umm...just trying to remember, I used to have the viking Megaquilter which was pretty much the same as the Pfaff Hobby I think. Anyway, have you tried using a larger needle. I am thinking I used a 90 or 100 but I also used King Tut thread. Machines on a frame can go faster then a sit down and sometimes, thread will shred if the needle is too small. Do you still have the manual? What size should the needle be if the machine is mounted on the frame? Also the thread guides can develop a groove which might shredd the thread. I am assuming the set up is older and has been used?