Repairing A4000 leaky NiCd damage?

[Lyndon Nerenberg]

On Jan 2, 2015, at 1:34 PM, Peter Coghlan <cctalk at beyondthepale.ie> wrote:

> In practice, I can't see how it would be possible to get the concentration of
> neutralising agent even approximately right and how it would be possible to
> cover all the contaminated areas and yet avoid getting it on non-contaminated
> areas and maybe causing new damage there.
> 
> And then there's the wondering whether the resulting wet salts will do different
> or worse damage than the original contamination before they are washed off
> and whether they might be dangerous to people?

The few times I have had to deal with this, I washed/cleaned with a relatively weak acid/base solution.  Household vinegar isn't all that acidic, and for a base I used a teaspoon of baking soda in cup of water.  After scrubbing things down with a soft brush to remove the caked on crud, the key is to rinse everything thoroughly with lots of distilled water.  A Waterpik full of distilled water is very useful to flush out residue and neutralizing solution from hard-to-reach places, and especially vias.  Afterwards, put the board under a fan to dry out.  (You don't need to hit it with a hair dryer.  A steady continuous airflow is all that's required.)

So far I have rescued two cell phones, one Pentax SLR, and an expensive Fluke DVM using this technique.

--lyndon