40. Coin Door
If you want your pin cab
to look authentic, a standard coin door is a must. The coin door has
been a fixture on pinballs since the 1950s, and the design has been
fairly uniform since the 1980s. It's so ubiquitous that I'd consider
it part of what makes a pinball machine look like a pinball machine.
Even if you haven't taken conscious notice of the coin doors on real
machines up until now, you've probably seen them often enough that
you'd notice that something was missing if you didn't include one on
your virtual cab.
Beyond the cosmetic value, the coin door also has some practical,
functional features that make it worth including. If you've only
experienced pinball as a player, as opposed to as an owner or
operator, you probably only see the coin door as the place you feed in
quarters. But for a machine you own and operate, which your cab will
be, the coin door actually has some other important functions.
For one thing, the coin door is the access port for opening the
machine up for maintenance work. Opening the coin door lets you
access the lever that releases the lock bar, which in turn lets you
take off the top glass, which in turn lets access the playfield, and
(on a real machine) lift up the playfield to get access to its
underside and to the interior of the cabinet.
The coin door is also the place where you'll find the "service
buttons": a cluster of three or four push-buttons inside the coin
door, which are let you access the operator menus in ROM-based tables.
These menus are where you set the game options: Free Play mode, 3 ball
or 5 ball mode, replays as extra balls, and so on. In a virtual cab,
you can always use your PC keyboard to access the menus, so the
physical menu buttons inside the coin door aren't absolutely required,
but I think they're a lot more convenient.
The inside of the coin door is also an excellent place to conceal any
added custom controls of your own. Some people put the volume knob
for their audio amplifier here, for example. It's obviously not a
great place for anything you'll access frequently, but it's ideal for
any operator controls that you only need to access once in a while for
Finally, the coin door is useful for its nominal purpose as the place
to insert coins. Even for a virtual cab, it's useful to be able to
feed in quarters - either for real or in a virtual way, such as by
pushing a button. In either case, the coin door is the ideal place
for the coin chutes and/or coin buttons. The reason it's important to
have some kind of coin feature in a virtual cab is that some tables
don't have a Free Play mode, so the only convenient way to play them
is to make them think you're adding quarters. The early solid-state
ROM-based games in particular tend to have very primitive software
with few or no configurable options. A lot of the older EM
(electro-mechanical) tables also lack coinless play options, although
for those you can at least add it yourself via scripting. In any
case, it's nice to have an easy way to add coins to deal with tables
you can't set to Free Play. One way is to make the physical coin
chutes functional, and another is to add a button that simulates
inserting a coin. I personally like having both options. Both
approaches are covered later in this chapter.
Buying a coin door
If you're salvaging an old pinball machine to use as your cab's body,
and it already has a coin door installed, you're set. If you're
building a new cab from scratch, you can buy a new pinball coin door
from an arcade parts supplier (see Resources
). You can
also look for used ones on eBay, although as always, check prices for
new parts first: used pinball parts on eBay tend for whatever perverse
reasons to be more expensive than new ones.
One really nice feature when you're buying a coin door is that most of
the different types can be used interchangeably, since they're all
designed to fit the same cutout. They've been using a standard size
since about the mid 1980s. Doors designed for Data East, Stern,
Williams, and Bally machines will all fit the same the standard
cutout, as long as they're for machines from the 1980s or later.
However, the different makes do have some differences on the inside,
such as the type of service buttons and the type of wiring plugs used.
Here are the top options currently available commercially:
- Williams/Bally WPC-era coin door, Williams part numbers 09-17002-26,
09-23002-1, 09-37001, 09-46000, 09-61000-1, 09-61000-1, and 90-96017.
These typically come fully assembled, with the lock and key, slam tilt
switch, brackets for two coin mechanisms, coin chute lamps,
coin switches, and service buttons. All of the electronics are
pre-wired to a 13-pin connector. The only parts not included are
the coin mechs (the little Rube Goldberg devices that check
inserted coins to make sure they're real). You can buy those for about $10 apiece and pop
them into the chutes if you want to be able to use real coins.
This is the door I used on my cab. I like it because it exactly
replicates the look of the Williams 1990s machines, which is the
cohort that includes most of my all-time favorite games. It
does have a couple of downsides, though: it's more expensive
than the SuzoHapp door below, and the design makes it way more
difficult than it should be to replace the coin inserts (the
little lighted coin chute labels saying "insert quarters").
WPC coin door (with my custom Pinscape coin slot inserts!)
- SuzoHapp universal coin door, manufacturer part number 40-0696-30.
This is a third-party replacement part compatible with OEM parts for
almost any machine from the mid 1980s or later. It's also
the factory-installed part on some of the newer Stern and Jersey Jack machines. This
one comes with all of the coin slot hardware installed, including
the coin mechs (for quarters), but it doesn't have any pre-installed
wiring and doesn't include service buttons.
This is my top pick for the DIYer. It's about 40% cheaper
than the pre-assembled Williams door above, and it's functionally
equivalent after you add the service buttons. The lack of pre-installed
wiring might actually be a plus in a pin cab, since you can wire it
with your own connectors instead of the obscure Molex
connector used on the WPC doors. The design is also nicer in
some ways than that of the WPC doors: it's easier to install the coin
mechs in this door, and it's much easier to install custom
coin slot inserts. The only downside, really, is that it doesn't
look exactly like the original WPC doors, although it's close
enough that most people wouldn't know the difference.
If you want service buttons (which I think you do!), you can
easily add them as an extra part. Buy the Stern 4-button service assembly
(part number 515-1963-00). Note that there's a similar service button panel
designed for the WPC doors, but it has a different mounting
bracket that won't fit this door, so be sure to buy the Stern version.
You get the same set of buttons with either
assembly, so there's no functional difference; it's just the
mounting hardware that's different.
One other minor feature missing in this door vs. the WPC door
is a slam tilt switch. You can add that separately if you want
100% parity with the Williams door. I personally don't see any
functional reason to include a slam tilt switch on a virtual cab,
since it's only present on the real machines to discourage extreme
abuse that you'd never subject your home machine to.
But you can certainly include it for the sake of completeness if you like.
SuzoHapp coin door, also used on most modern Stern machines
- Stern coin doors, for SAM machines (Stern part 501-5018-172) or
SPIKE machines (501-5018-173). SAM and SPIKE refer to the last two
generations of the Stern platform, not to specific table titles.
These are functionally about the same as the Williams door listed
above. The main difference from the Williams door is that these use
different connector plugs for the electronics. The SPIKE version is
actually the same equipment as the SuzoHapp option above, but adds
pre-installed service buttons and wiring.
- Data East coin door. These come bare-bones, with nothing installed
except for the key and the basic coin slot brackets (no coin mechs).
As a result, they're cheap. They're a good budget option if you
only want the facade of a door (without all the functional bits) for
cosmetics. I wouldn't recommend this if you do want all of the
functional elements, though: you probably won't save any money after
adding all of the parts it's missing compared to the turn-key options
above, and it'll be a lot of hassle to source the parts and assemble
- Smaller video game coin doors. If you're building a mini-cab, the regular
pinball coin door might be too large. There's a narrower type of door
commonly used in video games. Try SuzoHapp
for a variety of options.
- Fakes/Decals. If you only want the cosmetic effect of a coin door
without any functionality, you could use a 3D-printed plastic
façade, or simply a custom-printed decal with a photo of a coin
door (see Cabinet Art for more on decals). This might let you
squeeze out a little cost if you're on a tight budget, or if your
cab is too small for a real coin door.
Coin "mechs" (mechanisms) are the gadgets that validate coins inserted
through the slots in the door. These use a modular design, with a
standardized physical form factor, that lets you swap in mechs for
different types of coins or tokens. If you want to use quarters, you
install a mech that takes quarters; if you want to accept arcade
tokens, you install a token mech.
