Dabbler, I had the same type of problem this week with my Brother that my students use. For three different days a student would complain about it not sewing right and bunches of thread on the back side - they were quilting with the walking foot. I had them rethread the machine and all those things you usually do first, then finally put new thread onto a new bobbin from the spool of thread they were using. Bingo, that was the problem. Apparently that Brother CS6000i has to have the same thread on top and bobbin. Will remember that for the future.
Last edited by fmhall2; 10-04-2013 at 06:48 AM.