Funny you should write this today. I have a Bernina 820 and am having the same problem today! It is so frustrating to have spent a fortune on a machine that does not live up to it's name. I have done all of the troubleshooting as well, and it just happens about every 7 or 8 inches. I am even more frustrated that I cannot use monofiliment thread with this machine because the tension gets all screwed up...Okay...I am done complaining--back to the fmq
