Modding a vintage Japanese pachinko arcade game

Pachinko machines are traditionally purely mechanical, so Ben Heck thought he'd mod one to include electronic lights and sounds. The 8-bit gaming sound program is a great option, but Ben's fart sound program may be the keeper.

Ben uses a bunch of 2N4401 NPN transistors and does a test to see if he can pump 12 volts into the lights and control it with a 3.3 volt microcontroller. He uses bayonet style 44-42 bulbs rated at 6.3 Volts and duty cycles them so that they are only on half the time. This will allow them to work properly without being burnt out. Ben hooks up six transistors and six ports to the PCB to allow lots of options. He also uses a regulator to step down from 12 volts down to 3.3.
The 12 volt input is the same thing that goes to the audio amplifier. There is a capacitor for filtering that. There are transistor controls for six lights. The transistors are hooked up to the microcontroller. The 5 volt regulator takes a 12 volt max and knocks it down to 5 Volts before going to the microcontroller board. The audio output jack also goes to the audio amplifier. There are also four switches hooked up to the PCB: ball load good switch, good launch switch, jackpot switch, and drain switch. Ben mounts the PCB to the plastic on the machine. He then wires up the lights and the switches.
The Panchinko machine will include a system on light, a ready light, and jackpot lights. Once the lights are set and the rest of the logic is working, a selector is added for different sound effects.

Ben Heck's Ultimate Pachinko Rebuild - Vintage Japanese Arcade Mod (YouTube / The Ben Heck Show)