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Alkaline Battery Damage
A very common issue with many electronic arcade games is damage to the circuit board and components due to battery leakage. People tend to use the term 'Acid Damage' when in reality it is 'Alkaline' which is a corrosive, caustic base much like lye. The actual chemical compound that leaks out is Potassium Hydroxide and they off-gas hydrogen
Why are the Batteries needed? The batteries are typically used to allow saving of Settings, High Scores, RTC (Real-Time Clock) etc. The memory used is what is referred to as 'Volatile'; this means when power is removed, the information is lost. Some systems use a large electrolytic capacitor to store some energy so the battery can be replaced without losing data
- As an alkaline battery ages, it will self-discharge and eventually leak. This leaking can be the result of two factors
- Hydrogen gas is generated as the cell discharges and pressure builds. When the pressure is high enough, the seals will leak and cause a rupture.
- As Hydrogen is lighter than air, it will rise and can cause corrosion to devices above the battery
- The steel outer canister can corrode and rust away allowing the electrolyte (Potassium Hydroxide) to leak.
- Once the Potassium Hydroxide comes in contact with air, it absorbs carbon dioxide and forms Potassium Carbonate. This is a crystalline structure that will grow and spread out across the PCB over time.
- Dealing with Damage
- Remove the Alkaline Batteries! (Don't ever put Alkaline back in)
- Neutralize the board and components by using a mild acid (50/50 Distilled Water/White Vinegar)
- Scrub carefully with the solution and toothbrush to remove crystals and loose material
- Rinse in water (ideally distilled or RO (Reverse Osmosis))
- Air dry - a day or two
- Air Dry with fan
- Bake in oven @ 170ºF with door cracked for ~1hr.
- Non-Volatile Random Access Memory - Does not require external power to retain data
- Either in the same package (AA's), or Coin Cell (CR2032).
- Offboard Battery Holder
- Can still use Alkaline, but mount off board and extend wiring