Here is a picture of the custom driver boards

Starting from the left is the lamp drivers, then the coil drivers, then what I call special drivers (flipper on/off relay, GI on/off relay and other cabinet lamp drivers. The last board is a parallel port interface board. It uses 4 bit to 16 line decoders which lets me drive 16 lamps, 16 coils and 4 other special lines.

Click for larger image