Hi, I see some older messages about viking sapphire 830 and for all of you having trouble quilting, there was a defect where the thread hung up on the feed dogs when down..but it is fixable so take it back to where you got it. I now have a problem quilting when my top has fused material in it. It quilts fine on pieced tops but as soon as something is fused on the top, it shreads the thread and I can not quilt it. I have changed to a top stitch needle, changed the tension, changed thread etc. but nothing works. I pulled out my old singer machine and that quilts just fine on it so I know it is the machine. Anyone else experiencing this or have any suggestions? Thanks