I have a 3 year old Craftsman 1/2HP door opener. After replacing the battery in one remote, I have continually had issues with it not opening the door after reprogramming. I have reset the entire system and re-programmed only a single remote, and that one will lose its program after 5-6 uses. I will clear the system and program for the second remote and it will stop working after 5-6 uses again. I am quite sure my remotes are not the issue since I can make this happen with each individual remote including the keypad outside. Which part on the unit itself would have gone bad? Is it possibly covered under any warranty? Lastly, is it horrible to get inside the unit to replace what parts might need to be replaced?

Thanks much for any help that can be offered. I have read so many posts from others and it seems that others have been able to troubleshoot to a bad remote. It really seems after following all of the advice here, I have good remotes with a bad unit.