CHS-NEW LECTURE

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COMPUTER TROUBLESHOOTING SAFETY PRECAUTIONS There is no such thing as effective troubleshooting if safety has not been met The effectiveness of the troubleshooting comes only if there are no injuries tool and equipment failure due to mishandling peripheral malfunction due to misdiagnoses and mishandling and other things that marks the big 7-letter word - FAILURE So what should you do to be able to do Effective Troubleshooting Follow the three most important things below to find out how and what to learn 1 What you wear might save you Yes you did not read it wrong What you wear really matters specially if we are dealing with safety In big companies overall uniforms laboratory gowns and technicians gown are required to be worn in their work areas As freelance technicians we dont strictly follow company protocols but at least we must ensure safety through using proper clothing What is appropriate for every computer technician to wear are clothings that wont catch fire fast like cotton Nylon clothes should be avoided One must also wear clothes with shorter sleeves to keep the connectors and other things in the system unit from clinging to your clothing Buttoned shirts and clothing with dangling laces or similar should not be worn during computer troubleshooting Please dont use very loose clothes like the hip hop crews wear rings necklaces dangling earrings bracelets and similar objects as well 2 Electro-Static Discharge is not your bestfriend ESD is a form of electricity that can wreck havoc to your computer peripherals or its components How do you get ESDs Just everywhere upon walking when you rub your shoe against a carpet or combing your hair or just anything you rub against or touch To be able to avoid damaging your computer system unit you must discharge the ESD by using the ESD Wrist Strap while working with your computer But what if you dont have any ESD Wrist Strap Dont worry before opening up your unplugged computer system touch any unpainted portions of the system


unit for a few seconds This can significantly dissipate the ESD that you have in your body Also consider using Anti-Static Mat while working your your computer to ensure safety against Static Electricity But again grounding yourself to the computers chassis is enough to drain off the ESDs Since ESDs can damage computer peripherals and components it is best to store your removed components and peripherals in Anti-Static Bags 3 Working Safely with Electricity Whether your home outlet is 110 or 220 volts Alternating Current (AC) it can potentially kill you But before working safely with the insides of your computer let us be familiar first with the outsides of the computer In powerlines the electricity that flows through the lines are not perfectly stable The voltage may rise and fall and this action of the unstable voltage is called a voltage spike Though most devices can operate even with voltage spikes your computer cannot endure this spikes What your computer eats is a stable supply of electrical current The Automatic Voltage Regulator (AVR) does this job It regulates or flattens out the AC flow of electricity to be fed to your computer After the AVR your computer receives the regulated 110 or 220 V AC electricity into your Power Supply Unit (PSU) and converts it into Direct Current (DC) like 12 5 and 33 V respectively So we have in mind that the electricity we get from the outlet is 110 or 220 V unregulated and as it passes though the AVR it is still 110 or 220 V but the spikes are now removed - and still dangerous As the electricity from the AVR is received by the PSU it is converted to DC and is now less dangerous In other words if you are working with your computer turn off your system unit and unplug the power cord from the AVR If you might say that the DC current of the motherboard is small and can not cause you harm consider that the components of your computer are sensitive to electrical shortages


COMPUTER SAFETY DO AND NO LIST Dos - Wear anti-ESD Wrist Strap and if there is none drain off the ESD by touching the unpainted part of your system unit ESDs are known to destroy discrete devices like your RAM BIOS Chipsets and other components of your motherboard So take this precaution seriously - Wear proper clothing Use cotton and short-sleeved clothes during work If ever the computer your working on catches fire cotton most likely better resist burning than nylon clothes - Turn off the system unit and unplug the power cord from the AVR every time you will be working with your computer Keep in mind that there is a constant 5 volts DC electricity even if your computer is turned off with cords unplugged and AVR not turned off - Keep screws together If some screws unintentionally goes on the motherboard that will be disastrous Short circuit will likely be a big possibility if screws or other similar small metallic objects are misplaced It is best to keep a small canister to contain the screws or just put the screws back where they were taken - Clean your tools and equipment before and after use Take care of your tools because they will also take good care of you Tools and equipment in good condition lessens accident - Clean your system unit before fixing it - Fix your computer if it is broken Yes dont assume that the computer is broken lest youre sure it really is You might add up or make the problem yourself rather than to fix it - Backup files and drivers before anything else Files costs millions of dollars to other clients Our main concern before everything else is our clients files Fixing the hardware part of the computer is just next to saving and retrieving the files that the computer may contain So always prepare a large backup media for your clients


