TROUBLESHOOTING GUIDE
Problem Cause Check Solution Page
Needle thread
escapes at start
of sewing.
Te nsio n disc does not
open sufficiently.
Tension disc
opening
Adjust tension release.
Excessive pre tension ― Adjust pretension. 6
Needle too heavy for
thread
―
Use smaller size
ne edle.
Up needle sto p position
too high, thread removed
by thread take-up.
Thread take-up
height at up needle
stop position
Delay up needle stop
position timing.
15
Thread cutter
mec hanism does
not function.
Thread cutter solenoid
dose not function.
Check with tester
Replace thread cutter
soleno id.
Thread cutter signal not
transmitted.
―
Check cir cuits; refer
to motor adjustment
manu al
Thread wiper
does not
funct ion.
Needle thread remainder
too long.
― Adjust pretension 6
Timing too early; wipes
thread before tension
disc closes.
― Adjust timing.
Excessive material,
presser foot resistance
―
Replace with presser
foot having back
chan nel.
Thread wiper operation
too short
― Adjust operation time.
Mate rial end is
not cut during
sewing.
Gap betwe en upper and
lower knife
― Reposition upper knife 24
improper engagement of
upper and lower knives
―
Adjust overlap of two
kn ive s
24
Upper knife is dull ― Rep la ce up per k nife
Mate rial is not
cut properly at
corners.
Uppe r knife positioned
too far forward
― Reposition upper knife 24
upper knife posotioned
too far to rear
― Reposition upper knife 24
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