My 6 year old Sears 139.53635SRT1 garage door opener suddenly went belly up. It will not close. I hear a click in the housing (but no motor sound), the 75 W light comes on solid, not blinking, which would indicate an obstruction), and the LED on the back of the motor housing starts flashing in a pattern of 5 flashes, then dark; 5 flashes, then dark. This continues ad nauseum.
The IR door obstruction sensors are properly aligned, with their green lights on solid, indicating no blockage.
This happens even with the door unlatched from the opener chain (i.e., under no-load).