You may try removing the bobbin holder to make sure nothing foreign is embedded or around it. Once, after sewing over pins, which I KNOW I shouldn't do, my bobbin acted up and I found two badly bent and broken pieces of pins under the bobbin holder. They were bent enough to stick up and cause problems. Also, that would be a good chance to take a brush and clean out lint from that area, something I need to do more often! Debbie