14. TROUBLESHOOTING
Problem
Cause |
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| Remedy | Page |
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Upper thread breaks.
Lower thread breaks.
Skipped stitches occur.
Upper thread tension is too strong.
Needle is installed incorrectly.
Thread is too thick for the needle.
Thread
Damaged or burred rotary hook, needle hole plate or needle.
Thread melting (synthetic thread)
Thread path is incorrect.
Lower thread tension is too strong.
Corners of needle hole plate or bobbin case are damaged.
Clearance between needle and rotary hook tip is too great.
Incorrect needle and rotary hook timing.
Driver is contacting needle more than is necessary.
Needle is bent.
Needle is installed incorrectly.
Upper thread tension
Needle direction
Thread and needle
Thread
Damage or burring
Thread edge
Thread
Lower thread tension
Damage
Needle clearance
Needle bar lift amount
Clearance between driver and needle
Bent needle
Needle direction
Adjust the upper thread | 25 | |
tension. | ||
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Install the needle so that the | 21 | |
groove is facing forward. | ||
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Use the correct | thread | 21 | |
for the needle. |
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Adjust the tension and | 25 | ||
height of the thread take- | |||
up spring. |
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File smooth or | replace |
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the affected part. |
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Use a thread cooling | 21 | ||
device. |
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Pass the thread correctly | 22 | ||
along the thread path. | |||
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Adjust the lower | thread | 25 | |
tension. |
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File smooth or | replace |
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the affected part. |
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Adjust the needle clearance. | 43 | ||
the affected part. |
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Adjust the needle bar lift | 42 | ||
amount. |
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Adjust the driver needle | 43 | ||
guard. |
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Replace the needle. |
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Install the needle so that the | 21 | ||
groove is facing forward. | |||
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Needle breaks.
Needle is touching the rotary hook.
Needle is bent.
Needle moves about.
Needle is too thin.
Needle clearance
Needle bar lift amount
Bent needle
Needle and thread
Needle and thread
Adjust the needle clearance. | 43 | |
the groove is facing forward. | ||
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Adjust the needle bar lift | 42 | |
amount. | ||
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Replace the needle. |
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Select the correct needle for | 21 | ||
the | sewing | conditions. | |
Reduce the sewing speed |
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Use | the correct needle |
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for the material. |
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69 |
