I picked up a Space Station yesterday with some seriously possessed sound issues....When you start a game it starts to play the regular main theme for about 2 seconds, and then shifts to the multiball music for the entire time. Many sound effects are incorrect and overlap sometimes causing weird digital crap and distortion....however all the voices are there and are correct. At the end of the game it plays what should be the "normal" main theme as the end of game music and then has a bunch of garbled digital crap when it fades out and ends for about 5 seconds.....THEN (this is the REALLY weird crap) when in attract mode, after the attract sound is played the main theme will start playing super faintly (gotta put your ear on the speaker to hear it) non stop until a game is started. PLUS...when you go into sound test mode (during all and any tests, even switch test and display test) the "normal" main theme plays constantly...BUT....when you go to sound test and go to "main theme" it plays the multi ball theme again, just like when in game play.
The MPU has some very light acid damage on the two PIA chips below the holder and to the area to the right of those chips...I "neutralized" it for now and cleaned it up...i'll verify continuity tonite. That will all get replaced in time, parts are on order. I reseated all the sound chips, and threw on a new ribbon cable i had on hand. Other then the super light acid damage, all the boards match are super clean and hack free.
The game plays perfectly fine too. And the displays all read correctly.
Any thoughts/suggestions? I know system 11 really well...I've just never run into this specific issue, and i'm trying not to instantly assume it's the PIAs on the MPU....should I?