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Modifying a WPC-95 board for Audio Input

The P-ROC board does not handle audio in any way. If you'd like to use the built in WPC-95 hardware to playback the sound, you'll have to do some small modifications to the sound board, and connect it to to the output of the computer that is running the code.

Warning - Pinballcontrollers.com is not responsible for any damage that occurs as a result of this or any hardware modification you make.

Note: This modification was updated to this version on August 10, 2013. The previous description was a little more complicated and can be found here: Old mod description

Convert the stereo output from your computer to mono. Example:

  • Step 1 - Add a stereo connector to the WPC-95 A/V board.

I used a female 1/8" inline phone jack from Radio Shack (part#274-0274), soldered a 1k resistor to each lug, connected the other ends of the resistors together, and soldered the "signal" red wire to them. The "ground", purple wire, was soldered to the ground lug on the jack. See pics. Finally, A mini-alligator clip was soldered to each wire. The red/signal wire/alligator clip clips to the top of C9, and the purple/ground wire/alligator clip clips to the bottom of C35. See pic. If you accidentally reverse the connections or touch the top of R14 you won't damage anything. The mini-alligator clips seem to hold fine.

Stereo to Mono 1.jpg Stereo to Mono 2.jpg

  • Step 2 - Connect a stereo cable between your computer and the connector from step 1.

I used the following 10ft double shielded VGA cable with built in 3.5mm stereo cable from amazon (it has an extra long 3.5mm wire to attach to a laptop): [1]. I used this because I am also using an LCD in my backbox instead of a DMD. Any 3.5mm male/male stereo cable should work (recommend shielded). One end of this cable plugs into the computer. The other end plugs into:

Audio Board Connection.jpg

Sound is good without much hum. There seems to be plenty of adjustment range using the computer to set an initial volume and the coin door buttons to adjust around this level.