Brother BAS-343E Instruction Manual page 63

14. Troubleshooting
Problem
Upper thread is not
trimmed.
Thread jamming.
Poor seam finish on
reverse side of material.
Incorrect thread
tightness.
56
Cause
Fixed knife is blunt.
Movable knife does
not pick up the thread..
The movable knife does not pick
up the thread because of skipped
stitches at the sewing end.
Movalbe knife position
is incorrect.
Sub-tension is too weak.
Thread take-up spring
tension and height are
incorrect.
Incorrect needle and
rotary hook timing.
Shuttle race thread
guide is not separating
the threads.
Shuttle race thread
guide is not separating
the therads. incorrect.
Upper thread is not
properly tight.
Uneven upper thread
length.
Upper thread tension
is too weak.
Lower thread tension
is too weak.
Thread take-up spring
tension and height are
incorrect.
Check
Fixed knife blade
Shuttle race thread
guide position
Needle bar lift amount
Skipped stitches at
sewing end
Movable knife position
Sub-tension
Thread take up spring
tension and height
Needle bar lift amount
Shuttle race thread
guide position
Shuttle race thread
guide position
Upper thread tension
Upper thread length
Upper thread tension
Lower thread tension
Thread take-up spring
tension and height
BAS-343E
Remedy
Sharpen or replace the
fixed knife.
Adjust the position of
the shuttle race thread
guide.
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 tension and
height of the thread take-
up spring.
Adjust the needle bar
lift amount
Adjust the position of
the shuttle race thread
guide.
Adjust the position of
the shuttle race thread
gudie.
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.
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