JUKI LK-1900AN, Engineer'S Manual, Page: 107 / 140

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Trouble Cause (1) Cause (2) Check and corrective measures
1. Wiper cannot spread a thread. 1-1) Interference between wiper
and needle
1-A) Wiper mounting position is inad-
equate.
Adjust the wiper position.
1-2) Displacement of front-rear
wiper position
2-A) Wiper mounting position is inad-
equate.
Adjust the wiper position.
1-3) Thread holding before
wiper action
3-A) The right left wiper mounting po-
sition is inadequate (insufficient
distance to the needle).
Adjust the wiper position.
2. Abnormal noise 2-1) Backlash between the
oscillator and the shuttle
driver shaft is large.
Check oscillator gear positioning and adjust
the lower shaft gear backlash.
2-2) Too much clearance between
inner hook and shuttle driver
Adjust the clearance between inner hook
and shuttle driver
3. Deformation in sewn patterns 3-1) Too much backlash in the
Y feed gear
1-A) Backlash is too much in the Y
feed arm and the motor base.
Adjust backlash of motor base.
1-B) Backlash is too much in the Y feed
pulse motor and the motor base.
Adjust backlash of Y feed pulse motor.
3-2) Too much backlash in the
X feed gear
Adjust backlash of the X feed gear.
3-3) Travelling torque in X di-
rection is excessive.
3-A) The motor is pressed against the
X feed arm too strongly.
Adjust backlash of the motor.
3-B) The feed plate or the work clamp
foot is caught by the needle hole
guide.
Tighten the set screw further for the needle
hole guide.
3-4) Travelling torque in Y direc-
tion is excessive.
4-A) The pulse motor is pressed against
the Y feed shaft too strongly.
Adjust backlash of the feed motor gear.
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11. Troubles and corrective measures
(1) Mechanical parts