Here i will post specific details and diagrams in order to help experts in Tanzania’s charity to rebuild, upgrade/replace certain components in computer systems..

The shell of the Computer

I will begin with the Shell this is not necessarily and technical part of the computer but it is more of a body for it all to fit into and cover the inner parts to protect them from dust, with the shell you have to get a compatible motherboard and stick it into the shell back-side, from here screw it in with the screws that would have come with it or a screw that fits, there are other parts on the shell that can have parts screwed into it but i will come to them later.

The Motherboard

Next is the Actual motherboard itself Made mainly out of an epoxy resin which is a plastic material, something which is damp proof and which doesn’t conduct electricity. The motherboard connects the various components of a computer together via a series of minute paths. There are a few types of motherboard such as Full AT, Baby AT and the ATX, you can find out which one you have by measuring the motherboards dimensions.

If the motherboard is 12 inches wide and 11 inches long it is a Full AT However this model came with problem that you may experience later when installing other parts of the computer, such as PCI slot expansion cards for example the Video Card or Sound card.

The Baby AT is 8.5 Inches wide and 10 inches long and can be easily recognised by the DIN keyboard connector in the top right corner. Compared with the Full AT the baby is around two thirds it's size and incorporated with a 7 ZIF slot for the classic Pentium processors, i will cover processors later as well.

The Processor

Another of the main parts in a computer is the processor. The processor (also known as the CPU) is like the main brain of the computer, it interprets and executes all actions made by the user be they software jobs such as saving, opening or drawing in a paint programme. The overall speed of the computer is generally taken from the speed of your processor, so if you have a fast processor your computer has the potential to also be fast at calculations and tasks. a fast processor nowadays would be averagely around 600-700MHz .. Any CPU with these speeds will do almost any task you need of it, and almost any application or game in the market at present.

To remove/replace a processor, follow this step by stop guide (below)

 

Step 1 – Health and safety, remove all power supplies and plugs etc. from the computer before continuing to any other steps Anti-static wrist band connected to rubber map, which the computer is sat on to neutralise ant excess power that may still remain in the device.

Step 2 -  Remove the outer shell from around the computers frame, this allows for access to the computers inside parts.

Step 3 – lay the computer on it’s side with the motherboard on the bottom side, remove any plugs and leads that are in the way.

Step 4 – the latch on the processors case holding it in place, will come off easily if you just pull it up gently, after this the processor can be removes, and a new one placed in.

Step 5 – to remake the computer after having done this, repeat steps 3, 2 and 1 in this order.

RAM (Random-access memory)
There are two main types of RAM Volatile and non-volatile. Volatile memory means that when the system loses the power the RAM loses all data. Non-Volatile on the other hand sometimes abbreviated to NVRAM does the opposite, and saves memory even if the power is lost.

Another vital part of the computer it is important to get a ram that can cater for your speed of processor as if either is slower this will decrease the performance and therefor make the extra speeds from the other pointless. A decent processor to get these days is around £50, and can range between 1gig memory to 8gig for a decent amount of memory.

Random Access memory or RAM is used for storing data which is then fed to the processor for processing. The ram attempts to anticipate your next move by opening certain area of the computer should you use them, to minimise time it takes to do these actions.

The ram is connected to the computer in a small circuit board, which has the chips on containing to the memory. This is inserted into (commonly two) RAM slots, having two means you can add a lot more RAM to the computer and gives the computer a lot more potential in terms of efficiency and speed. The slots have two clips on the ends to hold the ram sticks in place.

HDD - Hard Disc Drive

The Hard Drive is similar to the RAM in the way that it stores digital data, and is non-volatile. Any programs or data that is on the computer is stored inside the hard drive, because of this hard drives must be considerably large in size to store an adequate amount of programs, such as Microsoft office, Adobe photo shop, any editing software , gaming applications and so on. Data is magnetically written with floating read/write heads on a film of air above the platter. Hard drives are becoming ever smaller and ever larger in capacity.

To install a hard drive or remove/replace follow the steps below

Before you begin, revert back to removing the CPU, health and safety must be followed to ensure safety at all times.

Attach anti-static equipment as before, and lay the computer on the mat.

Remove the shell of the computer
Remove all cables leading into the hard drive and use a screw driver to unscrew the hard drives screws.
The hard drive should slide out straight, easily if it doesn’t attempt to do it from a different angle as this may damage the hard drive if you force it.
Replacing the hard drive
Just slide the new hard drive in the same slot as the other, screw in the screws, reconnect the power cables and connector cables and put the shell back on. And you’re done.

Graphics card.

A decent graphics card will cost £50 at max and will provide all the visual effect you need. The graphics card generates and processes the visual part of the computer, the part you see on the monitor. When the computer need to show any visual information on the monitor the graphics card is called upon and makes Picture and videos which are played using the video card and help them to run smoother and add in colour enhancers.

The CPU tells send information about images to the video card which then interprets them and sends them along the connecting cable to the monitor. The images are created using binary code; this isn’t an easy process, the card creates a wire frame for the image then fills in the gaps, adding lighting texture and colour to the mix. For gaming pcs, the monitor has to do this process 60 times per second. Meaning if there were no graphics cards the workload would be too much for the computer to handle and would crash.

