# Old IBM mainframe cards



## resabed01 (Jan 15, 2013)

Has anybody run this type of scrap? My question is specific to the contact tips. I understand they are a karat alloy. Does anybody know the percentage of gold in the alloy? What are the other metals? 

I've cut some tips off and they are barely magnetic so I'm assuming there is some nickel or iron in there.

Thanks!


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## resabed01 (Jan 24, 2013)

Nobody's recovered gold from these before? I'm trying to get an idea on the yield for this so I'll make more informed choices when buying.
If I had nitric here I could run a test batch but that can't happen anytime soon.

Also, the PCB itself, does it have any PM value outside of the IBM aluminum capped IC chips?


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## Geo (Jan 24, 2013)

im sorry. i have processed them many times, but it was before i started keeping yield data. the pads are very thick compared to plated pins with several times the gold content by weight. the gold contacts are actual pads.i used AP and the pads are heavy and will not float.they weigh much more than gold foils from the same size pin. i loved processing the boards i had.


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## resabed01 (Jan 26, 2013)

Thanks Geo, I have the math down for how much each pad weighs but I'm unsure of the gold content. Assuming the alloy is 50% gold I'll still come out ahead.

I'll need nitric to refine these regardless.... better start looking for some.


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## eastky (Nov 30, 2013)

I happen to come a cross an old IBM board with the same clips as your board. It was in a flooded basement covered with mud and water. The business had moved out 10 or 12 years ago. So the board had been covered in mud and water for that long. 

I took it home and washed it off and the copper clips had corroded and I was able to pull the gold pad off the clip without and copper staying attached. I weighed 72 pads that would be 3 clips worth. Pulling off one plastic clip and removing the pads from them you would get 24 gold pads per clip.

I just recently bought a gold test kit and a scale. I paid $50.00 for a puriTest kit. The scale probably not the greatest.

72 of the gold pads weighed 0.3dwt = 0.4665 grams divided by 3 = 0.1555 grams per clip 24 pads. 0.1555 divided by 2 = 0.07775 grams of gold per clip. I have seen that the gold is said to be anywhere from 10 to 16 karat here on the forum. I tested it with 10 karat acid no action then I used 14 and the streak started to dissolve but not completely.

From my calculations there is $1.00 to $1.30 of gold per clip.


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## resabed01 (Nov 30, 2013)

I ran a batch of pads taken from about 1100 finger contacts this summer and the results were disappointing. I thought they were a alloy of about 8 karat gold/silver, maybe less. I know nitric acid would do a good job of removing the base metals but wouldn't touch the gold contact. I inquarted the insolubles with silver in an attempt to break the karat alloy. Where I was expecting about 9 or 10 grams of gold I only found about 1.5. After the nitric treatment the pads were quite thin.

My focus is now onto the rest of the boards. They look promising with the resistor networks and custom IBM aluminum topped chips, some have gold pins and traces..... also, lots and lots of Tan caps. I'm hoping I find plenty of Pd.


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## eastky (Nov 30, 2013)

Well if you did 1100 and got 1.5 grams that's not good. I have 6000 and was hoping for about 18 grams. That number I came up with in the other post was figuring about a 10 karat as the whole pad. I was thinking that the whole pad was 10 karat.
I guess its was just an overlay.

I will have a little over a pound of the aluminum cap chips when I get all my boards broke down. Just at a pound on the resistor networks. I have blue black and a light green color network chips. They have a ceramic interior and it looks like the traces are silk screened on to the ceramic. I took a piece of sand paper and lightly sanded the coating off to see the traces.

The small black and yellow ones are tantalum capacitors and monolithic through hole capacitors. If you haven't cracked any open yet you should. On the boards I have it seems those are about 50 percent tantalum and 50 percent monolithic caps.

I have about 4 ounces of the monolithic caps so for that I have broke open. Hoping for some palladium out of those.

I'm just collecting and reading right now not in a big hurry to get to it yet.


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## Cryptostack88 (Nov 9, 2022)

I have several of these boards. I'm new at all this and I'm not sure what resistors/capacitors contain PM. I also seen on the boards there is thin gold plated probably connectors some covered with plastic some with not covering. here are a few pictures.


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## orvi (Nov 9, 2022)

Little glass tubes with gold legs are germanium diodes. Some are very good with yields per weight, but they are very light by piece  leading wire to the germanium wafer is many times pure gold. Plated legs are just added bonus


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