Brother HE-800A ￿￿-￿.Skipped stitches

16. TROUBLESHOOTING￿

￿

Cause		Check			Remedy		Page
Rotary hook	Needle	bar	height	and	Adjust the needle and hook timing.
	needle bar lift amount				1. Adjust the needle bar height to “1” on the gauge.		72, 73
					2. Adjust the needle bar lift amount to “2” on the
					gauge.
	Gap between needle and				Adjust the gap between needle and rotary hook to
	rotary hook				0.01 - 0.08 mm. (Adjust to as large as possible		73
					without causing skipped stitches to occur.)
					* Check that rotary hook point does not strike
					needle in zigzag motion.
	Rotary hook lubrication				￿Too small quantity of lubrication oil will cause
					thread breakage. Adjust the quantity of lubrication		25
					oil.
							73
					￿The lubrication holes between rotary hook and
					rotary hook joint do not match up.
	Thread	twisted around			Remove any twisted thread from the inner	and	-
	rotary hook				rotary hook.
Upper thread amount	Arm thread guide position				Adjust the arm thread guide position		63
Bobbin case	Damaged		outside	of	Polish with buff or replace the part.
	bobbin	case and		bent	* Use the HE-800A bobbin case.		-
	bobbin holder spring, etc.

￿￿-￿. Skipped stitches

Cause			Check		Remedy	Page
Needle		Needle facing			As viewed from the direction of the face plate,	57
					attach needle so that the notched part of needle
					faces frontward.
		Needle installation height			Insert the end of the needle shank so that it touches	-
					the top edge of the needle hole of the needle bar.
		Bent needle			Replace needle	-
		Blunt needle tip or burr			Replace needle	-
		Thin needle			Use a needle with a count that matches the thread	-
					and material.
Thread	take-up	Thread take-up spring			Loosen the thread take-up spring tension or shorten
spring		tension and stroke			the stroke to such a degree that does not cause	63
					double hooking. Adjust it while checking bar tacking
					stitches.
Work clamp		Work clamp pressure			Increase work clamp pressure.
					* The standard height of the adjustment screw is	74
					approximately 30 mm, so tighten it further than
					this.
		Relation	between	work	Replace work clamp assembly that fits for sewing
		clamp	assembly	and	length.
		sewing length			* When using knits or woven materials, replace the
					parts with the –3 specification parts:	-
					Length feed plate (for specification -3), work
					clamp assembly (for knits), needle plate 1.2 (for
					specification -3)
Rotary hook		Blunt rotary hook point			Polish with buff or replace the part.	-
		Needle	bar height	and	Adjust the needle and hook timing.
		needle bar lift amount			1. Adjust the needle bar height to “1” on the gauge.	72, 73
					2. Adjust the needle bar lift amount to “2” on the
					gauge.
		Gap between needle and			Adjust the gap between needle and rotary hook to
		rotary hook			0.01 - 0.08 mm. (Adjust to as large as possible	73
					without causing skipped stitches to occur.)
					* Check that rotary hook point does not strike
					needle in zigzag motion.

93 HE-800A