[time-nuts] Completely OT: Removing electrolytics of leakingcapacitors from a pcb

Alan Melia alan.melia at btinternet.com
Wed Jan 19 14:36:20 UTC 2011

Hi Ulrich, yes its nasty. As far as I am aware the "liquid" electrolyte is
an alakali, sodium or potasium hydroxide. This retains the insulator
(aluminium oxide) on the plates by electrolytic action. When spewed on to
the PCB it is conducting and starts and electrolytic reaction that will eat
away the tracks. This will happen faster with power applied but will occur
if the circuit is unpowered. I have removed some of this, and the efflent
from leaky NiCd bats (Potassium hydroxide) with a swab soaked in vinager,
and then flushed the area clean and dried it in alcohol. It may depend on
how old and caked the deposit is but the sodium acetate (??) should be
soluble in water, where hydroxides and carbonates are not. The danger is
getting liquid trapped under components, alcohol is not too much of a
problem but vinegar left could be as corrorosive eventually as the
electrolyte guge if not fully removed.
I have never needed to try this on a tracked PCB but I dont see why it
shouldn't do the job. Others will not doubt comment :-))

Alan G3NYK

----- Original Message ----- 
From: "Ulrich Bangert" <df6jb at ulrich-bangert.de>
To: "Time nuts" <time-nuts at febo.com>
Sent: Wednesday, January 19, 2011 2:02 PM
Subject: [time-nuts] Completely OT: Removing electrolytics of
leakingcapacitors from a pcb

> Gentlemen,
> I know this is completely out of topic but I know there are some dedicated
> material experts among you. So please allow me to put the following
> forward:
> Is there any good suggestion available on how to remove electrolytic
> resulting from leaking electrolytic capacitors from a pcb? It is not a
> question of good looking, the coating seems to have a real "electrical
> conducting" property which is absolutely bad on higher-impedance circuitry
> as to be found on a Tektronix TDS45A scope mainboard, where the problem is
> encountered. The findings so far are that the classical method with
> isopropanol and a brush won't work. And the internet won't give precise
> answers for that problem.
> Any suggestion is highly appreciated!
> Best regards
> Ulrich Bangert
> www.ulrich-bangert.de
> Ortholzer Weg 1
> 27243 Gross Ippener
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