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Trouble
From the previous page
3-8) Feeding is inappropriate.
3-9) Pressing is inappropriate.
3-10) The thread tension device is
defective.
3-11) The needle hole of the throat
plate is too small.
3-12) The needle is too thin for the
thread to be used.
3-13) The needle is defective.
Cause (1)
From the previous page
7-D) The bobbin thread idles in the
bobbin case.
7-E) The bobbin has a flaw.
8-A) The timing of feeding is inap-
propriate, or the height of the
feed dog is too low.
9-A) The presser is floating.
9-B) The presser foot sole has little
or no relief (for thicker thread or
larger stitch length).
10-A) The thread tension disk is float-
ing.
13-A) A burr exists on the tip of the
needle.
Cause (2)
Adjust the tension of the idling prevention
spring with reference to "3.-(4)."
Remove a burr at the flaw portion, or replace
the bobbin.
Set the feed timing to a level slightly later than
standard (for cotton or spun thread). Set the
feed timing to a level earlier than standard (for
filament thread). Lift the feed dog height.
Adjust the clearance between the presser bar
holder and lifting plate. (The clearance shall be
within 0.8 to 1.2mm when the presser is close-
ly contacted with the throat plate.
Use a foot with a large thread relief on the
backside.
Adjust the timing of the thread tension disk
floating with reference to "3.-(9)-6."
Use a throat plate with a larger needle hole.
Change the needle or thread to be used.
Replace the needle.
Check and corrective measures
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