LK3-B430E Mark II
59
Problem
Cause
Check
Solution
Page
Needle breaks.
Needle is interfering
with rotary hook.
Clearance between
needle and rotary hook
point
Adjust the clearance
between the needle
and rotary hook point.
42
Upper or lower thread
is not trimmed.
Thread jamming
Needle bar lift stroke
Adjust the needle bar
lift stroke.
41
Needle is bent
Needle curve
Replace the needle
with a new one.
Sideways needle
movement
Needle and feed timing
Adjust the needle down
detection position.
49
Needle is too thin.
Needle and thread
Use the correct needle
for the material.
Electrical trouble
See #15 "The machine can-
not produce correct stitch-
es" in the table in 10-12-2.
←
89
Fixed knife is blunt.
Fixed knife blade
Sharpen or replace the
fixed knife.
Rotary hook thread
guide
Adjust the position of
rotary hook thread
guide.
42
Movable knife does not
pick up the thread.
Needle bar lift stroke
Adjust the needle bar
lift stroke.
41
Movable knife does not pick up
the thread because of skipped
stitches at the end of sewing.
Skipped stitches at the
end of sewing
See "Skipped stitches
occur."
Improper position of
movable knife
Movable knife position
Adjust the position of
the movable knife.
44
Sub tension is
insufficient.
Sub tension
Turn the tension nut to
adjust the tension.
Electrical trouble
See #16 "The thread
trimmer does not operate"
in the table in 10-12-2.
←
89
Lower thread tension
is insufficient
Lower thread tension
Turn the thead tension
nut in the bobbin case
to adjust the tension.
Inadequate tension
and height of thread
take-up spring
Tension and height of
thread take-up spring
Adjust the tension and
height of the thread
take-up spring.
4
Improper needle and
rotary hook timing
Needle bar lift stroke
Adjust the needle bar
lift stroke.
41
Rotary hook thread
guide does not separate
upper and lower threads.
Rotary hook thread
guide position
Adjust the position of
the rotary hook thread
guide.
42
Upper thread tension
is insufficient
Main tension
Turn the tension nut to
adjust the tension.
9. TROUBLESHOOTING