- Have a documentation on each computer being fixed A documentation will be your personal troubleshooting database This will be a handy future troubleshooting reference Your documentation will also serve as your guide as you go on with your troubleshooting - Do make use of the comfort of time in computer troubleshooting Do not be in a hurry when fixing a computer If you cant finish the fix on that day let the day pass and fix it by the morning Mistakes occur because of distraction and of the lack of concentration So slow down cowboy and fix that computer slow and accurate Nos - Forgetting everything with the Dos and leaving the brain on the bed while working Just remember all those Computer Safety Dos and I assure you youll never have to remember the Nos STEPS FOR A SAFE AND SUCCESSFUL SYSTEM UNIT ASSEMBLY AND DISASSEMBLY You might think that disassembly and assembly of the system unit is easy Yes it is provided that you have done it correct and safely The first thing that every computer technician should keep in mind is SAFETY You must think that electrocution and nasty cuts are the most common injuries a computer technician might have and we need to avoid it by following simple safety procedures To disassemble and assemble a computer is integral as being a Computer Hardware Servicing Technician Aside from electrocution we must also think that the computer that we are about to disassemble requires care Safety of the equipment must also be considered Not only thinking of the computers safety but also to that of your tools Your tools are your best friends and you need to take good care of them so they in return can make your job easy and fast Example if you just leave your software installer anywhere then accidentally falls to the ground and accumulates scratches Do you think you can still use the installer again Another thing to consider safety is on environment As computer technicians we


must be responsible to take our part to take care of the environment What things does computer technicians do that might have ill effects on the environment Printer inks cut wires PCBs in general electronic wastes And these electronic wastes are the hardest type of waste to recycle So be responsible as a computer servicing technician So listed below is the checklist for a safe and successful disassembly and assembly of the computer Steps to a Safe and Successful Disassembly and Assembly of a System Unit To Disassemble 1 Prepare all your tools a Long Philip Screw Driver b Rubber Eraser c Soft Wide Bristle Brush d Paper and Pen for documentation 2 Before opening the system case be sure to turn off the system unit Turn off and unplug the AVR from the wall socket as well After that unplug all the cables connecting to the back of the system unit After clearing all the connected cables put the system unit on an empty working table 3 Touch the unpainted part of your system unit with your bare hands to remove the ESD of your body This is an important part before opening your system case You might destroy your RAM Chipsets and other components of your motherboard 4 Remove the screws of the side cover opposite to the side where the ports are By most system cases if you are facing the back of the system unit the right side cover is to be removed Return the screws back to the screw holes to avoid losing them 5 Once the side cover is removed turn your system side down where the opened side of the system unit should be facing upward where you can comfortably look down on the inside of your system case 6 We are now ready to remove the components inside of the computer The first


