Thanks.

I have no doubt the codes are there somewhere, it's just a question of where.

As I said, the particular component in question is the Sony STR-D990, circa 1994.
The closest model number I can find in the database made available in the MX-900 editor is STR-D965. That provides a lot of functionality, but leaves me with the familiar problem of P-ON and P-OFF. The TUNER soft button will turn it on, and once on either the hard OFF or ON will turn it off. I went through this with the MX-500 and learned that discrete codes for power were available on the STR-D990, and I found them. Since the remote that came with the STR-D990 does NOT support the discrete power functions, I had to buy an OFA, poke the codes into it, and then use it to teach the MX-500. I can do that again with the MX-900, of course, but thought it strange to have to use a competitor's $20 remote to program the MX-900. (From other replies I now understand why that is, so no need to go into this issue.)

But, if you do know how I can find the P-ON/P-OFF for the STR-D990 in the MX Editor database, I would much appreciate your telling me. The documentation says if the exact model number isn't there one should use a generic one, e.g., SONY 1, SONY 2, ... SONY 41. By looking at the functions of those one by one I can find some that list discrete P-ON & P-OFF, but it looks like if I chose one of those instead of the STR-D965 I would lose a lot of other functionality. I'm thinking there must be a way to extract just the P-ON and P-OFF and insert them, like one can do with the OFA. Still haven't figured out how to do that though.

Again, thanks for you help. I do appreciate it, and I do like the MX-900 in many ways.

Ed