30
No Symptom Checkpoints Root cause Corrective action
Tension not aligned between movable and fixed blade.
Abrasion in blade groove of movable and fixed blade.
Wrong needle insertion.
Insufficient crossing quantity of
movable and fixed blade.
Too strong upper thread tension.
Too thick a needle for thread.
Take-up lever pulls out the upper
thread because the needle up and
down position is too high.
Check the crossing of
trimmer cam notch
mark and blade
Check the Up-stop
position of needle
Tension of fixed blade
Edge of movable and fixed blades
Direction of needle
Trimming errors6
Adjust tension of movable and fixed blade.
Replace movable and fixed blade.
Reinsert the needle correctly.
Adjust the stroke of movable and
fixed blade.
Adjust tension of upper thread.
Check thickness of needle.
Adjust the up-stop position of
needle.
7
Upper thread
is pulled out
when sewing
commences.
Too tight upper thread tension.
Too loose lower thread tension.
Too weak upper thread tension.
Increase tension of upper thread.
Reduce tension of upper thread.
Increase tension of lower thread.
Too strong lower thread tension.
Decrease tension of lower thread.
Upper thread
does not sink.
Lower thread
does not sink.
4
5
To Next Page
Loading...
Need help?
General
