Solution to remove leaked electrolyte from board?

[mysterfxit]

The two big caps on this subwoofer plate amplifier leaked. I'm going to replace them, but I was advised to clean the electrolyte off first.

Some of it's kind of flakey, but most of it is baked on. Rubbing alcohol seemed to have no effect on it. Is there any solution that can help remove it?

Thanks.

[Toasty]

Re: Solution to remove leaked electrolyte from board?

That could be some lacquer from the board that is burnt also.
A stiff toothbrush and elbow grease along with 91% isopropyl alcohol.
Any stronger solvent and you risk removing the lettering from the board and damaging the other caps bungs. There are some flux removers out there that would work that have a tetrachloroethylene isopropyl alcohol. (Puretronics brand)

Also, make a baking soda and water paste and scrub with the brush to deactivate the green corrosion around those component legs. Then flush it all with alcohol and allow to dry or use a hair dryer to speed the drying.

[mysterfxit]

Re: Solution to remove leaked electrolyte from board?

Awesome! Thanks!

[Toasty]

Re: Solution to remove leaked electrolyte from board?

I'd recap the whole bloody thing too.

Looks like a linear supply with that big transformer, so caps don't -have to be- low ESR. But it wouldn't hurt either...

[kaboom]

Re: Solution to remove leaked electrolyte from board?

This.

Although the 91% isoprop alchohol should do ok. I'll use the CRC when the electrolyte dries and leaves 'crystals.'

-Paul

[Evil Lurker]

Re: Solution to remove leaked electrolyte from board?

Scrubbing Bubbles shower cleaner. Uses quaternary ammonium compound. Takes ionic compounds right off since the active ingredient acts as a phase transfer catalyst. Its very mild pH wise and rinses clean with no residue. I've used it on everything from PSU's to motherboards with great results, strips off all organic matter, even cig smoke residue like its nothing.

[PCBONEZ]

Re: Solution to remove leaked electrolyte from board?

Scrubbing Bubbles shower cleaner. Uses quaternary ammonium compound. Takes ionic compounds right off since the active ingredient acts as a phase transfer catalyst. Its very mild pH wise and rinses clean with no residue. I've used it on everything from PSU's to motherboards with great results, strips off all organic matter, even cig smoke residue like its nothing.

That's a new one on me.
Have to try it sometime.
.

[delaware74b]

Re: Solution to remove leaked electrolyte from board?

I use CRC green-can brake cleaner to clean boards. Dries very fast, flammable (Acetone, Toluene, Methanol). Removes flux like crazy, I use it to deflux every board. Just be careful around plastics - will melt or deform plastic. I usually spray some on a cotton swab and clean the board with the swab.
I used it to clean some roof-top HVAC controller boards after they got wet (from a snow storm) and fried the voltage regulator sections.

[Toasty]

Re: Solution to remove leaked electrolyte from board?

>>I use CRC green-can brake cleaner to clean boards. Dries very fast, flammable (Acetone, Toluene, Methanol).<<

That will eat capacitor bungs like crazy too.

[Evil Lurker]

Re: Solution to remove leaked electrolyte from board?

How well does PERC (tetrachloroethylene - found in chlorinated brake cleaner) do on removing flux residue?

I think it would be safe for the backside of boards for defluxing, but like toasty said you don't want to ever spray it on the topside of a board.

Just for craps and giggles I have found kapton tape to be insanely resistant to solvents.. I havent tried a ketone such as 'tone or MEK but methylene chloride won't even touch it... and that is the active solvent in paint remover. Hell I even tried refluxing some transformers in boiling xylene hoping to get them to fall apart without success.

[PCBONEZ]

Re: Solution to remove leaked electrolyte from board?

>>I use CRC green-can brake cleaner to clean boards. Dries very fast, flammable (Acetone, Toluene, Methanol).<<

That will eat capacitor bungs like crazy too.

Agree.

In the nav/nuc field we occasionally used Trichlorotrifluoroethane [as called for by equipment specs] but that shit is a controlled substance now due to being an ozone gas that takes 90 years to break down.
.

[Toasty]

Re: Solution to remove leaked electrolyte from board?

That's the old "Freon" isn't it?

I still have 2 cans of FD Zero Residue cleaner from Tech-Spray from 25 years ago with that. Mil Spec, NSN, NASA, Bell Lab, USDA. lol

[PCBONEZ]

Re: Solution to remove leaked electrolyte from board?

It's 'a' Freon. There are ~lots~ of Freons.
'The' Freon you are thinking of was probably R-12 which is dichlorodifluoromethane.
Trichlorotrifluoroethane is called CFC-113.

[PCBONEZ]

Re: Solution to remove leaked electrolyte from board?

We used to use various freons to flush hydrocarbons from high pressure oxygen systems because at very high pressures even a -tiny- bit of hydrocarbon 'flying' through the pipe and striking the side in a bend of elbow can act as a catalyst to cause the SS piping to start burning inside the system. [Yes, SS will burn in 3000 PSI Oxygen.] This stuff is not like welding equipment where it's only high pressure in the tank. The WHOLE system is at 3000 PSI. If you wanna nasty fire to deal with try putting out burning SS with 3000 PSI of pure oxygen on it. Certifying those systems were properly cleaned was one of my jobs. My trainer was -literally- the one that 'wrote the book'. He wrote 'the' Standard which is used Internationally for 'O2 Clean'.

During my tenure they converted to something called NOC which is used instead of freon except in certain situations.
NOC is ~way~ nastier the Freon to handle. Makes hydrocarbons go poof. If a drop touched you, well, you are made of hydrocarbons. But it doesn't hurt metal.
.