I'm sure it's thread jammed in there. We have unscrewed the whole machine and can't get it to come apart, and under the bobbin area, which is where the problem is, is a metal bar that we can't get off or move even when we unscrewed it. We found a small white plastic thingy and that probably came off one of the plastic white gears.... ERRRRR. Now I'm debating on whether or not I want to get it fixed now or later and/or get another machine. I started up the FW and it's just so not the same.... But it sews so perfectly :)