
8. TROUBLESHOOTING
| Problem | Possible cause | Page |
5 | Skipped stitches at sewing | ・ Is the thread | * |
| start | Reduce the tension of the thread | |
| Thread unravelling at | ・ Is the thread |
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| sewing start | Lower the position of the thread | * |
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| ・ Are the trailing lengths of the upper threads too short after thread |
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| trimming? |
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| Adjust the pretension. |
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| ・ Are the threads not being trimmed cleanly? | 27* |
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| Sharpen the fixed knives, or replace the fixed and movable | |
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| knives if necessary. |
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| ・ Is the needle too thick? |
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| Try using a needle with a count that is one lower than the |
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| current needle. |
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| ・ Is the length of thread trailing out from the bobbin case after thread |
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| trimming too short? |
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| If the bobbin is spinning loosely, replace the |
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| the bobbin case. |
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| ・ Is the sewing speed too fast at the sewing start? |
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| Set the operation panel so that slow start is enabled. | 21* |
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| ・ Is the needle up stop position too high? | 24* |
| 0749M | Adjust the needle up stop position. | |
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6 | Uneven seam | ・ Is the presser foot pressure too weak? |
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| Adjust the presser foot pressure. |
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| ・ Is the feed dog too low? |
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| Adjust the feed dog height. | 30* |
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| ・ Is the bobbin scratched? | * |
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| If the bobbin is damaged, smooth it with an oiled grindstone or | |
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| replace it. |
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| 0473M |
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7 | Large degree of puckering | ・ Is the upper thread tension too strong? |
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| (excess tension) | Make the upper thread tension as weak as possible. |
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| ・ Is the lower thread tension too strong? |
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| Make the lower thread tension as weak as possible. |
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| ・ Is the needle tip blunt? |
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| Replace the needle if it is blunt. |
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| ・ Is the needle too thick? |
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| Replace with as thin a needle as possible. |
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| ・ Are the thread |
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| Make the thread | * |
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| ・ Is the thread |
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| Lower the position of the thread |
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| position as possible. | * |
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| ・ Is the presser foot pressure too strong? |
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| Adjust the presser foot pressure. |
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| ・ Is the sewing speed too fast? | 16* |
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| Gradually reduce the maximum sewing speed using the | |
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| operation panel. |
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| ・ Is the angle of the feed dog correct? | 30* |
| 0978M | Tilt the front of the feed dog down slightly. | |
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35 |