thing we need to do is remove the power supply To be able to remove the power supply remove first the molex connectors (the white plastic connector at the tip of the wires of the power supply) or the motherboard power connector drive power connectors the floppy drive power connector the sata power connectors and the four pin 12-volt motherboard connector With all power connectosr are removed from the motherboard and drives the power supply is now ok to be removed as well Always have the removed components placed in a remote and safe place away from where you are performing computer disassembly 7 With the power supply removed the data cable should be removed next This includes IDE SATA and floppy drive cables Secure the removed data cables 8 Next to remove are the RAM Video Card and other card peripheral components Again have them secured in a safe place and put the screws back Clean the connector edges of the card peripherals by rubbing the gold colored edge moderately with a rubber eraser then brushing off the shredding Do not attempt to clean the edge by blowing or brushing it off with your fingers Our body is acidic and you might only cause the edges to tarnish faster 9 Remove all drives This will include your hard drive cddvd drives and the floppy drive 10 Since all peripherals where removed the next thing to do is to remove the front panel connectors This will include the USB Front Panel (FP) and Audio header If you are not sure of which connector is being match to write down or document the connections and orientation of the connectors before removing them from the headers Remember that not all motherboards have the same header configuration so be careful and watchful while documenting 11 After removing the header connectors we are now ready to remove the motherboard To remove the motherboard locate first all the screws and lightly unscrew all screws alternately With this technique we are reducing the risk of warping or bending our motherboard It may not have a large impact on the bending of the motherboard but still it does have even a little Upon lightly loosening all screws remove all screws then Remove the motherboard by carefully and lightly pulling it away from the IO shield Why because we need to free the ports that are fitted from the holes in the IO shield After freeing the


motherboard ports from the IO shield holes lift up the motherboard and put it on the safe place 12 Clean the system unit chassis with your brush also clean your motherboard and the rest of the peripherals being removed To Assemble 1 Provided that all peripherals are clean and ready We are now going to assemble your computer In assembling back your computer what we have done during disassembling is just doing the reverse order to assemble it Since the motherboard was last to be removed it should then be the first to put back Remove the retaining screws from the standoff screws of the motherboard and let the motherboard seat on it with the ports facing out towards the IO shield Lightly push the motherboard to set its ports to the holes of the IO shield Put the retaining screws on the motherboard screw holes but do not tighten it yet Now be careful in doing this one and if this is your first time doing it it is best if you lend a hand for assistance Lightly push the motherboard towards to IO shield and lightly tighten the motherboard retaining screws alternately until all screws are tight enough but not too tight This is to ensure that your ports are protruding correctly out of the IO shield 2 Once the motherboard is secured put back the FP Audio and USB header connectors as you will be using your documentation for reference 3 Put back the drives to the correct drive bays 4 Connect back the RAM Video Card and other card peripherals to its proper slot inserting it properly and some cards will require screws to be secured 5 The data cables (IDE SATA floppy cable) should be connected to its proper headers and drives Remember the proper configuration of the placement of the cables specially if you are dealing with the IDE cables 6 After the data cables are properly connected put back the power supply and secure it with the screws you removed earlier After securing the PSU to the chassis connect the power connectors to the drives and the motherboard


7 Once all peripherals are connected properly have a final inspection by visually checking for loose connection or improper connection Once the system unit connections are thoroughly checked and verified connect the keyboard the monitor and the power connector then power up the computer This initial powering up of the computer while the side cover is open ensures us that everything is ok before putting back the side cover In case something goes wrong we can accessibly correct the problem right away If everything is fine shutdown the computer unplugged the AVR and remove the cables connected to the back of your computer Put the side cover back 8 Put the assembled computer back to its place and connect the rest of the cables and connectors Power it up and see if there are unusual effects of your disassemblingassembling procedure done earlier Remember SAFETY Do not neglect it Neglect can cause catastrophic effects

DISASSEMBLE A COMPUTER - EASY AND DETAILED PROCEDURE To disassemble a computer may be a very daunting task to anyone - at least to people with no or little knowledge or experience Does this mean it includes you Probably not you found our blog and you will be learning how to do things right and easy Yes By reading and following the detailed instructions that we will be providing you will be able to disassemble a computer correctly and easily Before we begin allow yourself to ponder with these questions Is it necessary to disassemble my computer Am I sure I can get things right Will I be able to put this thing back in one piece again By answering the questions above you will be able to evaluate yourself whether you are confident enough to do it (or whether your way or based on other reference like this blog) If you arent sure enough just read on and learn before doing any actual application


