Brother HL-7050 Service Manual page 261

I-20 Downward fogging of solid black
Possible cause Step
Toner cartridge 1
failure
High-voltage 2
power supply
PCB failure
I-21 Horizontal lines
Possible cause Step
Paper feed roller 1
Paper cassette 2
contacts
Check
Is the problem solved after
replacing the toner cartridge?
Is the problem solved after
replacing the high-voltage
power supply PCB?
Check
Are the feed roller shaft and
the ground contact connected
correctly?
Are the ground contacts on the
back side of the paper cassette
connecting correctly?
6-51
Result Remedy
Yes Replace the toner cartridge.
Yes Replace the high-voltage power
supply PCB.
Result Remedy
No Check the connection
between the shaft and
the ground contact.
Also check the ground
contact on the back of
the feed roller.
No Clean the contacts.
HL-7050 SERVICE MANUAL
Ground
contacts
(7)