I sounds like it "could" be the problem. I have the same machine and quilted a lot of tops. I finished one, cleaned it, changed the needle and could not get through a row without it breaking. I changed EVERYTHING. Finally I changed to a different spool of thread (same type,etc). Not a problem after that. I think I had a bad spool, which was replaced by the mfg with no questions asked. It was the same weight, etc. Just a different color. Once I changed it (knock on wood) I haven't had any problems. Have probably quilted 4 quilts since.