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Trouble
Cause (1)
Cause (2)
Check and corrective measures
5. The bobbin thread is un-
trimmed. (But the needle
thread is trimmed.)
5-1) The backward movement
of the moving knife is
insufficient.
1-A) The backward movement of the mov-
ing knife is inappropriately adjusted.
(The position of the knife operation
axis or the thread trimming cam in the
right-left direction is inappropriately
adjusted.)
Measure the backward movement length of the moving
knife.
Adjust the position of the thread trimming cam in the
right-left direction to set the backward movement
length of the knife to within 2 to 2.5 mm (SH:3 to 3.5mm)
if the measurement result is out of the range.
5-2) The position of the bobbin
thread at thread trimming
is unstable.
2-A)
A hook other than the specified hook is
used.
Check whether the current hook has a guide slit for the
bobbin thread.
If the hook has no such a slit, replace the hook with a
hook for threat trimming.
6. The wiper interferes with
the needle.
6-1) The height of the position
where the wiper is mount-
ed is inappropriate.
Mount the wiper appropriately.
