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| 14. TROUBLESHOOTING | ||
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| Problem |
| Possible cause | Page | |
| 3 | Skipped stitches occur | • | Is the needle tip bent? Is the needle tip blunt? |
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| while sewing. |
| If the needle tip is bent or broken, replace the needle. | Instruction |
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| • Is the needle properly installed? |
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| If it is incorrect, install the needle correctly. | manual |
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| • Is the machine properly threaded? | Instruction |
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| If it is incorrect, thread the thread correctly. | manual |
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| • Is the presser foot pressure too weak? | Instruction |
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| Adjust the presser foot pressure. | manual |
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| • Is the needle too thin? |
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| Replace the needle with a needle that is one rank thicker. |
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| • Is the presser foot too high? |
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| Adjust the height of the presser foot. | 70 |
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| • Is the needle and rotary hook timing incorrect? |
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| Adjust the height of the needle bar. | 73 |
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| Adjust the clearance between the needle and the rotary hook. | 76 - 77 |
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| • Is the thread | 69 |
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| 0621M |
| Adjust the tension of the thread |
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| 4 | Flattened zigzags appear | • | Has the treadle been depressed backward? |
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| in the stitch during |
| Do not press the treadle backward when the sewing machine is |
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| intermittent sewing. |
| stopped. |
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| (8550A) |
| (When memory switch No. 109 is set to “1”, needle zigzagging |
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| also occurs when the treadle is depressed backward, in order to |
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| prevent a flattened zigzag from being sewn if the treadle is |
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| depressed backward by mistake.) |
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| • Does the treadle move too easily when it is depressed backward? |
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| Adjust the force required to depress the treadle backward so | 79 |
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| that it is a bit heavier. |
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| 1406M |
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| 5 | Skipped stitches at sewing | • | Is the thread | 69 |
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| start |
| Reduce the tension of the thread |
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| Thread unravelling at | • | Is the thread | 69 |
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| sewing start |
| Lower the position of the thread |
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| 0622M | • | 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 needle bar at the needle up stop position at the sewing start? | Instruction |
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| Set the needle bar to the needle up stop position at the sewing |
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| start. | manual |
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| • | Is the length of the upper thread trailing from the needle hole too |
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| short? |
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| Upper |
| Pull about 50 mm of thread through the needle hole at the | Instruction |
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| sewing start. | manual |
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| thread |
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| <8560A> |
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| • | Is the trailing length of the upper thread too short after thread |
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| trimming? |
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| Adjust the upper thread feeding device. | 84 |
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| • Are the threads not being trimmed cleanly? |
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| Sharpen the fixed knife with a whetstone, or replace the fixed |
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| knife. | Instruction |
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| Replace the movable knife. |
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| • Is the length of thread trailing out from the bobbin case after thread | manual |
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| trimming too short? | Instruction |
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| If the bobbin is spinning loosely, replace the |
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| the bobbin case. | manual |
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| Adjust the tension of the lower thread presser spring. | 83 |
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| • Is the needle up stop position too high? | Instruction |
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| Adjust the needle up stop position. | manual |
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| • Is the sewing speed too fast at the sewing start? | Instruction |
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| Use the slow start feature. |
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| 0623M |
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| manual |
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110 |