I believe the Duetta has two different bobbin cases - are you using the right one for the thread you are sewing with (i think you are talking about the sewing side of the machine not the embroidery side of the machine). I know that can cause issues with tension.
This has happened to me... for me it was tension and mine was fixed by adjusting the little screw on my bobbin.
I am looking on line for some help for you
Here is how to adjust the tension for regular sewing.
http://www.youtube.com/watch?v=By...;feature=related
Thank you sew much stitchship. I am going to mention it to my dealer when I go for my quilting class on Saturday...
Do mention it. They have a lot of experience and they can fix things like these fast. I hope they can help you. Let us know how it goes.
hi klomond, Sometimes can be a thread-tension issue. But before touching the tensions, try putting a piece of stabilizer (tearaway or washaway) under your work. And use the proper embroidery thread in bobbin, or a pre-wound embr. bobbin.