reagent for detecting capacitor leaks?

[coppercone2]

Is there a indicator that you can use to detect small amounts of capacitor leakage? Perhaps old and evaporated or whatever it does.

Sometimes its not obvious if its external, flux or capacitor juice.

Something very sensitive to pH maybe? The idea would be to drip it on the board and look for a reaction, or brush it on.

Boards with conformal coating, glue residue and environmental contaminants are confusing.



Maybe there is some chemical that can make a UV signature if it reacts with capacitor residue? Or a smell?


I just pulled off some old conformal coating that was under some capacitors, some of it from under one capacitor was stained brown. I don't know if its flux they failed to clean, or capacitor juice, or even rust that came off a rusty component (I got rusty stuff brand new from DK before). It might help me understand whats going on this PCB, even though I am going to replace the capacitor, I want to know what has gone on.

[jpanhalt]

It would depend on the electrolyte.   Which one are you concerned about?  If it is the complex of ethylene glycol and borax (https://en.wikipedia.org/wiki/Electrolytic_capacitor ), a water rinse that will be alkaline, i.e., turn litmus blue.  Do not make the mistake of using litmus without water present.