Fullscreen HTML5Med Res (??MB)HTML4

Salvage It! By BRUCE PIERSON From Junk Bin to Junk Box: Wrecking Computer Components for Parts That “latest and greatest” computer you proudly bought three or four years ago is today’s door stop. Even if it still works, it’s as slow as a wet week and probably doesn’t even run today’s software. In this final instalment in the “wrecking computers” series, we look at what you can do with it – or any other obsolete/dead components. W ell, you could wreck them for parts. A good idea is to have a “junk bin” and toss anything that’s no longer needed into it. Junk Bin? What’s the difference between that and the “junk box?” Every hobbyist has a junk box: a place where you store an assortment of (usually) used or surplus parts that are too good to throw out and just might be useful . . . one day. On the other hand, a junk bin is like a “half way house” where you toss old and dead stuff, ready for wrecking (one day!), to get the parts to feed your junk box. So you have a look in your junk bin and you might find, just like those pictured above: • an old CD-ROM drive (still works but far too slow to be of any use) • a dead hard drive (well, your computer doesn’t recognise it so you think it’s dead) • a definitely dead floppy drive (umm, what’s a floppy disk!!) • a dead sound card siliconchip.com.au • a dial-up modem (wow!) • a ratty old speaker • and a dead graphics card You have some spare time, so you decide to reduce the amount of stuff in your junk bin, so that you can increase the amount of stuff in your junk box. So where do we start? The CD-ROM drive will be a good starting point. Usually, you can find four screws on the bottom. Once these are undone, the unit can usually be taken apart, sometimes requiring undoing some clips in the process. Then the front panel can be unclipped and the inside parts removed from the case. Then it’s just a matter of undoing screws and clips until you have everything removed. The PCB can then be processed for useful components using a soldering iron for the delicate components and then the blowtorch method for the rest of the components (see July 2014  57 SILICON CHIP February 2014). The remainder of the hardware really is junk to be binned. So let’s move on to the hard drive. Start by undoing any screws on the top cover. Then remove all the stickers, because the stickers may well be hiding two or three more screws, which must be removed before the top cover can be lifted off. Then it’s just a matter of undoing screws until everything is in pieces and you can see what you have from the exercise. You will need a small Torx bit for most hard drives, to remove the drive platter(s). The PCB on the bottom may be held on by Philips screws or Torx screws and in a few cases, Torx screws may be used on the case. It varies depending on the manufacturer and the size of the hard drive. Now for the floppy drive: there could be some screws holding the top on, or it could be just clipped on. There’s a wide variety of floppy drives and they vary as to how they are held together. Just undo any screws you find and un-clip any clips you find until the unit is completely dismantled. There’s usually a few components on the PCB that can also be salvaged in the process. Some of the more delicate items will need to be removed with a soldering iron before the rest can be blow-torched off. The sound card, dial-up modem and graphics card can be processed using the same approach. First, unscrew any screws, remove any jumpers and take off any heatsinks or other attachments. Arguably the jumpers and the heatsinks will be the most useful bits for your junk box! But the components can be removed with a soldering iron or blowtorch and the remaining junk binned. The speaker? What is there in a speaker, you ask? A nice, powerful little magnet that will make a quite good fridge magnet, if nothing more. To remove it, just grab some pliers and bend the front frame up until it comes off the magnet and there you have it. So, what did we get from these dead and obsolete components? The picture below shows the range of parts that was salvaged from each of the obsolete and dead items. Newer or older types of similar items will have a slightly different selection of parts, compared to these particular items. Here are the parts we salvaged for our junk box, as photographed below: CD-ROM drive to repair a DVD player with a faulty tray motor.) One drive belt to suit the tray motor Two rods One small magnet 26 assorted screws, Two tactile switches 18 electrolytic capacitors Six rubber mounts One jumper One LED One 3.5mm stereo socket One 3-position, centre-off momentary switch One PCB-mount dual potentiometer A few gears A selection of SMD components. From the hard drive: Two very powerful magnets. (Be careful with these as they can be quite savage. I suffered a crushed thumb when holding one of these magnets and getting too close to the other one, which jumped up to meet the first one, crushing anything in its path, which happened to be my thumb!) One platter (unknown use) Two bearings, One shaft One magnetic washer One washer Four aluminium brackets One jumper 25 assorted screws Several SMD components. From the floppy disk drive: One 33-pin connector One power connector Five springs 19 assorted screws One shaft One bush One LED One electrolytic capacitor One resistor Three micro-switches From the CD-ROM drive: Two motors, one a stepper type, with a gear and one a DC type, to load and eject the disc (with a pulley). (I once used a tray motor from a dead They won’t take up much storage space . . . so why not store ’em! You never know when you’ll need a couple of ‘XYZ’ widgets and you just happen to have a couple, removed from that old computer! 58  Silicon Chip siliconchip.com.au Four short lengths of hookup wire Some SMD components. From the sound card: Six headers Four 3.5mm stereo sockets One small transistor Eight wire inductors, One crystal Four ICs 14 electrolytic capacitors Some SMD components. From the dial-up modem: One isolation transformer One small PCB speaker Two small transistors One crystal Two greencap capacitors One ceramic capacitor One small round bridge rectifier Two screws Six electrolytic capacitors Two opto-couplers A few SMD components. From the speaker, A useful small magnet, which is quite strong for its size. There are usually two different types of 57mm speakers in computers. The other type has a smaller magnet, which can also be salvaged using the same method. From the video card: One heatsink Four screws/nuts from the video connectors 18 electrolytic capacitors Three video connectors Two 3A diodes One inductor One crystal Some SMDs components. So, that was quite a surprise as to just what was salvaged from those dead and useless items. At first glance, it may have seemed that some of the items would not have anything much in them worth salvaging but a closer look revealed quite a lot of goodies. It was worthwhile to salvage these parts before binning the leftover junk. Some of the items had some SMD components in/on them. These were salvaged by heating the back of the PCB until the solder holding the SMDs on melted and then the PCB was knocked on a hard surface to dislodge the SMDs. It’s really not much use saving any SMD that is tiny with multiple leads, but small capacitors and resistors may be useful for a project or repair in the future. You may have noticed that I haven’t yet tried to identify the small components above. That’s a job for another day, as at the same time I always test any component before using it, otherwise I may be introducing a fault that wasn’t there to start with! SC siliconchip.com.au July 2014  59