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5. Thread breakage at the time of
5-1) Thread release timing is
1-A) Floating of the AT thread tension
Adjust the amount of AT thread tension floating.
thread trimming.
defective.
disk is insufficient.
5-2) Thread spreading section of the
Paying attention to the blade section, polish with
moving knife has scratches.
polishing powder.
5-3) Shuttle upper spring has
Remove the scratches.
scratches.
5-4) Level difference between the
4-A) Thread is cut before trimming
Properly adjust the position of counter knife.
needle hole guide and the
with the blade section of the
counter knife is too high.
moving knife.
5-5) Clearance between the needle
5-A) Thread is cut before trimming
Properly adjust the position of counter knife.
hole guide and the counter
with the blade section of the
knife is too small.
moving knife.
5-6) Lower face of the needle hole
6-A) Thread is cut with the needle
Remove the scratches and polish with buff, or replace
guide has scratches.
hole guide.
the needle hole guide.
5-7) Thread spreading timing of
Adjust initial positions of the presser origin sensor,
the moving knife is defective.
thread trimmer, and the moving knife.
5-8) Thread take-up spring tension
Adjust the thread take-up spring.
is too low.
5-9) Scratched bobbin thread
Eliminate the scratch.
holder
Trouble
Cause (1)
Cause (2)
Check and corrective measures
