Good for you, I know that it takes practice to do FMQ'ing and I guess I'm afraid...I've done a pot holder with various stitches that is "OK" but when I think of a large quilt ARGH!!
Anyway, the problem I was having is that the bobbin holder sort of pops out, catching threads. The tech today said that it may be because the bobbin tension was too tight and he loosened it a bit. Of course, it sewed for him FINE! :) It's back in my sewing room and I"m getting ready to go and get her all set back up. Have you had any problems like that on your Sapphire 830? I have noticed that you can't use a partial bobbin or a needle that is even a hint of being used because in the past it hung up the threads.
Thanks!