Your new coin door assembly probably came without any mechs installed
- just empty brackets where the mechs go. So if you want your pin cab
to accept quarters or other coins, you'll have to buy the mechs
separately and install them in your coin door.
US coin doors (anything from the 1990s to present) are almost always
set up with two coin slots fitted with brackets for the standard coin
mechanisms. The pinball vendors (Pinball Life, Marco Specialties)
sell mechs that accept US quarters. Those run about $10 each.
You can also find mechs that accept other coin types besides US
quarters, but not at the pinball vendors; they only sell the quarter
mechs. Here are some leads on where to find mechs for other coin
- SuzoHapp sells mechs that accept
Canadian coins (quarters, loonies, and toonies), plus mechs for
several types of arcade tokens. They also sell matching arcade
- Coin Mechanisms, Inc. sells acceptors
for nearly all types of US coins, plus acceptors for numerous other
countries' coins. Navigate to Coin Doors, Coin Mechs & Face Plates
> Mechanism Coin Mechanisms.
- You might also find mechs for various coin types on eBay, but be
careful that you're buying a compatible mechanism. I'd consider only
mechanical coin acceptors, not anything electronic. The
electronic mechs are usually meant only for Asian and European
markets, where the coin doors have a different setup. The electronic
mechs usually won't fit a US coin door, and even if they do, they
might not interface easily to a virtual cab's key encoder.
Here are a few pictures to help you identify the right type by
physical form factor, if you're looking for a non-quarter denomination
Note that your mechs might have the stubby little posts coming out of
both sides. The SuzoHapp/Stern doors need all four posts to seat
properly, whereas the WPC doors only use the rear posts. The pictures
above show the WPC configuration with only the rear posts in place.
If your mech has all four posts, and you have a WPC door, no problem:
you can easily remove the unwanted extra posts by unscrewing them.
"Any Coin" dummy coin mech
The standard coin mechs described above are designed to accept
specific coins or tokens. Since they're sold for commercial use,
they're designed to validate the coin's authenticity by size and
weight. They'll reject anything besides the correct coin type.
For home use, you might not care about the validation part, since you
might want to use tokens or assorted coins instead of keeping a supply
of quarters on hand. In that case, there's an alternative dummy coin mech
available that accepts just about anything resembling a coin, without
trying to validate it:
The Any Coin mechs are drop-in replacements for the standard mechs, so
you should be able to use them in any of the common coin doors. The
price is about the same as the standard mechs, so the main reason to
buy them would be that you like the option of using assorted coins and
tokens instead of just quarters. They might also be less likely to
jam than the standard mechs, since they don't need the intricate
internal maze that the standard mechs use to reject invalid coins
(although I don't find that the real mechs jam much either).
I'm personally happier with the standard mechs, just for the sake of
authenticity. But then again, I rarely use coins anyway when
playing games on the machine, so it makes little difference at a
How to install a mech in a WPC door
If your coin mech has four of the little stubby posts, remove
the ones on the front side - the side that faces the coin door.
Simply unscrew the posts and set them aside (you can put them in your
misc parts drawer, or just discard them). The mechs often come with
all four posts installed, because some other coin doors require
them, but they won't fit into the WPC-style doors.
Coin mech with all four posts installed. You'll have to
remove the posts on the front (door) side before installing
the mech in a WPC-style door.
Open your coin door and find the brackets that hold the mechs. These
are right behind the coin slots. You should see a couple of big latch
levers near the top of the door, as pictured below.
There might be a cotter pin installed in each latch to lock it in
place; if there is, remove it. Pull the latch outward from the bottom
and flip it all the way up. (It might offer a little resistance when
all the way down, but you shouldn't have to exert too much force.)
The coin mechs fit in the space below the latch, in the area marked in
the photos (above and below) as the "seating slot". This area isn't
very well delineated - figuring out exactly where the mechs should
land is the hardest part of installing them, in my opinion. The
picture below shows more of a head-on view that might help. The
"slot", such as it is, is that open space between the two stubby
little protrusions along the front wall. You want to fit the front
bottom corner of the mech between those nubs.
That big adjoining opening in the floor is not part of the
seating slot, by the way. It's the opening that the coins drop
through. Don't try to squeeze the mech in there; it'll end up
resting right on top of that opening.
To orient the mech, find the big plastic lever that's alongside one of
the edges. (The lever is engaged when you press the "push to reject"
button to clear a coin jam.) When you install the coin mech, install
it with the lever facing up, and the hinge towards the back, facing
away from the coin door. The hinge side should also be the side with
the two posts.
Insert the coin mech into the slot. You'll have to insert it an
angle, as shown below, to get around the back end of the bottom
bracket. Orient it as shown, with the little metal posts sticking out
the back, and the metallic side of the unit facing you. At this
stage, there won't be any sensation that you're fitting the mech into
a slot; it just kind of sits there. But the bottom front corner
should be nestled between those two little nubs we pointed out above,
and you should push the mech as far forward as you can against the
If everything's aligned correctly, you should now be able to push the
bottom rear of the mech - the part where the bottom post is sticking
out in back - into the bottom bracket. This should straighten things
out so that the mech is square with the door. This will be a fairly
tight fit, but it shouldn't take a lot of force. If it doesn't slide
into the bracket fairly easily, the mech is probably sticking out too
far in back because you don't have the front aligned correctly with
the nubs. Try wiggling the front to get it more completely into the
little recess between the nubs. You might also have to slide it
upwards slightly to fully seat.
Now flip down the top latch (the one we flipped up in the first step).
It should fit over the top post at the back of the mech. If it doesn't
seat, try sliding the mech upwards a little, and try moving the
top back and forth a little to fit into the lever.
If you took out a cotter pin at the start of the procedure, re-install
Done! If you have a second coin mech for a second slot, the procedure
is exactly the same for that.
The blank space in the left half of the WPC-style door is designed to
accommodate a paper dollar bill acceptor. I haven't installed one of
those myself, so I don't have any installation instructions to offer
(and I doubt that most virtual cab builders would be interested anyway).
Some cab builders use the space for other purposes, such as audio
volume knobs or extra buttons.
How to install a coin mech in a SuzoHapp/Stern door
Open the coin door and find the brackets that hold the mechs. They're
right behind the coin slots.
Make sure the metal tabs at the top and bottom of the slot are in the
"open" position, meaning they're out of the way of the slot. Slide the
upper tab all the way up, and slide the lower tab all the way down.
Loosen the set-screws if necessary. (The brackets might take a little
effort to slide up and down even after loosening the screws, but of
course don't force anything.)
At the front of the area where the mech will sit, you should see two
little circular recesses at the front of the slot. These are where
the posts on the front edge of the coin mech fit.
Slip the mech into the space, fitting the posts on the front edge into
the recesses. Orient the mech as shown below, with the metallic side
facing you. You can also identify the orientation by the "ledge" that
sticks out on from one side of the mech. The ledge is at the top, and
should be on the side facing you.
The back of the mech should now align with the metal brackets above
and below. Slide the brackets so that the posts on the back of the
mech fit into the openings on the brackets.
Now all that remains is to tighten the set-screws to fix the mech in
European coin doors and coin mechs
My understanding is that the coin doors sold for European markets use
a different design that's not compatible with the mechanical quarter
acceptors used in the US. The European coin doors are set up for
electronic coin acceptors that can be programmed for multiple
denominations, to accommodate a wider range of coins. The electronic
coin acceptors have a different physical form factor from the
mechanical ones used in the US, so they need different brackets and
have a different installation procedure. I'm afraid I don't have any
experience with these, so I have to leave it up to you to figure out
the procedure. (If anyone wants to supply me with a photo sequence for
European doors, I'll be happy to add that here.)
Custom coin slot inserts
Each coin slot
on the coin door has a "reject" button at the top for clearing coin
jams. These usually come with pre-printed legends indicating the type
of coin accepted, usually "Quarters" or "25¢" for a US door.
