Controlling an older audio receiver issues

In my living room we have an H22 box with an RC64R (IR mode) and an older Yamaha receiver. When setting this up a coupe of years ago, it took a lot of effort to find some codes that would operate the receiver. I ended up with a code that would turn it on (on AV2), and another that would turn it off (on AV1). Both would require that I tap the PWR button twice to get it to work. I can control the receiver volume while on either AV1 or AV2.

The remote controls were getting "reluctant" and DTV sent me some new RC66 remotes. I got the codes from the original remote and input them into the new one. The power ON code would not work. In fact, both codes would now turn it off only. I checked all the other codes without success. I tried another RC66, same thing. I found an RC64 remote in the kitchen (without the R suffix) and it would operate the receiver power properly but neither would control the receiver volume, just the TV volume. The volume control is very important due to varying volume levels of different shows and commercials.

So, my last question is whether it is possible that ONLY the RC64R will work the same as the old remote. Seems unlikely as I thought that the RC64 and RC64R were exactly the same except for the RF function, which I do not use.

Is there a programming trick that I used two years ago that I cannot remember? Seems unlikely, too.

Thanks for any assistance.  Larry