typical GT1790A - Parallel Section Wobbling; Sewing Start Wobbling; Bar-Tacking Thread Appearance Issue; Stitches Floating Corrective Measures

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Troubles
Causes
Corrective measures
Page
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.
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11. The knife does not
descend after
cutting needle
thread.
1. Check whether the thread breakage
detector plate is properly adjusted.
 Adjust the detector plate. (Refer to the
Service Manual.)
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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. Check whether needle stop position is too
low and needle comes in contact with
needle thread trimmer when it closes.
 Replace the needle.
 Adjust the needle-to-hook timing.

Adjusting the installation position of
the needle thread trimmer.

Adjust again the installation position
of the needle plate seat.
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13. Dropping times of
the knife
1. Check whether the cloth cutting knife
dropping is set to plural dropping.
 Release the plural time setting.
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