JUKI MOL-254 Engineer's Manual page 35

Adjustment Procedures
1) Expel air from the machine.
2) Remove the side cover from the hook base.
3) Loosen two setscrews
adjust the timing of the thread trimmer cam. At this time,
check the timing of the thread trimmer cam with the thread
trimming cylinder pressed toward the left side.
4) Turn pulley while pulling by hand thread trimming
solenoid in the direction of A and bring the moving knife
to its travel end.
5) Move in the direction of B and adjust the thread trimmer
cam B so that the roller comes to the bottom of cam groove
of the thread trimmer cam B.
① Loosen two setscrews
move the tension release notch to the center of the slot.
Then securely tighten two setscrews
② After the adjustment, turn the main shaft in the normal
direction of rotation (➡ ) while pressing by hand the cam
follower in the direction of the arrow mark ( ⇦ ), ride the
thread release arm pin on the thread release notch. Then
detach the hand from the cam follower and make the main
shaft rotate in the normal direction.
Make sure that the tension release arm pin comes off the
thread release notch at the position beyond the highest
dead point of the thread take-up lever.
in the thread trimmer cam B and
in the tension release notch and
to fix the notch.
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Results of Improper Adjustment
○ If the timing between the moving
knife on this side and that on far
side differs from the standard
sadjustment, thread trimming
failure will occur.
○ If the timing of the moving knife
on this side at its travel end is
not adjusted properly, needle
thread may be cut short.
○ Length of remaining needle
thread after thread trimming may
be short. In addition, the length
may vary.
○ Slip-off of thread at the start of
sewing will result.