I had a Pfaff Grand Quilter on a Inspira Frame which I loved, and which is a clone of the Viking Mega quilter. It ran beautifully for months after I got it until one day...when the thread started breaking and threading. After trying everything -- and I mean everything - the light went off..... I had just dropped my bobbin case for he 1000th time. It was likely bent. I next purchased a spare bobbin case and a bobbin case 'DeWarper' from Quilters Apothecary. The Bobbin Case Dewarper gently adjusts the case so it is true to round. Any teeny nicks, flat spots and dents disappear to make it into a 'good as new' bobbin case. A truly round 2nd bobbin case gives you another weapon in your troubleshooting bag to isolate the problem. Anyway, since selling that machine and getting a larger Juki longarm I also now have a Bobbin Case DeWarper for it as well, and one bobbin case always sits on the dewarper, while the other is being used. If that case gets dropped or noticeable bad things are happening with stitching, I swap them out and that is usually the answer (the culprit then goes onto the dewarper). -Irene Scott