Sears Garage Door Opener problem
Model 139.53627SRT opens solid, tilt-type door (not rollup) about three feet and then stops. It does not reverse as if hitting obstruction. When i disconnect the door from the opener, the opener operates properly. I have lubricated all hinges points in door hardware and cleaned the track of the opener. When opening the door manually, I cannot feel any obstruction or hard place when passing through where the opener stops (about three feet). HELP!