US Championship V'ball

[celerystalker]

Bought a US Championship V'ball pcb (arcade Super Spike V'ball), and it's definitely having sound issues. It's a JAMMA standard pcb, but I only get static for sound, even after adjusting the amp pot. Any ideas?

[celerystalker]

So, I ran this in yet another setup with the -5v connected, and no sound. There is a buzz when the volume is on, but no music or effects. When I press on 2 of the capacitors around the amp, the buzz volume increases, but no hint of game sounds. When I run my finger along the amp pins, the buzz increases as well, but only on half of it, and there is no reaction on the other end. Any thoughts?

To clarify, I ran 3 other boards in this same setup: WWF Wrestlefest, Ninja Baseball Bat Man, and Devastators, and they all ran perfectly with sound.

[celerystalker]

I ordered another PCB for this game, and it arrived today. I was able to compare both side by side. All components are present for the sound, but the player 3 and 4 controller connectors are missing on the first one, as well as some of the related TTL chips. I'm getting the picture that this board was cannibalized for parts, and was likely damaged in the process and left as a 2 player.

The new board works great, and I can now confirm that this game does require the -5v for sound. Since all components are there on the other one for sound, I'm gonna start at the -5v pin on the board and start tracing back with my volt meter. Maybe I can find a little something. Interestingly, when I put the working board in a cabinet with no -5v, it acted like the old one even with -5v, which is what has me suspecting the -5v line on the board.