Capacitor Plague

"Capacitor Plague" is the colloquial term for a vast range of electrolytic capacitor failures, most often used when several capacitors on a circuit board are bulging or have burst. The following photo shows the cooked acidic residue that sprayed out from several capacitors hiding under the mechanical part of one of my DVD players.

In my case, the residue had been cooked onto the backplane and corroded several surface mount components. This cheap DVD player is a write-off. I could probably fix it, but it would be more trouble than it's worth.

Capacitor plague is common on older motherboards and video cards, as well as in other chintzy consumer electronics. When it happens, there's usually a hiss or a pop from the device. If you catch it (and clean up the electrolyte using flux cleaner or high-grade isopropyl alcohol if any leaked) before it ruins something else, you can usually buy and solder in replacement capacitors of equal value. Remember, though, that many capacitors are polarity sensitive.

Electronics repair tips:

  • If polarity is marked on a component (by a colored band down the side of a capacitor or a band around the positive end of a diode), mark the positive terminal on the board before removing the component. I usually just put a black dot near the positive terminal on the solder side of the board using a permanent marker.
  • Avoid confusion of parts by replacing only one failed component at a time.
  • Use a grounded work mat and a wrist strap to avoid a static discharge that could damage the part you're working on.

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