I would suggest Jamie Wallen's bobbin tension youtube video as a start. Put a practice piece on the frame and get out a piece of paper. Every time you adjust something, write it down. Sounds like tension is too tight someplace or you have a burr that is shredding your thread. I have a different system, but my bugaboo is getting lint or a thread between the bobbin raceway and where the bobbin case sits. If I get ANYTHING in there, BAM...shredding. I have turned into a troubleshooting queen! I even had the President of my system's company adjust my machine. NO PROBLEMS...as soon as he left BAM..shredding. I have been where you are! Take a deep breath and take one step at a time. (I always seem to find a solution after I cry...makes me so mad, but time after time. :sniffle: > solution.). Here is the link to Jamie's video. PM if you want. I am just hanging around today (sick dog, teen post-dental surgery and a cluttered house...)
https://www.youtube.com/watch?v=Q1mRhcquZTM
PS I have even had trouble with certain battings and backings. When I FINALLY finished a quilt and loaded another, not one problem. Also what size needle are you using? one dealer steered me to a Schmetz machine quilting needle. those are for DSM and NOT machines on a track frame! TRUST me on this! I am quilting with an 18 right now. I also use a 16 and rarely anything but those two.