Brother LH4-B800E Service Manual page 100

The following should be checked before adjusting the upper thread trimming.
Check the presser foot home position sensor position
Refer to "4-3. Adjusting the presser foot home position sensor position".
4-13-1. Adjusting the longitudinal feed arm assembly position
1. Turn on the power and set the sewing machine to the home position. Then press the RESET key to lower the
presser foot.
Check that the slot at the bottom of the upper thread trimmer lever set q is aligned with the edge of the washer
2.
w. If they are not aligned, loosen the bolt e and move the longitudinal feed arm assembly r back and forth to
adjust.
4-13-2. Adjusting the trimmer driving arm assembly position
1. Turn on the power and set the sewing machine to the home position. Then press the RESET key to lower the
presser foot.
Check that the overlap between the stopper w which prevents the trimmer driving arm assembly q from turning
2.
and the stop plate r of the upper thread trimmer lever set e is 1 mm.
If adjustment is necessary, loosen the bolt t and move the trimmer driving arm assembly q back and forward
to adjust.
e
w
Aligned
e
w
w
t
r
q
e
w
r
1 mm
q
e
LH4-B800E
r
q
r
1 mm
w
r
4. Adjustment
4 - 13