The legend is printed on a little piece of transparency film
sandwiched inside the button, so you can take that out and replace it
with a custom label. This lets arcade operators swap in labels saying
"Tokens Only" or "SBA Dollars", for example. For a virtual cab, it's
an opportunity to personalize your machine.
You can buy pre-printed inserts for common denominations, but it's
pretty easy to create your own custom inserts with a laser printer.
To help you get started, here are the dimensions for the most
common coin door types:
If you're not sure that your inserts match one of these layouts, you
can just measure the old one currently in your door after extracting
it, which we'll get to in the "how to install" sections below.
Your inserts will look best if you use white text and graphics on a
black field. That's the way the "real" ones look. The black
background should ideally be completely opaque, which is why you need
a laser printer; the ink used in ink-based printers just isn't opaque
When I created my labels, I had good results with plain white paper
printed on a laser printer. Your mileage may vary, though; laser
printers certain vary in how darkly they can print. I've seen posts
on the Web from other people who tried to create custom inserts this
way and weren't satisfied with the opacity. If you try it and find
that the results look too washed out when back-lit, you might try a
double layer approach: print a bottom layer on white paper, and a top
layer on laser printer transparency film. Cut out the two pieces and
carefully align them to overlay the graphics. The double layer of
toner should greatly improve the opacity of the black, and since the
top layer is clear film, it won't (much) dim the white parts. You can
try two layers of white paper if you don't want to spring for the
special laser transparency sheets, but the white parts will probably
be too dim with that approach.
Once you have the inserts printed, you still need to install them in
the buttons. The exact procedure for that depends on the type of coin
door you have.
I think white paper makes a better base layer than making the whole
thing transparent, by the way, because white paper will do a better
job of diffusing the back-lighting. The original inserts that come
with your coin doors will probably be printed on thin white plastic
film, which is probably even better than paper, since it doesn't have
the visible grain that paper has. You can find laser-printable
translucent film sheets on Amazon and at art-supply shops, but I
haven't tried any of them myself. (Try searching for "backlight film"
or "lightbox film".) If you've used a particular product that you'd
like to recommend, let me know and I'll pass along the recommendation
Replacing inserts in WPC coin doors
Fair warning: this process is a bit of a pain with the WPC doors.
(Which I hope you won't find to be too much of an understatement.)
I'd strongly recommend doing one chute at a time: leave one
chute fully assembled while working on the other one. That way, if
you get stuck during re-assembly, you can use the still-assembled one
as a reference to figure out how things are supposed to go. This
could be especially important if your door doesn't exactly match the
one I used to formulate these instructions. I'm sure there are some
little variations in different versions of this product that they've
shipped over the years.
To get to the orange button, you have to take off the entire top coin
mech bracket. Start by removing the coin mech itself (reverse the
procedure for installing a coin mech in this door, described above).
Then remove the four screws shown below.
The screw labeled "A" above attaches the bracket for the lamp that
back-lights the button. Pull the lamp out of the bracket (it'll be
sitting in a hole in the back of the bracket). You don't have
to disconnect the lamp or disconnect any wires. Just let the lamp
dangle from the wire.
Screw "D" holds down both the bracket and a wiring clip. Try to keep
the wiring clip attached to the wire to make it easier to put things
back the same way later. (I did warn that this was going to be a
The bracket should now be free, so gently remove it. It might be a
little tangled in the wiring, so if it doesn't come right out, gently
ease it out from under any wires pinning it down. Again, you
shouldn't have to disconnect any wiring at any point in this entire
You can now easily remove the orange button. In fact, it'll probably
pop out on its own when you pull out the bracket, because there's
a spring actively pushing it away from the door, and the bracket
was the only thing keeping it in place.
Note that you'll want to remove that entire black bracket that the
button is housed in, even if the button came out before you had the
bracket all the way out. It'll be easier to get it back together
later if you just take the bracket out entirely.
We've almost reached our objective of removing the old insert. The
orange button might look like a single piece of molded plastic with
the insert forever locked inside, but it's not. There's a removable
cover, and the insert is just under that. You should be able to see
the seam pretty easily about a millimeter from the front. The cover
isn't molded in or glued on; it's just held in place by four friction
pins. You should see a notch on each side along the seam. You can
stick a flat screwdriver in there and twist gently to pry the cover
off. Be gentle so that you don't break the little plastic pins, and
do the prying as evenly as you can. Pry a little on one side, then
pry a little on the other side, and rock it back and forth like that a
few times until the cover comes loose.
Once you have the cover off, just take out the old plastic film and
insert the new one. The cover has a very slight recess for the
insert, so I'd put the cover face down on a table, put the new insert
into the cover, and then reattach the back to the cover, keeping the
cover lying flat so that the new insert stays put. Align the pins
and press the two pieces together until flush.
Pay attention to the subtle asymmetry of the cover! One side has
curved corners, and the other side has square corners. You'll want
those to align when it's back together, so make sure you install the
new insert right-side-up.
Put the spring on the button stem, noting that the narrow end of the
spring faces the button.
The rest is just a matter of reversing the disassembly steps. It's a
bit of a hassle to get the bracket back in the proper position in the
door, especially since the spring-loaded button wants to keep falling
out. Be patient, and you should be able to get it seated again.
Remember to look through the coin button opening in the front side of
the door as you get the button seated - that'll make it easier to get
everything aligned again.
When you have the bracket aligned properly (with the coin slot and
button in the right place as viewed from the front side of the door),
hold it in place while you screw in the bottom screw (screw "C" in the
first photo above). That should be the longest of the four screws you
Fasten screw "B" (on the left side) next. That's one of the two
For screw "A" (at the top), remember that this also attaches the lamp
bracket. Use the smallest screw in this slot. Insert the lamp back
into hole in the back of the button bracket, and fasten screw "A"
though the lamp bracket.
Similarly, screw "D" (on the right side) attaches a wire clip, so put
the wire clip back in place (hopefully with all of the wiring still
threaded through) and fasten the screw through the clip. Screw "D" is
one of the middle-size screws.
Now you just have to repeat the whole thing for the second coin chute.
If it's any consolation, it should be easier the second time
through, now that you've had some practice.
Customizing the coin button colors: The WPC coin doors come
with orange plastic buttons, so you're kind of stuck with a Halloween
color scheme for your inserts (orange and black). But there's a way
to fix this: you can buy clear plastic replacements for the orange
buttons. With clear buttons, you can use whatever color scheme you
want for the printed inserts, and/or you can change the back-light
color, by replacing the white #555 lamps with color LED bulbs. For
the clear buttons, search for part number PBL-100-0072-00 at Pinball
Life, or 27-1081-CC at Marco Specialties. Both companies also sell
#555 LED bulbs in various colors.
Replacing inserts in Stern/SuzoHapp coin doors
If you opted for a SuzoHapp door instead of a WPC door, good news:
they made the process of replacing the inserts quite simple in these
doors - much less of a chore than for the WPC-style doors.
In the SuzoHapp doors, the orange button is held in place by an e-clip
on the button stem inside the coin door. To remove the button, just
pry off the clip. You might be able to get it off with fingers alone,
or you can use needle-nose pliers to pull it loose.
Removing the clip frees the button and lets you pull it out
of the door on the front side.
Removing the old insert is just a matter of sliding it out through the
paper-thin slot in the top of the button.
There's nothing holding the insert in place except friction, but
there's enough friction that it won't fall out on its own. There's a
narrower slot in the bottom of the button that you can feed something
super-thin into (try a folded piece of paper) to dislodge the old
insert, or you might try just blowing into the bottom slot.
Once the old insert is removed, simply slip the new insert in through
the top slot.
To put the button back into the door, just reverse the removal
process. Put the spring back on the stem, push the button into the
socket, and slip the e-clip back onto the stem on the inside. You'll
probably need to use needle-nose pliers to snap the e-clip into place.
