I found using my Oscope noise on the power cable going to the display board.
Appears DSI/DPI ribbon cable coupling RFI onto unshielded power cable.
I could actually move the front panel away from the board and the RFI was almost gone.
I put a 2x 3.5mm ferrite bead on the power cable. RFI noise has been attenuated greatly. It’s no longer audible.
Now just some birdies. I’ll deal with them.
So successful troubleshooting.
Took awhile to track down.
Fairly simple fix.
Kb4yho