Brother rh-918a manual Troubleshooting

13. TROUBLESHOOTING

Problem		Cause					Remedy				Page
Upper thread is not cut.	Knife is blunt.				Replace with a new knife.						63
	Knife does not move to the full
	stroke because air pressure is				Adjust the air pressure.						63
	too weak.
	Upper thread trimmer knife is				Install the upper thread trimmer
					knife so that it cuts only one side						66
	not picking up the upper thread.				of the upper thread loop.
	Movable knife is not picking up				Refer to the remedies given
	the needle thread because the				under	“Skipped		stitches		occur”	80
	last stitch is being skipped.				in this troubleshooting chart.
	Movable	knife	position	is	Adjust the position of the						66, 67
	incorrect.				movable		knife	or	the	loop
					spreader.
Lower thread is not cut.	Knife is blunt.				Replace with a new knife.						63
	Knife does not move to the full
	stroke because air pressure is				Adjust the air pressure.						63
	too weak.
	Movable	knife	position	is	Adjust the position of the
					movable		knife	or	the	loop	66, 67
	incorrect.				spreader.
Thread slips out of the	Thread nipper spring force is too				Adjust	the	force	of	the	thread	66, 67
needle at the sewing start.	weak.				nipper spring.
	Upper thread length is too short				Install the upper thread trimmer
					knife so that it cuts only one side						66
	after trimming.				of the upper thread loop.
	Needle and looper adjustment is				Adjust the needle bar height or						55
	incorrect.				the looper and spreader height.
	Not enough upper thread			is	Adjust	the amount			of	upper	57
	being fed out.				thread being fed out.
Material is not being cut	Cutting pressure is too weak.				Adjust the cutting pressure so						63
cleanly.					that it is strong enough.
	Knife and hammer are not				Grind the hammer surface.						62
	contacting properly.
	Knife is blunt.				Replace with a new knife.						63

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RH-981A