Brother 1270N - Manual (Page 148)

CHAPTER 6 TROUBLESHOOTING
6-26
I-3 Completely blank
Possible cause Step Check Result Remedy
Ground
contacts
Developing bias
contact failure 1 Are the developing bias
contacts between the printer
body and drum unit dirty? Yes Clean the electrodes
at both sides.
➃
Drum unit 2 Are the drum shaft and drum
electrode of the printer body
connected correctly? Yes Clean the shaft and
the electrode.
➀
No Check the connection
between the shaft and
the electrode.
➀
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.