Silicon ChipA Heart Transplant For An Aging Computer - December 1997 SILICON CHIP
  1. Outer Front Cover
  2. Contents
  3. Publisher's Letter: Compact discs are simply too expensive
  4. Subscriptions
  5. Feature: A Heart Transplant For An Aging Computer by Ross Tester
  6. Feature: Understanding Electric Lighting; Pt.2 by Julian Edgar
  7. Project: Build A Speed Alarm For Your Car by John Clarke
  8. Project: A 2-Axis Robot With Gripper by Graeme Matthewson
  9. Feature: Satellite Watch by Garry Cratt
  10. Project: Loudness Control For Car Hifi Systems by Rick Walters
  11. Project: Stepper Motor Driver With Onboard Buffer by Rick Walters
  12. Serviceman's Log: Encounters witha notebook PC by The TV Serviceman
  13. Product Showcase
  14. Order Form
  15. Feature: Radio Control by Bob Young
  16. Vintage Radio: Restoring a sick Radiola by John Hill
  17. Project: Power Supply For Stepper Motor Cards by Rick Walters
  18. Feature: Index to Volume 10
  19. Book Store
  20. Market Centre
  21. Outer Back Cover

This is only a preview of the December 1997 issue of Silicon Chip.

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Articles in this series:
  • Understanding Electric Lighting; Pt.1 (November 1997)
  • Understanding Electric Lighting; Pt.1 (November 1997)
  • Understanding Electric Lighting; Pt.2 (December 1997)
  • Understanding Electric Lighting; Pt.2 (December 1997)
  • Understanding Electric Lighting; Pt.3 (January 1998)
  • Understanding Electric Lighting; Pt.3 (January 1998)
  • Understanding Electric Lighting; Pt.4 (February 1998)
  • Understanding Electric Lighting; Pt.4 (February 1998)
  • Understanding Electric Lighting; Pt.5 (March 1998)
  • Understanding Electric Lighting; Pt.5 (March 1998)
  • Understanding Electric Lighting; Pt.6 (April 1998)
  • Understanding Electric Lighting; Pt.6 (April 1998)
  • Understanding Electric Lighting; Pt.7 (June 1998)
  • Understanding Electric Lighting; Pt.7 (June 1998)
  • Understanding Electric Lighting; Pt.8 (July 1998)
  • Understanding Electric Lighting; Pt.8 (July 1998)
  • Electric Lighting; Pt.9 (November 1998)
  • Electric Lighting; Pt.9 (November 1998)
  • Electric Lighting; Pt.10 (January 1999)
  • Electric Lighting; Pt.10 (January 1999)
  • Electric Lighting; Pt.11 (February 1999)
  • Electric Lighting; Pt.11 (February 1999)
  • Electric Lighting; Pt.12 (March 1999)
  • Electric Lighting; Pt.12 (March 1999)
  • Electric Lighting; Pt.13 (April 1999)
  • Electric Lighting; Pt.13 (April 1999)
  • Electric Lighting, Pt.14 (August 1999)
  • Electric Lighting, Pt.14 (August 1999)
  • Electric Lighting; Pt.15 (November 1999)
  • Electric Lighting; Pt.15 (November 1999)
  • Electric Lighting; Pt.16 (December 1999)
  • Electric Lighting; Pt.16 (December 1999)
Items relevant to "Build A Speed Alarm For Your Car":
  • Car Speed Alarm PCB patterns (PDF download) [05311971/2/3] (Free)
  • Car Speed Alarm panel artwork (PDF download) (Free)
Articles in this series:
  • Satellite Watch (January 1996)
  • Satellite Watch (January 1996)
  • Satellite Watch (February 1996)
  • Satellite Watch (February 1996)
  • Satellite Watch (March 1996)
  • Satellite Watch (March 1996)
  • Satellite Watch (June 1996)
  • Satellite Watch (June 1996)
  • Satellite Watch (August 1996)
  • Satellite Watch (August 1996)
  • Satellite Watch (October 1996)
  • Satellite Watch (October 1996)
  • Satellite Watch (December 1996)
  • Satellite Watch (December 1996)
  • Satellite Watch (February 1997)
  • Satellite Watch (February 1997)
  • Satellite Watch (April 1997)
  • Satellite Watch (April 1997)
  • Satellite Watch (May 1997)
  • Satellite Watch (May 1997)
  • Satellite Watch (June 1997)
  • Satellite Watch (June 1997)
  • Satellite Watch (December 1997)
  • Satellite Watch (December 1997)
  • Satellite Watch (April 1998)
  • Satellite Watch (April 1998)
  • Satellite Watch (January 1999)
  • Satellite Watch (January 1999)
  • Satellite Watch (June 1999)
  • Satellite Watch (June 1999)
Items relevant to "Loudness Control For Car Hifi Systems":
  • Loudness Control for Car Hifi Systems PCB pattern (PDF download) [01111971] (Free)
Items relevant to "Stepper Motor Driver With Onboard Buffer":
  • PC Stepper Motor Drivers DOS software (Free)
  • Buffered Stepper Motor Driver PCB pattern (PDF download) [07110971] (Free)
Articles in this series:
  • Radio Control (November 1996)
  • Radio Control (November 1996)
  • Radio Control (February 1997)
  • Radio Control (February 1997)
  • Radio Control (March 1997)
  • Radio Control (March 1997)
  • Radio Control (May 1997)
  • Radio Control (May 1997)
  • Radio Control (June 1997)
