Adjusting The Inner Rotary Hook And Rotary Hook Holder Overlap; Adjusting The Presser Foot Pressure; Adjusting The Work Clamp Lift Amount - Brother LH4-B800E Service Manual

4. Adjustment

4-6. Adjusting the inner rotary hook and rotary hook holder overlap

1. Loosen the screw e to adjust so that the tip of the rotary hook holder q does not protrude past edge A of the inner
rotary hook w.

4-7. Adjusting the presser foot pressure

1. The standard distance A is 30 mm (approximately 30 N).
2. Loosen the nut q and turn the pressure adjusting screw w to adjust the presser foot pressure.
When the rpessure ajusting screw w is tightened as far as it will go, the presser foot pressure will be about 70 N.
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4-8. Adjusting the work clamp lift amount

Turn on the power and set the sewing machine to the home position before making this adjustment.
1. Check that memory switch No. 05 (presser foot height at neutral position) is set to 10 mm. (If it is not set to 10 mm,
set it to 10 mm.)
2. Place a 10 mm gauge under the work clamp q and then loosen the screw w to make the adjustment.
Adjust the lift amount (including the play in the work clamp q and the pin e to 10 mm. If it is set to more than 10
*
mm, the work clamp will start lifting before lower thread trimming is complete, which may result in thread trimming
errors. Furthermore, it may also cause the presser foot lifter pulse motor to go out of step.
4 - 8
q
e
w
w
q
w
LH4-B800E
A
A
e
q
10 mm