Adjusting The Lower Thread Clamp Opening Amount; Adjusting The Bobbin Presser - Brother HE-800A Service Manual

4. ADJUSTMENT

4-15-4. Adjusting the lower thread clamp opening amount

Approx.
5mm

4-16. Adjusting the bobbin presser

3989Q
1. Turn on the power and set the sewing machine to the home position. Then press the RESET key to lower the
work clamp.
2. Loosen the set screw (1), and then adjust so that the bobbin presser (2) goes into the hole in the bobbin case
(3).
3. Check that the work clamp is at the home position, and then loosen the nut (4) and turn the screw (5) to adjust
the clearance A between the bobbin presser (2) and the edge of the bed to approximately 12.5 mm.
4. Turn off the power, move the lower thread trimmer cam lever (6) by hand in the direction of the arrow to check
that the bobbin presser (2) presses the bobbin firmly before the lower thread retainer (7) starts to hold the lower
thread.
Note: If this timing is reversed, it will cause problems such as an excess trailing length of upper thread.
98
Loosen the two screws (6), and then adjust so that
the distance between the lower thread clamp (4)
and the lower thread presser (5) is approximately 5
mm when the feed guide shaft (1) is projecting out at
the front and is firmly touching the roller (3) of
opening plate (2).
4350Q
HE-800A
4351Q
4352Q