Chamberlain Door Opener Issue

Hey Friends, I have a Chamberlain Door Opener, model#HD750WF, for which the wall mount function has quit working. I can open the door with my remotes and phone app but not with the wall mount. I pulled the wall mount opener from the wall and with two short wires, wired it to the unit but it would not work. Bought another wall mount unit and it does not work either. I have a flashing yellow light at the wall mount though. Thoughts and comments appreciated?

Machspeed wrote:Hey Friends, I have a Chamberlain Door Opener, model#HD750WF, for which the wall mount function has quit working. I can open the door with my remotes and phone app but not with the wall mount. I pulled the wall mount opener from the wall and with two short wires, wired it to the unit but it would not work. Bought another wall mount unit and it does not work either. I have a flashing yellow light at the wall mount though. Thoughts and comments appreciated?

Liftmaster has started using some proprietary components that used to be backwards compatible with older units or even different manufacturers. For instance if you originally had a 888lm wall control it needs to replaced with the updated 889lm wall control to retain all of the original features. You can try touching the original wires that were run to the wall control to see if it operates the motor. You just short the two wires together momentarily. Low voltage application so no risk of shock. If that still doesn't operate the motor something else is wrong. If you've had a power outage recently I've seen both the wall control and logic board fried in the same go from overvoltage.