I've written all new code for Stern Stars and implemented that code by replacing the M6800 processor on the MPU with a daughter card plugged into J5 of the MPU100. The new code features deeper goals, free play, multiple brightness levels for lamps, scores up to 4 billion, and a wizard mode awarded for completing the three major goals of the game.
The hardware build (less than $20) and game features are documented here:
(full code & up-to-date project details here: https://github.com/BallySternOS)
Here's a video of the Wizard Mode (which demonstrates a lot of the game's features):
I've also overhauled the self test, audits, and parameter control available through the switch in the coin box:
During the process of updating these rules, I created a new Bally/Stern OS that can be used on Bally AS-2518-17, -35, and Stern MPU100 or 200 boards with the addition of a daughter card as described. Calling it a "daughter card" is actually a bit fancy--it's just an Arduino Nano plugged into J5. That whole process is documented here:
The board takes a couple of hours to build and the parts are less than $20 (less than $10 if you buy supplies for more than 4 at a time). I'm hoping some people will give this mod a try on their Stars (it's easy to switch back and forth between the stock game and this mod) in order to get ideas for new features and potentially find bugs.
Stars with Arduino Closeup (resized).jpg