Question about liftmaster Chamberlain Garage Door Opener Transmitter 300MC

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Door goes up, Won't go down.

Opener will only go up. Will not go down. safety sensor lights are operating and set correctly. The overhead light comes on when the button is pressed. When the up limit switch setting is increased the door will go further upward until the switch makes contact and stops, but when I try to activate the door button again, nothing... Neither wall button or remote will make door go down, but it will go up...Help!

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It sounds like the limits are out of adjustment. With the door down, rotate the down limit until it clicks. Then raise the door manually, and set the up limit until it clicks. You should be able to hear the switch 'click' when it activates. Pay attention to which way the plastic nuts are moving on the screw going up and down. That way you know which way to turn them to set it.

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Posted on Jun 30, 2009


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