I have a Riccar if that helps at all. I'm not sure exactly how to explain it, but bottom line is that it won't stitch! It either will catch and the needle won't move, or it "sews" - with a clunk or two - but no stitches are in the fabric. I've taken the bobbin out repeatedly - this has happened before recently, but once I removed a stray thread it was back to normal. I can't find any threads this time though. Should I remove the cover plate to see if anything is in there?