With Regard To Thread Trimming - JUKI LS-1340 Manual

(2) With regard to thread trimming

Troubles
1 One or serveral stitches
skip at the start of sewing.
Causes
Thread remaining at the
needle top after thread
trimming is short.
Bobbin thread is not
clamped.
Needle is too thick.
Needle hole in the feed
dog is too large.
Pressure of the presser
foot is too low.
−
Checking
Check the routing of
needle thread.
Thread tension given by
the tension controller
No.1 is too high.
Check the rising amount
of the thread tension disk
No.2 at the time of thread
trimming.
Thread trimming timing is
excessively advanced.
There are scratches on
the moving knife and the
hook.
Position of the clamp
spring.
Pressure of the clamp
spring is too low.
There are scratches on
the clamp spring.
Needle thread removes
bobbin thread.
50
−
Corrective measures
T h r e a d t h e n e e d l e t h r e a d
correctly.
Make the winding of the thread
guide once.
Decrease the tension given by the
tension controller No.1.
Adjust so that the disk is raised
by means of the thread release
solenoid.
Refer to "5) Thread trimmer cam
timing" .
Polish with buff or replace the
part.
Refer to "2) Position of the counter
knife".
Refer to "2) Position of the counter
knife".
Replace the clamp spring with a
new one.
Increase or decrease the tension
of the tension controller No.1.
Replace the needle with a thinner
one.
Replace the feed dog with an
optional one with small needle
hole.
Increase the pressure of the
presser foot.