LM3800 problem: Openers sometimes open wrong door!

[ScaldedDog]

This just started in the last few weeks, but has now happened twice to me and twice to my wife:

We have two LM3800's and a regular Liftmaster. The three button remotes and my wife's Homelink remote are programmed to open each of the three doors. Four times now, though, when we're either opening or closing a door with it's dedicated button, one of the other doors will open. Hitting the same button again operates the correct door, but has no effect on the "other" door. In one instance, the correct button for the "other" door stopped working at the same time, and I had to reprogram it.

What's going on? These have worked fine for many months, and now this weirdness four times in two weeks. The only thing different that's happened is that we've had several very short power events that would reboot computers, but this hasn't had any obvious effects on the openers, other than resetting the clocks.

Ideas?

Mark

 

[jonsdoghouse]

I have three lm3800's in my shop and use the three button remotes to open the doors. I did have to replace on e of the boards the door would work with the control panel but not with the remotes. I called liftmaster and they sent me another board fairly easy to replace.

 

[Gary S]

My guess is that the programmable remotes are iffy. Like all programmable digital equipment, it will screw up sometimes. It is just the way digital electronics works. You could get a different programmable opener and it might be a little more reliable..............or not.
Remember, if they are programmable, then they are also unprogrammable.

 

[ScaldedDog]

This has happened with at least one of the LM 3-button remotes, as well as the Homelink remote in my wife's car, which has worked flawlessly for five years, and all the anomalies have been in the last two weeks. I don't think this is random chance.

Thought did occur to me that the problem might be related to all the garage doors coming on at nearly the same time, due to the power blips. If they hash the time to generate the rolling codes, that might cause the resulting code on two different openers to be the same. Does that make sense?

I'll call Liftmaster on Monday, but thought I'd post here first.

Mark