Ok.. Just try running the garage door by pushing the button and see if it catches the latch just fine. It will probably be just fine.... What your friend was trying to tell you to do is to grab the garage door and manually open or close it to catch the latch back onto the chain. You don't want to pull on the red cord when you are doing this - just grab the bottom of the door and either open it or close it to catch the latch. You REALLY don't want to do this with all your strength - or you might break something in the garage door latch.. It's usually harder to open and close the door - so it takes some strength to open it up without the help of the motor... but you want to go slowly when it's hooking the latch back up or you might break that part. Here's what is going on.... The Red pull handle thingey has a spring loaded latch inside it... kinda like how a door knob works. That latch grabs onto the hole on a plate connected to the door opener chain - and the garage door goes up and down when the motor runs. (It holds together like how a door latch holds a door closed) When you pull the string - you just pull the latch out of the hole in the metal plate connected to the chain.. like how turning a door knob lets you open a door.... and you can manually pull the garage door go up and down without the motor moving the chain. Does this make sense...

I have had the same issue the past six months — remotes work occasionally, then not at all — and nothing has solved the problem. I’ve spent considerable time on the phone with Chamberlain techs and we have tried everything from making sure there are no LED light bulbs to turning off the power to the entire house except the garage. Chamberlain sent me new remotes, and then a new circuit board and, and I have extended the antenna, and nothing has fixed the problem. interestingly, I have another Chamberlain opener on the other door in the garage and it operates perfectly. I’m out of ideas at this point, so I welcome any other suggestions.

It ssems that it tries to work when the chain is going one way but not reverse.

I figured it out. Problem with adjusting the limit switches was due to a missing pin on a gear that is on the main motor shaft that turns another gear that moves a plastic screw that hits the up and down limit switches. In other words, the internal up/down limit switches were not getting consistant feedback of the garage door position. Nothing that a twisty tie from a garbage bag couldn't fix. So that problem was fixed. The garage door now moves and it now moves up and down without whacking the header going down and the stop limit bolt (protecting the GDO motor unit) on the way up. I knew I was wasting time when the manual says a single rotation on either screw would result in a 2 inch travel change. and nothing I did was consistant. It either hit the bolt or header or it would just HUM and not do anything. I think the original problem of why the belt's tention spring/bolt came undone was due to excessive vibration due to non-sufficient belt tension. As soon as i got the garage door operational, I noticed it was hecka jerky initially going up or initially going down. Mid-travel was smoother. By tightening the nut (collapsing the tension spring) to the 1.25 inches specified in the owners manual seemed to make the garage door much smoother. When I have the time, I'll adjust the force screws down. I think I have them maxxed out right now. I'll also test the safety/reversing feature. For now, it open and closes smoothly. I'm happy. So, while the owners manual didn't tell me to open the thing up, common sense told me to. Also, this unit has a diagnostic feature. When you press the LEARN button, it will light up the diagnostic light and blink. 5 blinks told me the motor was overheated or the RPM sensor wasn't happy. No mention of what the RPM sensor was. I'm assuming something was stuck. Anyways, adjusting the limit switches got it moving and once I cracked open the motor housing case and saw the limit switches in action and saw how misaligned they were, it was a pretty easy fix. Glad I disconnected the door so I could cycle the belt for testing without crashing the door. that made way too much noise at 10PM tonight. Once again, thanks for your help and I hope something in this helps someone.