The coin door wiring harness
If you buy one of the pre-built and pre-wired coin doors, it will come
with a connector plug, known in the jargon as a "wiring harness", with
pins for all of the electrical connections inside the door. If you
want to take full advantage of the functional components in the door,
you'll have to connect the pins in the wiring harness to other
points in your cab:
- Connect the switches and buttons to your key encoder. This includes
the operator buttons, the coin chute switches, and the slam tilt
switch, if present. All of these connect to the key encoder following
the same pattern as other cabinet buttons, as explained in
- Connect the lamps at the top of the coin chutes to power, to make
them light up when the machine is on. You can optionally connect them
to your output controller to make them light up under software
control; if you want to go that route, connect them just like any
other feedback device, as explained in Feedback Device Wiring. In
my opinion, there's no good reason to go to that kind of trouble; I'd
just hard-wire them directly to power. That's exactly what the real
machines do, so there's no "realism" gained from controlling these
The wiring harness connectors on the pre-built doors are standard
parts, which means that you can buy mating connectors from an
electronics vendor like Mouser. I'd recommend doing exactly that: I
like using modular plug-in connectors wherever possible, because it
makes the wiring neater, and it makes maintenance easier if you ever
have to remove anything.
Some cab builders don't want to deal with the hassle of finding
matching connectors, so they use wire cutter to snip off the wiring
harness connectors and then make their connections either by soldering
the wires, or using a screw-down terminal block. I don't recommend
cutting off the connector, since you can't easily undo that, but some
people go this route for the sake of expediency.
Whether you use the pre-attached connector or cut it off and connect
the bare wires, you'll need to know how the wiring is all connected.
See the sections below for wiring diagrams for the various door types.
Williams 13-pin connector
The Williams coin door comes with a pre-wired 13-pin connector of this type:
. This connector is designed
to plug into a circuit board that has the mating header:
Here's how the pins in the connector are wired:
The 13-pin Williams connector.
The pin marked "Blocked key pin" is physically blocked in
the connector, so that the mating pin won't fit into it. The
matching pin on the PCB connector must be clipped off. This
ensures that you can't insert the plug backwards, or plug
it into the wrong circuit board. The "Middle coin" pin isn't
wired at all in coin doors for the US market, which only have
two chutes (left and right). The pin colors in the diagram
approximate the wire colors leading to the harness, but note
that some of the wires are striped in two colors; the diagram
only shows the base color.
The "All switch common" pin is daisy-chained to one terminal of each
switch and button, so it corresponds exactly to the "Common" terminal
on your key encoder and should be connected there. Each of the other
switch pins should be wired to the corresponding button input on your
The odd man out among the switches is the "slam tilt" wiring, which
has its own separate pair of pins rather than connecting through the
"common" pin. You can simply connect one of these pins (it doesn't
matter which) to the "common", and connect the other to the
appropriate button input for the slam tilt switch.
The coin chute lamp pins provide the 6.3V power connections for the
lamps that illuminate the coin chutes. These are normally hard-wired
to power on a real pinball machine, so I suggest doing the same in a
virtual cab. The lamps normally installed are incandescent #555
lamps, which are designed to run on 6.3V but will run (noticeably
dimmed) on 5V. Incandescent bulbs aren't polarized, so it doesn't
matter which order you connect (+) and (-) on these. See
Power Supplies for Feedback
for advice on adding 6.3V power to your cab.
You can connect the coin lamps to your output controller to put them
under software control if you wish, but I personally wouldn't bother:
it won't add much of a special effect, since the software will just
leave them on all the time anyway.
How to connect to the plug
Now that you know how the connector is wired, there's still the
matter of physically connecting wires to it. There are three main
- Cut off the connector and use your own wiring
- Use a "Z" adaptor and wire your own matching wire harness
- Use a custom circuit board
The first option is the most straightforward, especially if you're not
much into electronics as a hobby, but I don't like it much because
it's not easily reversible should you want to re-purpose the coin door
in the future. The Z adapter option is easy to understand, but it's
really about as much work as setting up a custom circuit board, since
you have to build the mating plug out of crimp pins. That's why my
favorite option is the custom circuit board. That takes a little more
up-front planning work, but the assembly process is easy and it's very
convenient to install and use once it's assembled.
Read on for the details on how to implement each option.
Custom circuit board for Williams 13-pin plug
On the original Williams machines, the 13-pin connector plugged into
the mating header on a small circuit board mounted on the left inside
wall of the cabinet. This circuit board in turn had other connectors
that led back to the CPU board (for the switch terminals) and the
power connections (for the coin chute lamps).
You can create a simple circuit board for this, using the 13-pin
header linked above. For your convenience, I've drawn up EAGLE plans
for a board that includes the pin header and breaks out the
connections for easy wiring to other points in your cab. You can have
this board made by OSH Park
under $10. Simply upload the EAGLE plans to their site and they'll
make 3 copies of it for you.
The board design includes a 6.3V regulator to provide the correct
voltage for the coin chute lamps. Just plug in a 12V supply (you can
use an ATX power supply for this). The on-board 6.3V regulator can
also supply power to up to four additional front panel button lamps,
which usually use the same 6.3V bulbs.
"Z" adapter for Williams plug
It might seem like
too much work to build a whole separate circuit board just to
accommodate that special coin door plug. The thing that would be a
lot simpler would be to find a mating wire-harness connector that you
could wire to your key encoder and power supply, and then just plug
the two connectors together directly, without any extra circuit boards
in between. There is a way to do this, but it requires a special
adapter plug that serves as a gender changer for the Molex plug,
so that you can plug two of the same Molex plugs together. The
adapter is often called a "Z Connector" because of its shape.
You can find these at pinball suppliers and some electronics
vendors. Search for part number MWWS156-1624. Get the version with
at least 13 pins (MWWS156-1624-13). A version with more pins will
work if you can't find the 13-pin version.
Once you have that part in hand, you can build your own cable
connector using the same connector that's on the coin door harness
). Then just plug
the two cables together using the "Z" adapter.
This option is marginally less work than the circuit board
approach above, and slightly cheaper. I don't think it's
quite as tidy, since it leaves these two big cable plugs
loose in the cab, but you can fix that easily enough with
some cable ties.
This connector is a "crimp pin housing" type. See
for help with ordering the necessary parts
assembling the connector.
Connecting to the bare wires
The most straightforward option is to cut off the 13-pin plug and
connect to the bare wires. If you're using a circuit board or a Z-adapter
as described above, you can obviously skip this section.
And I generally recommend you do use one of those other options, since
cutting off the plug is destructive and not easily reversible, and
because pluggable connectors are easier to work with later when doing
maintenance. But if you don't have the
patience for one of the more structured approaches above, this
is a workable last resort.
One fairly easy way to deal with the bare wires after
cutting off the connector is to wire them to a screw-terminal block
like the one pictured at right. Look for a terminal block with 12 or
more terminal positions. You can mount the block on the cabinet wall
adjacent to the coin door. Install the coin door first, then connect
each wire from the coin door to one of the screw terminals. Then you
can run a wire from each screw terminals to the corresponding
connector on your key encoder, in the case of the switch wires, or to
the appropriate power connections in the case of the coin chute lamps.
Alternatively, you can create your own wiring harness using a different
connector of your choice. I personally don't see a lot of benefit in
this approach, since it's about the same amount of work as creating
a connector that mates with the existing 13-pin plug.
Stern SAM connector
The SAM-era coin doors use a 12-pin Molex connector for their switch
wiring. Unfortunately, I haven't yet been able to confirm the gender
or pin pitch - it looks like a Molex .063" plug
), which makes the
matching connector the .063" 12-position receptacle
). But it could be
the other way around. If you're buying one of these doors, you'll
have to wait until you have it in hand to determine the exact plug type -
and when you do, please let me know which it is so that I can improve
the advice here!
