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Trouble Cause (1) Cause (2) Check and corrective measures
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7-D) The bobbin thread idles in the
bobbin case.
Adjust the tension of the idling prevention
spring with reference to 3.-(4).
7-E) The bobbin has a aw. Remove a burr at the aw portion, or replace
the bobbin.
3-8) Feeding is inappropriate. 8-A) The timing of feeding is inap-
propriate, or the height of the
feed dog is too low.
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
lament thread). Lift the feed dog height.
3-9) Pressing is inappropriate. 9-A) The presser is oating. 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 closely
contacted with the throat plate. DDL-9000C-S
only )
9-B) The presser foot sole has little
or no relief (for thicker thread or
larger stitch length).
Use a foot with a large thread relief on the
backside.
3-10) The thread tension device is
defective.
10-A)
The thread tension disk is oat-
ing.
Adjust the timing of the thread tension disk
oating with reference to 3.-(9)-6.
3-11) The needle hole of the throat
plate is too small.
Use a throat plate with a larger needle hole.
3-12) The needle is too thin for the
thread to be used.
Change the needle or thread to be used.
3-13) The needle is defective.
13-A)
A burr exists on the tip of the
needle.
Replace the needle. (It is advisable to use a
ball-point needle for synthetic thread.)
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