3
Condition
Cause
How to fix
Reference
6. Noisy
operation
1. Backlash between hook gear and
lower shaft gear is too great.
2. Lower shaft gear is loose.
3. Inappropriatte belt tension.
4. Not enough oil
See mechanical adjustment
“backlash (lower shaft gear)”.
Eliminate the looseness.
See part removal and replacement
“driving motor (dc motor)”.
Oil all moving parts.
P. 14
P. 26
P. 34
7. Deformation
pattern
1. Inappropriate feed balance.
2. Inappropriate needle swing
timing.
3. Top tension is too strong.
See mechanical adjustment
“stretch stitch feed balance”.
See mechanical adjustment
“Needle swing timing”.
See mechanical adjustment
“Top tension”.
P. 18
P. 16
P. 17