These are connected as follows (refer to the diagram at
right for pin numbering):
- Left coin
- Not used
- Right coin
- Not used
- Not used
- Slam tilt switch
- Back/Cancel service button
- Down/- service button
- Up/+ service button
- Enter/Select service button
- Key (blocked pin for orientation)
- Switch common
These doors appear to have an additional four-pin connector for power
to the coin chute lamps. I don't know the type of connector used
here, so again, please let me know if you have reliable information so
I can include it here. At any rate, the wires you want to connect in
that plug are the yellow and yellow/white wires: those connect to 6.3V
power. The bulbs are incandescent, so the order of the (+) and (-)
connections doesn't matter for these. You can leave the other two
To integrate this connector into your own wiring, you have basically
the same options as for the Williams 13-pin connector: you can either
build a matching plug, or you can cut off the plug and connect the
bare wires. I think it's a better idea to keep the plug for the sake
of ease of maintenance down the road, but that requires a little more
up-front work. Review the section on the Williams 13-pin plug above
for thoughts on these options.
Stern SPIKE connector
The SPIKE-era coin door wiring harness is terminated in two
connectors, each female 0.1" pin header connectors that connect to
0.1" single-row pin headers. These are common connectors that you can
find easily from electronics vendors; see Connectors
more on these. One of the plugs has the wiring for the service
buttons, and the other has the wiring for the coin chutes and
slam tilt switch.
The first connector, which has the service button wiring, fits a
6-pin, single-row 0.1" header. The pins are arranged as follows. The
"Key" is a blocked pin to ensure that you insert the plug in the right
direction; this pin must be snipped off on the header to allow the
plug to fit.
- (Key - blocked pin)
- Switch common
The second connector has the wiring for the coin chutes. This one
fits a 9-pin, single-row 0.1" header. The pins on this connector are
arranged as follows. There's no key pin on this connector, so you
have to be careful to plug it in the right way. You can identify the
end with the LED power pins by the yellow wires going to the plug.
- +5V (power to coin chute LEDs)
- 0V (power to coin chute LEDs)
- Switch Common
- Slam tilt switch
- Coin 5
- Coin 4
- Coin 3
- Coin 2
- Coin 1
Connect the coin chute LED pins to your 5V power supply. I recommend
connecting these directly to the power supply, since they're similarly
hard-wired to power on the real machines. But if you prefer, you can
connect the 0V side to a port on your output controller to place the
coin chute lights under software control. I don't feel that's worth
the trouble, since the software will just leave the lights on all the
time. See Feedback Device Wiring
for more details.
The Switch Common pins on both connectors correspond to the Common
port on your key encoder and should be connected there. Connect the
other button and switch pins to corresponding input ports on your
To integrate these connectors into your own wiring, you have basically
the same options as for the Williams 13-pin connector: you can either
build the matching connectors, or you can cut off the plugs and use
the bare wires. I think it's a better idea to keep the existing plugs
for the sake of ease of maintenance down the road, but that requires a
little more up-front work. Review the section on the Williams 13-pin
plug above for thoughts on these options.
Creating your own wiring harness
If you buy one of the basic coin door options that requires you to
install the wiring yourself, I'd recommend creating your own
plug-and-socket connector for it, rather than wiring everything
directly to other points in your cab. This will make future
maintenance easier. The Molex .063" wire-to-wire connectors are good
for this, as they come in a wide variety of pin counts. See
for more on building custom connectors.
Wiring to the key encoder
The service buttons are just like any other cabinet buttons, so wire
one terminal of each button in a daisy chain to your key encoder's
Common terminal, and wire the other terminal of each button to an
individual button port on the encoder. See
for more on the general wiring plan for
The coin chute switches and slam tilt switch all act just like
buttons, so wire them the same way.
All of the pre-wired door types provide wiring that's compatible with
the general key encoder wiring plan. They all use a Common wire
that's daisy chained to the various buttons; this corresponds exactly
to the Common terminal on your key encoder, so simply connect the two.
What about multiple Common wires on the coin doors? Some of the
pre-wired doors provide multiple Common wires for different groups of
buttons. You can just connect all of the Common wires together if
there are more than one. The doors that use multiple Common wires do
so for compatibility with the more complex "matrix" wiring used in
real machines from the 1980s and 1990s, where switches were grouped
into blocks that had separate commons. The key encoders we use in
virtual cabs have more modern electronics that allow a simpler scheme,
with a single common across all buttons.
If your key encoder is programmable, assign the coin door button ports
to keyboard keys as follows. (The first four items represent the
labels on the "service" buttons.)
- Cancel = 7
- -/Down = 8
- +/Up = 9
- Enter = 0
- Coins = 3 (see "How to set up multiple coin chutes"
- Slam tilt = Home
If your key encoder isn't programmable, and it uses a fixed set of
joystick buttons as inputs, you'll have to do the programming in
Visual Pinball instead of in the key encoder. Open the Visual Pinball
editor, with no game running, and select Preferences > Keys from
the menu. For each of the buttons you connected, find the entry in
the dialog for that button. (The Coin buttons are labeled "Add
Credit", "Add Credit 2", "Coin 3", and "Coin 4". The service buttons
are grouped together in a section labeled "Service Buttons".) Under
each button label, you'll find a drop list where you can select the
joystick button number assigned to each input. You'll have to repeat
this process with each version of VP that you intend to use on your
cab (VP 9, VP X, PhysMod5, etc), since each version keeps its own
If your key encoder isn't programmable, and it uses a fixed set of
keyboard key assignments, you'll have to pick the ports on your key
encoder that are already assigned to the keys listed above when wiring
these buttons. If your key encoder doesn't provide some of these, you
won't be able to use these buttons with that encoder. In that case,
you might consider adding a Pinscape unit purely for the additional
programmable key inputs. It only costs about $15, and the procedure
for wiring it for button inputs is essentially identical to the
procedure used for the commercial key encoders.
Check your VP "Coin 1" setting
Open the Visual Pinball editor and bring up the keyboard preferences
dialog (select Preferences > Keys from the menu). Check that the
entry for Add Credit is the 3. If it's not, click
the Add Credit button, then press the 3 key on the
While you're at it, also check that Add Credit 2 is set
to 4, and change it as well if necessary.
Make sure Add Credit is assigned
to 3 and Add Credit 2 is assigned to 4
Note that each version of VP (9, 10, PhysMod5) stores it settings
independently of the other versions, so you'll have to repeat this
process for each version of VP that you intend to use on your cab.
This is required even if you're using joystick input, and in
fact it's especially important if you're using joystick input
due to a bug in the VP core scripts. Current versions of the VP
scripts ignore these settings and always use 3 and 4
respectively, no matter what you set in the dialog. That's confusing
at best, but it's even worse if you're using a joystick, because VP
will internally map the joystick input to the key assigned in the
dialog. If that doesn't match the hard-coded 3 and 4
keys used by the scripts, your coin inputs will be ignored by most
How to set up multiple coin chutes
In the US, the most common coin door configuration is two slots that
both accept quarters. Each slot has its own separate switch, so
you'll have two inputs to connect to your key encoder. You have
two options for this:
- Wire the two switches together to the same key encoder input
- Wire them to separate inputs
If both slots accept quarters, I recommend the first option: wire both
switches to the same key encoder input, and assign this input to the
3 key on the keyboard. In the PC pinball simulators, this
represents the primary coin slot. You can instead wire the two slots
to separate inputs; if you do, use the 4 key for the second
slot's key assignment, as this represents the secondary coin slot in
the PC pinball software's mappings.
The reason I recommend using a single key encoder input for two
quarter slots is that it simplifies the software setup considerably.
Almost all Visual Pinball tables will handle the primary coin slot the
same way, but the handling for secondary coin slots can vary from one
table to the next. You'll have to use the operator menus to adjust
pricing options on many tables if you want consistent handling for the
The advice above only applies if your two (or more) slots all accept
the same coin denomination. If you're using slots that accept
different coins (e.g., dimes and quarters), you should wire each slot
to a separate key encoder input so that the software can distinguish
the different coin types properly. Visual Pinball allows up to four
distinct coin keys for this purpose. However, be warned that this is
a bit of a pain to set up in the software. You'll have to go into the
operator menu for each individual table to set up pricing options.