  • Radio Control (June 1997)
  • Radio Control (July 1997)
  • Radio Control (July 1997)
  • Radio Control (November 1997)
  • Radio Control (November 1997)
  • Radio Control (December 1997)
  • Radio Control (December 1997)
  • Autopilots For Radio-Controlled Model Aircraft (April 1999)
  • Autopilots For Radio-Controlled Model Aircraft (April 1999)
  • Model Plane Flies The Atlantic (May 1999)
  • Model Plane Flies The Atlantic (May 1999)
  • Tiny, Tiny Spy Planes (July 1999)
  • Tiny, Tiny Spy Planes (July 1999)
  • 2.4GHz DSS Radio Control Systems (February 2009)
  • 2.4GHz DSS Radio Control Systems (February 2009)
  • Unmanned Aerial Vehicles: An Australian Perspective (June 2010)
  • Unmanned Aerial Vehicles: An Australian Perspective (June 2010)
  • RPAs: Designing, Building & Using Them For Business (August 2012)
  • Flying The Parrot AR Drone 2 Quadcopter (August 2012)
  • Multi-Rotor Helicopters (August 2012)
  • Multi-Rotor Helicopters (August 2012)
  • Flying The Parrot AR Drone 2 Quadcopter (August 2012)
  • RPAs: Designing, Building & Using Them For Business (August 2012)
  • Electric Remotely Piloted Aircraft . . . With Wings (October 2012)
  • Electric Remotely Piloted Aircraft . . . With Wings (October 2012)
Items relevant to "Power Supply For Stepper Motor Cards":
  • Stepper Motor Card Power Supply PCB pattern (PDF download) [10112971] (Free)
  • Stepper Motor Power Supply panel artwork (PDF download) (Free)

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A heart transplant for an aging computer Should you buy a new computer or upgrade an existing one? Often it depends on how much money you have and whether or not you’re prepared to delve into your machine. By ROSS TESTER I WANTED – no needed – a new computer. Since purchasing my last computer just on two years ago, software had become so complex, so demanding that my current machine simply wasn’t up to it any more. I guess I’m luckier than the average computer owner. All told I have three computers at home, not because I’m greedy but more because until a couple of years ago I kept expanding the system as a new model came out. So I have managed to assemble a system which would do a small office reasonably proud. Then again, that’s exactly what my home system is for – a small of­fice. 4  Silicon Chip And while I also have a reasonable amount of hard disc storage (well, with two or more drives in each machine you’d expect that), the one thing I don’t have is performance. I have one computer with a fairly slow 100MHz 586 processor but the majority of my work was still being done on an old faithful 486 machine. Until fairly recently that didn’t matter too much because most of the crunching power I needed was done elsewhere. However, I had to prepare a colour brochure recently and sitting watching that infernal hourglass on the screen convinced me that the time had come! After all, Mr Gates’ hourglass was costing me money! But which way to go? The basis specs I had already decided on the type of computer I wanted. The basic specs were: (1) a proven motherboard with the fastest processor I could afford; (2) the best graphics card I could afford; (3) the most memory I could afford (absolute minimum 32Mb); (4) a very fast CD-ROM drive and a large hard disc (or two or three). With the price of computers almost in free fall over the past year or so, ABOVE: the new ASUS motherboard in “bare bones” form. At top left are the four sockets for 72 pin DRAM, below that the expansion slots – white PCI and black ISA. The large white socket at bottom right is the “ZIF” socket for the CPU. The board will take anything from a 33MHz 486 to a 200MHz Pentium (or equivalent). was it really a proposition to do what I’ve done every time before – upgrade the existing computer? Or would it be better to simply lash out and buy a brand new all-singing, all-dancing computer. After all, the sort of machine I wanted was being regularly advertised for about $2500 or less. “Oh no,” she said (she being the she who must be obeyed). “Not another computer. You already have three and you can only use one at a time.” Having seen all the advertisements for what amount to some very good machines, I’m still not sure she was right. But I was able to make a convincing argument for upgrading one of the existing machines. Ours is no different from many mum & dad businesses, “mum” is not only the one who must be obeyed . . . she The Matrox Millenium II graphics card that was purchased has 4Mb of memory (WRAM) on board, with provision to expand this to 16Mb. also keeps a pretty tight reign on the cheque book! Looking at it logically (how else do you look at