15. TROUBLESHOOTING- Page 63

15. TROUBLESHOOTING

BAS-341F, 342F

56

Needle bar lift amount

Upper thread is not
trimmed.

The movable knife does not pick
up the thread because of skipped
stitches at the sewing end.

Skipped stitches at
sewing end

Movable knife position
is incorrect.

Movable knife position

Adjust the needle bar lift
amount.

Refer to “Skipped
stitches occur”.

Adjust the position of the
movable knife.

34

32

Shuttle race thread
guide position

Adjust the position of the
shuttle race thread gudie.

33

Sub-tension is too weak.

Sub-tension

Turn the sub-tension nut
to adjust the tension.

13

Movable knife does not
pick up the thread.

Fixed knife is blunt.

Fixed knife blade

Sharpen or replace the
fixed knife.

Thread take-up spring
tension and height are
incorrect.

Thread take up spring
tension and height

Thread jamming.

Incorrect needle and
shuttle hook timing.

Needle bar lift amount

Shuttle race thread guide
is not separating the
threads.

Shuttle race thread
guide position

Adjust the tension and
height of the thread take-
up spring.

Adjust the needle bar lift
amount.

Adjust the position of the
shuttle race thread guide.

32

33

13

Shuttle race thread

guide is not separating
the threads.

Shuttle race thread
guide position

Poor seam finish on
reverse side of material.

Upper thread is not
properly tight.

Upper thread tension

Uneven upper thread
length.

Upper thread length

Adjust the position of the
shuttle race thread guide.

Adjust the upper thread
tension.

Adjust the sub-tension.

13

13

33

Upper thread tension is
too weak.

Upper thread tension

Incorrect thread
tightness.

Lower thread tension is
too weak.

Lower thread tension

Thread take-up spring
tension and height are
incorrect.

Thread take-up spring
tension and height

Adjust the upper thread
tension.

Adjust the lower thread
tension.

Adjust the tension and

height of the thread take-
up spring.

13

13

13

Problem

Cause

Check

Remedy

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