This is handled by the emulated ROM software, so there's no way to
share the settings among games; Williams and Bally and the rest sadly
lacked the foresight to build Internet cloud storage into their games
in the 1980s and 1990s. What's more, each table has its own unique
operator menu tree, so you'll have to learn how to use each one. The
Williams games from the 1990s have nicely designed menus that are easy
to navigate, but games from earlier generations can range from mildly
confusing to utterly obtuse, roughly in proportion to age. Be
prepared to hunt through the operator's manuals for older games.
To use two distinct coin denominations, assign the primary coin slot
to the 3 key, and assign the secondary slot to 4. You'll
have to go through your installed games and set up the suitable
pricing options in each one via its operator service menus.
If you're using three denominations, assign the third to the 5
key. Assign a fourth denomination to the 6 key. The PC pinball
software stops at four slots, so there's not much you can do on a
virtual cab with slots beyond the fourth.
Using the Reject buttons as virtual coin buttons
We've already mentioned that you should include some way to insert
coins, either real or virtual, because of the difficulty of converting
some older games to Free Play mode. If you're installing coin
mechanisms in the chutes and wiring the coin switches, you'll be able
to accomplish this using real coins. Alternatively, you can skip the
coin mechs and just install a "Coin" button that simulates coin
insertion. And in my opinion, you really should include a "Coin"
button even if you install real coin mechs, since it's fun to use real
coins once in a while, but only once in a while. You'll want the
convenience of a front-panel button the rest of the time.
The perfect place for
the "Coin" button, in my opinion, is the Coin Reject buttons at the
top of the coin chutes. You could just add another pushbutton to your
front panel of the same sort as the Start button, but that adds
clutter and makes the machine look less "real", since real pinballs
are almost all very minimalistic about buttons. The Reject buttons
let you hide the Coin button in plain sight, using a button that's
going to be there anyway. It's also an intuitive place for the
virtual Coin button since it serves a coin-related function already.
It's not realistic, of course; an arcade machine obviously isn't going
to provide a button that lets anyone add free credits. But that's
just all the more reason to "hide" the button like this.
Using the Reject buttons as coin buttons isn't just a matter of wiring
them to the key encoder, because there's no wiring to these buttons to
begin with. They're not the electrical kind of button that operates a
switch; they instead operate mechanical levers in the coin acceptor
mechanisms that widen the coin passage to help free jammed coins. To
make these into buttons we can wire to our key encoder, we have to add
microswitches in such a way that pushing the button operators the
Basic geometry of the coin reject button for
the Williams-style coin doors (other types vary slightly in the
details but have roughly the same layout). A plunger sticking
out from the back of the button engages the lever when pressed.
The button's total travel range is about ¾".
The obvious place to add a switch is just behind the plunger:
That's workable but not ideal. The problem is that the plunger has to
travel about ¾" in order to fully engage the lever that clears
jams in the coin mechanism. If you put the microswitch directly
behind the plunger as shown above, it'll block that full range of
motion. An over-zealous player could also push the button hard enough
to bend the microswitch or break it off its mounting. If you're not
using real coin mechs, though, this simple arrangement might work for
you, since you probably don't care about giving the button the full
range needed to clear jams.
The next most obvious arrangement, if you want to avoid blocking the
full travel range, is to position the switch at the end of the
plunger's travel. There's no good way to do that in such a way that
the plunger engages it directly, since as you can see, that large
lever is in the way. What you can do, though, is let the lever engage
This arrangement, like the first, works but isn't great. This plan
has the benefit that you can press the button all the way in,
but it has the drawback that you must press it all the way in.
That's unpleasant for players, because it takes a bit of effort to
push the button all the way in; there's a lot of friction and spring
force in the coin mech levers. It also makes the button feel very
different from the other front-panel buttons, which all take a light
Fortunately, there's a better arrangement that overcomes both of these
problems: it doesn't block the full travel range of the button, and it
lets you engage the coin switch with only a slight push. The trick is
to install the coin switch "backwards", so that the microswitch is
compressed by the coin mech lever in the normal position, and released
when the lever moves forward. It's backwards in the sense that
pressing the button releases the switch, and releasing the button
engages the switch.
This arrangement trips the switch after pushing the button only
a short distance, so it gives the button the same light touch as
the other front-panel buttons. And it doesn't get in the way of
the normal jam-clearing function of the button.
It takes a little finesse to get the positioning right. You have to
position the switch so that its metal arm is held down by the big coin
door lever when the button isn't being pressed. You also have to
arrange it so that the switch arm stays out of the way of the plunger.
This doesn't leave a lot of room to maneuver, but it can be done.
You'll have to improvise something for a mounting bracket for the
switch. My recommendation is to fashion a bracket from sheet metal,
or perhaps use a 3D printer to create a custom bracket with the right
geometry for your switch. There's a good attachment point for
whatever bracket you come up with, just above the coin chute where the
lamp holder is attached. You can unscrew the lamp bracket and add
your own bracket on top of it, fastening it with the same screw.
Microswitch added to Coin Reject button
in "backwards" arrangement, so that the spring-loaded coin lever
presses the switch when the Reject button is in its rest position.
Pressing the Reject button pushes the lever forward, which releases
the switch. The microswitch is mounted on an improvised sheet-metal
bracket. The bracket is fastened to the door with the same mounting
screw that fastens the lamp holder for the chute.
Recommended mounting point for the
microswitch bracket. The coin door should have a lamp holder
installed above the chute, on a bracket fastened with a machine
screw at the top of the chute. If you use a similar thin metal
bracket for the microswitch, you can share the mounting point.
Remove the mounting screw, layer your switch bracket behind
the lamp bracket, and put the screw back in through both brackets.
The microswitch isn't installed in this view; this is just
the "before" view to show where it goes. The purple and white
wires visible here are the power wires for the lamp.
Wiring the coin switch
If you use the "better" plan above, where the switch is installed so
that pressing the button releases the switch, the trick with wiring is
to use the switch's Normally Closed terminal. This is the terminal
that connects to the switch's Common terminal when the switch isn't
engaged (its "normal" position). That lines up with our "backwards"
switch arrangement. So with this mounting plan, simply connect the
wiring to the switch's NC and COM terminals.
If you're using one of the more straightforward plans where pressing
the button engages the switch, wire to the switch's NO (normally open)
and COM (common) terminals instead.
My advice for the next step is to solder the two wires from the
microswitch directly to the two terminals wired to the coin chute
switch directly below it. That will make button switch and the coin
chute switch interchangeable. They'll both end up wired to the same
key encoder input, so pressing the Reject button for one of the chutes
will have exactly the same effect in the software as inserting a coin
into that chute.
The diagram below shows this wiring plan, with one small adjustment:
we identify the existing "all switch common" wire, which is daisy-chained
in the pre-installed wiring from switch to switch, and we extend that
daisy chain to our new switches as well.
Wiring the Reject button switches. Identify
the "common" wire in the existing wiring first: this is the wire
that's daisy-chained between the existing coin chute switches.
Extend that daisy chain to one terminal each on your new switches.
Then connect the other terminal of your new switch to the corresponding
other terminal of the existing coin chute switch.
Wiring a Free Play mode switch
If you want to get really fancy, you can add a switch that enables
or disables the Reject button switches. That will let you turn
Free Play mode on and off as desired. This requires only a small
change the basic wiring plan above: splice a switch into the
"common" daisy chain wire before your first added switch. When
the switch is off, this will disconnect both of your added
switches from the common wire, so they'll do nothing when
pressed. When the switch is on, the common connection is
restored, so they'll work as normal.