a comput­er), I already had most of what I needed. First, the old 486 had a perfectly good tower case, complete with power supply, a flop- py drive and three hard disc drives with over 6Gb capacity. It also had a magneto-optical drive and not one CD-ROM drive but five (one is a highspeed drive, while the other four are integrated into a CD-ROM jukebox). As for the internal cards, there was December 1997  5 cause the I/O is now usually built in. Finally, there was the monitor, keyboard and mouse, all of which were fine. Buying a new computer would therefore duplicate much of what I had and leave me with the job of trans­ferring some of the components out of my existing system to the new machine. It didn’t make a lot of sense. So I went down the upgrade path. In the end, I saved a few dollars and I got exactly the configuration I wanted – after all, I chose it! I’m also very sure about the quality of the computer – something that can be a problem with some bargain-priced sys­tems. After all, if they are that cheap, something must suffer. The motherboard The difference between ISA and PCI cards is clearly visible in this photo. The top card is an Adaptec SCSI controller (ISA) while the lower is the Matrox Millenium II graphics card. Note the difference in the contacts along the bottom edges of the cards and the fact that the PCI card has its components on the opposite side of the card to the ISA. a SCSI controller (it handled one of the hard discs and the M-O drive), a graphics card which was good but not spectacular, a network card and an I/O card. The graphics card would have to go but I was happy with the SCSI controller and the network card. And if I bought a new motherboard, the I/O card would no longer be needed beAfter considerable research and then searching, we purchased an AMD 200MHz K6 CPU chip to go with the Asus motherboard. It offers excellent performance and was significantly cheaper than the Pentium equivalent. There are motherboards . . . and then there are mother­boards. Today, most use one of the Triton chipsets and there are several of these; eg FX, VX, HX, TX and LX. Note that only some of these support the recently introduced high-performance SDRAM, so choose carefully if you want to use this type of memory. Just how well a motherboard will perform depends not only on which chipset it uses but just as importantly how clever the designers have been. Some take shortcuts which might increase performance in one direction but degrade it in another. I remember only too well a mother­ board I bought a few years ago which worked perfectly well with good old DOS. Then Windows came along (actually Windows 3) and it simply refused to work. I took it back to the supplier and he swapped it, no problem at all. “We’ve had a lot of these motherboards come back recently,” he said. The new motherboard was based on the same chipset but from a different manufacturer. It ran Windows without a hitch. After perusing various catalogs and advertisements, I finally set­tled on an “ASUS” brand mother­board costing around $300. Although it uses the HX chipset and doesn’t support SDRAM, this particular board was good value at the time. Since then of course, the technology has moved ahead and now, six months later, you would probably choose one of the later models that does support SDRAM. The processor Everywhere you go these days you 6  Silicon Chip hear about the marvels of the Intel Pentium processor. They’re even advertising the things on TV! Until now, all my computers had been based on Intel pro­cessors but there was a new kid on the block which was getting a lot of attention. AMD, a company formed by former Intel staffers, had pro­duced a number of “clone” chips over the years with little suc­cess. But its newest offering, the K6, seemed to outperform the equivalent Pentium in just about every test I had read. Just as importantly, the K6 offered the MMX, or “Multimedia Extension”, capabilities which Intel had fairly recently started including. If the K6 outperformed the Pentium, how did the price stack up? It took a bit of digging when I first started this project (about six months ago) but eventually I found a couple of suppli­ ers who handled the K6. And, at the time, it was significantly cheaper than the Pentium equivalent. That quickly made up my mind. My new PC would have a K6 processor. That decision was the easy part. Getting my hands on one of the little beasties proved a lot more difficult! No-one had, or could get, stock. A lot of people advertised them but all had the same story: sorry, weeks away. I don’t know how many phone calls I made but in the end, perseverance