
11. TROUBLESHOOTING
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Upper | thread is | not | Movable knife is blunt. |
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| Replace the movable knife. |
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trimmed. |
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| Fixed knife is blunt. |
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| Sharpen or replace the fixed knife. | P. 68 | |||
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| Adjust the position of the shuttle race | P. 67 | |
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| Movable knife does not pick up the | thread guide. |
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| thread. |
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| Adjust the needle bar lift amount. | P. 66 | |
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| The movable knife does not pick up the | Refer to “Skipped stitches occur”. | P. 77 | |||||
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| thread because of skipped stitches at | |||||||
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| the sewing end. |
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| Movable knife position is incorrect. |
| Adjust the position of the movable | P. 68 | ||||
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| knife. |
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| Turn the | P. 30 | ||||
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| tension. |
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Thread jamming. |
| Thread | spring | tension | and | Adjust the tension and height | of the | P. 64 | |||
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| height are incorrect. |
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| Incorrect needle and rotary hook timing. | Adjust the needle bar lift amount. | P. 66 | |||||
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| Shuttle | race thread | guide is | not | Adjust the position of the shuttle race | P. 67 | ||
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| separating the threads. |
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| thread guide. |
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Poor | seam | finish | on | Shuttle race thread guide is separating | Adjust the position of the shuttle race | P. 67 | |||||
reverse | side | of | the threads insufficiently. |
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| thread guide. |
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material. |
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| Upper thread is not properly tight. |
| Adjust the upper thread tension. |
| P. 63 | |||||
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| Uneven needle thread. |
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| Adjust the |
| P. 30 | ||
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| Adjust the |
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| Needle thread is too long. |
| <When using the thread nipper | P. 30 | ||||
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| Turn the tension nut to adjust the upper |
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| thread trailing length to 35 – 38 mm. |
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| Needle is striking the button. | Refer to | sewing | P. 42 | ||||
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| pattern”. |
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Incorrect thread |
| Upper thread tension is too weak. |
| Adjust the upper thread tension. |
| P. 63 | |||||
tightness. |
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| Lower thread tension is too weak. |
| Adjust the lower thread tension. |
| P. 63 | |||
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| Thread | spring | tension | and | Adjust the tension and height | of the | P. 64 | |
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| height are incorrect. |
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| thread |
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Machine does not |
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| Check if the machine head switch cord | P. 17 | |||
operate when power is |
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| is disconnected. |
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turned on and foot |
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switch is depressed. |
| Machine head switch does not work. |
| Adjust the position of the switching | P. 25 | ||||||
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| Replace the machine head switch if it is |
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| broken. |
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78 |