Cleaning Contacts on old ISA Card

OK,

One of my Soundblaster 2 cards (8-Bit ISA) has contacts that are really oxidized or have some corrosion on them...

What is safest way to clean it all off and keep the card hopefully useful?

Also, while on the topic, what is the best way to try and clean up and corrosion on IC Chips (only small amounts)..

Even if it doesnt work, I wanna give it a shot as I have other SB 2's so losing it wont kill me...

Thanks!

It depends largely on how gentle you want to be. I'd rank things from most- to least-gentle:

1. Use De-ox-it or another aerosol contact cleaner. You could also use a soft cotton rag and a mild solvent such as isopropanol.
2. Use an art gum eraser (no abrasives)
3. Use a red (not white!) pencil eraser (white erasers, in my experience, tend to be more abrasive)

Remember that there is a plating of only a few microns of gold on gold edge connectors. It's quite easy to remove a lot of it simply by rubbing too much with an abrasive substance.

IC chips, pretty much the same thing, if you're working with gold-plated leadframes. If they're just tinned, or tin-plated, I'd just use a hot soldering iron and some rosin-core solder and just lay on a bit more. It will strengthen the leads and you won't run the risk of bending them.

I use soft pencil erasers, works fine.

A third vote for the eraser method.

The eraser didnt get the stuff at the top of the contacts off...its still a greenish color on some of them (not all)

Here is the photo (you can see the green oxidation or corrosion at the top...the gold contacts are there underneath..

http://i1197.photobucket.com/albums/aa437/Smack2k/photo-1.jpg

Can I use isopropyl alcohol or vinegar and Q-Tip for that last part?

As for the IC's, will give it a shot

I know a couple traces on the PCB may need cleaned and/or retinned, but I can do that as well...all part of trying to get this fixed just to see if I can..

Here is the result from the Gold Contacts...



How does it look? Do I need to clean further or does that look like it will work?

I still have the IC's to clean / traces to fix and let it dry out before I can test...but wanted opinions....

That's quite sufficient.

Consider that a such a contact is perfectly suitable for conducting currents of a couple of amperes. Then consider that most signals on the bus are in the low-milliampere range. PCB edge connections, when used with a quality socket are supposed to be more or less self-cleaning, due to the wiping action of the contacts (which nobody ever seems to wonder about cleaning).

In other words, don't obsess about it too much.

Do the board traces look OK there? I know the protective cover came off a little, but the copper looks good, so thinking its good...

MY IC's cleaned up nice too.

Thanks for the help..

Since this appears to be a 2-sided board, you can easily check the continuity of traces with an ohmmeter. But I've seen much, much worse.

OK, one more question...

How do I go about removing surface rust (or at least lessening it) from the Metal part of the slot cover on the card as well? I have it removed from teh card...

I guess I could find another, but curious about ways to clean this one up...

If you have an Auto Zone or O'Reilly's near you, look for a product called "Never Dull", which I believe is now marketed by Eagle 1. It comes in a can and consists of impregnated cotton. Rip out a small wad and go over your rusty parts. Works great - motorcycles, trucks, cars, whatever.

Don't use Nevr-Dull on a PCB! It's basically Stoddard solvent, a mild abrasive and a wax absorbed into shredded cotton rag. You don't want wax on your PCBs.

If it's bare metal on a case part, I'll use something like tripoli on a buffing wheel. Or you can try 0000 steel wool. Since you'll be removing the galvanizing in most cases, degrease (acetone works fine) and coat with an aerosol urethane clear varnish.

Chuck(G) said:

Don't use Nevr-Dull on a PCB! It's basically Stoddard solvent, a mild abrasive and a wax absorbed into shredded cotton rag. You don't want wax on your PCBs.

If it's bare metal on a case part, I'll use something like tripoli on a buffing wheel. Or you can try 0000 steel wool. Since you'll be removing the galvanizing in most cases, degrease (acetone works fine) and coat with an aerosol urethane clear varnish.

Click to expand...

Who said anything about using ever Never Dull on a PCB? We're talking rusty metal here. Don't put ideas in his head.

When I read this, I got worried:

How do I go about removing surface rust (or at least lessening it) from the Metal part of the slot cover on the card as well? I have it removed from teh card...

I guess I could find another, but curious about ways to clean this one up...

Click to expand...

Call me alarmist... As in "boy, that chlorine bleach worked wonders on my toilet bowl. I wonder if it'll work on teeth?".

Funny thing you mentioned tooth paste. I've used it the clean of mild surface rust and a few traces/contacts. It's less abrasive than Solvo Autosol. No need to bother going down to the auto accessory store either.

Ha...no, just the metal part of the card, the metal attachment part only!, I'd never do that to the PCB!

Smack2k said:

OK, one more question...

How do I go about removing surface rust (or at least lessening it) from the Metal part of the slot cover on the card as well? I have it removed from teh card...

I guess I could find another, but curious about ways to clean this one up...

Click to expand...

I highly recommend "Evapo-Rust". The stuff is just plain awesome. You can get it online or at Autozone. I have used it on hundreds of car parts. You just pour some in a container and completely submerge the rusted part. Let it set for a few hours to overnight, if the rust is really bad. Then rinse it off with water and dry it immediately and the part will be completely rust-free.

Evapo Rust won't harm plastic or rubber but you definitely wouldn't want to throw the whole card in there...just the bracket. It also won't damage paint as long as you don't leave the part in too long.

I use two methods for everything like this, though one of them is a little controversial.

First method, take a piece of rubber and gently rub away the dirt then get some paper, newspaper is good but printing paper will get it done - I also recently found that the card which Rizla boxes are made from is good - and rub that along the contacts. Rubbing card or paper on contacts is also a good idea if you make something from stripboard as it seems to make the copper cleaner and eases soldering.

Second method, brasso, gently applied to the contacts and left to sit until it turns white - DO NOT rub the contacts with the wadding! - just brush the solution onto the contacts. Problem with brasso is it tends to hang around, lighter fluid or alcohol will see to that (Swan's N²0-based one works best), dampen a tissue with it and rub the brasso away, you can then use the card method to remove anything that is left over.

Furthermore, brasso seems to work very well on heatsinks, even with a brand new copper heatsink (was a water block actually) I was able to lower temperatures by 3-7°C by polishing the surface or the heatsink and chip - you do apply force this time, leaving it to sit a while and then removing the leftovers with petrol. It seems to be good at removing some glues and most thermal compounds too.

Brasso also works with rust, but WD-40 gets it out of the way better, you can then clean that away, give brasso a go (because it removes the WD-40) and then clean that away as mentioned above.

Of course, if you're going to use brasso / alcohol / petrol you need a well ventilated area, many a time I've come away with my head spinning. Another thing to note is that it might react with the glue and thermal compounds (usually any left-over paste turns black) and I can't guarantee the safety of the fumes that may come from it...

Also keep in mind that this is coming from the man that attempted to use electrolysis to remove glue from a heatsink and almost passed out from the resulting gases... I did end up with a smooth, clean surface however.

Cool...now if you would have a little rust around the joystick / midi connector input (which is attached to the card), can you use that evapo-rust and paint it on only that part?

Or would the Never Dull be better for that part?

Here is a photo:

http://i1197.photobucket.com/albums/aa437/Smack2k/photo-3.jpg

Its just the metal surrounding the input, everything is fine.