JUKI LK-1900AN Engineer's Manual page 39

Adjustment procedures
1. If the thread on Side B cannot be cut, grind Side C . If the
thread on Side C cannot be cut, grind Side B .
(Caution) When grinding the side, make the angle more acuter
than 90 degrees.
Adjustment procedures
1. Turn off the power supply and look for any close contact be-
tween the AT solenoid 1 and the thrust collar 2 .
2. Loosen the three set screws 3 and remove the thread tension
cap 4 .
3. Hold the tension releasing pin adjust collar 5 not to let it rotate,
and loosen the nut 6 .
4. Turn the tension releasing pin adjust collar 5 and adjust the
gap between the thread tension discs 7 . (Adjustment of thread
tension disc floating)
5. Hold the tension releasing pin adjust collar 5 and tighten the
nut 6 . Mount the thread tension cap 4 by means of the set
screw 3 .
6. Turn on the power supply and set up the thread tension. Con-
firm that the thread tension discs 7 are closed.
Secure an acute angle.
– 27 –
Results of Improper adjustment
When less than 0.2 mm:
o
Thread on Side C cannot be
cut.
When more than 0.2 mm:
o
Thread on Side B cannot be
cut.
Results of Improper adjustment
If the amount of disc floating
o
is too less, the residual thread
length can be changed or short-
ened when the thread is thick.
If the amount of disc floating is
o
too much, the tension discs can-
not close completely and normal
thread tension may fail to be
chosen. This can be a cause of
imperfect sewing.