If you have a manual for your machine, check the "troubleshooting" advice. My machine was noisy and the stitches didn't look right. The manual troubleshooting tips said to change the needle and to make sure the bobbin was the correct size for the machine. The needle looked fine, but I changed it anyway. I had used a 15 bobbin because I had some already wound, so I changed to a 15J bobbin that came with the machine. It sounds fine and works right now.