Brother HE-800A ￿￿-￿￿.Work clamp is not raised (2) Pulse motor stepping sound can be heard

16. TROUBLESHOOTING￿

￿

￿￿-￿￿. Work clamp is not raised (2) Pulse motor stepping sound can be heard

	Cause				Check				Remedy		Page
Machine		stopping		Rotary	hook			touches	Adjust the needle up stop position.
position				lower	thread	retainer at			Retainer
				the stop position					Inner rotary
									hook presser
											77
										4021Q
Work	clamp		lifting	Work clamp lifting speed					Use memory switch No. 02 to retard the work clamp		79
speed is too fast.				setting					lifting speed.
Upper			thread	Interference			between		Check the standard adjustments with the upper
scissors				upper thread scissors and					thread scissors removed.		75
				work clamp					* Be particularly careful when sewing joints.
				Upper	thread		scissors		Apply grease to the inclined face of the opening		76
				operation					cam.
Lower			thread	Interference			between		Repair or replace the parts.
trimmer				fixed	knife	set,		lower	Lower thread
				thread	clamp,			lower	trimmer link A assembly
				thread presser and lower					Lower thread
				thread retainer.
									trimmer
									connecting rod		-
									Remove the shoulder
									screw to check.	4022Q
				Rubbish, dust or				thread	Remove all rubbish, dust and thread scraps from		-
				scraps present					the lower thread trimmer.
Loose screws				Check for loose screws in					Securely tighten all screws.
				the upper thread trimmer,							-
				lower thread trimmer and
				work	clamp			lifter
				mechanisms.
Work	clamp		lifting	Check	the	work		clamp	Change the settings of memory switch Nos. 04, 05,
height setting				lifting height setting.					06.
									* If the work clamp lifting height is too high, the		79
									lower thread trimming operation will not be timed
									together with the work clamp rising and the pulse
									motor may go out of step.
Threading				Lower thread threading					Insert the bobbin correctly and pass the lower
									thread through the bobbin case correctly.		60
									* If the bobbin is inserted back-to-front, it will spin
									loosely and the presser lifter may go out of step.
				Lower thread tension					Reduce the lower thread tension.
									* If the lower thread tension is too strong, the motor
									may go out of step.
									Use memory switch No. 02 to reduce the work
									clamp lifting speed setting to make the lifting speed
									slower.		61
											79
									Buff this section to reduce the
									thread retaining resistance.	4023Q

107 HE-800A