White Water — Sound Board Tantalum Capacitor Failure

The Machine

This Williams White Water (1993) came in with an audio problem, volume that would vary on its own and sound garbled or distorted. Usually after the game had been on for a few minutes, the volume would drop off to nearly nothing and turn distorted along with it.

Diagnosis

Before checking the board, the speakers and speaker wiring were tested and ruled out as the cause. With those confirmed good, the sound board itself came out for a closer look. One tantalum capacitor on the board had visibly broken open, and another had caught fire and failed outright, likely intermittently shorting the amplifier audio feed and causing the distortion.

This is becoming a very common failure on these WPC sound boards. The damage looks alarming when you first see a burned capacitor on the board, or see it catch fire when you power the game on after sitting for a long time, but it’s usually a straightforward and cheap fix once you know what you’re looking at.

Repair

Rather than just swapping the visibly failed parts, all of the tantalum capacitors in the power supply and amplifier sections of the board were replaced. Tantalum caps in this section tend to fail often, so replacing only the dead ones just means pulling the board again in the near future when the next one lets go.

Result

With the tantalum capacitors replaced, the sound board operates great, no fading or distortion after extended run time. If you own a WPC-89 pre-DCS game and start noticing audio issues, odds are high that one of more tantalums have failed on the board. It’s becoming an increasingly common failure on these boards as they age, especially if the game was off for a long period of time.

Note: A charred or split tantalum capacitor looks worse than it usually is. In most cases this is a simple capacitor swap, not a sign of deeper board damage. Don’t ignore it, since a failed tantalum can short and take out other components on the board if left in place for a long period of time.