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DEAD COMPUTER? DON'T THROW IT OR STOW IT: RAT I T! Perhaps you have an old PC which is ready for the tip. Before you put it out for the council cleanup, have a good look over it before consigning it to oblivion. It has lots of parts worth salvaging. OK, we admit it, there comes a time when all electronic equipment should probably be consigned to the tip. After all, no‑one has enough space to store all the electronic bits which come into your possession over the years. Therefore some of it has to be tossed out or given away. And this applies as much to old computers as to anything else. Perhaps our article on modifying 4  Silicon Chip a PC power supply in the December 1998 issue doesn’t appeal to you but you’re still loath to junk your old computer. Well, let’s have a look at it to see what can be scrounged. The monitor First, of all, have a look at the monitor. Most of these look pretty sad and sorry after six or seven years but if it is a VGA monitor, you are By LEO SIMPSON probably wise to hang onto it. It can be a handy standby just in case your normal monitor packs it in. How do you know if it is a VGA monitor? Look at the data plug: they're almost always a sub-mini “D” plug but VGA monitors have three rows of pins versus an EGA monitor's two rows. Or, if it is in half reasonable condition after a bit of spit and polish, Opening up the case revealed a treasure-trove of goodies and a lot of junk. A good example of the latter are the hard discs – in their day, worth a lot of money. But now, 40MB drives are not even good paperweights. However, there are plenty of bits and hardware worth salvaging here, even just to have a some spare parts on hand. you might even be able to get twenty or thirty dollars for it at a computer recycling store. It’s worth an ask! Moving to the computer, what can be salvaged here? First, pull out the video card and see what type it is – VGA or EGA (or earlier). A working VGA card is worth hanging on to. The chances are that the card is pretty pedestrian nowadays, even if it was a pretty fancy unit in its day. But again, it could get you out of trouble temporarily if your existing VGA card develops a problem. If your card is EGA or earlier (CGA/ Hercules/etc) it’s probably not worth saving. Other cards which are worth saving for a rainy day are things like hard disc controller cards, I/O cards, SCSI cards and so on. By the way, if you do need to use an old I/O card in a new computer, remember that many computers today have the I/O on the motherboard. You may need to move a jumper or two or change the CMOS setup to disable the on-board I/O before plugging in the card. possibility of using the RAM in Back to the computer: again, if the another machine (even that is getting floppy drives are still working, they less and less likely these days), most are worth saving. While a new flop- of the semiconductor complement is py drive might not cost a lot, if you not worth worrying about. Possibly have an old drive on hand, it could you might save a few CMOS chips and perhaps an EPROM which might be of pressed into service to replace a faulty drive - especially handy at 10pm on use if you’re able to program EPROMs. But there are other components a Sunday night! With the dramatic increase in hard drive capacity in recent years, though, the old drive is probably not big enough to be worth saving. Unless you want a paperweight, that is. What about the mother-board? Aha! That's why it died! The battery decided it was sick of Well, apart wearing its insides on the inside – and heavy corrosion was from the remote the result. This is a particularly common fault in old PCs. MARCH 1999  5 ing in the junk box are things like cable retainers and clips, if your computer has any. Power supply switch. OK, it mightn’t look pretty but it’s entirely functional! Before moving away from the power supply, don’t forget to hang on to the IEC cables. They’re very handy to have around – in particular, the IEC male to IEC female (monitor) cable. They’re relatively uncommon but very useful. And you’d be surprised how much a new one will set you back! That leaves the power supply as the remaining large component in the case. Computer case Maybe the power supply is dead but it is By now you have an almost empty still worth salvaging shell but there are still bits which are parts. For a start, there worth retaining. are the IEC male and Some of the cables to the hard discs female power sock- could be useful, as well as the speaker ets, the 12V fan and a and possibly the reset, turbo and powbunch of electrolytic er switches. If your old computer has capacitors. a LED readout for the speed indicator, Without working you might want to save the 7‑segment too hard, you can eas- displays. ily salvage $20 to $40 What about the metalwork itself? of components. Con- Well, by the time you are thinking of sidering the fact that a throwing the machine out, the case new 200W supply can probably looks pretty much the worse be readily purchased for wear. We give up. We can’t think today for about $30, of any practical use for it. that’s not bad going! But hang on – if it’s a tower case Don’t forget the larg- and the power supply and other bits er switching transis- still work (oh, you’ve already pulled tors and fast recovery the power supply apart – sorry about diodes, the cord grom- that!), maybe it’s a contender for a mets and the large heart (motherboard) transplant. AC filter capacitors. It’s not hard to do (see the article in The best part about this tower case is . . . the case! It's These AC capacitors SILICON CHIP, April 1997). You’ll end a beauty and lends itself very nicely to a motherboard are quite expensive. up with a modern PC for a fraction transplant. No stripping bits in this one! Also definitely worth of the cost of a new one. Why pay saving are any large or for new bits when the old ones work SC which could be worth salvaging. not‑so‑large toroid filters and finned perfectly? Things like the crystals and ceramic heatsinks. resonators, the header pins and their By the way, if you’re shorting links, the plastic stand‑offs saving semiconductors and perhaps the 5‑pin DIN socket for for the junk box, it is a the keyboard connector are worth good idea to check that having in the junk box. they are actually funcIf you have the time, you could tioning. Possibly you possibly remove the monolithic bymight also label them pass capacitors as well. By the way, with their original funcmost of these will be 0.1µF or .01µF tion if the type numbers –some can even be 1µF, all handy don’t mean anything. values to have. That’s probably all When removing the various cards there is worth saving in and other components you’re going the power supply unless to end up with a fair number of you can use the case itscrews. Hang on to them – they’re self. If you only remove really handy to have available. The the PC board you are left same thing applies to the backplane with a strong case with A few minutes work with a screwdriver and brackets which cover unused slots a built-in cooling fan, an soldering iron got these bits: stand-offs, screws, on the back panel. Unless they’re the IEC mains input socket jumpers (all very handy if you're playing with break-out type (most early computers (and output socket) and computers) – and even an EPROM and a couple of were not), hang on to them and their on many older power resonators (OK, so they're not so useful!). Another screws. Other hardware worth keepsupplies, even the on-off hour or so and we'd have a boxfull. 6  Silicon Chip