Just got a new RF 20 and have been setting it up. I couldn't find a code for the Yamaha 673, sowI picked a code that worked most of the commands. The volume only worked in steps, so I have tried to use the learn function to make it work properly. Now the Vol up/down doesn't work at all. The learn function seemed to work fine, but nothing happens when the button is pushed. Pulling my hair out. Any ideas?

Try copy and pasting the button onto itself. With issues where you copy a code onto a button that you wish to erase, this method copies the original code and then pastes it back on the button, which essentially erases the incorrect code that was pasted before. Not sure if it works with learned codes. I have VERY limited experience with that remote. Try the codeset I pasted in your other thread as well. Those codes should work fine.