paid off. Eventually, I found a supplier who had one available because of a cancelled order. Did I want it? I drove across Sydney to make sure I got it! A CPU cooling fan is essential for removing the large amount of heat generated by high-end CPU chips. It comes complete with a male and female power plug adaptor which allow a quick series connection to an existing power cable. Memory The price of memory today is a fraction of what it was even last year. That’s good news because most applications today appreciate every last byte of memory you can throw their way. In fact, some applications I use regularly won’t even wake up with 16Mb of memory. They want 32Mb and are even happier with 64Mb or more. Unfortunately though, the price of memory doesn’t increase pro-rata with the amount of memory. 16Mb sticks cost around $90 and 32Mb sticks around $180. But 64Mb modules cost $600, a price increase that’s closer to exponential! Therefore, until the price of large memory sticks drops even further, I’ll have to settle for the smaller sticks. Note that on this type of mother­ board, there are four memory sockets The CPU chip must be inserted with the correct polarity if you don’t want to see several hundred dollars go up in smoke – literally. No force is required to insert the chip – it is locked in place after insertion by pushing down on the lever shown, hence the name Zero Insertion Force (or ZIF) Socket. in two banks. Each socket in a bank must be filled with the same type of memory – eg, 2 x 8Mb for 16Mb. The other bank can have different sticks (as long as both sockets in the same bank have the same memory). In my case, I used 2 x 32Mb sticks to achieve the 64Mb I wanted. Of course, I could have chosen 4 x 16Mb but this would have meant my future options were cut off. As mentioned above, I really want more memory but having all four sockets filled would have meant throwing memory away in the future. And that led to frustration No.2. You’d think that memory would be pretty easy to get, wouldn’t you? Not so! When I finally placed an order, I was told that the wholesalers were out of stock of 32Mb modules and weren’t getting any more for a week or so. “We have plenty of 16Mb modules, though”. A few phone calls to other suppliers turned up the same story so I had to December 1997  7 Two 32Mb “sticks” give the computer 64Mb of memory. These were inserted into the Bank 0 sockets, while the two Bank 1 sockets were left empty. That’s for future expansion if and when memory becomes even more affordable. sit on my hands for several days! Graphics card Most “bargain” computers come with a fairly basic graphics card. However, if you do any serious work involving graphics or even play graphics-intensive games (I do the former, not the latter) you need a gofast graphics accelerator card. What these cards basically do is free the computer’s CPU of a lot of its housekeeping tasks. The CPU is then left to do the work it’s supposed to do, with the graphics management handled to a large degree by the card. The better the card, the more it can handle and the faster the machine, at least in general terms. There are a lot of cards around. Once again, after reading the reviews and technical information, I made what I believe is a very good choice: the Matrox Millenium II. The model I purchased has 4Mb of memory (WRAM) on board, with provision to expand this to 16Mb. That’s a lot of video memory but would be quite worth­ while for some applications. The one big sticking point is cost: you can put 64Mb of DRAM into your computer for a lot, lot less than you can put 16Mb of WRAM on the graphics card. As you can see, the choice of components for my computer upgrade has been a compromise all the way through. Given a blank cheque, I would simply buy the very latest 300MHz Pentium II machine with 384Mb of memory. But like most of our readers, blank cheques don’t come my way very often! Anyway, after a few phone calls and some running around, I now had the motherboard, the graphics card and the CPU. The new memory turned up a week later and I was ready and raring to go. Out with the old The fan was oriented so that it blows air across other heat-sensitive components on the motherboard. This particular fan clips onto the CPU; other fans latch onto the lugs visible on the ZIF socket. 