Temple of Doom and TRON to JAMMA Conversion
Arcade Hardware Hacking: Part II
Arcade Hardware Hacking: Part III
I’ve been dabbling a bit in amateur EE this summer as my interest in rehabbing arcade games has recently hit a peak. It started with this 40-year old trashed Indiana Jones: Temple of Doom Atari System 1 board I found for cheap. If the seller says, “was working last time I played it, but don’t have the ability to test it now”, that’s code for “I backed over it with my car”, and “it’s trashed and I need plausible deniability for financial reasons”. Nevertheless, it’s a pretty rare find and was one of the three arcade games I remember playing with my dad at the pizza joint before he got too sick, so the game has a lot of sentimental value. Even broken, a complete System 1 with IJ board was a steal for a few hundred bucks. Over the course of a few weeks and hours of reading through schematics, I identified and replaced a total of 11 bad ICs – probably the result of a past power surge. I finally got it running 100% after fixing a whole laundry list of things: sprites, audio, VRAM, NVRAM, speech synthesis, FM synthesis, multiplexers, and address lines.
JAMMA is an industry standard for arcade games, introduced to make it easier (and cheaper) to swap games and controls out without having to use an entirely different cabinet. It’s also what modern at-home systems (a “Super Gun” or a “Mini Gun”) use to play old video game boards on your own setup at home. A Super Gun interfaces with the JAMMA edge on a game board and supplies the necessary voltages and inputs, and plumbs the video and sound out to something that can be rendered on a monitor or CRT. My Super Gun (I own an Axunworks and a HAS, though I prefer Axunworks) sits on a coffee table in my office with an 18″ 1080p monitor, an OSSC Pro scaler, and four Nintendo Pro controllers using BlueRetro receivers. So as old arcade cabinets continue to rot, fall apart, or be exiled to the basement by now-married man-children’s wives, a conversion to JAMMA means that we can preserve some excellent games, allowing the community to play the boards on a modern TV without needing to keep (and upkeep) the very large wooden cabinets they used to come in – many of which were sadly generic. I usually mount my boards on acrylic to protect them at the front and back; this also lets me manage them like giant cartridges, rather than a stack of PCBs.