At least once a week, there is a post about someone getting a shock from their machine, they are missing the ground plug (or the game never had one from the factory) or even the whole power cord is gone.

I'm going to first run through the North American 115VAC system, then return to the Euro 220VAC system latter. Most of the 115v stuff will apply to the Euro system anyway.

Any voltage over 50v is dangerous, so my and Robin's legal team advises that you hire an electrician to do any electrical work. Don't do this stuff in the house alone. You can't press your LifeAlert necklace call button if you are unconscious or held in place by electrical current. Wear rubber soled shoes, turn off fuse/breaker box, unplug machine.

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PLUG DAMAGED OR GROUND PRONG MISSING
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Sometimes people only have a 2 prong outlet in their ancient house, so they start cutting the Equipment Ground off of all the plugs.

This is dangerous.

Not only has the Safety Ground been defeated, but often the plug can be inserted into the outlet upsidedown, causing the Hot to now be on the Neutral side (more on Hot and Neutral latter).

If you have a game like this, you often will feel an electric shock when you touch another nearby game at the same time.

This needs to be fixed right now, don't put this off.

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Inside the replacement plug, you will see 3 terminals.

They have 3 different colored screws to tell you what conductor is required.

GREEN = GROUND
SILVER = WHITE OR NEUTRAL
BRASS = BLACK OR HOT

This is very important, so look closely and understand what I'm talking about.

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Cut the old plug off the cord and discard. Don't take the old plug apart trying to save an inch of wire; we want all fresh material.

Always slide the body on the cord, before you strip the ends.

Otherwise you will splay out the copper strands. Or you might even forget about the body until after you have installed the plug, lol.

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Somewhere on the new plug body there is a strip gauge that tells you how much of the jacket and the conductor insulator to cut back.

With this Harbor Freight plug, it requires 1" of the Jacket to be cut back.

Be very careful not to nick the conductors inside the Jacket - that means you DON'T cut all the way though the Jacket. You score it, and then tear the rest of the way through.

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"Vid wait! My cord does not have any colored conductors on it! They are all brown!", I can hear a few of you saying already.

This means you have an older cord.

Older cords can be fine, but check them out carefully:

Q: Does the cord have 3 conductors?
A: Yes - you are still in the ball game.
A: No- replace entire cord.

Q: Does the cord show little cracks when you bend it into a tight loop?
A: No - you are still good to continue.
A: Yes - replace the entire cord.

Q: Does the cord have Ribbing down one side of the conductors?
A: Yes - you have a good cord.
A: No - replace the entire cord.

Just like any lamp cord in your house, 3-conductor power cords that don't have color coding have Ribbing to show the Neutral conductor. This is important to note, so look closely and don't mix it up with the other conductors.

Again, there is a Strip Gauge on the body of the plug that tells you how much conductor insulation to strip off.

On these Harbor Freight plugs, you strip back 3/8".

Don't twist the strands together for this type of connector (if the strands were being installed directly under a screw head, THEN we would twist them together, but here the strands are installed between two plates).

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Place the copper conductors between the clamp plates and tighten the clamp screws. DO NOT put the wire directly under the screw heads for this style plug.

Tight means 20 inch pounds if you have a torque wrench- tight means very tight, but don't strip the screw heads for the rest of us.

Note also that there is no extra bare copper showing above the clamp plates, nor is there any stray strands of copper. If you somehow screw up, just cut all the conductors back and start with a fresh section of cord.

Screw heads need proper conductor colors:

GREEN = GROUND
SILVER = WHITE, NEUTRAL or RIBBED
BRASS = BLACK OR HOT

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Finally, reassemble the plug and tighten the cord clamp.

Be sure to tighten the cord clamp evenly - do a few turns of each screw at a time. If you don't, the cord could pull free from the plug should someone trip over it or *gasp* pull the plug from the wall using the cord.

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REPLACING THE ENTIRE CORD
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Oftentimes, you need to replace the entire cord.

It could be:

1. The game is going into a commercial environment and replacement plugs are not allowed.

2. The cord is damaged, worn or brittle.

3. The game is an older EM that never had a 3 conductor, grounded cord

4. The game has been acquired without a cord (re-import or salvaged).

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Q: What kind of cord do I get?

A: Get an IEC style cord. They are $1 at any mom & pop computer store - usually piled up in bulk in a big cardboard box. Choose one with the thickest diameter cord, but really any computer cord will probably be fine. Most say 10-15 Amps on them, and no pinball machine draws more than 5 amps.

Get a long length, like 12 or more feet (most building codes require an outlet every 6 feet).

