The chain got loose and popped off the gear.
Loosen chain on garage door opener.
The chain connects to a threaded anchor that you can move in and out to tighten or loosen the chain as needed.
There are only a few ways that the chain can be tightened.
There may be an adjustment linked to the chain or an adjustment to the length of the door opener track.
Because chains are lubricated with grease you can expect to get a little dirty while putting the chain back on your opener.
The chain on my garage door opener seems to be sagging and rubbing on the track.
Garage door chains become slack from everyday use because of the vibrations created by the motor and the weight of the door.
Do you have a garage door chain that is loose and knocking against a rail.
Documenting how i repaired the garage door.
I am not a professional.
You may find that a loose garage door opener chain has less power to open and close your garage door or you may find that it is just hitting the door as it moves it and creating an annoying sound.
If you find that your garage door opener chain has become loose with time you may want to tighten it up in order to remove some of that slack.