# Hybrid chips embedded in goo



## qst42know (Jun 11, 2009)

Has anyone found a solvent for the jelly like silicone rubber compound usually found on hybrid chips?

I know incineration will reduce it to a white ash, and trichloroethane will swell and weaken it but it is hard to come by these days. A long soak in acetone (6 weeks) had little effect.


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## oldtimmer (Jun 11, 2009)

Sounds like some of the Nortel CPU chips. I do not know if yours is the same as the ones that I have.

I have found nothing that will disolve the encapsulating compound or "goo". Years ago when I worked on a module that had to sealed, we used a similar compound, and had a solvent to remove it so that we could repair them. It came in the kit but did not have a label as to what it was. It just had a label "xxxxx" solvent for 'xxxx" counpound. We used two different compounds, hince the different solvents. They were not labeled with what chemical(s) they were made of.

I got tired and just chopped them up and dropped the center part that I had cut out from the main figerglass CPU. Put in AP for a few days to disolve the base metal and then into HCl+Cl to disolve the gold. Worked OK. I have a second batch of 50 that I am currently tearing apart so that I can process them.

Hope that this helps. What brand of CPU are they? The Nortel ones have a copper foil that is gold plated that sits in a depression and the silicon chip sits on top of it. I comes out very easily and is not adhesived to the fiberglass nor is the silicon chip glued onto it.

Check posts that I have made under Nortel CPU and gel.


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## qst42know (Jun 11, 2009)

While I was waiting I found this compatibility chart. 

http://www.eximo.com.au/pdfs/eximo_flex_guide.pdf

I had some naphtha handy and it seems to be working. I'll know more tomorrow. I think I have some turpentine in the garage. I have to try it as well.

I'll need to find the ones I haven't cracked open as yet. I'm not certain of the maker but I think they are Fuji early 80s chips roughly 1" square by 1/2" thick. White ceramic plate chip, Epoxy potted in a plastic box with two rows of gold plated pins to solder to. I'll try to post a photo tomorrow.


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## qst42know (Jun 12, 2009)

As you can see an overnight soak in naphtha has swollen the gel to about 6 or 7 times its original volume however it still remains firmly bonded. It does act as a lens and you can see the gold wires and pads inside. The chip on the left is different but is of the same type. I checked the turpentine I had and it has dried out. I'll try to get some the next time I'm out.


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## Scott2357 (Jun 16, 2009)

I think what you need is something called Dynasolve. Here are some pictures from a local NASA auction where 2 -55 gal. drums of Dynasolve 185 sold for $66.View attachment 2
View attachment 1


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## wifitekman (Mar 26, 2010)

I recently came across an enclosed electical box with chips and this "goo"occupying the cavity. I tried a couple of things that did not work, but I did find that gasoline dissolved the goo. I placed the pcb (printed circuit board) covererd with this snot, in a coffee can with regular gasoline in it. Just enoough to cover the pcb. I let it soak for a minute and then brushed it with a parts brush. Wear good chemical gloves so you can pick up the parts and brush the goo off. The problem is the left over gasoline. I use gasoline to clean up greasy auto parts so it went into my waste bucket.


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## qst42know (Mar 26, 2010)

Please be more careful with gasoline. Gasoline fumes will travel great distances to find an ignition source. Many, perhaps dozens of yards from where you might be working. It's likely best if you change to kerosene for parts cleaning. 

The misuse of gasoline is often the subject of those face plant, arm broken, skate boarder videos. Finding oneself in the middle of a fireball is likely much worse than balls first on a handrail. 

I do appreciate the info and may try this on a couple chips but the cost of scaling this up safely is out of reach right now.


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## Harold_V (Mar 27, 2010)

wifitekman said:


> I recently came across an enclosed electical box with chips and this "goo"occupying the cavity. I tried a couple of things that did not work, but I did find that gasoline dissolved the goo. I placed the pcb (printed circuit board) covererd with this snot, in a coffee can with regular gasoline in it. Just enoough to cover the pcb. I let it soak for a minute and then brushed it with a parts brush. Wear good chemical gloves so you can pick up the parts and brush the goo off. The problem is the left over gasoline. I use gasoline to clean up greasy auto parts so it went into my waste bucket.


Your comments on the use of gasoline _have no place on this forum_. What you propose is nothing short of total stupidity. Please explore the use of Stoddard solvent in place of gasoline when a cleaning solution is required. Above all, please, NEVER RECOMMEND GASOLINE FOR CLEANING. IT IS FUEL, NOT A CLEANING SOLUTION.

Harold


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## texan (Apr 8, 2010)

The same precautions should be exercised when using any low flash point solvent as using a fuel (gasoline) as a solvent.

The problem with using gasoline is that today's formula for good old motor gas are the additives that the companies are putting in it...it's not your dad's motor fuel bunkie.

'Texan


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## Platdigger (Apr 9, 2010)

I would have no problem with that left over gasoline.

I have a homemade waste oil burning furnace that I sometimes use old gas in.....works a charm, and no smoke.
Oil or gas.


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## Palladium (Apr 9, 2010)

Platdigger said:


> I would have no problem with that left over gasoline.
> 
> I have a homemade waste oil burning furnace that I sometimes use old gas in.....works a charm, and no smoke.
> Oil or gas.



When we would use full oil to fire our big furnaces ( aluminum ) We would have Methanol 2% blended with it to help with viscosity issues. Methanol has a natural cooling ability that cools the air/fuel mixture entering the burner. With the air/fuel mixture being cooler it causes the air to be denser, thus more oxygen. This adds more btu potential to your fuel. With methanol having a high evaporation rate it helps lower your burner operating temperatures.


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## dtectr (Jul 6, 2010)

when i worked at a jewelry store/custom casting shop we manufactured lapel pins with colored epoxy as enamel. Very tough stuff. When we had to repair rejects the only product that would touch it was MethylEthyl Ketone (MEK), but it was awesome. Just submerge the part in it and after a good soak, the epoxy came out in pieces with no residue left on rhodium-plated SS or 10k gold. This is significant since my boss would blast the intaglio surface with glass beads to ensure a good bond.

Don't make the mistake i made of cleaning the pieces barehanded. it absorbs through your skin & is excreted through your breath, sweat & urine. You can imagine what it does to your organs. However, the safe, responsible use of it created no problems. in fact, it worked so good the EPA probably took it off the market & failed to find a suitable replacement.

just my "dos centavos".


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## Barren Realms 007 (Jul 6, 2010)

dtectr said:


> when i worked at a jewelry store/custom casting shop we manufactured lapel pins with colored epoxy as enamel. Very tough stuff. When we had to repair rejects the only product that would touch it was MethylEthyl Ketone (MEK), but it was awesome. Just submerge the part in it and after a good soak, the epoxy came out in pieces with no residue left on rhodium-plated SS or 10k gold. This is significant since my boss would blast the intaglio surface with glass beads to ensure a good bond.
> 
> Don't make the mistake i made of cleaning the pieces barehanded. it absorbs through your skin & is excreted through your breath, sweat & urine. You can imagine what it does to your organs. However, the safe, responsible use of it created no problems. in fact, it worked so good the EPA probably took it off the market & failed to find a suitable replacement.
> 
> just my "dos centavos".



I use to use that stuff doing fiberglass work if I remember right. Awsome stuff...


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## Lou (Jul 10, 2010)

It's still commercially available. 


Saw it at ACE the other day.


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