Vertical Streaks In A Dark Background - Brother HL-4140CN Service Manual

■ Vertical streaks in a dark background

<User Check>
- Clean the inside of the printer and the corona wire in the drum unit.
- Refer to the User's guide and remove the dirt on the exposure drum using a cotton swab.
- Replace the toner cartridge with a new one.
Step
1 Exposure drum dirty
2 Laser unit failure
■ Horizontal stripes
<User Check>
Step
1 Dirt on charged electrode
2 Bend of tray ground spring
3 Scratch on the heat roller
4 High-voltage power supply
PCB failure
Cause
- Clean the inside of the printer and the corona wire in the drum unit.
- This symptom might stop occurring after making several prints.
If the symptom continues, replace the toner cartridge with a new one.
- Replace the drum unit with a new one.
Cause
2-102
Remedy
Refer to "2.8 Drum Cleaning" in Chapter 5
and perform drum cleaning.
Replace the laser unit.
Remedy
Clean the electrodes of the drum unit and
main body. (Refer to Fig. 2-6 (P2-52)
Fig. 2-9 (P2-53))
Replace the paper tray.(Refer to
(P2-101))
Replace the fuser unit.
Replace the high-voltage power supply PCB
ASSY.
and
Fig. 2-13
Confidential