Leaking capacitors — how electrolyte quietly eats a cluster board

Many clusters of this era used small surface-mount aluminium electrolytic capacitors. With age and heat their seals fail, and the electrolyte seeps onto the board. It's conductive and corrosive.

What it does

• Creates leakage paths between traces — erratic needles and random warning lights.
• Corrodes copper under the solder mask, sometimes eating traces completely.
• Attacks vias, breaking connections between board layers.

The tell-tale signs

A fishy smell, a sticky or shiny residue around capacitor bases, green or dark discolouration on copper, or capacitors sitting slightly tilted on a crusty base.

Proper repair

Replacing capacitors isn't enough. The residue must be removed and neutralised, damaged traces and vias rebuilt, and the board cleaned before new low-ESR, temperature-rated capacitors go in. Skipping the clean-up means the corrosion keeps going.