Sounds fun with party
.
Thanks for looking into this, appreciated!
All sober.
Okay so assuming you simply detached the l3+ from its eth cable and walked it into another room.
You then plugged it into a new power outlet and are using an eth cable in the new spot.
Assuming the 3 good units in different room are all working.
Lets try detaching 1 good unit. leave it sit just out of the way.
bring the dead unit to the spot you detached a working unit.
plug the dead unit in boot and let us know if it works.
if it does not work put it aside.
reattach the good unit and boot it should work.
If all of the above is true then you know the problem is within the dead miner.