If you have a modern pinball machine ( mid 1990's or later) the IEC plug will just plug into a receptacle on the back of the game - no wiring required.

If you have an older game, you will cut off the female end of the IEC plug and solder in the wires directly.

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Q: All the little computer shops are out of business around my house, where else can I get a cord?

A: You can buy a 15 foot, 16 gauge, white or black extension cord from any hardware store (don't buy orange, or you will look like an amateur ), and cut off the female end.

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Q: Shouldn't I just just buy an "Appliance Replacement Cord"?

A: No, those are three times the money of just buying an extension cord of the same length and gauge, don't ask me why.

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Q: I cut the female end of of the cord, but the internal wires are Blue, Brown and Green/Yellow stripe ! Now what?????

A: Don't panic, those are Euro colors, and everything is still fine:

Blue = Neutral

Brown = Hot

Green/Yellow = Ground

(even if there were crazy color wires inside the jacket, just get your meter out and figure what conductor goes to what prong)

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WILLIAMS GAMES LATE 70s AND AFTER

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The power cord enters the cab, often through the backbox neck, through a plastic strain relief, gets tied in a knot (so it does not get pulled through the plastic strain relief), and finally is soldered to the Line Filter and the Fuse block.

The Hot wire (Black), gets soldered to the Fuse Block.

The Neutral wire (White) goes to the Filter.

The Ground wire (Green) goes to the grounding lug on the case of the filter.

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The Ground Braiding now runs from the Filter to every metal part on the game. The legs, the rails, the "ground plane" along the back of the backbox - everything metal that a human can touch is now safely grounded.

This means that all the metal parts are now a BETTER conductor of electricity to ground than you are - that is a good thing if you want you and your fiends to stay alive should a fault occur.

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Replace that monster 8 amp fuse with a 4 amp fuse.

If you put a "Kill-A-Watt" meter on a pin and set it to peak amperage, you never get above 2.3 amps, and many LEDed games are 1.5 amps.

Using a smaller fuse will mean that should a fault occur, the fuse will react much quicker; possibly saving your expensive transformer.

If you have ran a specific game through your Kill-a-watt and know it never peaks above 1.5 amps, you can change the fuse to 2 amps - the smaller fuse will make it safer yet.

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If you ever plug in a game and it instantly trips the house circuit breaker, it is often the MOV. The MOV sacrifices itself to save the rest of the game from a surge.

MOVs are very fast acting and thus very valuable to our games. Don't get lazy and bypass a blown one - replace it!

https://www.greatplainselectronics.com/products.asp?cat=76

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Note that 115vac power bypasses the fuse and runs to the Service Outlet inside the cab. This is so if the main 8amp fuse has blown, you sill have service power to plug in a lamp to work on the game.

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NEW POWER CORD FOR EM TYPE MACHINES

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Until the 1960's, most electrical outlets were the 2 prong type; so as you have probably noticed, many older EM pinball machines have 2 prong cords.

Even though 2 prong is "factory", you should still update your games to 3 prong grounded cords for safety. Your 40-60 year old cord is probably due for replacement anyway.

Inside the cab, you see the old power cord is bundled up with all the other wires with little sections of string. Don't try to cut all those strings out, you will make a mess. Just cut the old power cord off at each end of the bundle, and zip tie the new power cord along the outside of the bundle.

The Black/Hot wire from the new cord goes to the fuse and switch (assuming there is a switch).

The White/Neutral wire from the new cord goes to whatever spot the old, ribbed wire went to.

The Green/Ground wire from the new cord gets a Ring Terminal installed on the end of it, and is attached to the transformer case.

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The transformer case and brackets are often dipped in lacquer, so you should sand the attachment point down to bare metal.

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Finally, run a Ground Braid to the metal Legs, Coin Door, Lock Down Bar and Rails of the machine. This will protect the user by making those parts a better path to ground than the player himself is.

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WALL RECEPTACLE WIRED INCORRECTLY

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So you have a properly wired game, with a proper 3 prong grounded cord and you are still getting shocked when you play or touch two games at once? Often the problem is the wall outlet is wired incorrectly.

(again, I'm going to remind you that any voltage over 50v is dangerous and that you should have a qualified electrician repair the following problems)

The easiest and safest way to check your outlets is a $5 Outlet Tester:

GFCI Outlet tester.jpg

If you route games, you NEED one of these Testers in your tool kit. Every game you deploy should ONLY be plugged into a properly wired, tested outlet. Any child that even gets a slight shock from your game will cost you $50,000 - $1,000,000 regardless of any actual injury.

