DIY PC - Assembly

How to assemble the computer..

  In the old days, the basic advice for build for assembling the various parts which make up the PC was simple: Build up the computer bit by bit, checking the computer functioned as expected before continuing to add more devices. The assembly then becomes a long, but simple, process of upgrading:

  For example, you would start by setting up the processor, motherboard and PSU, switch it on, and see if it beeped. If everything seemed ok, then you would go on by maybe adding the video card, and then the floppy drive etc. There is still a lot to be said for building the PC in this way. It may take a little longer, but should you make a bad mistake, the chances are that you will only ruin a few pieces of kit.

  However, if you have enough confidence in your own ability and the parts themselves, (which are at least initially more reliable than they used to be), you can work the other way around, assembling the whole system at once. You then only have to remove bits one by one should you find a problem when you are done.

Read the motherboard manual. (again)

You really, don't want to fall down on this one. Make a list of all the jumpers which must be set, ready for them to be checked off. Learn the layout of the board. Make sure you know what voltage your CPU will require. Make sure your proposed memory configuration will be acceptable. RTFM. RTFM again.

Locate the motherboard fixings.

As you take the motherboard from its anti-static bag, remember why it was in there, and try to take care of it!

Before you get to work on the board, it might be an idea, to make sure it does actually fit your case. In some, 'baby' cases it can be a very tight squeeze.

Next locate the holes in the case which you will be screwing the motherboard down to. Do they line up? If they do, will the ISA/PCI slots on the motherboard still line up with the cutaways in the case? At this stage, you may need to drill some more holes. However, remember, not every hole on the motherboard must have a screw, so use your common sense. Modern ATX cases often have the 'legs' which the motherboard rests on built into the case as raised bumps - older cases require small hexagonal legs to be installed, (these should come with the case).

Setup the motherboard.

Set all the required jumpers now, while you have access to the whole board. Lay the board out on its anti static bag, or even better some foam. A fine nose pliers can be useful when setting jumpers, but is only really needed on badly designed motherboards, or when the motherboard is already installed. Check and recheck the jumper settings for bus speed, processor speed, clock multiplier and voltages.

    Make sure the CMOS battery jumper is connected, since this is usually left in the off position, for storage. While you are there, check the battery contacts are clean, since a PC with a dodgy clock is a real pain. The CMOS battery is generally a coin sized standard CR2032 (3v) which can be bought quite easily from many high street shops should yours fail at some time in the future. Take reasonable care not to soil the battery contacts with finger prints etc.

    Also at this time, install the main memory boards (and if necessary the level 2 cache memory). Take great care when handling the memory, since these are some of the most static sensitive parts in the computer. Remember to earth yourself to the PC case before you touch any of these items and try not to touch the memory chips themselves or edge connector at any stage. SIMMs can be quite tricky to position correctly, especially if you are unfamiliar with the connection arrangement. Take your time, but make sure that the boards are correctly seated before moving on to the next item to place. DIMMs are comparatively easy to install.

    While you are in an static-aware frame of mind, why not place any extra chips you might need onto your video/sound cards etc? Once this is done you will be able to take a little less care as you handle the rest of the components.

    Before inserting a Socket 7 processor, read the instructions on the box of the processor fan.

Depending on the type of fan, the clip which holds the fan and heatsink to the processor, may need to be placed on the socket first. Thus, you may need to create a sandwich of, fan/processor/clip before you insert. Anyhow, at this stage, do everything you can to keep the underside of the heatsink, and top of the processor clean, and grease free. They will need to be in as near perfect contact as possible.

    Insert the processor, taking care not to touch the pins if you can help it. The Socket 7 is called a ZIF socket, this stands for 'zero insertion force'. Thus to insert the processor, all that is required is to lift the lever on the side of the socket, line the processor up, and then replace the lever, at no stage will you have to push the processor down.

    The Pentium II is connected to the motherboard via Intel's propriety Slot 1. In this arrangement the processor already comes with a large heatsink and fan. The processor is mounted vertically, which means that it must be held at the sides by some pretty tough plastic supports, these should come with the motherboard, and be installed before anything else, (if they are not already). A fair degree of force is required to insert a PII into the Slot 1, however the most important thing to remember is that the force must be evenly given at each end of the processor, so that the top stays horizontal as it moves down into the slot.

