Brother MFC-8220 Service Manual page 226

CHAPTER 6 TROUBLESHOOTING
I-21 Horizontal lines
Possible cause
Paper tray
connection
failure
I-22
Possible cause
Drum unit failure
Drum unit
connection
failure
High-voltage
power supply
PCB failure
Step Check
1 Are the ground contacts on the
back of the paper tray
connecting correctly?
Light rain
Step Check
1 Is the problem solved after
replacing the drum unit?
2 Is the contact between the
drum unit and machine
connected correctly?
3 Is the problem solved after
replacing the high-voltage
power supply PCB?
Result
No Clean the electrodes.
Result
Yes Replace the drum
unit.
No Clean contact
electrode both on the
drum unit and in the
machine.
Yes Replace the high-
voltage power supply
PCB.
6-48
Ground
Remedy
contacts
(7)
Ground
Remedy
contact
(8)