114
LS2-B891, LT2-B892
17. TROUBLESHOOTING
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47
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76 - 86
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33
71
46
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59
59 - 61
65
66
Possible cause
〈
-705 specifications
〉
●
Is the trailing length of the upper thread too short after thread trimming?
Adjust the pretension.
Check if the upper thread is tangled somewhere in the thread path from the
thread stand to the needle tip.
●
Are the thread tension discs open during thread trimming?
Adjust the tension release amount.
●
Is the thread trimming timing too advanced?
Adjust the thread trimming timing.
●
Does the thread holding spring hold the lower thread after thread trimming?
Adjust the position of the thread holding spring.
If the thread holding spring tension is too weak, replace the thread holding
spring.
If the thread holding spring is scratched or damaged, replace the thread
holding spring.
●
Is the driving knife damaged?
If the knife is damaged, smooth it with an oiled grindstone or replace it.
●
Is the needle tip bent? Is the needle tip blunt?
If the needle tip is bent or broken, 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 machine properly threaded?
If it is incorrect, thread the thread correctly.
●
Are the presser feet riding too high?
Adjust the height of the presser feet.
●
Is the presser foot pressure too weak?
Adjust the presser foot pressure.
●
Is the rotary hook tip broken or worn?
Sharpen the rotary hook tip or replace the rotary hook.
●
Is the height of the needle bar correct?
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 needle guard position correct?
Adjust the position of the needle guard.
●
Is the needle and feed timing correct?
Adjust the needle and feed timing.
Problem
5. Skipped stitches occur while
sewing
