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9. TROUBLESHOOTING
CAUTION
(1) Please make sure to turn the power switch off before adjusting the sewing machine.
(2) If the adjustment is required while the power switch on, do not step on the foot switch by mistake.
Condition Cause Corrective
action
Reference
Upper thread is broken.
Upper thread tension is too
tight.
Adjust thread tension.
6-3
Strength of thread take up
spring is inappropriate.
Adjust thread take up spring.
7-17
Parts on needle plate, hook,
and presser foot touching
thread are damaged.
Grind parts or change parts.
-
The needle size is bigger
than the thread size.
Change the needle size to
suitable size.
-
Thread melts with heat.
Slow down the sewing speed
6-1
Use
needle
cooler.
-
Bobbin thread is
broken.
Bobbin thread tension is too
tight.
Adjust thread tension.
6-3
Parts on needle plate and
presser foot touching thread
are damaged.
Buff parts or change parts.
-
Thread tail is short.
Adjust thread tail with
pre-tension.
7-18
Upper thread is pulled
from needle hole when
starting sewing.
Thread take up spring
tension is too much.
Adjust thread take up spring
tension.
7-17
Frequent skip stitching
happens.
Clearance between needle
and shuttle hook is too big.
Adjust clearance between
needle and shuttle hook
properly.
7-3
Timing of needle and shuttle
hook is not proper.
Adjust position of needle and
shuttle properly.
7-2
Contact between needle and
driver is too tight.
Adjust clearance between
needle and driver properly.
7-4
Needle is bent.
Change needle.
-
Needle is at wrong position.
Fix position properly.
5-2
Trimming is not
functioned.
Fixed knife is dull.
Sharpen fixed knife or
change fixed knife.
7-16
Movable knife is dull.
Change movable knife.
7-15
