Next you can plug the CPU in place. There are now several different types of CPU to system board sockets available. If you've shopped carefully and have the correct combination of board and CPU, and if you read the manual you will see that there is only one way to plug the CPU into the socket. Be patient and gentle. Look the CPU and socket over carefully before you assemble them.
The RAM should be installed next. It should only fit one way. If you look carefully at the bottom of each RAM stick, you'll notice that there is a notch in it that makes it fit into the socket on the board only one possible direction. Again, be gentle, don't force it.
Now you need to set the jumpers for the CPU and, if applicable, for the RAM. Look in the manual for the CPU setting charts. There will probably be (at least) four charts for four "banks", or sets of jumpers to control the CPU settings. Each of these must be correct in order for the computer to function properly. The jumper banks will likely be broken down as follows:
* The CPU I/O voltage. This is a general setting for whole families of CPUs. There will probably be one setting for all older CPUs and one for newer ones. Whatever the arrangement, the manual should spell it out clearly.
* The CPU/Bus speed. This is the multiplier for the CPU speed. You should have a chart in your manual with settings for X2.0, X3.0, X4.0, X4.5, etc. This setting works with the CPU clock speed (next item) to set the final CPU speed.
* The CPU clock. This setting controls the speed (MHz) at which the CPU functions. For example, a 400MHz Pentium II CPU should be jumpered at 100MHz with the BUS speed multiplier set to X4.0. Thus 100MHz X 4.0 = 400MHz. Or, if you have a 300MHz AMD CPU, the setting would be 75MHz X 4.0 = 300MHz. This figure is a close approximation of the actual CPU speed. When you hear a computer referred to as a e.g. "450 Celeron", this is what someone is talking about.
* The CPU core voltage. Every CPU has certain specific core voltage requirements. Many chips have this figure stamped directly onto the chip itself. If you can't find it there, look in the paperwork for the CPU. The manufacturers web page should also have this information available.
Not all motherboards have jumpers, some have switches. Other motherboards don't have jumpers or switches, they have something called SoftMenu, which means you boot the PC when you have all the parts installed, and carefully look on that first black screen for a message that reads something like "Press DEL to enter Setup." Check the motherboard manual for details how to enter the Setup menu, or BIOS. Then look in the BIOS for an entry called SoftMenu or CPU Menu. Here's where you set the clock and bus speed. The advantage of this is that you don't need to fiddle with those pesky little jumpers that have the nasty habit of jumping out of your fingers (that's why they are called jumpers - I think) into the smallest crevice available.
Check the manual to see if your RAM requires any jumper settings. If so, just use the same methodical approach and you'll be fine.
Now it's time to plug in the ribbon cables.
Note: This article deals with IDE drives, since they are the most popular for the home user market. If you have SCSI devices in your setup, please check out our ultimate SCSI guide for details on how to easily install SCSI devices.
These cables connect the different drives (floppy drive, CD-ROM and hard drives) to the system board. Each ribbon is 12, 18 or 24 inches long, and will have two or three connectors. Note that the floppy drive ribbon cable will only plug into the floppy drive because of its different size. You can't plug it into the hard drive or CD-ROM. Also, you'll see that it will only plug into one connector on the system board. Most system boards label the connector "Floppy" or similar, so there is no mistaking where it goes. The floppy cable stands out a bit because it has a funny twist towards one end. Plug the connector at the end after the twist into your floppy drive, this is what makes it drive A:. If you plugged it into the middle connector before the twist, it would become drive B:. The connector on the other end of the cable, away from the twist, goes into the floppy controller connector on the motherboard. Additionally, each of the connectors for these cables will only fit into their respective sockets one way. This is accomplished with a locating pin placed on one side of the connector or with asymmetrically shaped connectors. It might be possible to jam one of these connectors into the wrong socket but it wouldn't be easy to do (if you could do it at all) and you would almost certainly damage the connector in doing so.
The Thin Red Line
Nope, we're not talking about the sorry excuse for a movie with the same name, but about the most important clue on how to connect the ribbon cables correctly. Along one side of the ribbon cable (both floppy and hard drive) you'll notice a red stripe. This marks the side of Pin 1. On every hard drive and floppy drive and CD ROM drive you'll find a marking somewhere around, over, under, at, near the plug that shows you where Pin 1 is. Usually this marker is a tiny number 1 printed or an obvious arrow pointing. The same applies for the opposite connector on the motherboard. Line up the red line on the ribbon cable with the marker for Pin 1 and you're golden.
Each of the ribbon cables will have either two or three plugs; one at either end and a third plug (optional) closer to one end than the other. The end of the ribbon cable with the lone connector is the side that plugs into the system board. This holds true for both the floppy and HDD/CD-ROM ribbon cables.
The hard drive ribbon cable can plug into one of two connectors on the system board. Both connectors are for hard drive cables, but one of these is the Primary IDE connector and the other is the Secondary IDE connector. Each of these has a similar though specific function. Your system board will accommodate up to three separate individual hard drives along with one CD-ROM drive. All of these items plug into these IDE ribbon cables, however, there is a particular order in which these items are connected. For now though, let's finish assembling the system board in the case.
Now look for a series of thin colored wires with small plugs coming from the inside front face of the case. These are the wires for the power switch, speaker, reset button, HDD light and fan in the front of the case. The little plugs will be labeled clearly. You will also notice that the plugs are notched, shaped asymmetrically and there will be a marking to indicate which is the number one pin. Now look at the corners of the system board for a series of little prongs sticking up. You'll know you've found them when you see the labels on the system board itself for the POWER SWITCH, FAN, SPEAKER, HDD (for the hard drive activity light) and POWER LED. They're usually all close together, bunched up in one corner of the main board. Note that the corresponding number one pins are labeled with a small triangular arrow head. They've made it basically foolproof. What with labels, specially shaped plugs and number one pin markers it's a straightforward job of plugging all those items in.
You should consult your motherboard manual for some help with plugging these cables in. Any decent manual has a clear diagram explaining exactly which pins are for what and how to connect the cables to them. Also, keep in mind that you can't really do much wrong with these cables. After you are done assembling and turn the PC on, watch the lights on the front of the case and make sure the switches work. If they don't, simply turn it off, reverse the plugs for the item(s) that didn't work, and you should be in business.
Looks like a good explanation
