Brother HL-1040, HL-820, HL-1020 manual Completely blank

I-3

Completely blank

Possible cause	Step	Check	Result	Remedy	HV.GND
					contacts
					(Fig.4-5)
Developing bias	1	Are the developing bias	Yes	Clean the electrodes
contact failure		contacts between the printer		at both sides.	➆
		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 the	Yes	Replace the drum
		drum unit is replaced?		unit.
Scanner harness	4	Is the scanner harness	No	Reconnect the
connection failure		connected securely?		connector properly.
		Is there any play in the
		connection?
Main / Panel	5	Are printing signals being input	Yes	Replace the main
sensor PCB		to the scanner?		PCB or the panel
connection failure		Is the problem solved after the		sensor PCB.
		main PCB or the panel sensor
		PCB replaced?
Scanner unit	6	Scanner interlock lever	Yes	Replace the scanner
failure		damaged.		unit.
		Scanner mirror is broken or	No	Replace the high-
		loose.		voltage power supply
				PCB.

IV-7