I won the Lightfight. I'll let you know what chip it uses.

I just noticed that the Entex Baseball (1) that I have has a three-position power switch- off/am/pro. Pics of the game just show off/on. But I don't see it routed to an input; instead, it looks like pro connects a 150K resistor to VDD (+9v). The other side of the resistor goes to pins 18 and 19, which are the oscillator pins, which are also (always) connected through a 47pF disc cap to ground. When the switch is am or off, the resistor is floating. So I'm guessing pro mode just makes the chip run faster?

It looks like it's wired the same on Baseball 3, but pro/am is on its own switch.