Quoted from KozMckPinball:Seriously. A mechanical switch that the ball contacts or even an opto. Ball runs thru/by and the walkman riffs a quick song bite. Even could tap into an existing ramp switch. Random riff from any of the 10-20 songs in the movie.
OP, let me know and I can help you make these more interactive?
The ball hits a micro switch from one of the ramps (depending on where we mount it) . Add a relay board to the OP's mod to turn the motor on for a set amount of time (20 seconds or whatever time). Could even add a Sparky TV mod to the play a music video of the song/songs. 2.0 version is add another small speaker in the cabinet, hook to its own amp that would play all the songs via mp3s. (I did this when I had Goonies) However, this might overlap the existing sounds included with the game.....but worth a try.
Keep the ideas coming and we can make this a killer mod!