Does your machine have handles with buttons on top of them, one for start/stop and the other for needle up/down? The connections inside those little buttons wear out and when they do, all kinds of weird symptoms develop, and this is one of them for me and my Gammill. Those switches need replaced from time to time, and for me and Gammills they are an easy do it yourself repair. My Gammill tech told me not to press the buttons down hard to make the switches last longer. He said to press the button slowly and gently from the edge just until it functions.