All good advice. Funny story about Janome 6600. Bought a used one for a terrific price the beginning of December.
Beautiful machine. Wanted to do FMQ so first I wound bobbins. This baby has a separate motor for bobbin winding. How great. Started to FMQ--going great for half an hour and machine has turn off for Safety Sake so I did and had a difficult time getting the quilt from under the needle. Cleaned out machine. Lots of lint due to thread I was using--connecting threads essential but sews great. Rethreaded and changed the needle. Still no go. Getting really upset. Back to the shop-what's wrong with this machine? Turns out that the thread I was using for winding bobbins got pulled up with the thread I was using to FMQ and wound itself around the crankshaft. When It was all cleaned out--it was a giant mass of thread. Lesson learned-never leave bobbin thread cone on machine when sewing. Now it sews beautifully. Hope you find out what's wrong with your machine. My shop was only a half hour away on good highway.