I'd like to help but I've been shocked more then I'd like to admit.

I know just enough to be real dangerous!! Lol
I can’t help except except to say, always unplug it.

I'll usually unplug the machine - it guarantees no issues from any machine and takes about 2 seconds to do. Add a temporary extension cord or a switched power strip if you want to turn it on and off to test it while working.

I'm also paranoid of dropping something that will join contacts that were never meant to be joined together by stray screwdrivers, screws, or whatever else.

Just don’t rest your forehead on the lockdown bar when you want to feel the force. It’s invigorating!

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Unplugging is obviously always a good idea, but once you know your way around the games it can be OK to have it plugged in especially if you’re trying to test.

Always always wear shoes so that you are not a path to ground. Be very careful when working with metal tools inside the game if it is powered on, so that you don’t create a short and start blowing fusesorgrt a good shock.

A good precaution is to plug the game into a GFCI (Ground Fault Circuit Interrupter) protected outlet, circuit, or power strip, similar to the one with a test button in your bathroom.

https://home.howstuffworks.com/question117.htm
https://en.wikipedia.org/wiki/Residual-current_device
https://www.homedepot.com/s/gfci%2520outlet
https://www.homedepot.com/s/gfci%2520circuit%2520breaker

How not to get shocked: unplug it. Then you are safe. Well, for an EM pinball machine anyway. Other things might have capacitors that hold a charge that can be dangerous for some time after it is unplugged, even fatal (like the old TVs and crts).

Standard safety protocol is to always turn off the power before poking around inside a machine. Yet, techs poke around inside with the power on all the time. Sometimes you just have to in order to get at a problem. If you are going that route, then the more knowledge you have, the better.

There are the standard rules of thumb. One says that you only ever use one hand while poking around in there. That way if you touch something live the current will go down your arm to your leg to the ground. If you have two hands in there it could make a path directly across through your heart. That would not be good.

It seems obvious, but it is best to minimize the use of any tools made of metal while inside the live machine. That shit conducts. Plastic or wood poker-arounder tools are better.

It is best to have a good knowledge of every single thing that is inside the thing you are working on. For an EM machine, you should know exactly what is going on at every point you are getting near. There is live 110 VAC coming in, and that is found at the transformer and fuse block area, and in some machines in the coin door. That’s an area to use the highest caution around. Everything else is around 50 VAC except the lights which are 6 VAC.

There is no DC in most EM machines. But some do have it. But really AC or DC are both dangerous. And, it isn’t the voltage that kills you, it’s the current. Standing barefoot on a wet floor while working on a live machine is not recommended.

Will it kill you if you accidentally touch a live voltage? Probably not. But it could. It will however let you know it. You’ll probably suffer more pain as a result of your fast reaction to the voltage as you jerk your hand away, bumping into whatever sharp mechanical contrivances are nearby or possibly even knocking down the playfield on top of your head. Like a hot stove, you learn quick to keep your distance.

Long ago I was an electronic tech and we did live troubleshooting on all sorts of equipment. I got shocked a number of times. Usually it was nothing bad, just a quick one that doesn’t do much of anything. But I did take a 230 VAC hit once, that one was pretty hefty. It was a shocker.

The bottom line is, if you have to ask, if you are not very sure of what you are doing, then cut the power. If you know what you are doing and maintain caution and vigilance at all times, you probably will be ok to work with the power on. But you shouldn’t. But we do it all the time. But it’s not recommended.

As a final note, it’s probably best to not work on a live machine while drinking or enjoying the recreational drug of your choice.

don't look at your weiner after swimming in cold water...........

I installed a DPST on/off switch. Turning it off eliminates both portions of the circuit similar to unplugging the machine. Power is at the switch but no where else.

On a concrete floor, have on foot wear that will insulate you from the floor. In bare feet you can become a route to ground.

I always unplug the machine from the wall outlet. Only takes a few seconds to do that and assures complete safety when working on the machine.

Unplug the game. I’ve been shocked by some older games with it off and plugged in.

Latex gloves or (better yet) finger condoms. Minimal insulation, but if you use plastic pry tools like they use to open iPhones you’re ahead of the game. Literally. Man vs. machine.

Remember to LET GO if you’re being electrocuted.

Write a song about it.

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Sometimes this isn’t possible. Not kidding. You can be physically fused to the power source if bad enough. Only killing the power will detach you.

If you are not an expert electrician unplug the machine.Safety First

A wear gloves with rubber / vinyl coating.

Unplug.

If you need it on, see note about gloves above. Big Note: some old machines don’t have polarized plugs. If plugged in wrong way, what should be neutral can zap you, or the $100 soldering station you might have to replace. Go on, ask me how I know.

Your questions are good, but tell me that you do not understand how to read schematics. If your game has a power on button, understand where it is in the circuit and what it does. This will tell you whether pulling the plug out of the outlet is actually necessary or not. Also understand that there are 110V circuits and low voltage circuits and know which you’re working on before you start making adjustments. As a general rule, I will only turn the game on while working on it if I am trying to visualize cause and effect as a part of troubleshooting. Otherwise, it isn’t necessary. I never work on the 110V circuits with the game turned on.

The best advice given was regarding GFCI protection. I have all of my games on a separate 20A circuit with the first outlet being a GFCI. Thus, all other games plugged in downstream are also protected. These devices work on the basic principle of “what goes in must come out”. If the current flowing into the game doesn’t equal the current flowing out, that must mean it’s flowing through something else like your hand. It will trip for difference of a few milli-amperes. These devices aren’t just for protecting you from a toaster being thrown into a bathtub.

