Here is a prototype concept to replace the sound board ( and aux board) of a system 3 pinball and play alternative audio file.
The sound board is pilot by 8 pin. ( 10 pin molex cable : 8 pin for audio number, 1 pin to reset/start the sound board and a pin not connected )
Sound file are code from 0 to 255 in hex
If pin are read in the good sequence , the sound number is the same one than the one you can extract from pinmame. - ( 22 music file & 110 total wav file for stargate ) So its realy easy to got the "original sound pack "with the good wav number...
I also found 2 commands : 0 for stoping all music and 190 for progressive stop.
Music are loop by default.
here is a video with original audio file extracted from pinmame :
here is a second video i did with some alternative audio file from the movie :
( I still do not spend lot of time to change wav file.
It s only a prof of concept from now )
i did some tweak since in the code and now it s near perfect i still have to insert some random option with wav file.
So the game is fully playable like with orignal audio board.
In the video you saw , i got problem with the ground and speaker. so the speaker sound wasn't nice.
I i use earphone the sound is like cd quality.
i am looking to add an amplifier so we could remove the original one of the pinball and get stereo sound.
The raspberry you see in video is used only for remote access ( wifi ) and usefull for change volume and record wav number ( and for testing )
the cost is minimal.
at least you need an arduino nano 20 $ and a wav trigger 50$.
it should work with any system 3 pinball.
I will post schematic and code if some are interested in a few days.