Brother HL-1040, HL-820, HL-1020 manual No AC power supplied, No DC power supplied

5.TROUBLESHOOTING MALFUNCTIONS

When carrying out countermeasures for malfunctions as described in this section, check connectors for contact failure before measuring the voltage at the specified connector pins.

M-1

No AC power supplied

Possible cause	Step	Check	Result	Remedy
Supply voltage	1	Is the correct voltage present	No	Inform the user that the correct
		at the outlet?		voltage is not supplied at the
				outlet.
Power plug	2	Is the power cord securely	No	Plug the power cord securely
		plugged into the outlet?		into the outlet.
Fuse (F1, F2)	3	Is the fuse blown?	Yes	If the fuse blows again
				immediately after replacing the
				low-voltage power supply PCB,
				check that there is not a short
				circuit somewhere in the AC
				power supply line.
Wiring	4	Unplug the power supply plug.	Yes	Replace the AC power cord.
		Is there a broken wire between
		the AC input connector of the
		low-voltage power supply and
		the power plug?

M-2

No DC power supplied

Possible cause	Step				Check			Result	Remedy
AC power	1	Is AC power supplied between						No	Follow the same check
supply		connectors CN1-L and CN1-N							procedure of M-1 “No AC
		when the power plug is							power supplied”.
		plugged into the outlet?
Wiring, DC load	2	Turn the power switch OFF						Yes	Turn the power switch OFF,
		and disconnect the P13							reconnect the connector and
		connector (panel sensor PCB).							turn the power switch ON
		Turn the power switch ON							again.
		again. Measure the voltages							If the protector circuit is
		between the terminals.							activated, check the connector,
		Do the measured voltage							the wiring from the connector,
		satisfy the prescribed value in							and the DC load.
		the table below?
Low-voltage								No	Replace the low-voltage power
power supply			PCB	+ lead pin		- lead pin	Voltage		supply PCB.
			Panel	P8-1		P8-4	Approx. 24V
PCB
			Sensor
				P8-2		P8-3	Approx. 5V

Caution:

If you analyze malfunctions with the power plug inserted into the power outlet, special caution should be exercised even if the power switch is OFF because it is a single pole switch.

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