My Juki 2200 QVP Mini was giving me fits when I started FMQ'ing my string quilt. Thread breaking, looping on the back. I finally stopped and did the whole clean up routine. I unthreaded, replaced the needle, removed the throat plate and cleaned there and cleaned the bobbin area using my handy-dandy LED flashlight. Sure enough there was a tiny piece of thread stuck in the bobbin case. I got that out and oiled everything up, put it back together and rethreaded and everything was fine. I FMQ'd the whole quilt with no more problems.