Chain driven garage door openers should have some slack in the chain for optimal performance.
Garage door opener sprocket broke off.
Over time the sprocket s teeth can wear and the chain may jump or skip when the opener raises the door.
If you are not confident in your ability to diagnose the problem call a local garage door service company.
Chain drive garage door openers have a sprocket that is attached at the top of the motor.
If the piece of metal that broke off is the piece where the j bar that connects your garage door opener to the door then you can repair this by installing a new operator bracket.
Sprocket is at the end of the opener rail closest to the garage door opening.
First we will address fixing the broken piece of metal.
The chain wraps around this sprocket as well as the gear and sprocket at the motor.
This gear kit on amazon.
If yours is a belt drive you need a kit like this https amzn to 2zqns.
Manufacturer and model number of your garage door.
Https amzn to 2uwvnkj i m working on a chain drive opener.
Over time though this slack can increase or the gear and sprocket assembly can wear and the chain may pop off the sprockets.