Clean up battery corrosion on a System 80 CPU board

Steps

• Take the CPU board out and desolder the four legs of the DataSentry battery; discard it.
• Cut off any green or gray part, keeping as much lead as possible, then heat each pad, pull the lead, add fresh solder and clear the hole with a solder sucker.
• Replace anything with discolored leads; usually Q2, Q3, Q4 and nearby resistors, chips Z2 and Z3 and crystal Y1.
• Sand all green or gray copper, including edge fingers, with 220-grit paper until bright.
• Scrub with a 50/50 white vinegar and water mix and a toothbrush to neutralize it; skipping this lets corrosion come back.
• Rinse with clean water, then twice with 99% alcohol.
• Tin any sanded fingers or traces with the iron and wipe smooth while hot.
• Refit new parts, socketing every chip, but not the old battery.
• Inspect the mating connectors and repin any corroded ones.

Battery leakage is caustic (potassium hydroxide); wear gloves and eye protection when handling a leaked battery and corroded parts.

Systems

• Gottlieb System 80
• Gottlieb System 80A
• Gottlieb System 80B

Related tips

• Clean battery corrosion before fitting new parts
• Remove the original DataSentry battery from every System 80 CPU board
• Fit a remote AA battery pack to a System 80 CPU board
• Resistor values in the CPU battery corrosion area
• Parts typically ruined by battery leakage on a System 80 CPU board
• Parts usually replaced in the CPU battery corrosion area
• Where the battery-area parts sit on the System 80 CPU board
• Using a memory back-up capacitor instead of a battery

Source: Repairing & Upgrading Gottlieb System 80 Pinballs from 1980 to 1989, Part One, Clay Harrell (pinrepair.com)