Why are there capacitors on some pinball switches? What do they do? Are they needed? PinballHelp.com

On many pinball machines like early solid state Bally and Stern games, you'll often see little capacitors on most of the playfield switches. Sometimes they're there but a leg is cut off. Why are they there? What do they do? And are they important? We'll talk about that.
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[@OilBaron100]

Great explanation, I’ve been scratching my head wondering what the capacitors are there for. I have a target that fires constantly or not at all, will replace the capacitor and see if it repairs the fault.

[@OilBaron100]

I replaced the capacitor (463K) and now the switch works as it should. No misfiring, no faults. Cheers

[@oliverarchitecture]

We just replaced a cap on a Mata Hari pop bumper that was bad. New game to us and having a blast fixing it with my son. We didn’t know why it was needed. This explains it perfectly!

[@Kaavoort]

Is this just a Bally/Stern issue? I have a Williams System 6 in which rollovers aren't being registered when the ball moves over them too fast. They work fine when triggered by hand or when the ball moves over them slowly, so I don't believe it's a gap adjustment problem. Would adding .01uf caps to the switches fix that also?

[@jsargent8195]

Great explanation! Thank you

[@waynegram8907]

I often see a Diode placed across the leaf switches in the playfield, what are the diodes used for? if you remove all the diodes on the leaf switches what will happens and why?

[@PinballHelp]

The diodes are necessary for the switches to operate in a switch matrix. Using diodes allows the CPU to "poll" the switch matrix and be able to tell which switches are closed. See: www.flippers.be/basics/101_switch_matrix.html for more details

[@waynegram8907]

@@PinballHelp What do you mean by "Poll" the cpu to "poll" the switch matrix? The Leaf switches that are closed should be enough i would think to let the cpu know that the switch is closed so I don't understand the purpose how the diodes are letting the CPU know that the leaf switches are closed. When the leaf switch is closed that should be enough to let the CPU know that the leaf switch is closed. Adding a diode logically doesn't make sense to me.

[@jayytee8062]

@@waynegram8907 They're probably there to act as a flyback diode. Maybe to stop arcing or emf ?? Just a guess....

[@daakrolb]

Great video. Guys making vids about pinball service are doing gods work! Found this one when looking for advice on my Fish Tales sound. I think I have to replace all the caps. Sound is really really low.

[@PinballHelp]

sound volume for fish tales can be controlled by the diagnostic buttons also

[@daakrolb]

@@PinballHelp Yessir. Thank you for your reply. When I adjust the volume, it does go up, but only slightly. It’s still very very quiet.

[@memyopinionsche6610]

My pet ferrets just gave birth to 3 microfarads. 1 negative and 2 positive. There so cute 😻.

[@randyginden3852]

Pinball surgery!

[@Astinsan]

Thought it was obvious what a cap does. Drop voltage/short current prevention

[@PinballHelp]

not in this case

[@Astinsan]

@@PinballHelp here is all the applications available for the capacitor with demo simple circuits.. not for you necessarily but for those interested in all the applications. The capacitor is one of the coolest inventions ever made. www.gadgetronicx.com/capacitor-working-tutorial-applications-circuits/