JUKI LK-1900AN Engineer's Manual page 117

Trouble
From the previous page
9. Thread chips generated in the
shuttle
10. Roll-in malfunction of remaining
thread at underside material.
Cause (1)
8-4) Stitch skipping due to the
heat
8-5) Uneven stitch tightness
due to the stretch of thread
9-1) Long needle thread at the
beginning of stitches
10-1) Protrusion of needle thread
Cause (2)
4-A) Sewing speed is too fast.
4-B) Needle is too thin.
4-C) Loop of the needle thread falls
down.
5-A) Sewing speed is too fast.
5-B) Tension of the thread tension No.
2 asm. is excessive.
1-A) The thread trimmer is used for
cutting.
1-A) Material does not keep close
contact with the needle plate.
1-B) Stitch size is short.
1-C) The needle thread is long.
Check and corrective measures
Change the maximum speed (electrical
components.)
Use a thicker needle. (Raise the number of
needle to be used.)
Attach the needle with the long groove ori-
enting slightly to the right (approximately 20°).
Use a needle cooler.
Reduce the speed by means of the speed
variable resistor.
Decrease the tension of tension controller
No. 2.
Needle thread clamp OFF
Adjust the needle thread length to 32 to 36
mm.
Increase the sewing length to more than 10
mm.
Change the feed plate.
Increase the sewing size to more than 10
mm.
Adjust the needle thread length to 32 to 36
mm.