JUKI J-350QVP, Instruction Manual, Page: 31 / 32

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If the sensor fails, the error message will be displayed.
(Error message indicates which sensor has failed.)
If the error message is displayed, please contact your distributor.
Troubles and Corrective Measures
If sewing difficulties occur, make sure the instructions are correctly followed. If a problem still exists, the reminders below
help to solve it.
Troubles Case Corrective measures Page
Stitches are
skipped.
1. The needle is bent or the needle point is
blunted.
2. The needle has not been attached to the
needle bar properly.
・ Replace the needle.
・ Attach the needle properly to the nee-
dle bar.
16
16
Needle thread
breaks.
1. The machine head has been threaded
incorrectly.
2. The needle thread tension is too high or
low.
3. The needle is bent or the needle point is
blunted.
4. The needle is not suited to the thread
used.
・ Correct the threading.
・
Properly adjust the thread tension.
・ Replace the needle.
・
Replace the needle by the one suited
to the thread used.
17
18
16
16
The bobbin thread
breaks.
1. The bobbin thread tension is too high.
2. The rubbing of the bobbin case spring
has produced a slot.
3. Scratches on the needle hole in the throat
plate.
・ Decrease the tension.
・
Replace the bobbin case.
・ Replace the throat plate.
18
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The needle
breaks.
1. The needle is bent or has been installed
improperly.
2. The needle hits the throat plate or the
presser foot.
・ Replace or correctly attach the needle.
・ Correctly position the needle, throat
plate, or presser foot.
16
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Stitches are puck-
ered.
1. The tension of the needle thread is not
balanced with that of the bobbin thread.
2. When the combination of the needle and
the thread is improper.
3. The needle is too thick for the material.
・ Balance the tension.
・
Properly correct the combination of
needle and the thread.
・ Replace the needle by the one suited
to the material.
18
19
16
Stitch perfor-
mance is bad.
1. The tension of the needle thread is not
balanced with that of the bobbin thread.
・ Balance the tensions. 19
The rotation noise
is too heavy or
too high.
1. Thread wastes accumulate in the hook.
・
Clean up the sewing machine. 28
The handwheel
does not rotate
smoothly or does
not turn.
1.
T
he thread is entangled and caught in the
hook.
・
Lubricate the hook, strongly turn the
handwheel clockwise and counter-
clockwise several times, then remove
the thread caught in the hook.
-
The sewing
machine cannot
perform sewing at
the beginning of
sewing.
1. Remaining length of thread is shorter.
2. Back tacking has not been carried out.
・ Loosen the tension controller No. 1
(turn to the left) to increase the remain-
ing length of thread after automatic
thread trimming.
・ Draw thread through the needle eyelet
to adjust the remaining length of thread
to approximately 5 cm.
・
B
e sure to carry out back tacking by
several stitches at the beginning of
sewing.
19
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19