Comments by "eDoc2020" (@eDoc2020) on "Old pinball machines are amazingly complex" video.

@2sk21 Most of the circuitry runs on AC, so snubber diodes would not work.
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@IkBenBenG I've never heard of pinball machines between full EM and near all electronically controlled. The ones I've seen worked on on from the late 70s use a switch matrix going to the MPU and most coils and controlled lamps are directly run from a driver board. A few coils like flippers and pop bumpers might be run by switches but all the logic is done electronically.
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With a little experience it should take much less than an hour to fix basic problems with such a machine. If you know what switches you pushes and what should be triggered then you just look at the schematic for what's in between. The real hard part is going to be designing everything. And a benefit is the failures will be visible, you can easily see if a switch is working or not but it's not as easy to see if a digital chip is bad.
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I didn't notice that but when you have physical access to the machine it's super easy. Just tap one relay* four times, another one two times, a third one 6 times, and so on.
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