I have an old Chamberlain 1/2hp (1991) chain-drive garage door opener with pressure sensors. Last night the unit began cycling up and down by itself. It would not completely cycle to the up or down position, but would only travel about 1/4 to 1/2 of the distance, then cycle again. I waited until it cycled to the full-down position and disconnected the power. Anyone have information for the do-it-yourselfer to correct the problem. Thanks in advance for any assistance provided.

I think your door springs may have slipped or your track needs lubrication. The opener is sensing too much weight so it reverses itself. Start by lubing the track with lithium spray lube

I think your door springs may have slipped or your track needs lubrication. The opener is sensing too much weight so it reverses itself. Start by lubing the track with lithium spray lube

Thanks ballengerb1,

I'm pretty sure it's something else. I hit the release and raised it fully by hand with little effort the full extent of the run. I should have made it clear that the problem occurs without human intervention. The door was down for several hours when it started up by itself. After I got it back to the down position last night (about 15 minutes of cycling) I thought the problem was resolved. I woke up at 5am with the door cycling again. That's when I pulled the plug.

Got any neighborhood kids know for mischief making? Just kidding. Does this unit have a wireless remote? Remotes can pick up unwanted signals from other remotes or radio devices. Try tightly coiling your antenna wire into a ball and wrap it with a sheet of aluminium foil, does this change anything? It could also just be a random short in the circuit board.

The unit has a hand-held remote and the wife's car has the built-in remote that is sync'ed. I'll give the antenna and circuitry a look. Thanks.