Board has been repaired.
Corrosion caused the sound CPU to fail as stated above. Everything re-capped and display issues are fixed too.
What appears to "look OK" on the surface to normal people, often isn't "OK" to a technician with experience and proper test equipment! This is true with many other things, such as automobiles.
Surface corrosion shows up at the pins of the IC's as dull grey solder, instead of shiny silver solder. If you have board issues, or quirks, take a look under the socketed chips if you can.
I really lucked out this time, and continue to learn about these amazing machines, and the people, like you Pinsiders, who are passionate about them.
I had K's socket my RAM chip as well, so I can install NVRAM, which I ordered.
Should be playing machine later today!
Thanks for following.