JUKI LK-1900AN Engineer's Manual page 63

Adjustment procedures
1. Needle thread clamp notch R adjustment
1) Loosen the two setscrews 1 .
2) Push the needle thread clamp link complete 2 in Direction
A so that the distance between the needle thread clamp
4 and the needle thread clamp base 5 becomes 21 mm.
Move the needle thread clamp notch R 6 in Direction D,
lightly push it toward the needle thread clamp cam plate 9 ,
and tighten the two setscrews 1 .
2. Needle thread clamp notch F adjustment
1) Loosen the two setscrews 7 .
2) Push the needle thread clamp link complete 2 in Direction
C so that the distance between the needle thread clamp
4 and the needle thread clamp base 5 becomes 23 mm.
Move the needle thread clamp notch F 8 in Direction E,
lightly push it toward the needle thread clamp cam plate 9 ,
and tighten the two setscrews 7 .
Results of Improper adjustment
If the distance between the nee-
o
dle thread clamp 4 and needle
thread clamp base 5 comes to
larger than 21 mm, release tim-
ing turns so early that unthread-
ing at the beginning of sewing is
caused.
If the distance between the
o
needle thread clamp 4 and
needle thread base 5 comes to
smaller than 21 mm, release tim-
ing turns so slowly that needle
thread remains on the back side
of the material is caused.
If the distance between the nee-
o
dle thread clamp 4 and needle
thread clamp base 5 comes to
larger than 23 mm, clamp timing
turns so early that needle thread
remains on the back side of the
material or jamming of needle
thread in to the needle thread
clamp 4 is caused.
If the distance between the nee-
o
dle thread clamp 4 and needle
thread clamp base 5 comes to
smaller than 23 mm, clamp tim-
ing turns so slowly that needle
thread clamp error is caused.
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