I bought a used Viking designer SE and have a lot of problems with the upper tension. I have spent a lot of money taking it to different dealers trying to get it fixed,but just caught it's problem the other day. I was sewing along doing a zig zag and it was going fine then all of a sudden it was making an awful noise and there was a wad of thread in the bobbin area which is what I had takin it for repair for. I just happened to see the thread was not feeding as it should. I looked on line and found that Viking electronic machines have a problem with their upper tension. My problem didn't show up with straight stitching but every time I tried to zig zag a seam it would jam after a little while. I called Viking and they told me that since I bought it used it no longer had any warranty. So if you want a machine that is covered for problems you should buy new! Anna