Cleaning vintage IC "legs"

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Cleaning vintage IC "legs"

OK, I put this in the Apple-1 area because many people use vintage chips in the Apple-1 replicas and the Mostek RAM chips, among others, tend to tarnish or have corrosion.

So I have tried the TarnX solution which is an acid which is used to clean silverware. It can make the legs brittle by micro-pitting them.

I was using an art eraser but you need to put pressure on the legs, which means you need to be very very careful.

The best thing is an abrasive block that Speedy got me from Germany which destroys itself while you are using it, but doesn't require much pressure. I lost the packaging so I'm not sure of the brand.

What do you guys use? I'm actually hoping someone has found something that works as well as the block Speedy sent me but that I can buy it myself in the states or on Amazon.

Thanks,
Cheers,
Corey

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For me, a big white art

For me, a big white art eraser. (as you have stated earlier)
I put the chip into a loose (unmounted) socket to protect the legs and "erase" the tarnish from the outside exposed legs, then put the chip legs up against a metal flat and carefully "erase" the tarnish from the lower part of the legs. Tedious, yes. Safe, well, not the safest but being careful helps a lot. It's a P.I.T.A. "manual operation" any way you look at it. The under-side of the legs is usually the hardest to clean. But overall, I think the eraser is most effective. Shaving the eraser end to an angled edge makes it easier and more gentle to the pins.

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That claening material is

That claening material is from Seno and its called "Polibloc":
https://www.conrad.at/de/polibloc-seno-2003-inhalt-1-st-529419.html
unfortunatly its not shipped to USA. But probably somebody may organize
a collective purchase and shipment.

The problem with "chemical cleaning" is that it changes atributes of surface and tarnisch
turns very fast back and in general even worse.

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A basic pink eraser is really

A basic pink eraser is really effective. You can one-up your game and use a more aggressive and abrasive white ink eraser if absolutely needed. When done, clean remaining debris with a damp cloth or alcohol and brush on a surface protectant. This is really the best choice for over 99% of the chips you will see in day-to-day restorations.

I had made myself a block/rod that I put the chip on. This way I can use as much pressure as I want without bending the pins.

For the kinds of chips you might find in a unit that was sitting in a barn, is full of rust and other forms or corrosion, there are other solutions like chemical acids, scraping, or grinding with a Dremel. And then you'll be replating those pins too. Perhaps replacing individual pins, among yet more advanced repair techniques. As a last resort a rare irreplaceable chip can be re-encapsulated.

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I used a bit of fine sand

I used a bit of fine sand paper and an eraser to clean the legs of the Mostek memory ICs on my A1. We considered chemical abrasives but decided to try this approach first as the corrosion wasn’t widespread.

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speedyG wrote:That claening

speedyG wrote:
That claening material is from Seno and its called "Polibloc":
https://www.conrad.at/de/polibloc-seno-2003-inhalt-1-st-529419.html
unfortunatly its not shipped to USA. But probably somebody may organize
a collective purchase and shipment.

The problem with "chemical cleaning" is that it changes atributes of surface and tarnisch
turns very fast back and in general even worse.

I may have found a place in Germany that ships to the US, but I guess I'd need to buy a quantity of the blocks. There was a place in the UK that seems to have carried it and would have shipped, but they say out of stock and discontinued.

Thanks again for the info,
Cheers,
Corey

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PCB Cleaning Scrub Block

Corey,

Perhaps this is it? Allied indicates that they have 7 in stock.

PCB Cleaning Scrub Block (40x30x19mm)

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Still in stock - and they

Still in stock - and they deliver also to USA - payment by paypal is offered:
https://www.buerklin.com/de/reinigungsschwamm/p/13l2950
but pay attention: additional 19% tax and shippping cost.

shipment is max. 3,0 kg so optimum would be order of 30 blocs.
Due to fact that this seems to become discontinued this is
probably "last chance to order" and organize collectionlist.

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Well looks like I may have

Well looks like I may have some options to order.

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I ordered three from Allied,

I ordered three from Allied, I guess we will know if this is the same thing in a few days...

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Well they arrived. It's the

Well they arrived. It's the same thing that I got from speedyG only the ones that arrived are larger blocks which is good, I won't use it up so fast.

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