Brother MFC-9840CDW, DCP-9045CDN Completely blank, Image distortion

Completely blank

User Check

- Replace the toner cartridge or drum unit with a new one.

Step	Cause	Check	Result	Remedy
1	Developing bias	Are the electrodes on the	Yes	Clean both electrodes.
	voltage	drum unit and machine
	conduction failure	body dirty?
2	Scanner harness	Is the scanner harness	No	Reconnect the scanner
	connection failure	connected securely?		harness.
3	Engine PCB	Is the problem solved after	Yes	Replace the engine PCB
	failure	replacing the engine PCB		ASSY.
		ASSY?
4	Laser unit failure	Is the problem solved after	Yes	Replace the laser unit.
		replacing the Laser unit?
5	Transfer HVPS	Is the problem solved after	Yes	Replace the transfer
	PCB failure	replacing the transfer		HVPS PCB ASSY.
		HVPS PCB ASSY?
6	Charge HVPS	Is the problem solved after	Yes	Replace the charge
	PCB failure	replacing the charge		HVPS PCB ASSY.
		HVPS PCB ASSY?

Image distortion

Step	Cause	Check	Result	Remedy
1	Laser unit not	Is the laser unit	No	Assemble the laser unit
	assembled	assembled into the		correctly and secure the
	correctly	machine securely?		screw.
		(Check if there is no gap.)
2	Incorrect radiation	Is the problem solved after	Yes	Replace the laser unit.
	angle of scanner	replacing the laser unit?
	diode
	Scanner motor
	rotation failure

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