTION:
• Image defects which appear periodically may be caused by failure of rollers. Refer to the table below and
determine the cause based on the diameter of the rollers or the pitch at which defects appear in the image.
No.
1 Developer roller
2 Exposure drum
3 Heat roller in the fuser unit
4 Pressure roller in the fuser unit
the drum unit with a new one.
it with a dry cloth.
This problem will disappear by printing approximate 10 pages. If the same
problem occurs, replace the toner cartridge.
Cause
Back of paper tray
Tray earth spring
Fig. 2-12
Parts name
2-71
Remedy
Clean the electrodes of the drum unit and
those of the machine. (Refer to
and Fig. 2-11.)
(1) Correct bending of the tray earth spring.
(2) Replace the paper tray.
Replace the fuser unit.
Replace the main PCB ASSY.
Pitch at which defects
Diameter
ø 16 mm
ø 30 mm
ø 17 mm
ø 25 mm
Fig. 2-10
appear in the image
32.5 mm
94.2 mm
53.4 mm
78.5 mm
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