AirPonti wrote on Nov 12^th, 2023 at 4:48am:

I just want to say that you are a gentlemen, scholar, and hero for this. Followed the instructions to a T and my radio and transponder panels are working! YEsssssssssssssss! Thank you!

Thank you very much!  Since I posted this I found another cause of the frequencies going blank:

The Avionics on/off toggle is set by default to the Page Up key.   In the CS 777 it causes the COM frequency displays to toggle off/on. This key is also used by the very popular Pushback Helper addon to toggle hide/display and may be used by other addons.  So its use can inadvertently cause the COM display to go blank.

Mike