These Testers are not foolproof (some unscrupulous person could tie the Neutral to the Ground screw behind the cover plate, and the Tester would display that the outlet is properly grounded), but they catch 95% of the common faults.

Of course, if you had an Outlet Tester, you would have already tested the suspect outlet, so how would an electrician test it without a fancy Tester? With a volt meter:

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Meter set on A/C

One probe in LARGE duplex slot, one probe in ground hole (Hopefully 0v?) if 120v Neutral is HOT (thus wired backwards)

One probe in the SMALL duplex slot, one probe in ground hole (hopefully 120v?) If 0v, ground is open ( thus not grounded)

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HOW MANY GAMES ON A SINGLE CIRCUIT BREAKER?

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By now you have probably heard that commercial arcades put 6 pinball machines on each 20A circuit.

How did they come up with that formula?

The National Electric Code wants circuit breakers to see 80% of their rated load. So for a 20A breaker, the ideal number is 16 amps.

Most pinball machines draw about 1.6 to 2 amps peak.

Some pinball machines with a ton of lamps may even draw 2.4 amps.

If you take any random 6 pinball machines at an arcade and measure their amperage draw at the breaker panel, you see that each breaker is seeing ~13 amps. Well under our 16 amp goal.

In your home, where you don't have to worry about employees moving games around and messing up your breaker loads, if you measured a 13 amp draw on a circuit, you could safely add one additional game and still be under your 16 amp target.

NO GROUND WIRE AVAILABLE IN DUPLEX BOX

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If your house is old, it may not have a Ground wire available at all inside the electrical wall box.

The best thing to do would be to run a new line of "Romex" back to the Breaker Panel and have a properly grounded outlet.

But if your house is a rental, or there is just no realistic way to run a new line, you can actually install an "ungrounded" GFCI and it will still trip on a Ground Fault.

As a bonus, the GFCI will protect all the other outlets that are connected 'downstream' from it; so try to make it the first outlet in the line to the Breaker Panel.

The GFCI will come with a bunch of decals that need to be applied to itself and the other downstream outlets notifying users that they are protected, but no actual equipment ground is available.

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RE-IMPORT WPC GAME WIRED INCORRECTLY

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If your re-import game is giving you a shock, check inside the metal shielding box.

With the game off, but plugged in, check if your incoming blue wire is somehow hot with your meter.

So, meter set on AC:

One probe on blue wire, one on green. Voltage (hopefully 0v)? (if 120v blue is HOT, and thus the Blue and Brown are wired in reverse)

One probe on brown, one on green. Voltage (hopefully 120v)? (if 0v, ground is faulty)

One probe on brown, one on blue. Voltage (hopefully 120v)?

The factory put that plastic plug in for export games.

Pull the plastic plug out.

Push the new service outlet receptacle all the way into the hole until it snaps in.

Hot (Black) conductor gets soldered to the small slot.

Neutral (White) goes to the larger slot.

Ground (Green) wire goes to the ground pin hole.

Use 14 gauge or heavier stranded wire. (some Marco plugs come with the wire already installed, in that case you don't have to worry about it).

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No, unfortunately not OK.

Those 3 to 2 prong converters do not provide any grounding protection.

Have an electrician replace your 2 hole outlet with a GFCI outlet. It's a 1 minute job.

It technically won't have a ground back to the circuit panel, but it WILL trip on a ground fault for safety.

You will then have this:

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Yeah, that's nice.

That is a big answer as different generations of pins need different procedures. Some you resolder wires to different lugs on the transformers, and others you move jumper pins around on a Molex.

The MOV is easier.

For North America replace the MOV with a 130V unit.

For Europe replace the MOV with a 275V unit.

The MOV goes across the mains line. Should the MOV see a surge, it will clamp down almost instantly, suppressing the voltage spike. It can do this many times without failing, but each spike probably damages the MOV a little.

Should it see a huge spike, the MOV will self destruct, often tripping the circuit breaker.

Once in a while, a MOV will fail open, and although it will not trip the circuit breaker, it is not protecting the circuit either. If you see discoloration of the MOV (like a brown or black dot on it), replace it.

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Yes, the 130V would be well worth the $1.

The lower the clamping voltage, the better the protection.

At my job, when we have MOVs that fail yearly in a certain location, we install a few MOVs in parallel in the same holes of the circuit board.

This allows them to "share the load".

Our engineers say that 2 MOV in parallel will survive 5x longer than a single in the same situation. 3 MOVs will last 20x longer....