Fixing the graphics card to the Motherboard –

To do this simply remove the shell like part one in the processors section and find the PCI slots there should be three, and slide the card in with the connectors on the correct side (going into the slot) another important thing is the make sure you’re putting the card in the right way, if you are doing this step correctly you shouldn’t need to force the card in, if you are having to force it and it’s not working try another side.

Computer power supply

A power supply unit is put in the computer and is sent general high voltage power, AC which is then converted and ready to send, the newly converted lower voltage DC power to the needy areas in the computer. In terms of compatibility of parts, the majority of power units are made to cater for ATX mother board styles. These also have the option to be turned on and off using signal from the mother board power options such as standby, restart, hibernate and shut down.

Connecting the power supply unit to the computer.

There are several plugs which come from the power supply:

P1, this connection goes to the mother board which give it power the connector is 20/24 pins.

P4, goes into the motherboard also, and is a dedicated power supply, this gives power when needed to the processor. 4 pins.

Molex are smaller connectors which go to the other various parts the disk drive and are 4 chords, made up of 4 different colours, red, yellow and two black.

When attaching power supply connectors you must have the machine turned off and be comply with health and safety rules I mentioned earlier

Network cards.

A network card (also called a Network Adapter or Network Interface Card, or NIC for short) is a small card that slots into the motherboard card slots and acts as an interface between the computer and a network.

Network card commonly have two LED lights, these are usually red/orange and green the green flashes to show that the card is receiving electricity, the other to show receiving Mbs or information.

Just like all other cards the computer must be taken apart to fit the card in, and health and safety rules must be obeyed to ensure minimal harm comes to the handlers if any.

Just like all other cards the network card is an expansion (like the graphics card and video card) on the motherboard which enables you to access the network interfaces.
 the computer must be taken apart to fit the card in after this it is inserted into the one of the PCI slots, and health and safety rules must be obeyed to ensure minimal harm comes to the handlers if any.

BIOS –

BIOS stands for basic input/output systems. These make sure all hard drives, CPU, ports and other chips function together properly. The bios are stored in a small microprocessor, and can be accessed by starting up your machine and pressing F2, this will bring up the different options, after this find the BIOS section. From this section you can edit and view all the speeds and settings of the various computer parts for example, you can edit the speed of the RAM, your CPU, its multiplier if it has one and how they interact with each other.  Only in dire circumstances would you need to upgrade BIOS and even so, the BIOS system is commonly soldered onto your hard drive so it’s not going anywhere.

To the left i have included A picture of the BIOS chip and a Picture of the BIOS set up screen 

The CMOS & CMOS battery –

All AT computers or later must have a small battery known as the CMOS on the motherboard of the system which provides power for the complementary metal Oxide semiconductor chip even when the computer is off. This chip basically remembers all systems configurations and setups such as Hard disk type, Time and date as well as the order in which parts of the computer are booted up upon start up. The CMOS battery allows the CMOS to preserve these settings.

The top right image is the CMOS chips battery, below it a smaller version of the chip itself.

Computer internal memory –

Most of the computer’s inside parts hold a specific amount of memory or have a “dedicated” memory which acts as RAM for that specific part.

Processor Cache – this is memory that is used with the processor to help it access data from the systems “mail memory” or RAM. The processor internal memory consist of two parts, L1 is the first of these; L1 accesses the data that it need to execute an action, L2  the other pulls information from the systems main memory that the L1 can easily access.

To the right i have included step by step images of how to set up virtual memory for windows vista.

RAM –

The RAM holds information so that the Main hard drive doesn’t need to be accessed so many times when searching for information that is required to carry out the users actions.

Video RAM –

This kind of internal memory can be stored in the video card’s dedicated memory chip or it can share the computer’s memory instead of its own chip the data is then sent to an image displaying device such as a monitor. Higher memory dedicated chips have become more popular with the raise of computer games and the intensive graphics that they use. Basically it takes the strain off of the computer memory. Some cards are up to 2gig and are constantly getting bigger.

Virtual memory –

Virtual memory is made up of an area I the hard drive which is saved for strenuous times for the RAM when it needs it the excess information will flow through into the Virtual memory relieving the RAM and helping to stop a system crash. The Virtual memory can be set up manually by the user. Below I have print screened and edited the images to make it clearer on how to set this up.

Boot memory –

This is where some of the BIOS are kept like its name suggests it helps to remember what the computer needs in order to boot up.

Ports –

On the back of your computer you will find several “plug sockets” Which will all be a different colour to help differentiate between the different types.

This image includes the most common ports you will find on the back of a computer.

There are many difference types of port type; by this I mean there are type definite categories which ports can be split into. The 1^st is (in terms of electrical signal transfer) a Serial port these send and receive one ‘bit’ at a time via a single wire pair. The 2^nd parallel ports send multiple bits at the same time over several sets of wires.

When the ports have been connected they require “handshaking” similar to its real life meaning, port and socket exchange information about transfer type, transfer rate and any other necessary details before data is sent.

“hot-swappable ports” this kind of port can be removed and reconnected while the computer is running. There is however one port which should never be removed while a computer is running; the keyboard PS/2 can cause permanent damage to some model of computers.

USB ports are referred to as “plug and play” ports as they are designed to begin the “handshaking” upon connection, so that they can be used straight away, another example of this kind is the fire wire port.