I have a strange issue here. I recently changed the logic board of my Chamberlain Liftmaster 41ac075-2a and I thought it was another bad logic board because there wasn't any response. However, after some troubleshooting, I found that when I unplug the RPM sensor, the lights would turn on and the logic board turns on as well (able to pair a remote and everything). Has anyone ever ran into this before? It sounds like the RPM sensor is causing the logic board to short but I some Google searches are typically when the RPM sensor goes bad, the garage door only moves 6 inches and stops or goes back... Any suggestion is appreciated.