I can only answer your Yamaha receiver problem now. Did you try the other 3 codes for receiver or the 4014 code for hifi component systems, or did the 4030 just work the best? Does it give you control of other functions, but not the on or standby?

I can't see any reason why you wouldn't be able to learn any commands from the original remote, including the on and standby.

Try clearing the component screen for your amp and then try to learn again
Commander off/muting
Set
Reset
Compo
Component button or label key
Yes

Hope this helps, and you are feeling better.

Ron