Originally Posted by DollyRose

Make sure the bobbin thread and the upper thread are the same make. And make sure the bobbin thread was wound on this machine and not another. Insure the bobbin case is inserted properly, the correct bobbin is being used, and the machine is threaded properly. Then CALL tech support. These are some of the first questions they will ask you...
The $85 up front is usually a security payment to insure that you will come back and pick up your machine! In my experience, it is well worth taking a machine in for repair, I always get the repair done and a 'lube and tune'. My frustration and the time spent getting worked up to the point that whatever is broken takes a flying lesson? Cheaper to take it to the repair guy...