garage door starts going down and stops. it goes back up and will not close. one of the sensors is yellow. take some toilet paper, or some very light rag and dust the RPM sensor over, under, inbetween
...light remains on and beep sound Chamberlain Whisper Drive Model 248754 is less than two years old. The red LED stays on and a beep sounds every 30 seconds or so. The manual only says "contact for ...
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