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46
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Troubles
Cause (1)
Cause (2)
Checking orders and corrective measures
From the previous page
2
.
Top end of needle thread appears on the
fabric at the sewing start.
3. The wrong side of fabric at the sewing start
is dirty. (Needle thread remains long under
the fabric.)
Length of bobbin thread at the sewing start
is too short.
Knotting of needle and bobbin threads at
the sewing start is hard to be performed.
Needle thread remaining at the top end of
needle after thread trimmingis too long.
Needle thread remaining at the top end of
needle after thread trimming is too long.
Needle thread remaining at the top end of
needle after thread trimming cannot be
short since throat plate, needle and presser
foot are improper.
Top end of bobbin thread is pulled in bobbin
case due to running idle of bobbin.
Pressure of bobbin case holder is too high.
Bobbin thread is cut short since there are
scratches on the hook.
Speed of the sewing machine at the sewing
start is high and bobbin thread is hard to
be interlaced.
Tension of thread tension No. 1 is too low.
Thread trimming timing is too late.
Counter knife excessively recedes.
Refer to the previous item [Needle thread
remaining at the top end of needle after
thread trimming is too long.]
Refer to the previous item [Needle, throat
plate and presser foot used are improper.
Presser foot pressure is too low.]
Increase tension of bobbin case holder.
Increase bobbin thread pressure.
Decrease pressure. However, take care of idle running of bobbin.
Correct scratch on the hook, or replace the hook.
Perform one to two stitches of soft start at the sewing start.
Increase tension of thread tension No.1.
Checkc and adjust the cam timing referring to the item (3-5).
Adjust the counter knife referring to the item (3-7).
Refer to the previous item [Needle thread remaining at the top
end of needle after thread trimming is too long.]
Refer to the previous item [Needle, throat plate and presser foot
used are improper. Presser foot pressure is too low.]
