Garage Door opener works sporadically
Our Sears opener is 9 years old. It now opens sporadically - often just a few inches or a few feet before stopping, the lights (on the drive box) shut off, then come back on after 10 to 30 seconds, and we start all over again. I have disconnected the door thinking it is jammed, and the mechanism acts the same way - so there is no jam present. Any thoughts anyone??