My genie garage door opener h6000a just up & quit working right. It acts like something is in the way of the beams at the bottom, but there is nothing there. When I push the buttom, it comes down about 2 or 3 inches & then goes right back up. If I disengage the door from the garage door opener, the screw turns. I tried disconnecting unit for a short time & then plugged it back in, but that didn't work. Any suggestions?