I bought my Janome 7700 a couple of months ago and I was getting little loops on the bottom of my work until I adjusted the tension of the top thread. I had to play with it a little to get it right. Also, when I wind a bobbin I guide the thread up and down with my finger to get the bobbin wound more evenly (I have to do this on all my machines) and I make sure the thread is not loose on the bobbin.