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3-4) The thread trimmer fails to catch the
4-A) The last stitch at the end of sewing skips.
Check the installing position of the needle and the
needle thread.
hook timing, and adjust them.
4-B) Timing of the thread trimmer cam is too
Check the timing of the thread trimmer cam and
early or too late.
adjust it.
4-C) Top end of the moving knife has been
Replace the moving knife with a new one.
damaged or has scratches.
3-5) The thread trimmer rails to catch the
5-A) Stroke of the moving knife is too small.
Check and adjust the initial position of the moving
bobbin thread.
knife.
5-B) Bobbin thread path is inappropriate.
Check the bobbin thread path.
(Bobbin thread slips off the bobbin
thread guide of the inner hook).
5-C) The tip of the moving knife has been
Replace the moving knife with a new one.
damaged or has scratches.
5-D) The position of the moving knife is too
Check the height of the moving knife referring to
high or too low.
[3.-(11)-5), -6) and -(12)-4) Height of the Moving Knife].
5-E) Bobbin thread tension excessive
Reduce the bobbin thread tension.
3-6) The thread trimmer fails to trim the needle
6-A) The moving knife blade fails to match the
Check the height of the moving knife and counter knife.
thread and bobbin thread.
counter knife blade in height and direction.
6-B) The moving knife blade fails to match
Replace the moving knife and counter knife with
the counter knife blade in height and direction.
new ones.
6-C) The counter knife fails to provide a
Adjust the knife pressure. (Refer to [3.-(10)-3) and
sufficient pressure.
3.-(11)-3) Knife Pressure]).
6-D) The moving knife fails to operate.
Check the installing position of the moving knife
driving arm A and adjust it.
Check the operating condition of the needle thread
trimming solenoid or the needle thread trimming air
cylinder.
Check the timing of the synchronizer, and adjust it.
6-E) Bobbin thread tension excessive
Reduce the bobbin thread tension.
Trouble
Cause (1)
Cause (2)
Check Procedure and Corrective Measures
Continued from the previous page