Salvaging sockets from computer stuff

[Ben N]

I finally got around to tossing some old computers, but not before seeing what could be salvaged. I started pulling apart a modem, and got a bunch of metal film resistors, but the most useful thing on there are a mess of 16-pin IC sockets. Problem is, the holes are plate-through, and sucking/wicking the solder does not get them loose enough. It seems as though I need to heat all 16 pins at once to get them out. I seem to recall that this came up before, but I can't find the thread. Anybody have any useful experience here? BTW, basically the same problem pulling anything with more than two pins--I couldn't get a tranny out, either.
TIA
Ben

[caress]

it might have been rg that advised heating the back of the board with a blowtorch and banging it against something to remove most of the components at once.

[Mark Hammer]

16-pin sockets cost less than 20 cents each, typically.  It takes about 15-20 minutes of work to safely extricate one from a double-sided computer card with all pins intact.

How much is minimum wage where you live?  If it's a rare, expensive, or easily extricated chip then it can be worth the effort, but many times it isn't.

I find the most frustrating types of removal are when several pins are soldered to a very extensive ground plane whichj sinks away any heat you apply to the pins to reflow the solder.  If the card itself will be tossed, then the simplest thing is to get your Dremel, stick a cutting bit in there, and carve the region of the chip away from that ground plane.  When the heat-sinking role of the ground plane is drastically reduced, the solder will flow more easily and removal is facilitated. 

Same is true for those lovely low profile electrolytic caps.  Keep your eyes peeled for 1st generation 8-bit and 16-bit sound cards in the $3-as-is bin.  Those things are usually loaded with 4u7, 10u, 47u, and 100u/16v caps that are nice and small.  The leads may not be that long, buy I find they are long enough to fit a great many PCB layouts.  Again, caps are cheap too, but I find these caps are a delightfully small size, permitting populated boards to slide neatly and comfortably under pots and toggles in some otherwise cramped quarters.  So, worth scavenging if you don't have a ready source of them.

[Ben N]

16-pin sockets cost less than 20 cents each, typically.  It takes about 15-20 minutes of work to safely extricate one from a double-sided computer card with all pins intact.

How much is minimum wage where you live?  If it's a rare, expensive, or easily extricated chip then it can be worth the effort, but many times it isn't.

Excellent point. But isn't everyone here at least a little obsessive compulsive?

I am thinking of taking a heat gun to the back of the board, and see where that gets me.

[boyersdad]

PSU's have lots of cool stuff to salvage. IEC jacks, panel mount switches, wire, fuse holders, heat sinks, transformers, regulators, large caps, etc.

Just recently I took some tantalum and ceramic caps off an old 486 motherboard for a fuzz. Works great

[The Tone God]

The plastic in most sockets is not very heat resistive. Torching or desoldering the sockets can likely cause the socket to deform making your time and effort meaningless.

Personally I wouldn't bother.

Andrew

[Hanglow]

I love scavenging. I've got about five BBC computers in my loft, as well as an amstrad 1512 that I have yet to butcher. Time to go rummaging again...


I thought its not a good idea to use old electrolytic caps as they have a tendency to wear out? Or did I just make that up?

[boyersdad]

I thought its not a good idea to use old electrolytic caps as they have a tendency to wear out? Or did I just make that up?

Quite true. However, the ones I used came from a (nearly) year model supply, so I'm not too worried about them yet. But I wouldn't use anything more than about 5 years old. Everything else should work until the end of time though.

[Meanderthal]

 If you're ever lucky enough to get ahold of some REALLY old computer pcbs(from the room sized computers of a simpler time) ya might just find yourself with hundreds of transistor sockets... populated by 2N404a trannys...

[boyersdad]

Funny you should say that. I just happened to get a few boards COVERED in 2n404. Unfortunately, they were not socketed. They just have a plastic disc that lays between the tranny and the board.

I have probably 4 or 5 dozen of the 2n404, and several other mystery RCA metal can trannies (some may be Si says my father).

I just need to learn how to get the hfe without a transistor test function on my DMM and I'll be all set to make a few FF's.

[Meanderthal]

 Just pop em and swap em. You have enough to find a few good combinations no doubt.

[Mark Hammer]

Again, I highly recommend use of a cutting bit in a Dremel.  You can carve around the solder pads so that the trannies just fall out the board with these big fibreglass "slippers" on their feet.  You can then either clip the soldered parts of the leads off if they are long enough, or apply heat and pull them off.  The trick of it is that the more places the heat has available to flow to, the harder it is for enough local buildup of heat to create adequate solder flow to dislodge the transistor lead.  You can always protect the transistor itself with heat sinking on the case.

While this is relatively safe for the transistor, the fibreglass dust is not exactly healthy for the user, so make sure to do this with a filter mask, in a place where children and others at risk won't breath the dust.

[petemoore]

  Even wire cutters dispenses some phelonic dust when I trim around something I'm trying to get out of it's 'huge slipper'...not too hard, sometimes it may split the wrong way..if I think so, I'll start with a 45 angle cut / away from the item, then trim little chunx off from that...you might have to twist and clip some leads...