By the way, the main reason I protect my games with GFCI is not for working on them but rather for coin door, lockdown bar, etc protection.

Do not review the cost of your pinball parts order!

Enjoy the day Shane

I have to admit I'm a little surprised / impressed by the level of caution being expressed here. Good topic.

I'm an electrical engineer by education and too many years of hands-on experience, working in the field of electrical power quality. I have worked mainly / mostly with larger 3 phase systems (hospitals, industrial facilities), 480 VAC and do a lot of work with grounding and bonding of electrical systems, equipment, etc. Although the OSHA rules regarding protective equipment and Arc Flash have gotten a lot more stringent over the years, in the bad old days I've made more than my share of live measurements. I've gotten bit once - a 400Hz power converter at the factory; fortunately just hand to wrist, a light touch and not through the heart.

So I have to admit that pinball circuitry (6V / 30V, even the line voltage) never really concerned me - I had / could read the schematics, knew where the line voltage components and wires were so as to stay clear, knew to turn off the power working in those areas. I turn the power off to adjust contacts, replace components and such but mostly to avoid getting caught in a mechanically moving part. It still scares the crap out of me when I'm looking into an open / energized game and accidentally brush the flipper button. But yeah, a lot of time troubleshooting demands working live.

Of course, working with 40-50 year old games that many hands have worked on and with insulation breakdown, frayed wires, etc. anything could be live.

GFCI, definitely a great idea. Polarized and properly wired plugs, also important. If you are working on a machine, remove anything metal - bracelets, chains, rings, watches, fitness trackers that can become easy paths for electricity. And now that I'm thinking of it, I have a couple of wooden chopsticks in my pinball kit to use when I want to reach in and poke something or energize a relay during troubleshooting without getting my hand or a metal tool too deeply into the guts.

Don't want to be shocked? Then don't read the for sale ads here on Pinside.

Almost made it 2 days. Lol got a little zap today.

If I'm doing adjustments or setting up connections for troubleshooting, I'll just unplug so it's a no-brainer. If I'm actively probing around while it's on, I just be mindful of my body and hands/tools at all times. It's very easy when your head's upside-down and backwards inside these games to accidentally bump into something or drop a tool or do something else stupid.

Be mindful too that depending on the game, the direct line voltage from the wall could be snaking throughout the game (and not necessarily all localized to one area like near the transformer).

In the ten years I’ve been sticking my fingers inside these games, I think I’ve received around a dozen shocks. All of them have been just mild tingles because I was wearing shoes and not touching anything grounded. The line voltage just bounced against my skin because of the high resistance. It was never painful, just alarming.

Has anybody here gotten a BAD shock from a game? I’m talking about the kind where the current passed through you because some other part of your body was grounded.

Hi leckmeck +
read here (from "A true Story ..." ) https://pinside.com/pinball/forum/topic/skylab-my-first-pin-with-reels-#post-4469763 - and maybe also post-19 and post-24. Greetings Rolf

Yes. Two games side by side, non polarized plugs, worn fish paper on the coin doors. Put a hand on each one and got the real thing. The games weren't even open. They were just sitting there, waiting for someone to install new 3 pronged plugs.

I run an earthing cable up to the lock down bar chassis and coin door, particularly Gottliebs, on all the machines I work on, unless factory earthed. My machines are running at 240v so that's not good if you touch the wrong bit! I am used to, but never complacent, working on live circuits as one mistake could hurt or worse. And remember too that older games live 1950s William's use 50v circuits and these too hurt if you get things wrong. And remember too that a lot of bank reset coils carry high voltages too. If in any doubt though, unplug from the wall outlet and stay safe.

1) I echo all replies about unplugging it.

2) Like @Gotemwill mentioned, use the schematics. Trouble shooting paper is worth while. At worse you'll spend a few hours refreshing you mind about the components in question.

3) I echo @JudeRussell and handiness of wooden chopsticks and the like.

4) Know a hack job when you see it. We have the web and YouTube, so use them. See @rolf_martin_062 story on the Sky Lab thread.

5) This is implied in many responses but I'll spell it out... Take your time. The tortoise wins the race. I recommend a little journal about your pin or project. It's useful to know where your head is at or possible theories about the situation. Especially when real life interrupts you. And handy for general maintenance reminders or that strange hum or to keep an eye on that left pop bumper.

6) I'm surprised this hasn't been mentioned so this is my real 2 cents... Bread boarding. Most engineers use it for prototyping but its useful for trouble shooting. Rig up a piece of ply with the offending components and test/tweak outside the rats nest. A good switching power supply is useful. Coils rated for 50vdc will still energize with 5vdc albeit with delay and much less vigor. Depends on what you're trouble shooting, timing issue are probably best left on the play field. Take pictures/movies and toe tag everything during the process. Don't trust sticky notes or your memory.

It's a good point on where to focus your time. When I'm troubleshooting the average problem, atleast 50% of the time is spent tracing the schematics and figuring out where to put the probes. Power-up the game, collect the data, then go back to the schematics. Of course there are exceptions ..

Got any examples of when this would be useful? Just curious .. I breadboard a lot for other (mostly digital) projects, but haven't run across any problem yet on an EM where it would make sense to break out the breadboard.

Ha! Ask Clay Harrell....