You may be wondering: “why would I want to disassemble a computer in the first place?” There are several reasons why you will have to do some level of computer disassembly. Perhaps the most frequent reason is to upgrade.

Why upgrade a computer

Computer technology changes very quickly. The state-of-the-art computer you buy today may be out of date in a year and obsolete in two, unless it is upgraded. The best way to extend its useful life is to upgrade it frequently. This may include:

• adding more memory.
• changing to a larger hard drive.
• or going for a faster modem.

Another reason for computer disassembly is repair. Computers break. A hardware malfunction inside the computer requires some level of disassembly. Finally, you will have to do some disassembly to add a new capability such as a sound card, DVD-ROM drive, modem, or a network card.

Considerations before computer disassembling

The important thing to remember when disassembling a computer is to document everything. It is embarrassing and sometimes costly to forget how everything goes back together. The probability of getting everything properly in order is by a detailed documentation process.In particular, you should document where the various cards inside the computer are located; how the cables are routed and oriented; the hardware used; and anything else that might cause a mix up when getting things back.

Electrostatic discharge

Let’s review electrostatic discharge or ESD. When working inside the computer, more damage is done by electrostatic discharge than by any other single factor. In fact, any time the computer is open, you risk damaging the circuits inside by electrostatic discharge. That’s the bad news. The good news is this risk can be eliminated by a few common-sense precautions.The first action to observe is the use of anti-static wrist strap. It is a simple conductive strap. One end fit around your wrist; the other is clipped to the ground on the computer. It dissipates attempts of electrical charge accumulation. It keeps your body and the computer chassis at the same potential, virtually eliminating the risk of ESD.

Use of anti-static wrist wraps

• If you are concerned about deliberately grounding your body when around electronics, set your mind at ease. A resistor built into the wrist strap limits the current to a safe level should you inadvertently brush against a live terminal.
• While the anti-static wrist strap greatly reduces the risk of ESD damage, there are some other precautions that should also be taken. You should turn off power to the computer and that for other devices connected to it before doing any disconnection on the computer.
• It is advisable to leave the computer system plugged in. The reason for this is that the ground-wire on the cord will keep the chassis at ground potential.
• Also, it is good practice to use ant-static mats on your work bench and on the floor where you will be standing. These are conductive mats that, when properly grounded, prevent the build-up of static electricity.

Circuit boards

Circuit boards are especially vulnerable when they are unplugged from the computer. You should be very careful to handle the boards only by their edges. Do not touch the components, the foil pattern, and the board connectors. When not in use, keep the boards in conductive anti-static bags. These simple precautions will go a long way toward eliminating the danger of ESD damage during computer disassembling.

Disassembling a computer

• firstly, turn off power to the computer and anything else that is connected to it, such as the monitor and printer. Never connect or disconnect cables from “live” equipment. Once the power is removed, disconnect the external cables. Disconnect the monitor and set it aside. The monitor is connected to the VGA connector on the computer. Once disconnected, you can recognize the VGA connector by its fifteen pins, arranged on three rows of five pins each.
• Disconnect the keyboard and set it aside. Some older keyboards use a large, round five pin connector called a DIN plug. Others use a smaller, round six-pin connector called a PS/2 type connector and others, the majority today are a simple plug and play.
• Disconnect the mouse and set it aside. Some computers use a serial mouse that connects to COMM1 serial port. In this case, the connector is a nine pin D- shaped affair with the male end connected to the mouse. Others use the small, round six-pin PS/2 connector, and others use a plug and play.
• Once everything is disconnected, you are ready to remove the cover. Look for the four screws along the narrow lip of the cover where it overlaps the back of the computer. Be very careful not to remove the screws that hold the heavy power supply in place by mistake. Once the screws are removed, lift the cover off by sliding a few inches and lifting it up.

The motherboard

The large board that occupies the lower left quarter of the chassis is called the mother board. This single board contain the microprocessor, the various buses, and the interface circuitry. It also provides bus slots and sockets for a wide range of expansion boards. The motherboard is called by a variety of other names. Throughout its history, it has been variously called the system board, the planar board, the baseboard, the main board, and the logic board. In this article, we will call it the motherboard.

Power Supply

• Another prominent item that is easy to locate in any computer is the power supply. It is usually a metal cage with AC outlets accessible through the chassis on one side and a bundle of colorful cables on the other. The power supply converts the AC line voltage into low level DC voltages used by the various components inside the computer.
• In today’s global economy, the manufacturer of the computer is never quite sure where the computer will end up. Most computers use a power supply that will accept either 115 volts AC or 220 Volts AC so that it will work in a variety of countries.
• Two types of PC power supplies are common today. With the so-called AT type, the output voltages produced by the power supply are +5 volts DC,+12 volts DC, -12volts DC, and -5 volts DC.