SunStar KM-341BL, User Manual, Page: 21 / 22

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Errors and Troubleshooting
1) Troubleshooting
NO. Error Check Cause Handling Measure
1
2
3
4
Needles are
broken.
Thread is
broken.
Thread tension
is improper.
When sewing
starts, the
upper thread is
escaped or
sewing skip
occurs.
Direction and height of
needle insertion
Needle
Feed dog timing
Lifting of needle bar
Height of needle bar
Gap between needle
and hook
Method of thread
placing
Needle
Direction, height of
needle
Upper thread tension
Lower thread tension
Movement range of
thread take-up spring
Thread tension
Tread take-up spring
tension
Gap between opener
and hook
Direction, height of
needle
Needle
Placing the thread
Gap between needle
and hook
Check the highest
needle stop position
The direction of inserting a needle is
wrong.
A needle is crooked.
The feed dog timing for needle bar
movement is bad.
The timing of needle and hook is bad.
The timing of needle and hook is bad.
The timing of needle and hook is bad.
The thread placement is wrong.
The needle is crooked/The tip of the
needle is broken.
The direction of the needle is wrong.
The upper thread tension is too
strong.
The lower thread tension is too
strong.
The movement range is too wide.
The upper and lower thread tension
is improper.
The tread take-up spring tension is
improper.
The gap between opener and hook
is improper.
The needle position is wrong.
A needle is crooked/ The end of the
needle is broken.
How to place thread is wrong.
The timing of thread and hook is
improper.
Because the needle's highest stop
position is not proper, the thread
take-up removes the upper thread by
pulling it when the sewing starts.
Insert the needle in a right direction
and push it into the deepest position.
Replace the needle.
Adjust the timing of feed dog.
Adjust the timing of needle and hook.
Adjust the timing of needle and hook.
Adjust the timing of needle and hook.
Place the thread in the right way.
Replace the needle.
Insert the needle in the right way.
Adjust the upper thread tension
properly.
Adjust the lower thread tension
properly.
Adjust the movement range of the
spring.
Adjust the upper and lower thread
tension.
Adjust the tread take-up spring
tension.
Adjust the gap between opener and
hook.
Insert the needle in the right
direction.
Replace the needle.
Properly place the thread.
Adjust the timing of thread and hook.
Reset the position of the needle's
highest stop position.