A lot of arcades had as many machines as you could fit into a place. You rarely got to see the side art of the cabs, and when you did, it was usually when they were fixing the one beside it.
I'm just starting to work on an Apple iPad app to catalogue arcade machines, parts, circuits, manuals, schematics, etc...
The idea being you can select a company, say Atari, and the cab or board in question, Centipede. From here you can view the history of the cab or other general information, the board layouts. On selecting a board tapping on an I.C. will show you an overlay of that chip with pinouts and whereabout on the board it connects to. Also hints and tips on troubleshooting the boards, or alternative chips if one tends to be faulty.
I'm also looking at a testing kit that attaches to the board, or ZIF socket testing, similar to the some other projects on here, but again processed directly through the app.
It's a long project and I'm only getting started, but hopefully show the slow progress on here once I've got something to show.