# whats on a pc motherboard?



## fafrd (May 17, 2007)

i have multiple questions on whats on a standard motherboard from a home or business pc i know about the gold pins and intel proccessers they are pretty simple to find but their is so much on the boards and i don't know what is worth the effort to remove i would like to remove them all but i have not come up with a way to simplify it and no i'm not lazy just energy effcient i tried a regular heat gun but it takes to long to get the solder to liquid form is their a better way other than a heat gun or a torch i do not want to ruin the boards if any one can help me with these i would be in your debt greatly seen's i have about 30 boards that need to be done fafrd yes i'm editing this i will take pics later today of the boards and things that i have questions on and post soon ok i can't seem to upload them can anyone give me some help here?


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## lazersteve (May 27, 2007)

Here's a link to another thread on the subject:

Processing Boards

Read thru the entire thread it's got a lot f good info in it.

Steve


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## dwt9999 (May 28, 2007)

Something I have been doing lately is using toaster ovens to melt the solder and remove all the items off of mobo, isa, pci and processors. It has worked well for me, you just need to remember the safety equipment. There are a few item that may POP OFF inside. 

On a side note I have also been using it to dry all my coffee filters with. With a setting of over 450' F it chars the filters until all that is left is product and dust.

Lew


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## lazersteve (May 28, 2007)

Lew said:


> There are a few item that may POP OFF inside.



Lew,

The items that pop are electrolytic capacitors. They are designed to fail this way when the temperature exceeds their rated value (between 85 C and 105 C). They produce a brown gas that smells of dead fish and leave a messy brown goo on the board usually. The dead fish smell comes from the amines used in the electrolyte. I don't recommend using the oven for any other purpose after one of them has blown in the oven. I also would not advise breathing the brown fumes which the popping capacitors emit. 

You could prep the boards by removing the electrolytics with a sharp chisel before you put the boards in the toaster.

This is a novel idea, I may give it a try someday.

Steve


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## PhillipJ (May 28, 2007)

I like to use an air chisel. It buzzes the parts off fast and leaves the solder behind. But you have to be kinda carefull as the parts like to fly.

I got a small one at Harbor Freight for around $7 on sale.


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## jimmy759 (Jul 10, 2007)

I tryed a toaster oven to see if I could remove parts easily from a regular board all I got a was a bad smell and a burnt board only a couple of resistors fell off.

But I'm gonna have to play with the settings and see if I can get the internal tempurature of the toaster oven to just about the melting point of 60/40 solder.

Then give them a good wack while still warm.

but so far the chisel seem like a better idea.


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## aflacglobal (Jul 10, 2007)

the melting point of 60/40 solder

What is that by chance ? I mean exactly with the mixing of the alloys.


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## goldsilverpro (Jul 10, 2007)

60Sn/40Pb melts at 370 deg F. The eutectic mix of 63Sn/37Pb melts at 361 deg F. The eutectic is the particular alloy of the two metals that gives the lowest possible melting point. Anything higher or lower than 63% Sn gives a higher melting point.

http://www.chemguide.co.uk/physical/phaseeqia/snpb.html


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## aflacglobal (Jul 10, 2007)

Chris , Their is a method of dipping the board into hot lead solder or something, i'm not quite sure what it is to heat the solider and remove it.

What could we might use at that temp that would be both safe and stable.
See where this is going ? All liquids and metals don't boil at this point.

Huuuummmmm :?:


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## goldsilverpro (Jul 10, 2007)

I made a big mistake in my previous post but I corrected it. I said 370 C, but it is 370 F, for 60/40.

I know of nothing hot you could dip it in to remove the solder. You might be able to melt it but the surface tension would keep most of it on the board. 

A standard way of soldering components on boards is a wave solder machine. The components are put into place with the leads running through the holes. The solder (maybe, a ton or more) is melted in the machine and a wave is mechanically created. The board is run horizontally over the crest of the wave and all the components are soldered. After running a lot of boards that have components with gold plated leads, the solder will become contaminated with gold and will produce bad solder joints. The gold can run 2 to 4%, at this point, if I remember right. At only 1%, for 2000# of solder, this is 292 oz. of gold. There have been all kinds of schemes to get the gold out. One of the best was developed by the U.S. Bureau of Mines. They melted the solder, added some aluminum, and stirred the melt. The aluminum picks up the gold. The aluminum doesn't alloy with the lead tin and floats on top. It is skimmed off and the gold is recovered from the aluminum.

We used to use coconut oil (I think) to re-flow plated tin. Tin melts at 450 deg F. We had a large dangerous tank of very hot oil. We tin plated the parts, dried them, and dipped them in the oil. The tin melted and produced a very bright finish. During this process, none of the molten tin came off. The surface tension held it on the parts.


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## jimmy759 (Jul 10, 2007)

This weekend i'm gonna pull out my tempurature guna and slowley raise the tempuirature in the toaster and find the best point to be able to wack the board on the grating to remove the parts but do as little damage to the board as possible.

I have some boards that I believe are fully plated in gold so i do not want to damage them plus the smell is pretty tough to deal with.

Also is there some sort of filter around that i can use maybe to filter the air around the toaster oven so that I may work by it more safely.

Kind of like a range hood I guess. But I would need a proper filter. 

I will post my findings on the weekend if I have time to do it weather permitting.


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## lazersteve (Jul 10, 2007)

Jimmy,

The bulk of your bad fumes are most likely the electrolytic capacitors on the boards venting. They are designed to pop between 85C and 105C depending on the type of capacitor. They smell like dead fish when they vent (pop). If you remove them before toasting you can save yourself from the bulk of the stinking cloud.

Here's what they look like:

[img:51:94]http://www.goldrecovery.us/images/electrolytic1.jpg[/img]

The plastic sleeve can vary in color from orange, brown, yellow, blue, black, etc. 

The surface mounted variety look like this:

[img:97:115]http://www.goldrecovery.us/images/electrolytic2.jpg[/img]

Steve


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## jimmy759 (Jul 11, 2007)

I wouldn't say it smelt like bad fish.
It smelt like almost plastic or even flux but extremely strong.

There was only one capacitor on the boards thatt were put into the oven.

By the way i go the oven for free it was used and somewhat dirty. so i could carless what happens to it. but its temp gauage goes above 560 F.

And the toast option doesn't work anymore.


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