3
PROBLEM
CAUSE
REMEDY
REFERENCE
6. Noisy
1. Backlash between shuttle hook See mechanical adjustment
P. 14
operation
gear and lower shaft gear is
“Clearance between needle and
too great.
hook (NO. 2).”
2. Lower shaft gear is loose.
Eliminate the looseness.
3. Inappropriate belt tension.
See mechanical adjustment
P. 22
“Motor belt tension.”
4. Upper shaft gear is loose.
Eliminate the looseness.
5. Not enough oil.
Oil all moving parts.
7. Deformation of 1. Inappropriate zigzag
See mechanical adjustment
P. 11
pattern
synchronization.
“Needle swing.”
2. Inappropriate disengagement
See mechanical adjustment
P. 21
of cam follower.
“disengagement of cam follower.”
3. Upper thread tension is too
Adjust upper thread tension
P. 8
strong.
correctly.
4. Inappropriate feed balance
See mechanical adjustment
P. 19
BALANCE
"Feed balance on stretch stitch."