A Heath kit vintage 1970 era. The printed circuit board had NO pre-installed components, no disk drives, and no monitor (had to use an old B&W TV) and everything had to be soldered. Unfortunately my skills with a soldering iron lacked a LOT and apparently I had pooled a few connections because when we turned it on, smoke rolled out of the case. My father was there for the "start up" and said "that's pretty impressive, what else can it do?". I simply broke down in tears. It didn't kill me and it did make me stronger .... enough so to get one of his friends to help me build the next generation which worked for a lot longer! Can't remember the details now but it was very crude and had very little you could do with it but it was a "computer" no less. Everything was written in basic language and of course, once you turned it off you lost what was programmed into the memory ... but I was a GOD and it was my byte domain!