# CPU's



## stihl88

Hi, i have the opportunity of picking up approx 100 of these processors for approximately $250
As you can see they are approx 1.5" x 1.5" and have gold top and bottom and looks like gold solder also.

That's about all i know of these processors so i'm just wondering if anyone has come across these before and what the expected yield per chip might be?

If no known data on these processors is known then could one take the gamble and expect approx 150mg-200mg of Au per chip?
Even at 100mg per chip that would be ok for me as a learning curve of processing them at least.

Thanks guys


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## stihl88

Well i did end up buying these CPU's, theres a gold brazing around the edge of the lid and inside also.

The bottom lid is magnetic and plated but the other Top lid which is also plated is some sort of weird metal ive not seen before.
It's quite heavy, is non magnetic and doesn't really respond at all to strong Nitric??? Not sure what this is.
When i use light sandpaper it buffs up to almost Mirror finish but most strangely it kind of cracks almost
how slate rock breaks when broken. I put it on my Multimeter and it is conductive also.

I would like to know what this foreign metal is before i start processing these CPU's

All help from the Pros appreciated.

Regards
Stihl88


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## Anonymous

Most of that stuff sells for about $100 a pound on ebay,so a little over $300 for just under 4 pounds isn't too bad of a deal.


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## glorycloud

how many chips are there? Are they new?

Duh - (100). 8)


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## Anonymous

I saw the auction and they all looked desoldered.


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## lazersteve

Top lids of this variety are typically copper tungsten alloy.

Steve


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## stihl88

*Hi Glorycloud>* PM sent.

*Hi Mic>* They are all intact and gold solder untouched. I'll post some more pics soon of them cracked open.

*Hi Steve>* Thanks for the confirmation on the lids, the only thing is that it doesn't really react to the Nitric at all
which i guess will be a good thing when it comes to refining them. I would have thought the copper would react to the nitric...

I spoke with the seller again today and he seems to remember that they may have been intended for military hardware...
The pins/feet are very magnetic but not exactly sure what material, hopefully not Kovar.


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## Anonymous

stihl88 said:


> Hi Mic> They are all intact and gold solder untouched.


Hey bud.What I meant was they looked like they had been desoldered from boards,not that the lids had been desoldered.
And yes they were designed for military application.Although these particular chips are not up to normal mil-spec requirements ie:thermal and shock resistance,they are mil-spec chips.Vitesse has a large contract with the R&D department of our military,and I was fortunate enough to get several thousand of there chips last year.I think you should do just fine on these,however after you finish processing the gold from the outside,I'd be interested in buying them to grind up the ceramic and get the gold on the inside.Just shoot me a PM if you are interested in that.


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## stihl88

Ok thanks Mic, i shall see how i go. My next step is buying in some Chems instead of using poor mans everything which takes some time and effort to make and extra dangers involved also. When i get some Chems in I'll start processing these, I'll do some test CPU's first to see how consistent they are or more like how consistent i am.

BTW, they have never been soldered they are just pre-tinned on the legs that's all.

Regards

Bud :mrgreen:


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## stihl88

Well Ive finally done some processing on these CPU's, after a long bath in AP and Oxygen bubbled through the solution for a few days Ive managed to get to the easy Gold and have so far salvaged and refined 9.7g, this came from the under plate, some of the top plates and the legs of the CPU's. Ive still got to get the Gold from the rest of the top plates and the gold that lies inside the inner circuit. 

The gold inside is likely pure and can be processed in straight AR but i will not do this until i process and remove the top plate somehow??? 
I am reluctant to heat the top plate and remove it but fear that this may be my only option. The bottom plate which was highly magnetic (Kovar?) was easily dissolved by the AP/bubbler process but the top plate (Copper/Tungsten alloy?) has hardly been touched by the AP process which i find strange because Lasersteve has had luck with them in the past... I may start with a fresh batch of AP now that the bottom plates are gone and see how this goes.

Anyway i wanted to show you guys the foils that i removed from approx 95 of these processors, keep in mind i still have the inside to process with AR and the Top plates need the rest of the foils removed also.


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## lazersteve

The top plates are stripped using AR while they are still on the cpu housing.

Steve


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## Anonymous

9 grams without the top plates is pretty darn good.You should have close to that still in the top plates.Run the chips through a mill and you'll expose the hidden leads within the substrate.


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## dtectr

mic said:


> 9 grams without the top plates is pretty darn good.You should have close to that still in the top plates.Run the chips through a mill and you'll expose the hidden leads within the substrate.


 mic
How small do you go on the milling? Lazersteve once recommended 200 mesh, or a little larger than 1/16th".
dtectr


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## stihl88

lazersteve said:


> The top plates are stripped using AR while they are still on the cpu housing.
> 
> Steve



I still want to get to the gold plating underneath the top plate and i was thinking that i might have to bite the bullet and melt them off with a torch first.
I was reluctant to melt them off at the start because they were dual bonded with the silicon chip inside and would break and get messy after prolonged heating while trying to get the top lid off, now that the bottom lid is gone i was thinking it may be a whole lot easier to melt the top lid off now which would expose both top and bottom layers of the lid.


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## lazersteve

I've taken a few off with my oxy/act rig. Get the enitre ceramic red hot and the top slides right off of the ceramic housing.

Don't bank on finding any gold under the top, there is no good engineering reason for the braze under the top to be gold, only plated on top from the outside. The ones I pulled off came from a Pentium Pro and a Cyrix MII. Neither showed any visible signs of gold under the top lid or in the braze, so I did not purse the project any further.

Maybe you will find something.

Steve


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## stihl88

Thanks Steve, Ive investigated a bit further and i believe that these top lids are only single sided.
They could effectively be referred to as a bottom lid due to the internal design as you can see here.


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## Lionhead

I have approx. 20 pentium pro's and I would like to remove the lids (including the inside the cpu chips) or better yet be able to scrap off the gold after putting the chips into a solution. Any idea's as to how to go about this process?


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## rasanders22

I dont know about tugsten/copper alloy, but tungsten will dissolve in 30% h202. I think costs would make it prohibative though. It requires a lot of of peroxide to dissolve a little bit of W


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