I've seen the big 2 page Viperrwk thread re: Gottlieb Sys 3 sound and read it.. two or three times now but I'm still at a loss so maybe someone out there can lend a hand.

http://pinside.com/pinball/forum/topic/gottlieb-system-3-sound-boards-troubleshoot

Gottlieb Sys3 Super Mario bros. No LEDs light up on the main sound board or the aux sound board, totally dead on both. SOMETIMES the aux sound board LED will go solid at boot up.. rarely. All voltages going into both boards are correct (5v, +12v, -12v). Getting no sound at all, no screech at startup, nothing. When you crank up the volume you can hear the hum of the speakers though. Replaced ribbon cable between the boards (because one of the pins was busted off), reseated all connectors and socketed chips.

Game works 100% other than the sound issue and a small opto issue I have to work out still. (probably just a reflow)

Thanks guys.

Viper to the rescue!

Don't have ram just lying around though.. more to order.