8  Silicon Chip The first step is to disassemble the existing computer. Before you start attacking it with a screwdriver though, you need to let your computer know it’s about to have a transplant. Yes, the computer has a brain – but it’s not that clever! LEFT: the “System” Icon in your control panel (click Start, Settings, Control Panel) opens up the path to all the information about your particular computer. BELOW: removing devices drivers (as distinct from physically removing the devices) from your computer is easy: just highlight the item to be removed and then click the Remove tab. A confirmation box comes up to make sure you really want to do it because it’s a pretty radical step! Click on OK and the device no longer exists. Every time you turn on your computer, it “knows” what it has inside it. When you add new hardware, you need to load driv­ers to make that hardware work. That information stays on the hard disc and is loaded when the computer is “booted”. Making wholesale changes to hardware - especially the moth­erboard – is almost certain to addle the poor computer’s brain so it won’t know where (or more correctly who) it is! The way around this problem is to first remove all the existing device drivers so that the machine can rediscover its new hardware. To do this, you first activate the Control Panel (via My Computer or Start, Settings), then double-click the System icon and select the Device Manager tab. This presents you with a list of the devices in your machine and you select each one in turn and click the Remove button. As far as the computer is concerned, this is a pretty radi­cal step so it double-checks each time to make sure you really want to do it. And, of course, once it’s all done, the computer is no longer usable. The next step is to exit Windows, turn the computer off and remove all plugs from the back, including the power cords. This done, the cover can be removed and the various expansion cards (sound, video, etc) removed by undoing the screws on the back­plane. It’s important to handle the cards by their edges only, to avoid any possibility of static damage to the onboard components. Incidentally, I’ve removed and replaced literally hundreds of cards and motherboards over the years and have never damaged one. No, I tell a lie – there was that time I dropped one on the floor and ran over it with the chair wheel. However, I have never damaged one through static electricity. Of course, there can always be a first time and Mr Murphy says that it will be either the most expensive or the most irreplaceable card that cops it. If at all possible, leave any cables connected to the cards in place so that you don t get them back-to-front on reassembly. In some cases, the motherboard mounts underneath an L-shaped power supply. Usually, it can be slid out from under the supply but we have seen cases where it is such a tight fit that the power supply itself must first be removed. Fortunately, this is quite simple – normally just four screws hold it in place. Typically, the motherboard will be mounted on a number of plastic pillars held captive in keyed slots and will be secured by a single screw. Once this screw is removed, you simply slide the motherboard towards the edge of the case and then lift it out with its stand-off pillars intact. Clean the case If it is more than a year or so old, you will probably find your computer is filthy inside. The fans do a great job of keep­ing everything cool but they December 1997  9 Here, the motherboard has been mounted in the case, ready to accept the various I/O cards. The difference between ISA and PCI slots is clear: the four white sockets are for PCI cards, while the three black sockets accept ISA cards. Note that we changed the fan pictured on a previous page to one with more power. also suck in dust. While the comput­er is disassembled give the case a good spring clean. Preparing the motherboard There are only a couple of steps you need to take here: insert the memory, install the CPU; and set any required jumpers on the board. OK, so that’s really three steps. I never was good at maths. First start with the memory. 10  Silicon Chip As previously discussed, memory comes on “sticks”. These consist of a number of memory chips on a small PC board and are simply inserted into the appro­priate sockets on the motherboard. This is usually just a matter of sliding the board into the socket at an angle and then pushing it to near-vertical until it is held in position by two retaining clips. Note that each memory board has a corner cut-out so that it can only be inserted one way. Never try to force memory into the socket if it doesn’t want to go – chances are, it’s the wrong way around. Also note our comments before about memory banks. The two Bank 0 sockets must each be filled with the same type of memory, as must the Bank 1 sockets. However, the memory in Bank 0 can be different to the memory in Bank 1. Normally, the Banks are