Capacitor plague

[Axtman]

I am currently working on a modern (probably 90's) Rivera Fifty Five Twelve amp. I first noticed the leaking capacitor pictured below. I also found a few more electrolytic caps that test bad (high ESR or no ESR). Almost all of the e-caps on the board are bad! Here is the kicker....they are Nichicon caps!



Some of the radial caps leaked onto the board. What do you guys use to clean up the oily electrolyte mess?

I sure hope that traces are not eaten away.

[Helmholtz]

I also found a few more electrolytic caps that test bad (high ESR or no ESR).

No ESR means zero ESR (= perfect).

What do you guys use to clean up the oily electrolyte mess?

Warm water on a cotton swab.

[Axtman]

Yes Hemholz you are correcct. A "perfect" capacitor would show 0 ESR. As you know every capacitor has at least some ESR. In my case two capacitors did not register at all on my ESR meter.

[Helmholtz]

In my case two capacitors did not register at all on my ESR meter.

I guess that means a very high ESR exceeding the limit of the meter (often displaying as OL = over limit).
A very high ESR is just the opposite of "no ESR".
Only an ideal cap would have no ESR.

[Axtman]

Heimholz,
Yes you are correct. I misspoke. The capacitor has very high ESR and does not register at all on my CapAnalyzer 88A meter.

[The Dude]

Flux remover or most electronic cleaners also work well for removing electrolyte from the circuit board. I have no doubt you have some bad caps by your description. That said, are you sure some of what you are seeing isn't flux or glue rather than leaking electrolyte? You'll likely be able to tell if it's electrolyte by the smell. when you heat the cap lead to remove the cap, leaking electrolyte has a very "distinct" smell.

[Helmholtz]

If you can't remove it with warm water on cotton swabs, it's most likely not electrolyte.
Remember electrolyte is an ion conductor and ions love to swim in water.

[Axtman]

I was able to clean it with a Q-Tip and a small amount of Simple Green. It is definitely electrolyte and not glue.

[Helmholtz]

So water alone did not work?

Electrolytes are good conductors. Make sure there's not enough left below components to act as a conductive path between leads.

[The Dude]

Also, I'd recommend higher temp caps for those you replace, especially for those caps right near that regulator/transistor with the heat sink. It will never cease to amaze me that designers put electrolytic caps right next to high heat sources.