1. If the needle is bent or the needle is installed reversely, replace the new needle or install the needle correctly.
2. If the tension of the thread take-up spring is too large or there is no thread take-up spring, loosen the thread take-up spring and install a pick-up spring. The thread spring can solve the problem.
3. If there is a fault caused by burrs on the hook tip of the rotary hook, use fine sandpaper to lightly grind off the burr. 4. If the position error of the rotary hook and the needle is too large, adjust the rotary hook and the needle. location can be resolved.
