I have a Genuino MEGA board.
Bare-naked - nothing connected to it except USB cable.
It makes all the usual bloops when connected via USB
The IDE says it is connected and code Uploads OK with
no errors or diagnostics, and yet the serial output is dark.
Reset button causes LED blinkage
Another identical board works OK, emits serial data...
Isn't the USB serial port literally used for both code loading
and for subsequent COMMs ?
What is whacked ? and/or how to resolve the wackiness ?