12. TROUBLESHOOTING
BAS-311H
149
Problem Cause
Remedy
reference
Lower thread winds to
one side.
Height of bobbin winder tension
assembly is incorrect.
Adjust the height of the bobbin
winder tension assembly.
CD Instruction
manual
Lower thread winding
amount is incorrect.
Bobbin presser position is incorrect.
Adjust the position of the bobbin
presser.
CD Instruction
manual
Needle is too thick.
Select a needle that is suitable for
the sewing conditions.
CD Instruction
manual
When threading the thread through
the needle, allow a distance of
approximately 40 mm between the
needle hole and the end of the
thread.
CD Instruction
manual
Upper thread trailing length is too
short.
Adjust the sub-tension so that the
upper thread trailing length after
thread trimming is approximately 40
mm.
CD Instruction
manual
Amount of lower thread being fed
out from bobbin is too small.
Set the feeding amount to
approximately 30 mm.
CD Instruction
manual
Thread unraveling at
sewing start.
Sewing start speed is too fast.
Adjust the sewing start speed.
CD Instruction
manual
Rotary hook tip is missing.
Replace the part.
Needle is too thin.
Needle is too thick.
Select a needle that is suitable for
the sewing conditions.
CD Instruction
manual
Needle is bent.
Replace the needle.
CD Instruction
manual
Needle is not installed correctly.
Install the needle so that it faces
correctly.
CD Instruction
manual
Needle and rotary hook tip are
touching.
Adjust the driver needle guard.
P.88
Clearance between needle and
rotary hook tip is too large.
Adjust the needle clearance.
P.89
Needle and rotary hook timing is
incorrect.
Adjust the timing.
P.88
Replace the needle hole plate with
one with a smaller needle diameter.
Use a thinner feed plate.
* Recommended thickness: 1.5 mm
Process the work clamps and the
feed plate into shapes that can hold
the material near the seam.
CD Instruction
manual
Skipped stitches occur.
Material is flapping.
Adjust the intermittent height of the
intermittent work clamp.
CD Instruction
manual
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