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Trouble
Cause (1)
Cause (2)
Check and corrective measures
12. The bird’s nest at the start of sew-
ing is big.
12-1) The remaining length of
needle thread after a thread
trimming is long.
By strengthening the first thread tension, short
-
en the remaining length of needle thread after
a thread trimming.
Lengthen the pitch of one needle at the start of
sewing to make the needle thread to be tucked
under the presser.
For example, make a reverse stitch to be a
condensed stitch and set the number of nee-
dles to one needle in order to enlarge a pitch.
13. The situation of crossing over the
multi-layered section of the mate-
rial is imperfect.
13-1) The height of a feed dog is
low.
At the time of passing over the multi-layered
section of the material, raise a feed dog with
the custom switch.
14. Needle thread breakage at the
start of sewing
14-1) The needle thread presser
device is put on.
1-A) Thread is cut by the needle
thread caught under the press-
er and because needle thread
presser device is put on.
The needle thread is made easy to pass
through by losing the presser.
In the case of the AK-154 device of the (stan-
dard) digital specification, the presser at the
start of sewing is slightly lifted to make the
needle thread easy to pass through.
(U290: AK operating time when the thread
presser operates is enlarged.)
In the case of the device of the full digital spec-
ification, the presser at the start of sewing is
slightly lifted to make the needle thread easy to
pass through.
(U290: AK operating time when the thread
presser operates is enlarged.)
15. Faulty thread trimming (The nee-
dle and bobbin threads are not
trimmed.)
15-1) Wear of the cutting portion
of a thread trimming knife or
loop spreading knife
It is replaced by a new knife.
15-2) The amount of engagement
between their cutting portions
is insufficient.
The amount of engagement between them is
adjusted with an eccentric pin.
