Adjusting The Presser Foot Home Position Sensor Position - Brother LH4-B800E Service Manual

4-3. Adjusting the presser foot home position sensor position

1. Turn on the power.
* Do not set the sewing machine to the home position.
2. Move the trimmer driving arm w in the direction of the arrow to move the upper thread trimmer driving link q until
it is stopped by the face plate.
3. Loosen the screw e, and then move the dog r by approximately 1 mm in the direction of the arrow past position
(A) where the work clamp sensor turns on (the work clamp sensor LED lights). (This is the provisional position for
the work clamp home position sensor. The final position is determined when making the adjustment in "4-13-8.
Adjusting the upper thread scissors opening timing".)
4. Set the sewing machine to the home position, and then press the RESET key. Check that there is no impact noise
and that the motor does not go out of step when the presser foot is lowered.
If the adjustment is not correct, the presser foot may touch the upper thread trimmer driving link q and the roller
*
y of the thread trimmer drive lever t, and this may cause the motor to go out of step.
* Make this adjustment before carrying out "4-13. Adjusting the upper thread trimming".
* After making this adjustment, check the tension release of the tack tension control and the upper thread trimming,
and adjust if necessary by referring to the respective adjustment procedures.
Approx. 1 mm
y
q
q
LH4-B800E
(A)
r
t
4. Adjustment
e
w
4 - 5