Question about liftmaster Chamberlain Garage Door Opener Transmitter 300MC

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Grage door reverces and goes back up after touching the ground

I hava a Lift master 1/2 hoursepower opner. After changing out the main drive gear the door will close but goes back up upon touching the ground. How do I fix this?

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  • Thomas F. Schneider May 11, 2010

    Ajust the door so that it does not hit the floor so hard? Their is a limnit switch of some sort to stop it for going past a certain point. I am unsure which type it uses but if it goes past that point ,  it goes back up.

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ADJUST THE CLOSE LIMIT SWITCH UNTIL THE DOOR CLOSE SOFTLY, UN CAN DECREASE IT BY TURNING THE FLAT SCREW COUNTERCLOCKWISE.... VERIFY THAT BOTH LEDS OF THE PHOTOCELLS ARE ONE.. OTHERWISE U GONNA HAVE TO ALIGN THEN OR REPLACE IT!

Posted on Mar 09, 2009

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Try adjusting the close shut off switch.(limiting switch) It sounds like when the door shuts, it has too much pressure. The sensor picks this up and reverses the door.This is a saftey feature. It just needs adjusting

Posted on Mar 07, 2009

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