ELNA 1000 Sew 75 Service Manual page 5

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