Brother HL 5030 - B/W Laser Printer Service Manual page 208

CHAPTER 6 TROUBLESHOOTING
I-4 All black
Possible cause
Corona failure
Harness
connection
High-voltage
power supply
PCB failure
Main PCB
failure
User Check
(1) Clean the corona wire of the drum unit.
(2) The drum unit may be damaged. Install a new drum unit.
Step Check
1 Is the corona wire dirty?
2 Is the corona wire broken?
3 Are the charge electrodes
between the printer body and
the drum unit dirty?
4 Is the laser unit connected to
the main PCB correctly?
5 Is the problem solved after
replacing the high-voltage
power supply PCB?
6 Is the problem solved after
replacing the main PCB?
Result
Yes Clean the corona wire
with the wire cleaner.
Yes Replace the drum
unit.
Yes Clean both
electrodes.
No Connect the harness
between the laser unit
and the main PCB
correctly.
Yes Replace the high-
voltage power supply
PCB.
Yes Replace the main
PCB.
6-28
Ground
Remedy
contacts
(2)
(3)