First computer, like so many people here, ZX81.........Don't touch that RAM pack!
First computers worked on, Datapoint 2200 with a full 16k of RAM and had twin tape decks so operators could do key-to-tape work..........Boy when they went up it was real fire and brinstone!!!!! Proper flames, none of that pussy fuse blowing
You had to have a real death wish to switch them on after repair