All One Color; Dirt On Back Side Of Paper - Brother HL-4140CN Service Manual

■ All one color

<User Check>
- Replace the drum unit with a new one.
Memo
You can check this image defect with the function code 71.
(Refer to "1.4.17 Color test pattern (Function code 71)" in Chapter
Step
1 Corona wire failure
2 High-voltage power supply
PCB failure
3 Laser unit failure
4 Main PCB failure

■ Dirt on back side of paper

Step
1 Dirt in the paper feed system
2 Fuser unit dirty
3 High-voltage power supply
PCB failure
Cause
Clean the electrodes of the drum unit and
main body. (Refer to
Fig. 2-9
Replace the high-voltage power supply PCB
ASSY.
Replace the laser unit.
Replace the main PCB ASSY.
<User Check>
- This symptom might stop occurring after making
several prints.
- Clean the belt unit.
- Replace the waste toner box with a new one.
- Replace the belt unit with a new one.
Cause
Wipe dirt off.
Replace the fuser unit.
Replace the high-voltage power supply PCB
ASSY.
2-100
5.)
Remedy
Fig. 2-6 (P2-52)
(P2-53))
Remedy
and
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