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Gold vs tin simms and simm sockets

T

Tetrium

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At some point I read that, before DIMM's became standard, SIMM's came in 2 different flavors, Tin and Gold, and that SIMM sockets also came in those 2 flavors and that mixing the 2 different flavors would result in oxidation onto the gold.

At one point I went through my old stuff and I had some gold memory and some tin memory (I've gotten all that stuff from different sources) and as I went through my motherboards I noticed that almost all had tin sockets!
The only mainboard I currently own that has gold sockets is an Acer VI15G VLB board which seems like a standard socket 3 VLB/ISA board

Does anyone know what kinds of motherboards were using gold memory sockets back in the pre-pentium age? I seem to never come across one?
 
IBM PS/2 systems did (used gold leads). Also server systems most likely did because tin oxidizes and gold does not. Commodity gear used the cheap stuff, especially when the service life of the product started to get so short that corrosion was not an issue in most places.
 
I've heard the gold-tin mixing subject with varying viewpoints. In all my experience, I've never noticed any tendency of mixed socket/component plating to matter much at all. Perhaps it matters in severe environments.
 
Tinned contacts will corrode / oxidize. Gold contacts will not.

I ran a computer repair center in NE Texas from 93 to 97 and the ONLY time I ever ran into any problems with SIMM corrosion was when a mouse got in the computer and used the SIMMs and SIMM sockets as a bathroom. ;)
 
channelmaniac said:
Tinned contacts will corrode / oxidize. Gold contacts will not.

I ran a computer repair center in NE Texas from 93 to 97 and the ONLY time I ever ran into any problems with SIMM corrosion was when a mouse got in the computer and used the SIMMs and SIMM sockets as a bathroom. ;)
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I wonder if that works anything like peeing on an electric fence, lol. Must hurt for a while if it doesn't kill ya.
 
channelmaniac said:
Tinned contacts will corrode / oxidize. Gold contacts will not.

I ran a computer repair center in NE Texas from 93 to 97 and the ONLY time I ever ran into any problems with SIMM corrosion was when a mouse got in the computer and used the SIMMs and SIMM sockets as a bathroom. ;)
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This can get to be almost religious in tone on the audio forums. There's at least one vendor out there who says that gold socket-tin edge = good, tin socket-gold edge=bad. But these are the same people who sell gold-plated wall outlets and solid-silver line cords.

In most tame circumstances, it shouldn't matter. If you worry about contact resistance with tinned contacts, get yourself some Cool-Amp and put a layer of silver down.

If you think a mouse is bad, you ain't seen what cat pee can do to a PCB--dissolves the traces right through the solder mask.
 
Chuck(G) said:
This can get to be almost religious in tone on the audio forums. There's at least one vendor out there who says that gold socket-tin edge = good, tin socket-gold edge=bad. But these are the same people who sell gold-plated wall outlets and solid-silver line cords.
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Those kind of audiophiles really bug me. They think they can hear the difference!! I heard about some people who did not believe in paying $30 per foot of speaker wire testing some Monster Cable with some expert audiophiles. They took the Monster Cable to one set of speakers, and some other wire to the other. Turns out those expert audiophiles liked the other wire better. And the other wire happened to be two coat hangers!! Haha!!

Kyle
 
Those kind of audiophiles really bug me. They think they can hear the difference!!
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Agreed. Those who are light on the basics sometimes have a little trouble staying on the ground, and instead formulate ideas that float into the stratosphere. Good riddance, I say.
 
I did tech support for IBM consumer models and certain model series had tin sockets, and them some others had gold sockets. There were several times when a user would call in with weird problems only to find out there's gold SIMMs in a tin socket. I can validate that it DID cause problems. I mean, think about it, two dissimilar metals touching? Nothing good will come from that. It's also discussed in the Upgrading a repairing PCs book.
 
This one got me thinking because in piping systems, you need to use a di-electric union between two different metals, such as copper pipe and steel pipe.


I did a slow web search (someone cut a fiber line between CA & AZ today) of "dissimilar metals" and came up with the following:


"Galvanic corrosion (some times called dissimilar metal corrosion) is the process by which the materials in contact with each other oxidizes or corrodes. There are three conditions that must exist for galvanic corrosion to occur. First there must be two electrochemically dissimilar metals present. Second, there must be an electrically conductive path between the two metals. And third, there must be a conductive path for the metal ions to move from the more anodic metal to the more cathodic metal. If any of these conditions does not exist, galvanic corrosion will not occur."


