Pentium IV based SMD breadboard.  - Page 1
Forum section: electronics / projects

author: Evil Lurker
author_rank: Regular Contributor
timestamp: January 15, 2015, 01:00:59 am
content: Ok so a couple years ago I was interested in the possibly of getting scrap gold off PCbs and other electronics and during my research one of the things I discovered was that if you take one of the green or brown "organic" CPU packages from a PIII, PIV, Athlon XP, so on and so forth and heated it to just above the point where the solder on the CPU melted and gave it a gentle tap the pins would easily fall right off. Suffice to say I never got that much gold out of the things and more or less abandoned the idea as it was more of a pain than it was worth. Now fast forward to yesterday where I made a new discovery.It happened as I was stripping SMD components off some junk socket 478 and one lone socket 754 motherboards using a heat gun to be used as guinea pigs to improve on my SMD soldering skills. Of course the CPU sockets came off as well and afterwards when I was looking at them to get a better idea of how they held the CPUs in place it was then when I noticed that the pins on the CPUs were spaced on inline 0.05" centers, the same as many common SOIC DIP packages. Then I got to thinking about the pins... instead of being cylindrical, they looked more like small nails with a head on top for various electromechanical reasons. Not just plain old nails either, they were gold plated pins with solder pads on top of them already pre-tinned from having once already been attached to a CPU. Then the proverbial light bulb over my head came on... just for craps and giggles what if I could solder some scrap CPU pins onto one of the surface mount chip leads using the ZIF socket itself as a pin holder to keep the pins precisely held in place during the soldering process?Well after a bit of trial and error, turns out the socket 478 CPU pins were a tad bit too small. Socket 462 CPU pins were almost perfect being larger in size, but the solder pads on top of the pins were too large in diameter to give sufficient clearance in between the SMD IC leads without risk of shorting once soldered on. However it turned out that socket 370 pins were virtually perfect and almost fit flush with the mounting surface of the socket 478 ZIF socket. After a little bit of solder paste and quick trip through my improvised SMD reflow oven the end product was essentially a miniature through hole LM324 with 0.05" lead spacings all in perfect alignment. This lead to additional fappage and other components being done the same way... I now have SMD chip capacitors, diodes, trim pots, transistors, and even a few larger SMD devices all with pins soldered onto them. After a bit more refinement to the process I have found that the hardest part of soldering CPU pins onto SMD components is simply getting the little buggers into the ZIF socket holes.Anyways I think I might be onto something, perhaps even one or more patentable products so I don't want to give too much way at the present time as to ideas for ways to interconnect all the components but basically there may come a time in the next couple years where state of the art breadboards are essentially large ZIF sockets and it will be possible to mount SMD ICs and other components into sockets just like their larger older through hole counterparts... the basic interconnect for that has already been made in the form of header that was once used to attach a daughter board onto a graphics card back in the day , all it needs is a few mods and it is ready to be put into use.Will try to get some pictures up later.