It sounds like her thread is jumping out of the take-up lever... if she does take it in to the dealer there is a free fix for that where they add a little guard to prevent the thread from coming off. Also Janet's comment on making sure that you hear the "click" when pulling the bobbin thread thread through the tension area is important. If thread nests on the bottom it's usually a top tension issue. I can almost always hear a clunking sound when my thread jumps off the take-up lever. I have an 830 and a Diamond and I love them both...