Brother 1250, HL-1030, 1240 Malfunctions, No AC power supplied, No DC power supplied, Pcb

CHAPTER 6 TROUBLESHOOTING

6.MALFUNCTIONS

When taking 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 off the power switch and					Yes	Turn off the power switch,
		disconnect the P3 and P5						reconnect the connector and
		connectors on the engine PCB.						turn the power switch on again.
		Turn on the power again.						If the protector circuit is
		Measure the voltages between						activated, check the connector,
		the terminals. Do the						the wiring from the connector,
		measured voltage satisfy the						and the DC load.
		prescribed valued in the table
		below?
Low-voltage	3						No	Replace the low-voltage power
			PCB	+ lead pin	- lead pin	Voltage
power supply			Engine	P5-2	P5-3	Approx. 24V		supply PCB.
PCB				P3-10	P3-9	Approx. 5V

WARNING

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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