clearly identified on the motherboard and in the manual. Note that you must completely fill a bank or leave it completely empty. As long as Bank 0 is filled, Bank 1 can be left empty or vice versa. Now we move on to the CPU. As we are playing with the best part of five hundred dollar’s worth of chip, it should be left in its protective cover until the last moment. You must also take all the usual precautions for handling CMOS chips; ie, don’t touch the pins, discharge yourself to the case, and so on. To install the chip, first locate the small dot or slightly angled corner on the CPU – this aligns with a blank area (where one hole is missing) on the motherboard socket. Most sockets used these days are ZIF (Zero Insertion Force) types. These have a little lever alongside the socket which is un­ clipped and raised to allow the CPU to be inserted. It is then lowered and locked to hold the CPU captive in the socket. When the lever is raised, the CPU should drop easily into the socket. Because of its pin layout, the CPU can only go in one way, so you can’t get it wrong unless you’re completely ham-fisted and force it in so that one pin is bent over. High-end CPUs such as the K6 or Pentiums require forced air cooling, so that they don’t run too hot. This is achieved via a miniature fan which clips to either the CPU or to the socket underneath. Smear some heatsink compound on the fan heatsink before you place it on the chip and then lock the connecting clips into place. The fans which clip to the CPU have tiny levers which are squeezed together to force the clips apart. The fans which clip to the socket have a one-piece clip which mates with lugs on the socket. Either way, mount the fan so that its airflow is directed across any heat-sensitive componentry on the mother­board – on the new motherboard we selected there were several components with heatsinks attached immediately alongside the CPU socket. Refer to your motherboard manual if unsure. The fan’s power is supplied either from an adaptor plug/socket set which attaches to one of your power supply plugs or, in some cases, via a dedicated power socket on the mother­board. If it is the latter, connect the fan now. Otherwise, leave it until final assembly. Setting the jumpers There are several sets of jumpers on the motherboard which must be set according to the speed and type of your CPU. One important setting is for the CPU voltage – get it wrong and you could damage the CPU. You will need to determine the correct setting from either the CPU itself, from documentation that comes with it or from documentation that comes with the mother­board. In our case, the correct voltage for a K6 (2.9V) was print­ed on the chip. In addition, a sticker was included with the motherboard, because the manual made no reference to a K6 chip (the K6 was released after the mother­board). Another two jumpers are used to set the bus frequency and the bus ratio. Most motherboards today can be set to run at a bus frequency of 50MHz, 60MHz or 66MHz, with the CPU running at a multiple of this frequency (the bus ratio). For example, a 200MHz CPU runs on a 66MHz bus with a bus frequency ratio of 3 (ie, 66 x 3 = 200 or thereabouts). It’s just a matter of setting one jumper to select the bus frequency and the other to select the bus ratio, to set the speed at which the CPU runs. The details will all be listed in the manual for your motherboard. Incidentally, don’t be tempted to run the CPU at a speed higher than its designated rating – eg, a 100MHz CPU at 2x on a 66MHz bus (equivalent to 133MHz CPU) or even 2.5x. While this sometimes appears to work, the CPU was never designed to run at this speed and often fails through overheating. The system will also be crash-happy. Other jumpers on the motherboard may also require changing, depend- There are the various jumpers on the motherboard which need to be checked and/or set. Go through the manual carefully to find out what’s required. ing on your particular setup. There’s only one way to find out and that’s to carefully go through the manual. seem to mate with a hole in the case, a blind standoff might be called for. Reassembly What’s this? Your old cards don’t match the slots on your new mother­ board? Over the past few years there have been several standards for slots: 8-bit ISA, 16-bit ISA, VESA and PCI to name but a few. Older cards are more likely to be ISA and most new motherboards normally have at least three ISA slots and almost invariably they will be 16-bit. Any 8-bit ISA cards you want to use can be simply plugged into half of a 16-bit slot. VESA cards won’t fit into anything but VESA slots and new