The game never boots and the GI flashes about once a second. Voltages are good and the driver board stays in reset.

Stuck in reset with GI flashing: address line eaten by old battery corrosion

Cause: The A0 address trace from the CPU to the RAM, running under the RAM socket, had been eaten away by corrosion from a battery leak years earlier.

Checks

• Check continuity on every trace between the CPU and the ROM and RAM chips, including under sockets.
• Look for green or grey corrosion near the old battery position.

Fix

• Neutralise the corrosion, clean the area, repair the broken trace and fit new sockets.

Systems

• Sega/Stern Whitestar

Games

• South Park

Source: Pinball Repair help group!! (Facebook group)