EM Pinball 101: Strange Buzz and Scoring Problems?

This is a common problem that happens with old electro-mechanical pinball machines. One minute it’s playing fine, then the next there’s a loud buzz and/or the scoring runs continuously or doesn’t score properly. What’s the deal with that? I’m going to show you one of the most common causes.

How to work on electro-mechanical switch stacks on pinball machines

Switch stacks are the primary parts of electro-mechanical pinball machines, triggering game activity. I go over in this video, how they work, the different types of switch configurations, and how to clean and maintain them so they work reliably.

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How to replace or repair EM pinball latch relay parts/articulating arm/rollers

Ok, that’s a mouthful huh? This is a continuation of a previous series of videos I’ve done on fixing deep ruleset issues in EM games, and now that we’ve found what’s wrong, let’s fix it!

First, here’s a video on how to replace the latch relay – there’s another post where I demonstrate how to remove the backplane from the game so it’s easier to work on.

And in this next video, if you don’t have a replacement part, I show how with a little ingenuity and a #4 tap, you can fabricate your own roller for the articulating arm.

Now that it’s fixed… let’s see how the game plays!

How to remove the inside/backplane from an EM pinball machine?

Sometimes when you have to do more extensive work to relays in an old electro-mechanical game, you can’t bend over the cabinet. You need to get all those assemblies on a bench to service. I go over how you can remove the insides of a game so you can more easily access the components.

The next video in this series goes into repairing a broken latch relay.

The backplane (bottom panel) is typically held in place by a few specific things that need to be un-bolted before it can be removed: Several bolts on the panel itself, then some Jones plugs that attach to the wiring harness going to the playfield and backbox, then the power button, and finally, the board holding the tilt/plumb bob and Jones plug going to the coin door.
The tilt board is removed with a few screws, then detach the coin door Jones plug.
Also don’t forget the power cable has to go too, which may require unbolting the head to pull it through the inside.