Troubles And Corrective Measures - JUKI J-350QVP Instruction Manual

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
Stitches are 1. The needle is bent or the needle point is
skipped.
2. The needle has not been attached to the
Needle thread 1. The machine head has been threaded
breaks.
2. The needle thread tension is too high or
3. The needle is bent or the needle point is
4. The needle is not suited to the thread
The bobbin thread 1. The bobbin thread tension is too high.
breaks. 2. The rubbing of the bobbin case spring
3. Scratches on the needle hole in the throat
The needle 1. The needle is bent or has been installed
breaks.
2. The needle hits the throat plate or the
Stitches are puck- 1. The tension of the needle thread is not
ered.
2. When the combination of the needle and
3. The needle is too thick for the material.
Stitch perfor- 1. The tension of the needle thread is not
mance is bad.
The rotation noise 1. Thread wastes accumulate in the hook.
is too heavy or
too high.
The handwheel 1.
does not rotate
smoothly or does
not turn.
The sewing 1. Remaining length of thread is shorter.
machine cannot
perform sewing at
the beginning of
sewing.
2. Back tacking has not been carried out.
Case
blunted.
needle bar properly.
incorrectly.
low.
blunted.
used.
has produced a slot.
plate.
improperly.
presser foot.
balanced with that of the bobbin thread.
the thread is improper.
balanced with that of the bobbin thread.
he thread is entangled and caught in the
T
hook.
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.
・ Replace the needle.
・ Attach the needle properly to the nee-
dle bar.
・ Correct the threading.
・ Properly adjust the thread tension.
・ Replace the needle.
・ Replace the needle by the one suited
to the thread used.
・ Decrease the tension.
・ Replace the bobbin case.
・ Replace the throat plate.
・ Replace or correctly attach the needle.
・ Correctly position the needle, throat
plate, or presser foot.
・ Balance the tension.
・ Properly correct the combination of
needle and the thread.
・ Replace the needle by the one suited
to the material.
・ Balance the tensions.
・ Clean up the sewing machine.
・ Lubricate the hook, strongly turn the
handwheel clockwise and counter-
clockwise several times, then remove
the thread caught in the hook.
・ 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.
・
e sure to carry out back tacking by
B
several stitches at the beginning of
sewing.
– 30 –
Corrective measures Page
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