Here is exactly what happend, hopefully this may help. I sat down and sewed on a piece of scrap before starting my project. As I was sewing my stitch length knob became unscrewed and fell off all on its own. I took off the plates and I had to move the piece inside the plates to get the knob screwed back. I used my manual the best I could . . . (it is so bad and not user friendly). I am wondering if somehow it is stuck in this reverse mode, but looking at my manual, it looks like I have the model that does not go in reverse. Here is my motor information: Cheering Sewing Machine co. Model QL-400 . I have messed with the switch that I thought was the forward/reverse switch on the motor and it does nothing. I have no idea what do to. I have not had this long and I am just getting comfortable and good with sewing with it. Any other suggestions? Thank you!