    If you have the time you could do worse than to fit and remove some internal cards, into the ISA, PCI and AGP slots to loosen them up a little. This might save the motherboard some stress later on since some edge connectors are very stiff to begin with.

Fix the motherboard into the case.

    Locate the screws, and spacers, so that the motherboard will be firm, even if placed on it's side.

    Make sure that the under side of the motherboard is not shorting on the case at any point. On many tower cases you first secure the board to a side flap which is then folded up into its correct position in the case and secured. ATX cases often allow the entire motherboard and cards to be screwed to a plate outside of the case to be inserted later. If you have a tower case place it onto its side to continue the build process.

Connecting the power leads.

With the PSU OFF (PSU's internal fan NOT running!) it is time to wire the motherboard for power. Firstly locate the PSU leads. There should be a mess of them sticking out the end of the power supply. There will be groups of coloured leads with three different types of connectors. The motherboard is powered by two leads with 6 wires, or a single large connector. The other devices in the computer, are all powered by leads of 4 coloured wires, a with large or small connector depending on the device.

Firstly connect the motherboard leads. On an AT motherboard the connectors should be positioned so that the black wires on each lead are next to each other, when fitted into the motherboard. ATX motherboards have only a single large connector.

Next, connect the processor fan's lead. In a Socket 7 motherboard this will be a short lead which connects to one of the larger 4 wire general purpose power leads, and provides a continuation of that lead to power one of the other internal devices. If you do not connect the free end to any other device, make certain the lead will not fall into contact with the Heatsink or Fan. In a Pentium II board the PII fan will have a short lead which should be attached to a small power socket on the motherboard nearby.

Fit the other power leads, as you fit the other internal devices. The floppy disk drive will require the smaller type of connector. Other devices such as Hard disks and CDRoms will require the larger type of general power lead.

    Do not be confused by leads which appear to have more than 4 wires to their connector, these are merely where a power lead has been doubled up, by adding a second connector in parallel to the first. [Usually this extra is of the smaller type].

    Unused leads are merely left, out of harms way. In the process of fitting and refitting, the connectors can become misshapen, if this occurs, use the fine nosed pliers to bend the internal pins into proper points.

    Finally, using the motherboard manual, and some common sense, fit the case's LED leads to the correct positions on the motherboard. If there is a 'turbo' lead, then you will not find a space for it, since Pentium motherboards do not have this function. You might like to fiddle around until you can connect it to a second HD.

Fit the internal cards.

How many cards you decide to fit at this stage is up to you. A bare minimum would seem to be sensible. Fit the video card, and I/O card, if you need one.

All other cards may be fitted as 'upgrades', which you should be very familiar with doing already.

Fit the serial and parallel port leads onto the motherboard, or I/O card if necessary, and make sure you use the holes provided in the case, rather than take up an ISA slot space. To do this, unscrew the external port sockets from the ISA plate, force open the correct size hole in the case and fit.

Fit the internal devices.

    Floppy and hard disk drives may be fitted now, depending on how confident you are with your construction job so far. Insert floppy and CR drives from the front of the case.

    The floppy disk is powered by a 4 wire lead with a smaller connector, and you can have fun working out which way up it should go.

    Both the hard and floppy drives should be secured with the correct length of screw, and care should be taken not to over tighten them. The floppy disk may require you to force open the slot on the case, to allow its fitting.

    The final job is to make the, increasingly untidy innards of the computer worse, with the addition of the ribbon cables to the drives. Ribbon cables are marked on one side, and this should be matched to Pin 1 of the cable connector on the motherboard, though a mistake here, shouldn't result in any damage. The master IDE HD should be the first onto the cable, if appropriate set the master/slave jumpers the HD.

Finishing off.

Before switching on you should check all the work you have done so far. Tidy up the cables with cable ties, placing them in such a position, that they will not be able to foul the processor fan, or any other component.

    Check the power leads to the motherboard again.

    Make sure the speaker is connected, and that it is securely fastened to the case.

    You have built your PC.

A page from James David Chapman's website. Located at: http://www.users.globalnet.co.uk/~jchap/ Site mirrored here at: http://www.j.chap.btinternet.co.uk
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