motherboards don’t have VESA slots, so these cards will have to be replaced. Fortunately, the majority of cards these days are much cheaper than they once were. If you are buying new cards, PCI will give you the best performance and compatibility. However, note that some cards are only available as ISA types. Before inserting the cards, take a few minutes to plan their location. You can either end up with a dog’s breakfast of cables going hither and thither, or you can make it logical and neat. Naturally, the more drives, etc you have, the worse cabling will As you might expect, reassembling the case is basically a matter of rev­ ersing your disassembly steps. But (there’s always a but, isn’t there?) your new motherboard may well be a different size to your old one. Fortunately, the mounting hole locations are standardised and you should have no problem there. To be sure, place the motherboard in the case and check the line-up. The standoffs will have to be removed from your old moth­erboard so you can use them on your new one. To remove them, grip their tops with needle-nosed pliers and push them through the board. Some motherboards have an edge-mounting standoff. This prevents the board from flexing, especially when cards are in­serted into the slots. My old board had one of these but the components on the new board were too close to the edge to fit this stand-off. Other types of standoffs you might find used include blind types which do not fit into holes in the case but again are designed to keep the board straight. If you have a hole on your motherboard which doesn’t Card insertion December 1997  11 ROM PCI/ISA BIOS (PI55T2P4) PNP AND PCI SETUP AWARD SOFTWARE, INC. Slot1 (RIGHT) IRQ Slot 2 IRQ Slot 3 IRQ Slot 4 (LEFT) IRQ PCI Latency Timer :  Auto :  Auto :  Auto :  Auto :  32 PCI Clock DMA  1  Used By ISA : Yes DMA  3  Used By ISA : No/ICU DMA  5  Used By ISA : No/ICU IRQ    3  Used By ISA IRQ    4  Used By ISA IRQ    5  Used By ISA IRQ    7  Used By ISA IRQ    9  Used By ISA IRQ   10  Used By ISA IRQ   11  Used By ISA IRQ   12  Used By ISA IRQ   14  Used By ISA IRQ   15  Used By ISA :  No/ICU :  No/ICU :  Yes :  No/ICU :  No/ICU :  Yes :  No/ICU :  No/ICU :  No/ICU :  No/ICU NCR SCSI BIOS USB function ISA MEM Block BASE : No/ICU :  AUTO :  Disabled ESC : Quit ↑ ↓ → ← : Select Item F1 : Help PU/PD/+/- : Modify F5 : Old Values (Shift)F2 : Color F6 : Load BIOS Defaults F7 : Load BIOS Defaults Fig.1: if you have non Plug’n’Play ISA (legacy) cards, then you need to reserve their IRQ assignments in a section of the CMOS setup labelled “PnP and PCI Setup” (or similar), as this screen mock-up shows. This prevents a PNP operating system such as Windows 95 from attempting to assign those IRQs to PnP cards. In this case, IRQs 5 and 10 have been reserved for ISA non-PnP cards. be. But at least plan it to look as good as it can be. When inserting cards, make sure that they are fully insert­ed into the slot at both ends. They sometimes look like they are in, but one end is not quite seated. At best, the card won’t work. At worst, you could do some damage. Always make sure the card is secured to the backplane with the appropriate screw. And if you manage to drop a screw onto the motherboard, make sure you fish it out immediately. Don’t put it off until later – it’s easy to forget and could easily short components or tracks together later on. Traps for young players The major problem people have when assembling (or reassem­bling) a computer is the cabling. Would you believe it was also the only problem I had? And that was after having done this job many times before – and being wary of the problem! The first job is to fit the power plugs to the motherboard. There are two plugs which must be inserted the right way around. Simply remember that black goes to black – there are black wires on both plugs and these 12  Silicon Chip go together. The plugs insert one way around only and as long as black goes to black you’ll get it right. If you haven’t removed the plugs from your cards, you shouldn’t have any problems. But if you have, be aware that most cables with IDC plugs can be inserted two ways: (1) the way that works; and (2) the way that doesn’t! Almost invariably, pin 1 is the pin with the red stripe. And usually (though not always), pin 1 is marked on the mother­board. If it isn’t you may need to refer to your manual. Finally, make sure that all cables are seated completely. This is where we got into trouble: none of the CD-ROM drives worked when the machine was turned on. After much frustration, it turned out that the connector was lifted very slightly off the motherboard