Stuart,
The most likely cause would be static discharge when swapping the display.? Static precautions must be used when handling the Raduino.? AFAIK it is impossible to damage the Si5351 through programming unless the load on the chip is outside of specification.
From what I have read, the failure seems to happen when adding the Nextion mod.? That involves removing the Raduino and modifying the display connections.? The uBitx that I repaired was a Nextion mod request.
73
Evan
AC9TU
