Brother 1240, HL-1030, 1250 service manual Completely blank

CHAPTER 6 TROUBLESHOOTING

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

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