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Troubles
Causes
Corrective measures
Page
8. Thread frays.
1. Number of stitches of tie stitching is too
small.
2. Width of tie stitching is too wide.
○ Increase the number of stitches of tie
stitching at the end of sewing.
○ Narrow the width of tie stitching at the
end of sewing.
9. Length of needle
thread remaining at
the end of sewing is
too long.
1. Width of tie stitching is too narrow.
2. Tension of tie stitching is too low.
○ Widen the width of tie stitching at the
end of sewing.
○ Increase tension at the end of sewing.
10. Needle thread
breaks at the start of
sewing, or the wrong
side of seam is dirty.
1. Tension at the start of sewing is too low.
○ Increase tension at the start of sewing.
11. Knife drops even
when needle thread
is cut.
1. Check whether the thread breakage detec-
tor plate is properly adjusted.
○ Adjust the detector plate.
(Refer to the Engineer's Manual.)
–
12. Needle breaks.
1. Check whether needle is bent.
2. Check whether needle comes in contact
with the blade point of hook.
3. Check whether needle thread trimmer
comes in contact with needle when it
opens.
4. Check whether needle comes in the center
of the needle hole of throat plate.
5. Needle stop position is too low and needle
comes in contact with needle thread trim-
mer when it closes.
○ Replace the needle.
○ Adjust the needle-to-hook timing.
○ Adjust the installing position of needle
thread trimmer.
○ Re-adjust the installing position of throat
plate base.
–
13. Knife drops plural
times.
1. Check whether the cloth cutting knife drop-
ping is set to plural dropping.
○ Release the plural time setting.
