I recently purchased a Singer 338 mostly for the cabinet it was in. I thought they had plastic gears. I was surprised to find mine is all metal inside. I didn't get any Fashion Discs with it and the needle bar won't move up and down. I notice that when I move the stitch width selector, the needle bar moves in and out. It has a belt on it, the motor works, and it spins the bobbin winder but when I try to straight stitch, nothing moves. I know you need a Fashion Disc for the zigzag feature but do you have to have one in it to straight stitch?