115
LS2-B891, LT2-B892
17. TROUBLESHOOTING
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66
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59 - 61
Motor Instruc-
tion Manual
46
Possible cause
●
Is the needle and feed timing correct?
Adjust the needle and feed timing.
●
Is the feed dog height correct?
Adjust the feed dog height so that it is 0.5 mm when the feed dog is at its
highest position.
●
Is the presser foot pressure too weak?
Adjust the presser foot pressure.
●
Is the needle bent or is the needle tip broken?
Replace the needle if it is bent or broken.
●
Is the needle scratched?
Replace the needle.
●
Is the needle properly installed?
If it is incorrect, install the needle correctly.
●
Is the needle too thin or too thick for the thread?
Replace with a needle which is suitable for the thread.
●
Is the upper thread tension too strong or to weak?
Adjust the upper thread tension.
●
Is the tension of the thread take-up spring too strong or too weak?
Adjust the tension of the thread take-up spring.
●
Is the operating range for the thread take-up spring too large or too small?
Decrease or increase the operating range for the thread take-up spring.
●
Is the thread path not smooth enough?
Use a file with a fine grain or sandpaper to polish smooth the thread path.
●
Is the rotary hook tip broken or worn?
Sharpen the rotary hook tip or replace the rotary hook.
●
Is the rotary hook thread path damaged?
Smooth the rotary hook thread path or replace the rotary hook.
●
Is the clearance between the needle plate and the inner rotary hook stop-
per correct?
Adjust the position of the opener.
●
Has the needle been pushed in fully during installation?
Install the needle correctly.
●
Is the height of the needle bar too low?
Adjust the height of the needle bar.
●
Is the needle and rotary hook timing correct?
After adjusting the needle bar height, adjust the needle and rotary hook
timing.
●
Is the sewing speed too fast, causing the thread to break due to heat?
Reduce the sewing machine speed.
●
Is the material feeding correctly at sections where the thickness changes
(such as joints and pockets)?
Increase the presser foot pressure.
Problem
6. Uneven seam
7. Upper thread breaks