Several people have mentioned having problems with various replacement bobbins in their FWs. My SIL asked me to adjust her machine for her because the tension wasn't right. The tension was fine. It was the bobbin that her FW didn't like. I don't remember now where she purchased them.... one of the box stores. So, I guess you could try your replacements and see if your FW likes them or not. I know that others on QB have said the bobbins from sew-classic have worked for them. There are other places where you can order replacements that work well.... someone will mention them as well.