Hello, my (older) Craftsman garage door opener part number 41A5021-3C is acting up and I could use some help. Here's what's happening and what I've tried/confirmed so far.

Starting yesterday neither of the two remotes will open or close the door. Before that for about one week the remotes would open but not close the door. I replaced the batteries in both remotes but that didn't help. Pushing the button inside the garage opens and closes the door perfectly. No need to hold the button in or anything like that. One press does the job. There are no odd noises coming from the opener and it slides on the rails nice and smooth. The chain is semi-tight. It doesn't droop and the gear the chain runs on is well lubricated. The safety sensors work fine. One has a green light and the other is amber. If I block the path the green light turns off. If I close the door and block the path the door raises back up. Everything except the remotes appears to work as expected.

The last thing I tried was pressing the "reset" button on the back of the opener. I tried pressing it first then the big button on the remote. Tried pressing the big button on the remote and then the button on the back of the opener. I tried keeping each one pressed while pressing the other. After messing with this reset button that's when the remotes stopped opening the door. And I noticed too that the small LED light next to the button no longer flashes when I press the button on the remote. I'm not sure if that means anything but I have a feeling that's an indicator the opener is (or is not in my case) receiving a signal from the remote.

I have a feeling the board that receives the signal from the remote might be the problem but I haven't opened the opener itself to look for any burns or damage.

If there are any garage door experts out there I would greatly appreciate any suggestions for anything I might have missed or done incorrectly... specifically I'm not sure about that reset button and how to use it since i don't have the manual.

Thanks in advance