Lee. I have 2 Project Runway Brothers. I thought I had killed my oldest brother so ran out and got another one...tried the old one a week later and it was working fine. The old one was showing wear (since I dropped it a few times and had to tape the cord on to keep it on). So I am glad I got the second one...if nothing else for cosmetic reasons when I take it to classes and quilt guild. I had the exact problem with the bobbin thread on the newest machine as you are describing. I read the manual to no avail and checked for foreign threads etc. I found if I didn't over load the bobbin and I ran the thread around the plate on the bottom (circular plate to cut the thread) when I pulled my thread up with the top thread it stayed in place over the bobbin and sews beautifully. These are my work horse machines. I have other machines but, really prefer the PR Brothers. Hope this helps