13. TROUBLESHOOTING
Problem
Upper
thread
is
not
trimmed.
Poor stitch finish on
underside of material.
Incorrect tightening of
the thread.
73
Cause
Movable knife is not cutting cleanly.
Fixed knife is not cutting cleanly.
Movable knife is not picking up the
upper thread.
Movable knife is not picking up the
upper thread because the last stitch is
being skipped.
Movable knife position is incorrect.
Sub tension is too weak.
Thread trimming air cylinder speed is
too slow.
Thread trimming air cylinder operation
timing is too delayed.
Incorrect tightening of the upper thread.
Upper thread trailing length is uneven.
Upper thread tension is too weak.
Lower thread tension is too weak.
Thread take-up spring tension and
height are incorrect.
Position of arm thread guide R is
incorrect.
Intermittent
height
of
presser foot is too low.
Upper
thread
does
correctly from hook stopper.
Feed timing is too fast.
Upper thread forms the seam poorly.
Thread scraps and dust in rotary hook.
Replace with a new one.
Sharpen the fixed knife or replace it
with a new one.
Adjust the position of the movable
knife.
Adjust the needle bar lift amount.
Refer to "Skipped stitches occur".
Adjust the position of the movable
knife.
Turn the sub tension nut to adjust the
tension.
Adjust the speed of the thread trimming
air cylinder.
Advance the operation timing for the
thread trimming air cylinder.
Adjust the upper thread tension.
Adjust the sub tension.
Adjust the upper thread tension.
Adjust the lower thread tension.
Adjust the tension and height of the
thread take-up spring.
Adjust the position of arm thread guide
R.
intermittent
Adjust the intermittent height of the
intermittent presser foot.
not
release
Adjust the overlapping amount for the
inner rotary hook and hook stopper.
Retard the feed timing.
Select the correct needle hole plate.
Smooth the thread path.
Select the correct intermittent presser
foot.
Increase the thickness of the feed
plate.
Clean away the thread scraps and
dust.
BAS-342G PS
Remedy
Reference
P. 62
P. 62
P. 59
P. 57
P. 72
P. 59
P. 24
P. 11
P. 35
P. 24
P. 24
P. 24
P. 24
P. 55
P. 56
P. 32
P. 58
*
*
*
*
*
P. 53