Circuit cards, Cpu's and PCB's.. did you know?..

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AuMINIMayhem

AuMINIMayhem

Well-known member
Joined
Apr 19, 2007
Messages
491
Location
New Hampshire and Maine
I work in a CCA factory (Circuit Card Assembly).. before anyone asks, hell no I can't get the scraps, it's government property at that point, they dispose of it.. too much accountability to try and snag some.. At any rate here's my point. On all the threads about CPU's and circuit cards, etc I have yet to see anyone mention one critical thing that may be impeding some of your results..

Most manufacturers put CC (conformal coat) on their CCA's and PCB's (printed circuit boards).. CC is basically like a clear nailpolish that goes on very thin (in the microns range) that coats EVERYTHING on the CCA with a protective layer.. depending on the CC (there's a bunch of different types), this stuff can be damn near impossible to take off, short of picking it off, as it was designed to stand up to the harshest of environments (yes including heat, cold, acids, etc).. you may want to look into ways of stripping this stuff off first if you suspect there may be some on there.. it's very hard to detect (if cc'ed properly) by the eye.. a really good way to check is to break out the soldering iron and try to desolder one of the components.. if it takes an excessive amount of heat or you just can't get the solder to wick off, you're almost certainly dealing with a conformal coated assembly..

The worst cc to deal with is parylene.. good luck if you're stuck with that.. it's a b@#$ to remove..

Here's some interesting info that may be of use..

http://en.wikipedia.org/wiki/Conformal_coating

http://en.wikipedia.org/wiki/Parylene

http://www.asymtek.com/news/articles/2000_02_nepcon_conformal_coat.pdfhttp://en.wikipedia.org/wiki/Parylene
 
Hey AuMini. I know this post is super old, but I just have to throw my two pennies in. I worked for an electronics manufacturer and I did the Conformal Coating. After the boards left my station and went to QA, they were tested and if they failed went back to tech. Tech would take a stainless steel brush and scrub the CC off the bad component. I found later that if you get a sanding cup for a cordless drill (long fingered columns of abrasives) you can clear off a good portion of it while keeping most of the component intact, slightly thinner. They can be found near the sandpaper in any hardware section of nearly any store. Hope this info helps some people.

dennis
 
I know of no big boys that treat boards like that. No respectable refiner I know of leaches boards - whether whole or incinerated. Too expensive, bulky, slow, and inefficient. They ALL incinerate, grind in a ball mill, screen at about 8 to 10 mesh to separate the metallics from the pulp (powder), and melt the metallics. The metallic bars are sampled by drilling or by glass vacuum tubes in the melt. The pulps are thief sampled. The bars and pulps are weighed and shipped to a primary copper smelter for refining. Fast, efficient, no chemicals, and the only waste is slag and bag house dust. Been there. Done that - for a good part of my life.
 

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