Other places to hide buttons in the coin door
Many cab builders these days prefer to minimize the number of visible
buttons on the front face, to better replicate the uncluttered look of
a real pinball machine. You might like the aesthetics of fewer
buttons, but sometimes you do want a few extra buttons for the sake of
functionality and ease of use. One way to resolve these conflicting
goals is to create "secret" buttons that function like regular
pushbuttons but don't look like buttons. We saw above how you can do
this with the Coin Reject buttons, taking a standard feature of the
coin door that's there anyway, and turning it into a pin cab
pushbutton - you get a functioning extra button without any added
visual clutter. The coin door offers a few other opportunities
for secret buttons:
Coin return slot flaps: If you don't plan to implement working
coin chutes, you can use the little flaps in front of the coin return
chutes as secret pushbuttons. Just install a microswitch behind each
flap, so that pushing the flap operates the switch. (This won't work
if you do want working coin chutes, since you'll want to leave the
return chutes clear, so that you can remove rejected coins as usual.)
Coin door lock: If you're using an entirely fake coin door,
it'll probably have a fake lock tumbler, to simulate the appearance
of the real doors. If that's removable or made of flexible plastic,
you could position a microswitch behind it and use it as a button.
Dollar bill acceptor plate: All of the modern coin doors for
the US market (including the WPC, Stern, and SuzoHapp models) include
removable rectangular plates where you can install a dollar bill
acceptor mechanism. The space behind these plates on the inside of
the door is always left open, to leave room for the bill reader, for
operators who install them. I've never heard of anyone installing a
dollar bill reader in a home-use pin cab, so this space usually goes
unused. You could either drill one or more holes in the plate and
install pushbuttons, or replace the plate with your own button panel.
This isn't really hidden the way the other ideas above are, but you
can at least make it inconspicuous by using low-profile black
pushbuttons. Alternatively, with a little improvisation, you could
make the cover plate itself into a button by attaching a hinge on one
side and placing a switch behind the plate.
Adding an extra service panel
The inside of the coin door is a good place for any extra
"operator" controls you need in your cab. I wouldn't put
anything you might access frequently here, but it's great
for controls you use occasionally, since it avoids adding
any visible clutter to the exterior of the cab, but is
still in easy reach when you need them. Some examples
of suitable controls:
- Night Mode switch
- PC hard-reset button
- Plunger calibration button
- Master volume knob for your audio amplifier
- Audio mute
- TV power controls (in case you have a balky TV that doesn't always
power on at the right times, or that needs to be power cycled occasionally
because it loses the signal from the PC video card, like my DMD
monitor occasionally does)
Most of the modern US coin doors have a large open space next to the
coin chutes where you can install a dollar bill acceptor, and include
mounting screws in that area. That makes a good place to mount
an additional set of buttons.
You can buy an extra operator button panel of the same sort that's
already installed in the WPC doors, and install it in the dollar bill
reader area. Those control panels are just rows of ordinary buttons,
so they're easy to wire for any control that uses a momentary switch.
These are also fairly easy to improvise using individual pushbuttons
and a sheet-metal bracket.
The extra service buttons in my pin cab, inside the coin door,
in the space provided for a dollar bill acceptor.
Coin door position switch
On real pinball machines, there's switch inside the coin door that
detects when the door is open and closed. You'll probably want to
install one of these on your virtual cab, for reasons we'll come to
The coin door switch works like the light switch in a refrigerator
door. The switch is located just inside the door at the bottom of the
hinge. A metal actuator plate attached to the door presses down on
the switch's plunger when the door is closed.
Above: Coin door switch on a 1990s Williams machine.
These machines typically use two switches stacked vertically; you
can see the individual switch plungers. One switch is the high-voltage
power supply safety interlock, which cuts power to the playfield solenoids
when the door is open. The other switch is a logic input to the CPU
that lets the ROM software detect when the door is open.
Top view of the switch and actuator, to make
the geometry easier to see. The "actuator" is just a fixed metal plate
attached to the door that presses down on the switch plungers when the
door is closed.
The switch is a safety interlock on the original arcade machines. The
50V power line that supplies voltage to the big solenoids on the
playfield is routed through this switch, which disables the 50V feed
as soon as the door is opened. That helps avoid electric shock when
working inside the machine.
The ROM software on machines from the 1990s and later also monitors
the switch. When you open the door, the software typically does three
- Displays a message to let the operator know that the high-voltage
power has been turned off
- Enables access to the game's setup menus through the operator
- Enables write access to the game's non-volatile memory, so that
settings changes made through the setup menus can be saved
Which brings us to the reason to include a coin door switch in your
virtual cab. When you're running a re-creation of a modern game,
you'll have to send the "coin door is open" signal to the VPinMAME
emulator before the software will allow access to the menus. That
might seem like a ridiculous restriction to replicate in a simulated
version, but remember, we're usually running the original ROM
software, so everything in the software works just like on the
real machines. Even odd things like this.
If you really want to avoid installing a coin door switch, there are
ways to work around the ROM warnings, such as pressing keys on the
keyboard to simulate the door switch. But why bother? Installing the
switch is pretty easy and cheap, and it makes things work exactly like
they're supposed to. I think it's easier in the long run to set it up
like the software expects.
The answer to the virtual pin cab FAQ,
"Why do I need a coin door switch?" With many games from the DMD era,
a message like this will appear on the DMD if you try to
use the operator menu buttons while the coin door is closed. This
is a safety precaution on the real machines, but it carries
over to virtual cabs because we're running the same ROM software.
Toggle mode or switch mode
The old, bad way of handling the coin door switch was as a
"toggle" button. That is, each time you opened or closed the real
coin door, you had to send a key press to Visual Pinball to toggle the
open/closed status of its simulated coin door.
Up until recently, that was VP's only way of handling the coin door
switch. This comes from VP's desktop heritage. In desktop play, you
don't have an actual coin door with a switch; you do everything with a
keyboard and mouse. So VP gave desktop users an easy way to simulate
an imaginary coin door: press a key to open the imaginary door, and
press the same key again to close it.
Needless to say, this desktop/keyboard scheme made things tricky for
cabinet builders with real coin doors. The "natural" way for a door
switch to operate is to be ON or OFF according to whether the door is
open or closed. There's no simple way for a switch to "press a key"
whenever it changes between ON and OFF, which is what the old
VP model asked it to do.
Fortunately, VP now has a option that lets cab builders wire their
coin door switches the natural way. You don't have to worry about the
old "toggle" scheme any longer. The installation and wiring
instructions below are all designed with the new and better system in
mind. You'll have to do a little setup work in VP to enable the new
"switch mode", since the old "toggle mode" is still the default, but
it's fairly easy (certainly easier than setting up the physical
switch as a toggle control), and we'll explain everything below.
If you read forum posts about the coin door switch, be warned that
you'll see a lot of material about setting up toggle-mode switches,
and it might make you worry that we're missing something important:
everyone on the forums says it's so hard! My advice is to just keep
reminding yourself that all of that is old and obsolete advice, from
back in castle times when toggle-mode was the only option and you had
to get your Internet on AOL dial-up. If you follow the instructions
below, the result will not only work, but will work more reliably than
the old toggle schemes did.
In your virtual cab, you'll wire this switch to your key encoder, just
like any other button (see Button Wiring
). This means
that you can use almost any type of switch or button. Many people
improvise with an ordinary microswitch, for example. My recommendation
is to do it the easy way and use the same parts they use in the real
- Switch: Williams part no. A-18249-1, A-18249-3; Stern 180-5136-00
- Mounting bracket: Williams 01-12676
You can search for those part numbers at any pinball or arcade supplier
to find the correct parts. You can also find equivalent switches under these
part numbers: Cherry E75-E79, Lamp PP2-1H7-2A2.
You can also use an ordinary microswitch, but I find those harder to
set up for this situation, because they have very short throws that
require pretty precise alignment. The plunger switches are much
easier to set up for this, especially if you're using the
purpose-built mounting bracket, mostly because they have nice long
throws that give you lots of leeway in aligning them.
