# Old SIM RAM MODULE for processing



## realtechedo (May 23, 2017)

I have in possession hundredd of these kinds SIMM RAM for processing. But I want to know if in the forum anyone has processed such RAMs because, the fingers leads seems to silver in colour and not the usual RAM fingers that looks like gold plated. Again, will the ic chips on these kinds of RAMs also contain gold wire bonding since the are really old types. Please, your candid response will be appreciated. Attached is a photo snap of the said RAMs types.


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## kernels (May 23, 2017)

The fingers are tinned (tin plated) so worthless, the chips may or may not have gold bond wires, I have never had enough of those to test the chips by themselves, they usually just go in with the rest of my 'legs' container. 

If you have access to a microscope, you can sometimes break chips in half and see the gold or aluminum bond wires. Just don't confuse the leads inside the chip with the bond wires.


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## kurtak (May 23, 2017)

As kernels said - the fingers are plated with "tin" - they are not silver plated

The IC chip will most definitely have gold bonding wires in them but they are a lower yield chip because of the thick epoxy casing 

Kurt


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## glorycloud (May 23, 2017)

These old SIMMs can be "priceless" to collectors of old computers. Ebay is a good
place to check values for them BEFORE you snap / cut the worthless tin fingers off. 8)


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## goldsilverpro (May 23, 2017)

You need to look inside for gold in a few of the ICs. If you remove an IC, hold it on its edge on an anvil, and tap it with light to medium force along its edge, on an anvil with a hammer, it should eventually split and expose the lead frame tips (where the wires are bonded to), the wires, the chip, and the pad where the chip is mounted to. With some, I have had good luck squeezing them slowly, edge to edge, in a vise. With that, you might not have to remove them from the board. If you get the IC package to split without crushing everything and are able to view the entire inside cavity, you will be able to see any and most all gold that is present - it will be yellow. There is no hidden gold except maybe what is directly under the chip. If you see no yellow, there is no gold.

Silver is not used on fingers. Any white metal on the fingers will be tin. With zero value tin plated fingers, I sure wouldn't expect much value inside of the ICs. Low grade or no grade, I would think. If the bonding wires are white, they are aluminum.


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## anachronism (May 23, 2017)

goldsilverpro said:


> Silver is not used on fingers. Any white metal on the fingers will be tin. With zero value tin plated fingers, I sure wouldn't expect much value inside of the ICs. Low grade or no grade, I would think. If the bonding wires are white, they are aluminum.



You'd be quite surprised at what these refine out to Chris.


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## goldsilverpro (May 23, 2017)

anachronism said:


> goldsilverpro said:
> 
> 
> > Silver is not used on fingers. Any white metal on the fingers will be tin. With zero value tin plated fingers, I sure wouldn't expect much value inside of the ICs. Low grade or no grade, I would think. If the bonding wires are white, they are aluminum.
> ...



What do they run? What's plated in the ICs? Are the wires gold?


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## realtechedo (May 24, 2017)

kernels said:


> The fingers are tinned (tin plated) so worthless, the chips may or may not have gold bond wires, I have never had enough of those to test the chips by themselves, they usually just go in with the rest of my 'legs' container.
> 
> If you have access to a microscope, you can sometimes break chips in half and see the gold or aluminum bond wires. Just don't confuse the leads inside the chip with the bond wires.



Thanks, i really appreciate your time nd exxplanation. Thanks kernel


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## realtechedo (May 24, 2017)

Thanks to all in this forum expecially to those who always take time off despite their heavy and occupied shedules to contribute to POSTS and provide their candid support and explanations. Thanks you all and God bless.


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## anachronism (May 24, 2017)

goldsilverpro said:


> anachronism said:
> 
> 
> > goldsilverpro said:
> ...



Whilst I have not run individual sticks I've had 500Kg of mixed silver edged product refined and it came out at over 35% of the yield of normal gold edged ram. This particular stuff was within the mix in reasonable quantity merely because we have never thought to separate it out.


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## g_axelsson (May 24, 2017)

Boardsort is paying $5 for tin plated RAM and $15 for gold plated RAM. So generally there should at least be a third of the gold in the tin plated ones. And all of the gold is inside the chips.

I have sorted out all my 30 and 72 pin SIMM and I'm selling to computer collectors. I'm taking $2-$6 per module but so far I have only sold two. I'm in no hurry to refine these so it can wait, I have plenty of other scrap to work with.

Göran


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## realtechedo (May 24, 2017)

g_axelsson said:


> Boardsort is paying $5 for tin plated RAM and $15 for gold plated RAM. So generally there should at least be a third of the gold in the tin plated ones. And all of the gold is inside the chips.
> 
> I have sorted out all my 30 and 72 pin SIMM and I'm selling to computer collectors. I'm taking $2-$6 per module but so far I have only sold two. I'm in no hurry to refine these so it can wait, I have plenty of other scrap to work with.
> 
> Göran



Thanks at your comment but is it possible to refine such SIMM RAMs and get pure 99.9% tin because pure tin is also expensive. And if this is possible what will really be the steps to achieve this.

REALTECHEDO


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## g_axelsson (May 24, 2017)

Of course it is possible to recover the tin, but most of it will be in the solder connections. The "tin plate" statement is a bit wrong, at that time they used tin lead solder so the surface consists of 60% tin and 40% lead. It is called HASL, High pressure Air Solder Leveling, they dipped the board in hot solder and used compressed air to blow away any excess.

There will not be a lot solder on circuit boards, after precious metals copper is the next valuable metal. But except for the really big companies using smelting I don't know of any company recovering tin and lead at a profit.

Modern electronics uses lead free solder so it is 96% or more pure tin, sometimes with up to 1% silver and usually a couple % of copper.

Göran


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## goldsilverpro (May 24, 2017)

In general, the recovery of base metals (Cu, Sn, etc.) from electronic scrap is a losing proposition for the amateur refiner, with very few exceptions. Tin, in this case, is a loser.


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## anachronism (May 24, 2017)

goldsilverpro said:


> In general, the recovery of base metals (Cu, Sn, etc.) from electronic scrap is a losing proposition for the amateur refiner, with very few exceptions. Tin, in this case, is a loser.



I agree 100% it's just being a busy fool to even try. Pick your battles.


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## realtechedo (May 24, 2017)

Thanks to all your contributions and i really apprrciate your time. So. Should i sell all because i have up to say about 780 pieces of that modules or should i go with processing and refining?


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