Unicorn LS2-H530, Operation Manual

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TROUBLESHOOTING GUIDE
Problem Cause Check Solution Page
Thread
fraying or
breakage
Burr in thread path ―
Remove with
sandpaper.
Blunt needle tip ― Replace needle. 4
Skipped
stitches
Improper needle
installation
Needle facing,
height
Reinstall needle. 4
Wrong needle for
application Needle size,
length
Replace needle with
larger count needle.
Bent needle
Blunt tip
Needle Replace needle. 4
Blunt rotary hook point Rotary hook point Replace rotary hook
Improper threading Threading Rethread. 4
Poor presser foot
contact
Presser bar
pressure
Tighten presser foot
adjustment screw.
Presser bar height
Adjust presser bar
height
Improper needle to
rotary
hook timing
Needle bar rise
Adjust needle to
rotary
hook timing 8
Needle bar height
Adjust needle to
rotary
hook timing. 8
Needle to rotary
hook timing
Tighten presser foot
adjustment screw.
8
Needle thread remainder
too short; does not
remain in material.
― Adjust pretension. 6
Bobbin spins during
thread cutting and
bobbin thread
remainder gets too
short; won't rise.
Bobbin presser
spring
Replace bobbin
presser
spring.
Thread take-up spring
tension too weak, won't
raise bobbin thread.
Thread take-up
spring tension
Adjust take-up
Spring
tension
6