How to Build an RPU Board
Instructions on how to source parts and solder them together to make your own RPU board for cheap.
Diagnosing Sound Issues
A list of all the reasons you might not be getting sounds, and the ways you can fix those issues.
6820 PIA Chips
The 6820 PIA (Peripheral Interface Adapter) chips are how the M6800 talks to the outside world.
Overview of MPU
The Stern MPU-100 is identical to the Bally AS-2518-17 board. At least I think it is. I’ve worked on both…
What is Retro Pin Upgrade?
Installing new code on your machine is relatively cheap & easy. There are plug-and-play and DIY approaches available. You can write your own software too if there’s no new code available for your machine.
The Beginning
This project began with a need to fix an old Stern Stars. Once it was playable, the real work began.
Controlling a Stern MPU-100 with an Arudino Nano
After repairing a Stars machine (Stern, 1978), I started thinking about how I could improve the rules of the game. Stars is fun, but …
B/SOS Displays
The games I’ve worked on have five 6-digit displays. There are four player displays and one for credits/ball-in-play. These …
Original B/SOS Hardware
Interfacing the Arduino Nano to the MPU is really easy using the J5 connector on the board. The J5 connector is at the …