pcbheaven has a youtube video about using a heat gun to clean parts off old circuit boards. See How to salvage parts from old PCBs, even from motherboards!”>How to salvage parts from old PCBs, even from motherboards!
I used a Harbor Freight heat gun for the purpose. At high heat, it’d take up to half a minute to get solder soft enough for parts to fall out. Care was needed to avoid burning to board. A gun like I used will heat up a fairly large area of the board at one time which has upsides and downsides depending upon what you are trying to do. I found using a screwdriver to tap leads protruding through the board often helped to dislodge parts although sometimes I needed to get on the parts side and do a bit of ‘persuasion’ to get the part off.
The suggestion in the video is to get an aluminum pan to rest the board on and catch parts falling off the board. The solder drippings shouldn’t stick to aluminum.
There is an appropriate caution in the video to make sure there is good ventilation and that you wear heat protective gloves and goggles. You’ve not only got the lead solder to worry about but also fumes from hot circuit boards and parts so do take care.
Another technique from JumperOneTV was about Desoldering Through-Hole Parts With Compressed Air. This was a contrast to the solder sucker in that an iron was used to liquify the solder then shot of compressed air was applied to shoot the solder out of the way to clear the terminal. The compressed air illustrated was a typical 80 PSI shop air compressor with a blast nozzle often used to blow debris and dust out of work areas. Again, proper precautions are necessary as this one splatters hot solder around as well as providing some fumes – but probably not the fume risk as the heat gun.
Old computer motherboards are a good source for electrolytic capacitors, toroids, pin headers, sockets, and common jacks. The audio jacks look interesting for building radio interface boxes and the old PS2 keyboard and mice connectors could also be useful for device interconnections as there are a lot of surplus cables with molded plugs around. The pin headers and such things could be useful for such things as connecting LCD displays to processor boards in your builds.
Besides the hazard and risk precautions, keep in mind that you are salvaging parts and not circuit boards. It is likely the boards will not survive the process very well. These techniques are not for pulling selected parts for repair but rather clearing boards of parts.
As for identifying and testing the parts before you add them to your parts bins, there is an interesting device for about $25 on Ebay. It looks to be the standard microcontroller and LCD display with a program that will examine parts to determine what it is and then display pertinent data. I ordered one of those and will relay my experience when I get the chance.
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