Brother MFC-8460N Service Manual page 354

(I-3) Completely blank
Possible cause
Step
Developing 1
bias contact
failure
Drum unit 2
Drum unit 3
failure
Toner 4
cartridge
failure
Scanner 5
harness
connection
failure
Main PCB 6
failure
Laser unit 7
failure
Check
Are the developing bias
contacts between the
machine body and drum
unit dirty?
Are the drum shaft and
drum electrode of the
machine body connected
correctly?
Is the problem solved after
replacing the drum unit?
Is the problem solved after
replacing the toner
cartridge?
Is the scanner harness
connected securely?
(Check if there is any play
in the connection.)
Are printing signals being
input to the laser unit?
Is the problem solved after
replacing the main PCB?
Is the scanner interlock
lever damaged?
Is the scanner mirror
broken or loose?
9-31
Remedy
Result
Yes Clean the electrodes at
both sides.
Yes Clean the shaft and the
electrode.
No Check the connection
between the shaft and
the electrode.
Yes Replace the drum unit.
Yes Replace the toner
cartridge with a new
one.
No Reconnect the connector
correctly.
Yes Replace the main PCB.
Yes Replace the laser unit.
No Replace the high-
voltage power supply
PCB.
Ground
contacts
(4)
(1)
(1)
Confidential