Radio Head Unit Unresponsive

[sroth004]

Greetings all, looking for opinions and suggestions on an issue with the radio in my '05 4.8is:

- Radio is the stock widescreen (16:9) that came with the vehicle. I replaced the screen myself about 2 years ago, radio has worked fine until this situation
- When vehicle is started the radio and its screen starts its "boot up" as normal and presents the full set of menu options
- Turning the right dial selects the menu choices as normal, however;
- When pressed, neither dial activates the intended function, meaning the radio does not turn on nor can I select any of the non-radio options such as GPS, Turning off the screen, etc...

What I've done so far:

Based on various topics here and elsewhere I have:

- Tested the battery and charging system, both fine (12.6 with car off, 14+ with vehicle running); I did replace the battery a couple of months ago as it was 11.6 with vehicle off and I was having a variety of weird but known electrical symptoms. All of those issues resolved with the battery replacement.
- Removed, tested and reinstalled fuses 7, 72, 73, 74 and 75, i.e., all related to audio, gps, phone, etc... (I was sure to confirm the gps had shut down prior to removing the fuses)
- Removed the BM53 radio and confirmed the battery/radio well is dry, the connections are clean and solid (disconnected/reconnected) and removed and tested the 10 amp fuse in the radio
- I tested the radio after each step with no change meaning no power, no orange power light, unable to activate any of the on screen or physical button menu choices

- Is there anything I have not tested or suggestions on next steps?
- Any thoughts on whether the issue is with the widescreen head unit, the BM53 radio or another component?
- Any suggestion on a repair service? I have seen a few listed on-line, has anyone used one of these with success or failure?

Thanks in advance,

Steve