Chamberlain Garage Door Opener 1/2 hp Part # 41AC 050-1M 102 1499A Door sensors repeatedly go out of alignment since installation of new Opener unit since install several months ago. I am now unable to realign them, which renders the opener unusable. The light on the motion sensor remains on for long periods of time, turns off and on when no one is in the garage; Learning Light" flashing yellow, not green. Can you help me? I haven't been able to locate the owners manual online for troubleshooting ideas.