The Vid Kidz Engineering Pause Button Hack
A Robotron mini used during development- http://www.habosarcade.com/RobotronProto.htm
Larry DeMar response, Dec 2013- Looks like my handy work and it’s a hack, not an option. I would socket a chip carrying irq, pull that pin out of the socket (bend leg sideways, then piggyback a 7402 (or whatever quad or-gates is) soldering power and ground to the chip below and gating the irq signal with the pause button.
You had to cut the watchdog pad to stop the game from resetting when paused.
That mod is one we made to the CPU board in each development cabinet, among others to allow a custom interface box to interact with the debugger. The box had a reset button (connected to reset), a toggle switch which determined whether the reset started the debugger or the game, an “abort” switch connected to the NMI pin of the 6809 which halted the running program giving control to the debugger, and the “pause” switch connected to the aforementioned circuit. I put the pause circuit and switch (in the coin door) in all of my home games, and did the mod for other developers’ games. It is likely that I put that switch and mod in that game.
Pause Button Rom Hack by a Fan- http://www.coinoplove.com/romhack/romhack.htm