Revere, MA
I have some questions about the inner workings of pinball electrical components. First, though, a tool that I use to try to map this stuff out:
The first question I've got is how the solenoid circuit works, on a component-by-component level. I understand that when "the computer" wants to fire a coil, it provides just enough voltage to a transistor to complete the coil's connection to ground for long enough to fire the coil. "The computer" then kills that voltage, which turns the coil off.
I can duplicate this kind of thing pretty easily in the circuit simulator, but when I look at a wiring diagram, I have no idea how it actually works. For example, let's look at page 3-8 on the Star Trek TNG manual.
High Power Solenoid Circuit.jpg
I've tried to re-create this circuit in the circuit simulator using the link at the bottom of the post.
It looks like this:
High Power Solenoid Circuit 2.jpg
I feel like there's a lot of stuff in this circuit that is unneeded. Why do I need the capacitor, resistor and ground connection right after the bridge rectifier? Why do I need the 50V line up top? Why do I need all those different NPN and PNP transistors?
Am I meddling in things outside of my understanding, or is there a way anyone can break some of this down for me? I'm tired of thinking of all of this stuff as a black box, and want to be able to intelligently diagnose issues without just poking at it, and I feel like this kind of thing is a good step.
If you want to re-create this circuit in the circuit simulator, use this link. Copy the text into the simulator's Import box and hit "import".
