Happy day. I fixed it myself. I 've been having tension problems for days and I messed with the bobbin,made it worse of course. So I went on youtube typed in brother pe 770 bobbin tension and found a tutorial on what to do. The guy made a weight using 5 quarters and scotch tape,he then hung the bobbin case by the thread and when the bobbin case was just right it slowly went to the floor. I tried it and it worked. I sure did not have the money right now for a in the shop repair. So to celebrate I'm making a mug rug. So I have to pat myself on the back and learned don't mess with the bobbin case anymore
Bev