I also have restored a 1932 Buckley Deluxe digger and other antique arcade games from the 40's. I am a collector and restorer of mostly mechanical slot machines and trade stimulators. Hoping someone may be able to help me bring this one back to life. found it via some posts from here about the Mills Model M. I am not much of the electronics guy but am capable of running a few tests on circuits etc.

I am sure something plugs into this, but what might that be ? In one of the pics you will see a pin connector that looks similar to one of those old radio tube pin connectors it has 4 wires on it. If I manually push the switch on the payout finger I can hear a click coming either from the black box counter or directly next to the black box behind the sheet metal, also if I hold this same switch in it's closed (pay) circuit and manually push the counter switch on the hopper the counter on the black box increases. The machine has an activator switch on the jackpot vertical finger payout.

The mech drops 20 coins so this would leave the hoppers work to displace $7 in nickels.This is a nickel machine. The electronic side of the machine is set pay only one payout and that would be the jackpot payout. I have a Mills Model M that has a hopper.