MECHANICAL SEWING DISORDERS
C1
First of all, please refer to the paragraph entitled "
maintenance
" in the instruction manual,
especially when machine does not turn freely by turning the flywheel by hand. If necessary,
check and adjust tightness of motor belt.
Given below are the most frequent disorders. In most cases, they can be remedied by checking
the adjustments in the following order. However, before checking the adjustments, make sure
that the threading is correct and that all the thread passages are okay.
1. Skipped overlock stitches
Check and adjust if necessary:
- Needle bent or with a dull point - replace needle
- Needle not set correctly - refer to "
changing the needle
" in the instruction manual
- Burrs on upper or lower looper - polish
- Burrs on stitch tongue - polish
- Excessive tension on the needle thread
- Height and orientation of needle bar
- Clearance between point of lower loopers and needle
- Clearance between upper and lower loopers
- Timing of upper and lower loopers against needle
- Feed timing
2. Skipped chainstitches - Cover hems
Check and adjust if necessary:
- Needle and chain looper thread tensions not balanced
- Needle bent or with a dull point - replace needle
- Needle not set correctly - refer to "
changing the needle
" in the instruction manual
- Burr on chain looper - replace or polish
- Dull blade edge on moving cutter - replace
- Chain looper needle clearance
- Chain needle guard clearance
- Angular position of chain looper
- Orbital timing of chain looper
- Chain thread take up lever timing
- Height and orientation of needle bar
- Needle plate spring plate bent
- Clearance and position between back of chain looper and needle L0
Note: For more information, see pages
ANNEX
ΦΧ
.
Summary of Contents for 745 -
Page 1: ...745 845 SERVICE MANUAL 2 2 5 5 1 3 5 NA 6 0 B 1 2 1 T P T P...
Page 18: ...a HEIGHT AND ALIGNMENT OF CLOTH PRESSER BAR 4a 5 b c 4 7mm...
Page 24: ...TIMING OF LOWER LOOPER 8a A B C D b a 5 2mm R1 Fig 1 Fig 2 Fig 3...
Page 51: ...ANNEX SETTING POSITIONS OF SL DF DIALS b c f d g e 2 1 C B A...
Page 61: ...M E M O...