From what I read in the article, gold plating has a 0.00V anodic index, while tin plating has a 0.60V index.
See the article for more info on the environmental conditions and the index difference that can be tolerated within those environments, but it looks to me like while we have met the three conditions necessary for dissimilar metal corrosion, it's not enough to worry about in a temperature controlled environment (which is actually the worst - store them outdoors and you'd be fine). ​

You can see the full article here:
http://www.engineersedge.com/galvanic_capatability.htm​
 
Thanks all ;)


Back when I started getting interested in older hardware (2002/2003-ish) I used to gut any computers I found without actually knowing what I was taking home lol!
So now I have lots of parts at home and have much more gold memory then I do gold socketed mainboards...that got me wondering and thanks to you now I know :).

It's just such a shame that people are/were throwing away perfectly working computers only for the reason that it was too old or too slow. Often it was broken which cold be repaired by replacing only 1 lil part!
I'm glad I'm not the only one wanting to keep these computers alive, I actually find it much "cooler" having a working 486 then I do a working Pentium 4. It takes being creative making such an old slow systems of any use and here are people that do just that :).

The older a computer is, the harder it is to get to work and the more rewarding it is if you finally got it to work!


Right now I have just one mainboard that has gold simm sockets so I got plenty of gold memory for it.
FYI, the mainboard I'm talking about is an Acer (AOpen) VI15G socket 3 VLB board.

If it is normal for these "cheaper' mainboards to have tin sockets, then it's all the more strange as to WHY this particular mainboard has the golden simm sockets.
 
Not just the cheaper motherboards. I've got a couple of Intel P1 motherboards here with tinplate sockets. Must not have been an issue for the Intel engineers and I've observed no problems in the 11 years that I've had them.

Look, if it bothers you, you can always pen-plate gold onto your tin connectors. Or you can tin-plate your gold SIMMs. Whatever floats your boat.

http://www.caswellplating.com/kits/plugnplate.htm
 
I don't know about tin/gold interaction, but gold-plated pins definitely do corrode under certain conditions; pretty well all my ICs with gold-plated pins that were stored in certain kinds of anti-static foam have corroded pins, to the point that some pins have fallen right off. Haven't noticed the same problem with tin-plated ones; they do oxidize, but that can be cleaned off.

Anybody else have that experience?

(No mice have peed on 'em AFAIK)
 
From what I know of plating technology, gold plating is typically very thin--maybe 10 microns--and very soft and somewhat porous. Tin plating is usually much thicker. Does it matter? I don't know.
 
Chuck(G) From what I know of plating technology, gold plating is typically very thin--maybe 10 microns--and very soft and somewhat porous. Tin plating is usually much thicker. Does it matter? I don't know.
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I think it matters. The gold is crap. :)

Gold is cheap because it is so thin. For professional audio use, where things actually get used, the gold wears off right away and the items look bad in a short time. It wears off by touching it with your fingers! It's just a marketing tool in that world. I think that the important thing is what's underneath. For regular audio stuff, I like chrome because it doesn't wear off and stays clean. BTW, I've seen lots of tin on old electronics and it always seems to work years later. Except for internal use like increasing yields in integrated circuits, my feeling is that the gold craze is just cosmetic.
 
MikeS said:
I don't know about tin/gold interaction, but gold-plated pins definitely do corrode under certain conditions; pretty well all my ICs with gold-plated pins that were stored in certain kinds of anti-static foam have corroded pins, to the point that some pins have fallen right off. Haven't noticed the same problem with tin-plated ones; they do oxidize, but that can be cleaned off.

Anybody else have that experience?

(No mice have peed on 'em AFAIK)
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That is the nasty black anti-static foam. I've lost dozens of hard to find chips because that stuff deteriorates and corrodes the pins of the chips. I switched to the pink anti-static foam exclusively. I've not had any problems with chips sitting in the pink foam for 6+ years. It's not as conductive as the black foam, but far less risky to use.
 
channelmaniac said:
That is the nasty black anti-static foam. I've lost dozens of hard to find chips because that stuff deteriorates and corrodes the pins of the chips. I switched to the pink anti-static foam exclusively. I've not had any problems with chips sitting in the pink foam for 6+ years. It's not as conductive as the black foam, but far less risky to use.
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Is this the soft black sheets often found packaged with new motherboards you're talking about? If this stuff somehow damages hardware...I've used those sheets quite extensively so it would be good to know if this stuff is any bad.

Edit:My apologies for being offtopic.
 
No, I think what's meant is the rather stiff black neoprene foam that DIP ICs are usually jammed into for storage, generally referred to as "lead insertion ESD foam". Stuff that gets nasty as the neoprene degrades with age. Modern replacements use polyurethane or polyethylene instead of neoprene.

P_PROTEK_ESD-Foam-BlackInsertionGrade.jpg
 
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