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Trouble Cause Corrective measures Page
5. Stitch skipping
often occurs.
1
The motions of the needle
and shuttle are not properly
synchronized.
™
Correct the positions of the needle and
shuttle.
115
2
The clearance between the
needle and shuttle is too large.
™
Correct the positions of the needle and
shuttle.
115
3
The needle is bent.
™
Replace the bent needle. 18
4
The driver excessively bends the
needle.
5
Length of needle thread
remaining after thread trimming
is too long. (In the case of stitch
skipping within the 2nd to 10th
stitch from the beginning of
sewing)
™
Correctly position the driver.
™
Reduce the thread take-up spring
pressure or increase the thread
tension applied by the thread tension
controller No. 1.
115
21, 22
6. The needle
thread comes
out on the wrong
side of the
material.
1
The needle thread tension is not
high enough.
™
Increase the needle thread tension. 21
2
The tension release mechanism
fails to work properly.
™
Check whether or not the tension disc
No. 2 is released during bar-tracking.
3
The needle thread after thread
trimming is too long.
™
Increase the tension of the thread
tension controller No. 1.
™
Correct the position of the moving knife.
21
4
Number of stitches is too few.
™
Turn OFF the thread clamp.
5
When sewing length is short (End
of needle thread protrudes on the
wrong side of sewing product.)
™
Turn OFF the thread clamp.
6
Number of stitches is too few.
™
Use the lower plate, the hole of which
is larger than the presser.
7. Thread end of
the 1st stitch
comes out on
the right side of
the material.
1
Stitch skipping at the 1st stitch
™
Adjust the hook timing faster by a 1/2
stitch.
2
Needle used and thread used
are thick in terms of the inner
diameter of the intermediate
presser.
™
Increase the inner diameter of
intermediate presser.
3
Intermediate presser is not
properly positioned in terms of
the needle.
™
Adjust the eccentricity between
intermediate presser and needle so
that needle enters in the center of
intermediate presser.
8. Threads break
at time of thread
trimming.
1
The moving knife has been
improperly position.
™
Correct the position of the moving
knife.
118
9. The thread
clamp is
entangled with
needle thread.
1
The needle thread at the sewing
start is too long.
™
Tighten thread tension controller No. 1
and make the length of needle thread
40 to 50 mm.
25
10. Uneven length
of the needle
thread
1
The tension of thread take-up
spring is too low.
™
Increase the tension of the thread
take-up spring.
22
11. The length of
needle thread
does not
become short.
1
The tension of thread tension
controller No. 1 is too low.
™
Increase the tension of thread tension
controller No. 1.
21
2
The tension of thread take-up
spring is too high.
™
Decrease the tension of thread take-
up spring.
22
3
The tension of thread take-up
spring is too low and motion is
unstable.
™
Increase the tension of thread take-
up spring and lengthen the stroke as
well.
12. The knotting
section of
bobbin thread
at 2nd stitch at
the sewing start
appears on the
right side.
1
Idling of bobbin is large.
™
A just the position of the moving knife. 118
2
The bobbin thread tension is too
low.
™
Increase the bobbin thread tension. 21
3
The needle thread tension at 1st
stitch is too high.
™
Decrease the needle thread tension at
1st stitch.
™
Turn OFF the thread clamp.
13. Wiper fails to
work. (Return is
defective.)
1
Needle entry of the last needle
is the same as that of the sewing
start, and the resistance of
thread and cloth is large.
™
Shift the needle entry point of the last
needle.
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