socket at one end, which meant that some of the pins weren’t making contact. It looked OK but it wasn’t – pushing the connector hard on solved the problem. Setting up the system If you have only swapped the motherboard and left every­ t hing else basically intact, you shouldn’t have to go through the rigmarole of reinstalling Windows 95. However, if you change hard discs at the same time, then you will have to reinstall the operating system on the new disc. These days, you don’t have to tell the CMOS what your hard discs are – with modern mother­ boards, they are auto-detected! A modern motherboard will have a “Plu­ g’n’Play” (PnP) BIOS. When it was first introduced, this earned the nickname “Plug’n’Pray” because it didn’t always work exactly as it should. These days, though, a PnP BIOS generally works quite well, although some of the cheaper expansion cards can sometimes cause problems. However, most problems with PnP occur when you mix old style (ie, “legacy”) ISA cards and PnP cards. Legacy cards are cards on which you manually set the IRQ (interrupt request) assignment and any other resources required by the card (eg, the memory I/O range). This can be done by using on-board jumpers or by means of a software setup utility. The problem is that a PnP operating system such as Windows 95 doesn’t automatically detect any IRQs that have been set in this manner. As a result, it may try to automatically assign an IRQ that has been taken by a legacy card to a PnP card. The result is a resource conflict with either one or both cards not working properly. Reserving IRQs Fortunately, there’s any easy answer to this problem. The trick is first write down the IRQs that have been assigned to the legacy cards and then go into your CMOS setup and reserve these IRQs so that the operating system cannot grab them. You normally do this via a section of the CMOS labelled “PnP and PCI Setup” or similar – see Fig.1. For example, if you install a legacy ISA card that requires IRQ 10, then you change the setting for the line “IRQ 10 Used By ISA” from “No/ICU” to “Yes”. Note that the screen mock-up shown in Fig.1 is for an Award BIOS. Your BIOS may show a somewhat dif­ferent arrangement but the basic principle is still the same. Note that you may also have to reserve DMA channels for legacy ISA cards (especially sound cards). Check the manual for the device to find out its requirements. Once the IRQs have been reserved, This window is accessed by double clicking the System Icon then the Device Manager tab. It presents you with a list of everything in your computer – as far as your computer is concerned. Double clicking on any item with a “+” symbol reveals the individual devices being controlled, along with any conflicts. the remaining IRQs will be automatically assigned to the PnP devices and there should be no conflicts. To check this, open Control Panel (via “Start” and “Settings”) and then double-click the System icon. Select the Device Manager tab and you will see a list of devices in your ma­chine. If there are any conflicts, you will see a yellow exclama­tion mark next to the particular device. If any devices are conflicting, click the Details button to find out which device is causing the problem. If you haven’t reserved the IRQ for the legacy card in the system BIOS, then doing so should solve the problem. Alternatively, try setting the legacy card to an unused IRQ and don’t forget to reserve this in the system BIOS so that it cannot be grabbed by another card that’s added in later. Note that there are some IRQs which are used by certain devices by convention. If at all possible, these conventions should be maintained to avoid future conflicts. Finally, if you get yourself into a In this case we’ve double-clicked on the SCSI Controllers entry to reveal all the information we need to know about our SCSI controller; ie, its settings, the driver it uses, addresses, IRQs and so on. Fortunately, we have no conflicting devices but if we did, this screen would show them. Double Click on the Computer Icon in the System Properties window and you can see which interrupt request (IRQ) assignments are used in your computer, and by what. You can also check the I/O (input output) settings, DMA settings and the memory being used by that device. mess, try starting off with a “barebones” system (ie, as much as you need to get the computer started) and then add the expansion cards in one at a time. Get each card going prop- erly before adding the next. Provided you approach the job in a methodical manner, you should be able to get everything up and running without SC too many hassles. December 1997  13