Brother DCP-8020, Service Manual

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MFC-8420/8820D/8820DN, DCP-8020/8025D/8025DN
SERVICE MANUAL
6-37
I-3 Completely blank
Possible cause Step Check Result Remedy
Ground
contacts
Developing bias
contact failure 1 Are the developing bias
contacts between the machine
body and drum unit dirty? Yes Clean the electrodes
at both sides.
(4)
Drum unit 2 Are the drum shaft and drum
electrode of the machine
connected correctly? Yes Clean the shaft and
the electrode.
(1)
No Check the connection
between the shaft and
the electrode.
(1)
Drum unit failure 3 Is the problem solved after
replacing the drum unit? Yes Replace the drum
unit.
Toner cartridge
failure 4 Is the problem solved after
replacing the toner cartridge? Yes Replace the toner
cartridge with a new
one.
Scanner
harness
connection
failure 5 Is the scanner harness
connected securely?
(Check if there is any play in
the connection.) No Reconnect the
connector correctly.
Main PCB
failure 6 Are printing signals being input
to the laser unit?
Is the problem solved after
replacing the main PCB?
Yes Replace the main
PCB.
Laser unit failure 7 Is the scanner interlock lever
damaged? Yes Replace the laser unit.
Is the scanner mirror broken or
loose? No Replace the high-
voltage power supply
PCB.
CCD unit 8 Is the problem occurring on
CCD replacement? Yes Replace the CCD.
User Check
(1) Check for the setting of originals.