We have a Behringer X-32 and two S-16 digital snakes. We were running our audio from a laptop (using a plethora of adapters--all passive--to go from 3.5mm stereo to xlr) to one of the digital snakes and then running a long cat5e cable back to the mixer. We noticed some "popping" in the speakers, almost like it was on a timer, there would be a regular "pop"--though not that loud--but noticeable, something that could almost be disregarded as a pop from a microphone.
Long story short: the ports in our mixer are now fried and we can't get a connection to the digital snakes. The screen on the mixer flickers when we try.
Port 'A' died after we randomly powered the mixer down to move it and fired it back up again. Port 'B' died after we discovered we had no control over the levels coming in from the laptop, so we rebooted the mixer to try and fix the problem, but when it came back on, the same flicker was in the screen as before and port 'B' was now dead.
One guess is that somehow we had inadvertently created a rudimentary capacitor somewhere that was building up capacitance and discharging it down the cat5e cable, which effectively killed the port in the mixer by death by a thousand cuts, but we're not sure. Another guess is that the signal from the Mac book was too hot, and fried the ports.
What could have caused our ports to fry? The only thing we did differently from other shows was plug the laptop into an XLR port in the snake instead of into the mixer using an RCA cord.