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How to use MPF with WPC machines

You can use MPF to control existing Williams / Bally / Midway WPC, WPC-S, and WPC-95 pinball machines.

1. Connecting the physical hardware

You can use a FAST Pinball Retro Controller or P-ROC to interface with an existing WPC machine.

In all cases, you remove the existing MPU board from the backbox of your machine and replace it with the new controller. You then connect up all the existing cables and connectors to the new controller, so in effect the new WPC controller becomes the new MPU of your machine.

A few notes:

  • Both the P-ROC and the FAST Retro controller have USB connections on them, and the actual "code" that makes up MPF runs on a computer which remotely controls the pinball controller (and therefore the machine)
  • Switch connectors are connected directly to the P-ROC or FAST Retro controller.
  • Drivers, coils, lamps, and GI are controlled via the existing WPC power driver board (which is connected to the P-ROC or FAST Retro controller via the existing 34-pin ribbon cable).
  • The existing WPC sound board in the backbox is not used, as sounds are generated via the computer running MPF. There are articles online showing how you can modify the existing sound board to add a headphone plug you can connect into the computer running MPF, though most people end up replacing the speakers with new ones and a more powerful and better sounding amp. This means you can remove the existing sound board from the backbox.
  • The existing DMD, if you choose to use it, is unplugged from the WPC DMD driver board and instead plugged into a 14-pin header on the P-ROC or FAST WPC controller. This means you can remove the existing DMD driver board from the backbox.

For the P-ROC, connect your machine according to the P-ROC connector mappings.

FAST Pinball Retro controller instructions are available on their site.

More technical information can be found in the PinWiki Williams WPC page.

2. Configuring MPF for WPC machines

In order to use MPF in a WPC machine, you need to configure the driverboards: section of your hardware platform.

If you're using a FAST WPC controller, it will look like this:

  platform: fast
  driverboards: wpc

And if you're using a P-ROC:

  platform: p_roc
  driverboards: wpc

Note that with the P-ROC, it is very important that you specify driverboards: wpc in your config if you're using a WPC machine. The reason for this is the P-ROC can be used to control either PD-16 (the P-ROC driver boards) or WPC driver boards, but the polarity of each type is the inverse of the other.

In other words, if you put a P-ROC in a WPC machine but specify driverboards: pdb, when you run MPF, it will disable all the drivers, but since the polarity is reversed, it will actually enable every driver in your machine at once. This will (1) be very loud and cause you to jump back about 10 feet, and (2) blow all your fuses.

3. Configuring switches

When using MPF with WPC machines, you can use the switch numbers from the machine's operator's manual. The exact format depends on the type of switch:

Matrix switches

Matrix switches start with the letter S, followed by the switch number. For example:

    number: s41
    number: S45

Note that the "S" is not case-sensitive.

Switch numbers in WPC machines correspond to the column and row, so switch "11" is column 1, row 1, switch "26" is column 2, row 6, etc. This means that there are no 0s or 9s in a standard 8x8 switch matrix.

Also, some WPC-95 machines have a 9th column in the switch matrix (meaning they'll have switch numbers 91-98). In this case, just enter those switch numbers like normal, and MPF will notice that there are switch numbers in the 90s and automatically configure the controller hardware to use the 9th column.

Our experience with using MPF with many different WPC machines is that many times, the switch numbers in the operator's manual are incorrect. (We see this in many 25% of WPC machines.) Usually it's the case where two switches have been swapped, though sometimes there are unused switches that really are used and vice-versa. So if you don't get switch activities that you expect, check out neighboring switches to see if the numbers are wrong.

Direct switches

Direct switches (which are typically the coin and front door switches) are entered with the SD prefix, then the number, like this:

    number: sd1
    number: SD8

Again, case doesn't matter.

Fliptronics switches

Fliptronics switches (on machines that have them) are entered with the SF prefix.

There are 8 Fliptronics switches on machines with Fliptronics. Typically four of them are used for flipper buttons, and four are used for EOS switches. (The flipper buttons on most Fliptronics machines actually have two switches stacked together behind each flipper button. If you push the flipper button part way in, the switch connected to the lower flipper engages, and if you push the button the rest of the way in, the switch connected to the upper flipper engages. This means if you're good, it's technically possible to flip just the lower flipper without flipping the upper one (or it's possible to hold a ball on the lower flipper while flipping the upper one).

That said, some machines needed a few extra switches for other things, and if they don't have four flippers, it's possible that the extra Fliptronics switches are used for other things.

You would use Fliptronics switches in your config like this:

    number: sf1
    number: sf2
    tags: player, right_flipper
    number: sf3
    number: sf4
    tags: player, left_flipper

4. Configuring coils & drivers

The drivers section of your WPC machine's operators manual will list all the driver numbers as well as the devices they're attached to. Note that WPC machines use drivers for coils, motors, and flashers. You only enter your coils and motors in the coils: section of your config. Flashers go in the flashers: section (discussed below).

Configuring regular coils

To configure the regular coils (from the "Solenoid / Flasher" table in your machine's operator's manual, enter the letter C followed by the solenoid number, like this:

    number: c01
    default_pulse_ms: 25
    number: c02
    default_pulse_ms: 25
    number: c03
    default_pulse_ms: 25

Fliptronics coils

You'll also see a section in the solenoid table in your ooperator's manual with "Flipper Circuits", like this:


That section shows the 8 driver outputs that are connected to the Fliptronics board (if your machine has one).

For those coil numbers, you can either enter C followed by the number, or the four-letter code indicating which output the driver is connected to, like this:

  • c29 or FLRM - Lower Right Main (Power)
  • c30 or FLRH - Lower Right Hold
  • c31 or FLLM - Lower Left Main (Power)
  • c32 or FLLH - Lower Left Hold
  • c33 or FURM - Upper Right Main (Power)
  • c34 or FURH - Upper Right Hold
  • s35 or FULM - Upper Left Main (Power)
  • s36 or FULH - Upper Left Hold

Many machines do not use all eight of these, and many machines also connect Fliptronics coils up to other random things (typically magnets and diverters).

An example in your config might be:

    number: fllm
    default_pulse_ms: 30
    number: fllh
    allow_enable: true
    number: flrm
    default_pulse_ms: 30
    number: flrh
    allow_enable: true
    number: c35
    allow_enable: true
    number: c36
    allow_enable: true

5. Configuring lights (lamps)

Lights are configured with the letter L followed by the lamp number from the manual:

    number: l11
    subtype: matrix
    number: L12
    subtype: matrix
    number: L13
    subtype: matrix
    number: l14
    subtype: matrix
    number: L15
    subtype: matrix
    number: l16
    subtype: matrix

See lights: and light_player: for details on how to use them.

5. Configuring GI (general illumination)

GI strings are configured with G followed by the number, like this:

    number: g01
    subtype: gi
    number: g02
    subtype: gi
    number: g03
    subtype: gi
    number: g04
    subtype: gi
    number: g05
    subtype: gi

See lights: and light_player: for details on how to use them.

6. Configuring flashers

Since flashers in WPC machines are technically drivers (coils), they are also configured with the letter C followed by their number similar to coils.

    number: c17
    number: c21
    number: c22
    number: c23
    number: c24

See flashers: for details on how to use flashers.

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