A few years ago, I found an old electromechanical pinball machine out for the trash. At some point, the back box connector (the part that connects the square top part with the scoreboard to the table) was severed.

I spent a couple of days tracing out the schematic and wiring everything up again, cleaning contacts and doing some basic repairs like changing lightbulbs and rubbers. By the end of the process, I had a playable pinball machine.

What was really an eye-opener for me was how the game was "programmed". Timing was handled by flashing lightbulbs and game state was maintained by relays and wheels that triggered stacks of switches. Really a different way of thinking about how to build up a game.

I didn't play game enough and want to spend the time to keep it running, so I donated it. It was really enjoyable to fix it up (once) and figure out how everything worked. I might do it again some time!