I am having continual problems with the thread tensions on this machine. It comes loose or jerks and breaks or bunches up. The bobbin won't stay set either. The tension screw comes loose and I have had to tear out seam after seam after seam. I don't know what to do except see what the warranty information is. I am traveling and my manual is at home. I'm in Washington and the manual is at home in Iowa. Frustrated!