6. TROUBLESHOOTING
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Upper thread breaks. | Upper thread tension is too strong. | Adjust the upper thread tension. |
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| Needle is installed incorrectly. | Install the needle correctly. |
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| Thread is too thick for the needle. | Use | the | correct | thread | for |
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| Thread | Adjust the tension and height of the | P.5 | |||||||
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| Damaged or burred rotary hook, | File smooth or replace the affected |
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| needle hole plate or needle. | part. |
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| Thread melting (synthetic thread) | Use | a | thread |
| cooling | device | P.136 | ||
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Lower thread breaks. | Lower thread tension is too strong. | Adjust the lower thread tension. |
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| Corners of needle hole plate or | File smooth or replace the affected |
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| bobbin case are damaged. | part. |
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Skipped | stitches | Clearance between needle and | Adjust the needle clearance. |
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| P.101 | |||||
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| rotary hook tip is too great. |
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| Incorrect needle and rotary hook | Adjust the needle bar lift amount. | P.100 | |||||||
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| timing. |
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| Driver is contacting needle more | Adjust the driver needle guard. |
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| P.101 | |||||
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| Needle is bent. | Replace the needle. |
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| Needle is installed incorrectly. | Install the needle correctly. |
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| Instruction | ||||
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| Needle thread is too short. | Adjust the thread | lever | P.114 | ||||||
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| stroke. |
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| P.115 | ||
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Needle breaks. |
| Adjust the needle clearance. |
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| Needle is touching the rotary hook. |
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| Adjust the needle bar lift amount. | P.100 | ||||||||
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| Needle is bent. | Replace the needle. |
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| Needle is too thin. | Use | the | correct | needle | for |
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| material. |
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| Refer | to | “6. | CHECKING | THE | Instruction | |||
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| Needle is striking the button (438) | SEWING | PATTERN” | in |
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Button breaks. (438) |
| Refer | to | “6. | CHECKING | THE | Instruction | ||||
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| Needle is striking the button | SEWING | PATTERN” | in |
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| Instruction Manual. |
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134 |