The capacitor is usually located under a metal cover that is on top of the motor. It's easy to spot. Caps are dangerous , and you need to discharge it before removing it.
I used the "Tap a Draft" system for years before I finally got the money and the room for a keg set up. The Tap a Draft fits nicely on a shelve in the fridge and is easy to dispense with the CO2 cartridges. I have never used the "pig" set up but I'm guessing it works the same.
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