Installing the switch
You should install your coin door before installing the switch, so
that you can use the coin door as the alignment guide. You'll
also want to remove the playfield TV or lift it up so that you
can access the inside of the coin door area from above, with the
coin door closed.
Start by installing the switch in bracket, as shown at right. The
rotation of the switch doesn't matter.
Close and lock the coin door. Position the switch so that the plunger
is pressed against the actuator plate on the coin door, and pressed
down most of the way so that the switch is in the "on" position. It
doesn't have to be pressed in 100%, but it should be pressed in most
of the way, to ensure that the actuator will reliably engage the
switch every time you close the door.
Once you have a good position mapped out, hold the plate in place
while you mark the locations of the screw holes on the front wall
of the cab.
Remove the switch assembly and drill some small pilot holes at the
screw locations you marked. (Be sure not to drill more than 1/2" deep
so that you don't drill through the front face!) I recommend using
1/2" #6 wood screws for this (and most other things that you need to
attach to the inside cabinet walls). Remove the switch from the
plate, and screw the plate securely to the wall using your pilot holes
as a guide.
The plate should now be positioned properly, so you just have to pop
the switch back in. Before you do, though, you might want to connect
the wires, since that's easier while the switch is dismounted.
Once you're ready to re-mount the switch, slip it back into the
mounting plate opening, then test that the switch clicks on and off
when you open and close the door.
Wiring the door switch
If you're using one of the big "plunger" switches recommended above,
it might look a bit confusing, since it'll have six terminals. It's
easier than it looks, though, because we only have to connect wires
to two of the terminals: the Common (COM) and the Normally Closed (NC)
for one of the two switches inside the device. For the Lamb and
Cherry switches listed above, use these two terminals:
Check the labeling on your switch to make sure it matches this
terminal layout. On the Lamb switches, they usually print the
legends COM1, NC1, NO1, COM2, NC2, NO2. Other switches might
use a notation like this:
Labeling on some switches of this type. The
numbered circles represent the switch contacts; the vertical lines
lead out to the corresponding external terminals. The diagonal line
shows the "Normally Closed" (NC) connection, that is, the terminals that
are connected when the switch is at rest, with the plunger not
depressed. The other terminal is the "Normally Open" (NO) terminal.
This type of diagram can be ambiguous because it doesn't show
clearly which terminal is the "Common" and which is the NC. In
the case of these plunger switches, the outside terminal
is typically the Common. So the correspondence with the COM/NC/NO
labeling format is 1=COM, 3=NC, 5=NO.
The terminal layout for the Cherry and Lamb switches listed above
is the same, but it's always a good idea to check the labeling to
be sure your switch matches. You can double-check with a multimeter
in continuity test mode if you're not sure how to read the labeling.
Once you've identified the COM and NC terminals to use, wire your
switch to your button encoder like this:
Why use the Normally Closed side? Don't people usually use
Normally Open when wiring a switch? Yes, that would be
more typical, but in this case VP lets you wire it either
way, and our VP setup instructions below assume you're
wiring to NC. Given that it's all the same to VP, we
suggest wiring to NC because of the effect it will have
on your regular keyboard input. Wired this way, the
key encoder input will be OFF whenever the coin door is
closed, which it probably will be most of the time. That
means the key encoder won't be sending any key presses on
behalf of the coin door as long as the door stays closed.
When you open the door, it will return the switch to its
default position, connecting the NC side of the switch
and turning the key encoder input ON. So your key encoder
will tell the PC that you're holding down the End key
whenever the coin door is open. When running VP, this
won't make any difference. But when you're not
running VP, wouldn't you rather not have the key
encoder sending the extra End key press all the time, so that
you can use the End key on the keyboard for text editing
and other functions? That's why we suggest wiring things
this way: as long as the coin door is closed, the coin door
won't cause any extra key presses to register on the PC.
How to choose which key encoder input to use
- If your key encoder has a special dedicated input for "Coin Door",
- If your key encoder has a special dedicated input for the "End" key,
- If your key encoder is programmable, use any free input. Run the
setup program for your key encoder (e.g., for Pinscape, run the
Pinscape Config Tool; for i-Pac, use the i-Pac setup program). Find
the input that you wired the switch to. Set this input to send the
keyboard End key to the PC.
- If your key encoder isn't programmable, and uses joystick buttons as
inputs, use any free input, and note the joystick button number
assigned to that input. Run Visual Pinball - don't load or run a
table; just open the blank editor. (Click Cancel if VP shows an Open
File dialog.) Select Preferences > Keyboard in VP 9 or "Keys,
Nudge, and DOF" in VP X. Find the section in the middle labeled
"PinMAME Buttons", and find the entry for "Door (END)". Underneath
that label, use the drop list to select the joystick button number
assigned to the key encoder port you selected. Note that you'll
have to repeat this process with each version of VP (9, 10, PhysMod5,
etc) that you intend to use, since they all keep their own independent
Setting up the door switch in VP
As described earlier, Visual Pinball is programmed by default for
desktop users who use the keyboard to simulate an imaginary coin door,
by pressing the End key on the keyboard to "toggle" the door's
open/closed status. That's no good for us, since we're using a
real coin door with a real position switch. Fortunately, VP can
handle this situation as well, but we have to specifically tell
it to override the defaults.
If you're already read through Pinball Software Setup
, you might
recall my advice to set up a "customization log" - a text file on
your cab's desktop where you record special changes you make to your
VP setup, so that you can repeat them the next time you update to a
new VP version. This is one of those situations! Make a note of
the changes you make here.
- Make sure no VP windows are open
- In the Windows desktop, go to your Visual Pinball installation folder
- Open the Script sub-folder
- Find the file VPMKeys.vbs. Right-click it and select Edit
from the menu. (If that doesn't work for some reason, open Notepad,
then select File > Open from the menu to open this file.)
- Find the following lines:
toggleKeyCoinDoor = True
inverseKeyCoinDoor = False
- Change those lines to:
toggleKeyCoinDoor = False
inverseKeyCoinDoor = True
- Save changes (Ctrl+S)
The next time you run VP, it will read this script when you run a
table, and the table should respect these keyboard settings for
handling the coin door switch input. Note that these scripts are
shared by all versions of VP installed in this same folder, so you
don't have to do anything extra for the different versions.
Setting toggleKeyCoinDoor = False changes from the default
"toggle mode" that desktop players use to the switch mode that
inverseKeyCoinDoor = True
tells VP you're using the "Normally
Closed" wiring recommended above in Wiring
the coin door switch
: it tells VP that the key is pressed when the door
is open. (I wish they'd chosen more intuitive variable names for
this!) If for some reason you prefer to use "Normally Open" wiring
for your switch, leave the default (False) setting in effect for this
What about Future Pinball or others? As far as I know, VP is
the only available pinball emulator that currently uses emulated ROMs,
which makes it the only one where the coin door switch is used at all.
All of this extra setup should therefore be irrelevant to other pinball
If you install coin
acceptor mechanisms in your coin chutes, you should install a
container under the chutes to capture inserted coins. You don't want
them bouncing around loose inside the cabinet where they could come
into contact with wiring or make other mischief.
The easiest solution is to use a real pinball cashbox, like the one
pictured at right. There's a standard design for these, with slots in
the lid that align with the coin chutes. See the "Cashbox" sections
in Cabinet Body
and Cabinet Hardware Installation
for more on
how to install these.
The only downside of the standard cashbox is that it's rather large:
about 10.5" wide and 11" deep. That consumes a lot of floor space at
the front of the cab that you might prefer to use for PC parts, fans,
or feedback devices.
If you want something more compact, you can improvise a smaller box
using wood, plastic, or cardboard. For my own cab, I didn't have
enough space for the regular cashbox, so I found a rectangular plastic
food container of about the right height, and used an X-acto knife to
cut slots in the lid that line up with the coin chutes. A bungee cord
hooked to a eyelets in the cab floor holds it in place. It's not an
elegant solution, but it doesn't have to look nice given that it's
hidden inside the machine.