Brother 1250, HL-1030, 1240 service manual Scanner failure, Fuser failure, PCB 24V DC?

CHAPTER 6 TROUBLESHOOTING

M-8

Scanner failure

Possible cause	Step	Check	Result	Remedy
Harness	1	Is the connection of the	No	Reconnect the connector
connection		scanner motor connector P12		securely.
failure		on the engine PCB secure?
Power supply	2	Is the voltage between pins 1	No	Check if +24V DC is supplied
input		(+24V DC) and 2 (GND) of		between pins 2 (+24V DC) and
		connector P12 on the engine		3 (+24V RET) of connector P5
		PCB 24V DC?		on the engine PCB. If not,
				check the power supply output
				on the low-voltage power
				supply PCB.
			Yes	Replace the laser unit.

M-9

Fuser failure

Possible cause	Step	Check	Result	Remedy
Poor thermistor	1	Is the contact of connector P6	No	Reconnect the connector.
harness contact		on the engine PCB good?
Blown thermal	2	Remove the fixing unit and	Yes	Replace the fixing unit.
fuse		measure the resistance
		between the input connectors.
		Is it open circuit?
Thermistor	3	Is the thermistor installed	Yes	Replace the fixing unit.
failure		properly?
			No	Reinstall the thermistor
				properly.
Halogen heater	4	Remove the fixing unit and	Yes	Replace the halogen heater
lamp failure		measure the resistance of the		lamp.
		halogen heater lamp. Is it
		open circuit?
Heater harness	5	Is the heater harness	No	Reconnect the connectors
connection		connector connected to the		securely.
failure		low-voltage power supply PCB
		and fixing unit secure?

NOTE:

•This problem will be cleared if leaving the printer power ON for ten minutes.

•If the heater is cooled down sufficiently, this problem may be cleared by turning on the printer power switch while pressing the panel button. Be warned, however, that this operation will melt the fixing unit if the heater is hot.

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