Brother BAS-311G service manual Electrical Mechanism

			8. ELECTRICAL MECHANISM
Problem	#17 Intermittent presser foot does not drop during sewing.
	Cause	Inspection/Remedy/Adjustment	Replacement if a malfunction
5. If the presser foot does not		1) Disconnect connector P3 (PPM) from the	Pulse motor P assembly
move and [E300] is displayed,		PMD P.C. board, and measure the resistance
there is a malfunction of the		between pins 1-2 and 3-4 at the cord-side
pulse motor or cord.		connector.
		OK if 2-3 Ω
		After measuring, insert P3.	PMD P.C. board
		2) If 1) is OK, there is a malfunction of the PMD
		P.C. board.
	4888Q
Problem	# 18 Sewing machine does not operate during sewing and [E120] is displayed.
	Cause	Inspection/Remedy/Adjustment	Replacement if a malfunction
1. Malfunction of sewing machine		Check connector P4 (UVW) of the power supply	Motor cable
motor cord		motor P.C. board and the sewing machine motor
		connector.
2. If the fuse (F1) on the power		1) If the fuse (F1) is blown, check the resistance	Power supply motor P.C.
supply motor P.C. board is		values between all pins of the connector P4	board
blown, there is a malfunction of		(UVW) and the pins of the fuse (∞ Ω) and
the main P.C. board.		replace the fuse.
		2) If the fuse blows again, replace the power
		supply motor P.C. board.
3. Sewing machine motor overheats		1) Turn off the power and let the sewing	Motor cable
and the thermostat inside the		machine stand for 30 minutes.
motor operates when the sewing		2) Turn the power back on; OK if operation is
machine is operated at short		normal.
cycle.		Avoid repeated sewing of sewing data that is
		less than 15 stitches.

BAS-311G, BAS-326G 133