Question about liftmaster Chamberlain Garage Door Opener Transmitter 300MC

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We have 2 openers and both have lost their signal range to where the doors wont even open at times.

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  • shanedunlap8 Mar 10, 2009

    No I haven't yet but one of the remotes is built into our escalade so it is powered from the vehicle and it is happening on two seperate openers. It did the same thing last year I believe there is some sort of interference problem I just don't know where to start looking. Nothing has changed in my home

  • pandaman113 May 11, 2010

    hos old are they and when was the last time you replaced the 12volt battery inside your remotes. both of them tell me it's the remotes need new batteries good luck

  • kev442 May 11, 2010

    Did you change the batteries?


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Replace the batterys 12volts

Posted on Jun 20, 2009

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Hi and welcome to FixYa, I am Kelly.
This almost sounds like the door safety optics near the bottom of the door is not working or the optics path is blocked with something. Check the path between the 2 sensors for any obstructions. You may or may not see the red optics light path between sensors as some of these are infra red.

If the path is clear start looking at optics wiring near the sensors and all the way to the opener terminal board for any signs of damage. If all of that appears fine... then your probably going to have to replace the up/down limit switch assy.

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There really are several things that can cause this:
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5. Stripped worm gear in the opener that has caused the door sequence timing to change on the limit switches.
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Even for professionals some of these can be very time consuming to isolate and repair. (you can tie up as much money in repair labor costs as it would cost to replace the opener. Since you did not indicate how old your unit was or the exact garage door opener model number, the response above is very generic. I am not telling you to replace your opener. Only advising you of what can be high repair costs.

If your not that mechanically inclined I would call a garage door installer and ask that if he can not repair your opener what would be the replacment cost. Negotiate a diagnosis / repair cost vs replacement cost over the PHONE. Explain the symptoms and see what they say. (Call more than one before making a commitment!) Expect to hear all of the answers I mentioned above.

Thanks for choosing FixYa,

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