Brother mfc8440 Service Manual page 256

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Possible cause Step
Print paper 1
Toner sensing 2
failure
(machine side)
Toner cartridge 3
failure
Drum unit failure 4
NOTE:
The following cases increase the possibility of this problem.
• Acid paper is being used.
• The drum unit is at the end of its life.
• There is dust or paper powder.
Check
Does the paper being used
meet the paper specification
(weight, etc.)?
Is the sign "Toner Empty"
displayed on the LCD even
after removing the drum unit
and toner cartridge?
(Be sure to close the cover
after removing the drum unit
and toner cartridge.)
Is the problem solved after
replacing the toner cartridge?
Is the problem solved after
replacing the drum unit?
6-49
MFC-8440/8840D/8840DN, DCP-8040/8045D/8045DN
Result Remedy
No Recommend to use the
specified types of paper.
Yes Recommend to change to
freshly unpacked paper.
Yes Toner sensor failure. Clean the
toner sensor and check the
toner sensor connection.
Yes Replace the toner cartridge.
Yes Replace the drum unit.
No Replace the high-voltage power
supply PCB.
SERVICE MANUAL