I doubt that the problem is in the threading. I had the machine serviced in Dec of last year. It sat for three months before I sewed on it and it was doing that from the beginning. The warrenty only covered two months so I was out of luck. I made a baby quilt on it and had to change colors about 4 times. Does anyone know approximately how much it will cost to repair the hook assembly or the tension disk? I am replacing the machine shortly and had intended to sell it to offset the cost of the new machine.