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9. TROUBLESHOOTING
(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
Upper thread is broken.
Bobbin thread is
broken.
Upper thread is pulled
from needle hole when
starting sewing.
CAUTION
Cause
Upper thread tension is too
tight.
Strength of thread take up
spring is inappropriate.
Parts on needle plate, hook,
and presser foot touching
thread are damaged.
The needle size is bigger
than the thread size.
Thread take up lever stroke is
different from standard
setting.
Thread melts with heat.
Bobbin thread tension is too
tight.
Parts on needle plate and
presser foot touching thread
are damaged.
Bobbin case size is smaller
than the thread size.
Holding pressure of the
bobbin thread is too tight.
Thread take up spring
tension is too much.
Thread tail is short.
(Pre-tensioner spring is too
tight.)
Sewing speed is
inappropriate when starting
sewing
Corrective action
Adjust thread tension.
Adjust thread take up spring.
Grind parts or change parts.
Change the needle size to
suitable size.
Adjust thread take up lever
stroke
Slow down the sewing speed
Use needle cooler.
Adjust thread tension.
Buff parts or change parts.
Change the thread size to
suitable size.
Adjust holding pressure of
the bobbin thread.
Adjust thread take up spring
tension.
Adjust thread tail with
pre-tension.
Use [e-stitch] function.
(Program mode > Sewing
speed group > OPLC is ON)
- 51 -
Reference
5-10
6-7-2
-
5-1
7-5
Operation
panel section
-
5-9
-
-
7-6-3
6-7-2
6-8
Operation
panel section
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