18
4
Causes of Trouble and Troubleshooting
1) Sewing machine troubleshooting
No
Symptom
Checkpoints
Root cause
Corrective action
1
2
3
4
Needle breaks
Thread breaks
Sewing is
skipped
Upper thread
does not wind
Reinsert the needle correctly
Change the needle
Adjust the timing of feed dog
Adjust the needle and hook timing.
Adjust the needle and hook timing.
Adjust the needle and hook timing.
Thread the needle correctly
Change the needle
Insert the needle correctly
Reduce tension of upper thread
Adjust take-up lever spring
Reinsert the needle correctly and
push in to its highest level
Change the needle
Insert the thread in the right way
Adjust the needle and hook timing.
Adjust the needle and hook timing.
Adjust the needle and hook timing.
Adjust the thread adjusting device
Reduce the tension of upper thread
Enhance the tension of lower thread
Needle is inserted into wrong position
Needle is bent
Bad timing of feed dog
The needle and hook timing is bad.
The needle and hook timing is bad.
The needle and hook timing is bad.
Wrong threading
Bent needle or broken needle tip
Needle inserted in the wrong position
Too tight upper thread tension
Loose upper thread
Needle is inserted into wrong
direction
Needle is bent
Wrong direction
The needle and hook timing is bad.
The needle and hook timing is bad.
The needle and hook timing is bad.
The length of the remaining upper
thread is too short
Too tight upper thread tension
Too weak lower thread tension
Direction and height of
needle
Needle
Ascending level of
needle bar
Height of needle
Gap between the
needle and the hook
Threading method
Needle
Direction and height of
needle
Upper thread tension
Working capacity of
take-up lever spring
Direction and height of
needle bar
Needle
Threading
Ascending level of
needle bar
Height of needle bar
Gap between the
needle and the hook
5
Upper thread
falls out when
starting to sew
Adjust Tension of the upper thread
Correct the thickness of the needle
Find out needle top stop position
Tension of the upper thread is strong
Needle is too thick for thread
The position of Needle top and lower
Check for Needle top
stop position
