Okay. In troubleshooting a video issue I've been having on my candy with a PC connected, via a JPAC, I disconnected that and connected back the Tetris board that came with the cabinet. The power supply started up. What? Why? I dunno. Okay, I guess it works now.
While I was thinking about it, I disconnected the audio coupling from the 'stereo' jack and reconnected it to the 'mono'. Audio! Well, okay, now I know the audio amp works. Great. Controls work, too. Well, that's always nice.
Now's where the juju gets weird. Half-way through a game of Tetris, the graphics start to go wacky - the image turns to sort of like a half silhouette - the power supply fan runs faster, and then the graphics gets jumbled and the game resets.
question 1: does this just sound like a funky PS?
question 2: okay, the audio amp works. Apparently the JPAC doesn't make it turn on, though. How do I easily bridge that gap so's I have sound for Mame?