Month: October 2025

Arcade Board CAD Files Now Available

Now that I’ve cleared the appropriate IP hurdles with my employer, I’m able to make the CAD files available for the arcade boards I’ve blogged about recently. Included in this repo are adapters for:

• Atari Multi-System JAMMA Edge
• TRON / Discs of TRON
• RoadBlasters
• Spy Hunter
• Universal JAMMA Edge
• Williams Multi-System JAMMA Edge
• New: Arduino-Compatible Microcontroller Edges (Atmel 328)

I haven’t blogged about the Williams interface, however it is essentially a universal edge with a signal combiner, op-amp, and -12V boost inverter to support Williams games. I’ve Joust and Defender running on it at home quite happily.

All of these CAD files are for educational use only.

Repository URL: https://github.com/jzdziarski/jamma/

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Arcade Hardware Hacking: Part III

Spy Hunter (Steering Yoke, Gear Shift Latch, and Lamp Conversion)

Arcade Hardware Hacking: Part I

Arcade Hardware Hacking: Part II

Spy Hunter is a well loved classic, and by far the most challenging and ambitious title I have worked on to date. While the purists will insist that the only way to enjoy the game is on the original arcade hardware, many (many!) adaptations to various consoles have been met with incredible success. My goal was to adapt the original arcade version of this to work on my coffee table with a JAMMA super-gun, or in a JAMMA multi-cabinet that wouldn’t necessarily have a dedicated steering yoke or pedals. To accomplish this, Spy Hunter comes with many new challenges over and above other games I’ve adapted:

1. The MCR board uses a daughter board to obtain readings from potentiometers for both the steering wheel and accelerator. Unlike TRON’s spinner, these controls are entirely analog and are read into absolute values using an ADC (analog-to-digital converter). There is one data “bus” (a shared, physical pathway) sharing inputs ultimately into the MCR board for both steering and accelerator, and the value being read is determined by a separate pin on the main board (which enables the corresponding analog input). In the digital world, both values remain in state and depending on what the main board calls for, you must provide the correct value to the pins.
2. One of the more ingenious ways to avoid piracy, Bally/Midway used a lamp panel to display the weapons available to the player at any given time, along with a flashing lamp indicating when the weapons van could be summoned. Along with the steering controls, this helps bind the software to the hardware of the cabinet. Without this lamp panel, the user has no idea when they can call the weapons van (unless they see it parked by the side of the road), what weapons they have readily available, or if they’ve expended them. A lamp driver reads the latches set by the game and illuminates the correct bulbs.
3. The board has two separate audio channels, one for effects and one for music. A daughter board named the “Cheap Squeak Deluxe” plays the Peter Gunn theme (which was supposed to instead be the James Bond theme, but Midway couldn’t obtain the licensing). Sound is mixed across two separate amplifiers in the sit down version of the game. I’ll have to merge four audio channels (L and R) into a single mono channel suitable for JAMMA.
4. An accelerator pedal must somehow be adapted to controller buttons. This is a somewhat sensitive problem, as nuanced work with the pedal is key to playing the game well.
5. The gear shift is a physical stick that shifts between high and low. This, too, will need to be adapted to modern controls. I’ll end up doing this in the form of a toggle.
6. In addition to emulating all of this, the adaptation must somehow be easy to play with a controller or joystick. I’m using a BlueRetro Bluetooth adapter with a Nintendo Pro Controller, so with use of the extension harness, I’ll have six buttons at my disposal.

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