Adjusting The Needle Up Stop Position; Adjusting The V-Belt Tension - Brother LH4-B800E Service Manual

4. Adjustment

4-23. Adjusting the needle up stop position

1. The needle up stop position is adjusted so that the index mark w on the machine pulley q is inside the mark r
on the belt cover e. If adjustment is necessary, loosen the screw t of the machine pulley q and adjust the
position of the machine pulley q. The machine pulley q stops later if it is turned clockwise, and it stops earlier if
it is turned counterclockwise.
The screw y is a screw for detecting the machine stop position, and should not be loosened.
NOTE:
If the index mark w is not inside the mark r when the sewing machine is started, error code "E-02" will be displayed.
Turn the machine pulley q to move the index mark w to the correct position and then start the sewing machine.

4-24. Adjusting the V-belt tension

1. Remove the screw, and then remove the belt cover.
2. Turn the two nuts w to adjust so that there is 10—14 mm of deflection in the V-belt q when it is pressed at the
midway point with a force of 5 N.
NOTE:
If the V-belt is too loose, or if the V-belt is stretched, the following problems could occur.
a. The stopping position may shift;
b. The needle bar may drift when the sewing machine stops;
c. An extra stitch may be sewn when the sewing machine stops;
d. An abnormal noise may be heard due to the V-belt slipping; or
e. The V-belt may become too loose and contact the cover.
If any such problems occur, adjust by following the procedure described above.
4 - 28
y
e
r
w
w
LH4-B800E
q
t
q
10 - 14 mm