Retro Pin Upgrade (RPU) is a custom Printed Circuit Board (PCB) that expands the functionality of Solid State pinball machines (Bally, Stern, Williams, Atari, etc.). All the plans and software I’ve developed for RPU are free & open source (GPL 3.0 license).
This isn’t a board replacement for a pinball machine—it’s a low cost add-on to a working machine. With a the flip of a switch, you can play original rules or new rules on your pinball machine.
Learn more about RPU - What is Retro Pin Upgrade?
