Measures - JUKI MO-644DN Instruction Manual

Maintenance
Before you call for help: Trouble and corrective measures
The following problems should not be regarded as the machine trouble. Check the following table before you call for
help from us.
Trouble
Fabric does not feed
Needles break
Thread breaks
Stitch skips
Poor stitches are for-
mation
Seams flute or wave,
especially when sew-
ing knits
Seams pucker
Motor trouble
When the trouble is not corrected by the above measures, contact your local dealer.
Cause (reason)
• Presser foot pressure is too low.
• Needles are bent, or the needle point is blunt.
• Needles are incorrectly attached.
• The material cloth is excessively stretched.
• The machine is incorrectly threaded.
• Thread tension is too high.
• Needles are incorrectly attached.
• Needles are bent or needle point is blunt.
• Needles are incorrectly attached.
• The machine is incorrectly threaded.
• Thread tension is not proper.
• Presser foot pressure is too high.
• Differential feed is set incorrectly.
• Thread tension is too high.
• Differential feed is set incorrectly.
• The motor makes noise.
• The motor will not rotate.
• Unusually large sparks are emitted.
Corrective measures
• Increase the presser foot pressure
by turning the presser foot pressure
adjusting screw to the right.
• Replace the needles.
• Attach the needle correctly.
• Hold the edge of the material cloth
lightly with your hand when sewing.
• Rethread the machine correctly.
• Adjust the thread tension properly.
• Adjust the needles correctly.
• Replace the needles.
• Attach the needle correctly.
• Rethread the machine correctly.
• Adjust the thread tension properly.
• Reduce presser foot pressure.
• Adjust differential feed to N - 2.
• Set the thread tension adjusting dial
to the smaller value.
• Adjust differential feed to 0.7 - N.
• Replace the carbon brush.
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