To browse this website, you should unconditionally agree to its terms and conditions. If not, please stop and leave now.

Site Logo

How To Assemble A PC By Hand

As mentioned in my article PC Hardware Explained, anyone with a screwdriver can assemble a personal computer (PC) by hand. The components of a PC are modular in nature. They do not have to be welded or wired or tied together. When a few screws, levers, and plugs are in place, a PC is ready to go. In this article, you will learn about assembling a PC. You will need a set of Philips screwdrivers and some old newspapers for it. (Get it from an electric hardware shop.) That's all.

Before I start, I would like to stress the importance of handling PC components with care. If a pin is bent or a solder joint becomes loose, the entire component will become unusable. Also, before handling PC components, discharge your body of excess static electric energy by (grounding yourself by) touching a reasonably big metallic object such as a steel chair. You must not be dropped beads of sweat on the components. So make the room comfortably airy but not very drafty. Do not wear loose clothing or keep screwdrivers in your shirt pocket (you may drop them). So, let's start.

When you buy the components, buy the motherboard, CPU (processor), and RAM (memory) from the same shop. Ask the salesman to fix the CPU and RAM modules to the motherboard and test it. (He will have a spare ATX cabinet and a monitor (computer display) to and perform the BIOS POST (Power On Self Test). This is important because you know for sure that the most important components of the PC are working order before you leave the shop. Also, this eliminates that chance of your damaging the CPU when you try to fix it on the motherboard.

If you have no option but to fix the CPU yourself, then refer the motherboard manual and follow that method prescribed there exactly. Different CPUs have different methods to installing the CPU. Apart from the CPU, a heatsink-fan combination (to dissipate heat generated by the CPU) will also be needed to be fixed at that time. Both AMD and Intel processors come with factory-supplied heatsink and fan combinations. However, AMD CPUs are the easiest to install. DO NOT INSTALL THE CPU WITHOUT HEATSINK AND FAN.

ATX Cabinet

First, spread the newspapers on the floor and place the ATX cabinet (case) on it. The left side of the cabinet usually comes loose if you remove the screws that fasten it on the back of the cabinet. When you buy the cabinet, a set of screws, washers, and nuts will be available in a plastic bag or cardboard box kept inside the cabinet. Find this and keep it aside. Next, connect the SMPS unit (power supply) to top part of the cabinet using the nuts provided with power supply or the cabinet. When you are done, you should be able to see the sockets for the power supply and CRT (computer display) set on the back of the cabinet.

You will also notice that a set of wires hanging from the power supply (SMPS) and another set of wires from the front side of the cabinet. Now, set the cabinet with its right side to the floor. Place the ends of the wires from the SMPS outside the cabinet. Do the same for the wires from the front side of the cabinet.


Now, take a good look around inside the cabinet. The metallic base you see is where the motheboard will sit. Notice the holes where some nuts can be screwed in. Now, take your motherboard and check it out - top to bottom and left to right, and front and back. (Hold the motherboard by its edges.) Notice any certain holes on the motherboard that match those on the metal base in the cabinet?

Placing the motherboard on the ATX cabinet

Now, gently place the motherboard on the base of the motherboard and identify holes on the motherboard matches those on the base. Take the motherboard out and place it outside again. Check the plastic bag that came with the ATX case. You will find some brass bolts that have threads inside as well as on the outside. Take at least six of these and screw them on the holes on the base of the motherboard.

Next job is to fix the motherboard. Here, you have to take some care because the top-left side of the motherboard contains ports such as USB, keyboard, and mouse, which actually project and stay outside the cabinet. These ports actually jut out of appropriately-shaped holes on the back of the cabinet. Some cabinets may have a nothing but a big window in this area. If you check the loose items that came with the cabinet, you will find a metal plate, which can be fixed on this window. This plate has appropriately shapes for the ports of the motherboard. Ensure that you have fixed this plate before you bring the motherboard in.

Fixing the motherboard on the cabinet

Now, bring the motherboard inside again and place them on top of these bolts. Do you get the idea now? The threads on the bolts hold on to the motherboard and when the screws from the motherbard are fastened on top of the bolts, we have the motherboard fastened on a solid foundation inside the cabinet! So... you take some screws from the plastic bag and tighten the motherboard to the cabinet.

Next, you have to connect the power cables from the SMPS to the motherboard. This cable usually has the biggest connector in the set of wires from the SMPS so identifying it is easy. Another important cable that needs to be connected is the CPU fan cable. You may have to refer the motherboard manual for a diagram, which will clearly identify the connectors for these. Rest of the wires from the SMPS are usually connected to devices such as hard disks, DVD drives, floppy drives, graphic card fans, and cabinet fans.

Next job is to place the IDE devices such as hard disks and CD/DVD drives. CD/DVD drives go through the front on to 5.25-inch racks there. To remove the plates on the front insert your hand behind them, push the fasteners on the sides inwards while gently pushing the plate forward. A hard disk must be inserted from the inside of the cabinet on a 3.5-inch drive bay in the front of the cabinet. If you have a floppy drive, it should also be placed on a 3.5-inch drive bay. IDE drives must be fastened on their left and if possible right sides with nuts that come as part of the package. Some cabinets are so designed that you don't have to use any nuts at all. Next, take some molex connectors at the end of cables from the SMPS and connect them to the PATA IDE drives. This is necessary to provide electric power to the drives. SATA drives need special power SATA power connectors. If your SMPS do not provide them, then you have to use molex-to-SATA power connectors, which must to be connected to a molex connector on one end and the SATA drive on the other end. Next, you need to provide data connections to the drives. PATA hard disk and optical (CD/DVD) drives must be connected with 80-pin and 40-pin 40-wire parallel IDE cables. These cables are usually in beige color. SATA hard disks must be connected with the smaller SATA IDE cables. These are usually are in red color. After connecting the data cables to the drives, you need to connect them to the motherboard. Refer the motherboard manual to identify the correct SATA or PATA connectors on the motherboard.

Now comes the trickiest part - connecting the LED cables from the front of the cabinet to appropriate pins on the motherboard. For this, spend some time on studying the markings on the cables, the motherboard diagram, and the pins on the motherboard itself. With some trial and error, you will be able to connect to the motherboard wires for the power on/off button, PC reset button, power on/off LED, hard disk activity LED, and cabinet speaker. If not, just go ahead and connect the power supply unit to the mains. When you do this, the CPU fan will spin for a few seconds and then stop. This is normal and this is how ATX cabinets work. Now, use your screw driver to short the pins in the motherboard that you think could be the ones for power button. If nothing happens, try the same for other pins that may be the right candidates. (Refer the manual again.) If the PC starts, it means you have identified the correct set of pins. Now, connect the wires to these pins. Using a similar method, you will be able to find the pins for the reset button also. Only in this case, the CPU will restart rather than start.

When you are finished connecting the pins, you can populate the slots in the motherbaord with your graphics card, sound card, etc. This over, connect your monitor's power cord to the SMPS. If your SMPS does not have an outlet connect it to the mains directly using an appropriate cable. Most CRT monitors come with two sets of cables. After that, connect the video signal cable to the graphics card.

Power on the system and see if everything seems to be fine. Set up the BIOS and install your OS. Sometimes, you may have to remove your PCI cards and place it in another slot. Or, you may have to assign a different IRQ to a card or device. You can then close the cabinet. Switch off the system. Mark and bundle the wires.

Store the manuals and driver CDs in a safe place. Download and install driver updates for your hardware and write them to CDs after installing them.