Liftmaster LA400 problem

[dmillik]

I have a Liftmaster LA400 that hasn't worked in a while. I replaced the batteries yesterday and the only way I can get it to work is to pull the small receiver board and re-seat it. I then push the SBC button and it will close/open. I cannot get it to open/close until I pull the board again and re-seat it.

Obviously something is shorting out or maybe the receiver board is bad. Does anyone have any thoughts or suggestions on this?

Thanks.

Don

 

[s10xtremist]

I've never experienced this problem. But, from your description, I'm led to agree that the receiver board is causing a problem. When you remove/reinsert the board, does the operator respond to the remote? When you say it opens and closes after pressing the SBC, I'm assuming that you have the auto close timer enabled- You press the button once for the gate to open, then it times out and closes. It won't repeat this until you remove/re-seat the board. This correct?

 

[dmillik]

Thanks for your quick response.

"I've never experienced this problem. But, from your description, I'm led to agree that the receiver board is causing a problem. When you remove/reinsert the board, does the operator respond to the remote? Yes. When you say it opens and closes after pressing the SBC, I'm assuming that you have the auto close timer enabled- I am not sure about this. You press the button once for the gate to open, then it times out and closes. It won't repeat this until you remove/re-seat the board. This correct? Yes."

Yes, when pulling the receiver board and re-seating it, the device becomes 'energized' and allows the gate to open or close depending upon its current position either from the SBC or the remote. (However, it seems like you might have to press the remote a couple of times to get it to work). It will then only go back to the original position if the receiver board is pulled and re-seated again and then either the SBC or the remote button is pushed.

I hope this helps.

Thanks.

Don

 

[s10xtremist]

The auto close timer is the knob all the way to the right. Turning this knob all the way to the left until a slight click is heard/felt turns it off. Anywhere to the right after this click turns the timer on and increases the time delay the further you turn it to the right. You said it opened and closed one time each time you pressed the SBC or remote. I understood it as you press the SBC or remote one time, the gate opens, then closes, and won't do this again. Or do you mean you press the SBC or remote and the gate opens, then won't close unless you remove/reinsert the board then press the SBC or remote? The one cycle thing is what's strange.

Have you tried running it without the board in place? I don't recall if the operator will work without it. I know the remote won't work. I don't know any way to diagnose whether it's the main board or that receiver board. I don't think you can even get just that receiver board, unless a gate technician has one on an otherwise failed board and would hook you up. If I was a tech servicing this issue, I'd swap the control board to eliminate any possibilities. Make sure it's sealed and clean inside your control box- no ants, dirt, moisture, etc. These things attract ants like sugar.

 

[dmillik]

In clarifying, one push of the button only opens or shuts the gate depending upon its position. You have to re-seat the board to get it to go back to its original position. I believe we have tried it with the receiver card pulled, but will double check.

The inside of the control box is very clean and sealed.

There is something about re-seating the receiver board that resets it. It appears as if something is shorting out and the re-seat fixes it.

Thanks.

Don

 

[s10xtremist]

That makes more sense now. But, it still doesn't narrow the problem down to the receiver or main board. Try it with the receiver board off. If it works as normal with the SBC, then you can either find/purchase/acquire a new receiver board or wire a Liftmaster 412HM receiver (under $40) to it and your remotes will work again.

 

[dmillik]

And if it doesn't work properly with the receiver board off, then it is probably the main board. Don' you agree?

Thanks for your help.

Don

 

[s10xtremist]

There's nothing else it could be.

Let me know if it works or not without the receiver board. I'm just curious.