Here are some things you need to consider before you begin to disassemble your computer 1 Safety - Safety should be a priority specially that you are dealing with electricity precious data and expensive computer parts to handle Find out more about computer troubleshooting safety here 2 Tools - Though are are many tools a computer technician should have we can however do the job well with fewer tools A long philip screwdriver a wide bristle brush and a rubber eraser This are the basic tools need to disassemble a computer 3 Notes - Whats a note for If you are to disassemble a computer and unsure of which things is first to remove and how it is positioned sometimes you get disoriented of the proper procedure and end up having the computer dumped in a bin Note taking is essential so that it will serve as your personal guide Believe it or not I have been working as a computer technician for more than five years now and still maintains a notepad All are now set for the procedure Again think safety have the appropriate tools and have a notebook alongside to take down important notes Lets begin to to disassemble your computer or system unit 1 Find a suitable insulated table (or wooden table) to begin with your work 2 To avoid any accidental electrocution be sure to unplug your computer from the AVR And then remove the other connectors at the back panel or back side of your computer (where you can see some wires going to your mouse keyboard and others) leaving the computer or system unit totally detached At this moment you wont be needing any tool for the removal of the components 3 We are now ready to remove the side covers At the back side of your computer you should see some screws locking the covers but which side cover should we remove Can you see where the ports are located If they are located on the left side then you need to remove the right side cover and vice versa Use your Philip screwdriver to do this


4 Once the correct side cover is removed lay down the computer on the table so that you will be seeing the insides from above In this manner it will be a lot easier to remove the components 5 You may now begin to remove the computers components Here is a short list of which components should be first removed

1 Power Supply Unit (PSU) - remove the molex connector or power cablings (with redyellowblackorange wires) from the board and drives When you remove the connectors try to swivel it along its length

2 Data Cables (IDE and SATA) - carefully remove these cables by swiveling it Removing all cables clears the space for us to work things easier

3 Card Peripherals - this should include removing the RAMs Video Card Modems Sound Cards and other card peripherals Be sure to remove them properly

4 Drives - DVDBlue Ray and hard disk drives should be removed after the card peripherals Be sure to put back the screws back to the drives upon removing it

5 Front Panel Connectors - since every motherboard has its own configuration we need to take down notes of the proper orientation of the pins But if you memorize it the better Asus and intel board are almost having the same front panel pin configuration Other boards like ECS and IBM boards have the same pin configuration as the latter This is where we will be taking notes draw the pin configuration if possible

6 Motherboard - be very careful in removing the motherboard avoid scratching any surface on the motherboard as there are many surface mounted components soldered on it And after removing the motherboard put it in an area where there is insulation on its bottom or best put it in a anti-static bag

7 Processor (CPU) - removing the processor requires a bit of technical skill

6 After all the components are taken apart clean them with the brush that you have Dust will accumulate heat and can destroy your computers components 7 Do not forget to clean the connector edges of your peripheral cards The connector edges are those shiny gold-colored edges of your RAM Video card and other similar components Use an eraser to do the cleaning but if you have a flux cleaning agent that should do the job better Using an eraser just lightly


scrub on the connector edges and then brush off the shredding Remember to always clean the computer every time you take it apart This is how a computer should be disassembled Again safetyproper tools and note taking is your arsenal Drop your fear start learning and to disassemble a computer is just one of the many things you have to learn in troubleshooting computers If you have any question about computer disassembly please do not hesitate to comment and I will help you out in no time

BEGINNERS GUIDE TO TROUBLESHOOTING COMPUTER HARDWARE If you are trying to learn how to fix computers and dont know where to start this is the right place for you When learning how to fix or troubleshoot computers one must have a trusted guide and clear instructions to followComputer hardware servicing is not that hard as you may be thinking and not as easy as some people claim A step by step approach of teaching should favor the student and that is what this Beginners Guide to Troubleshooting Computer Hardware is promoting for you to learn computer hardware servicing fast easy and free Before we proceed with our tutorial let us first assess things that you currently learn about computers and yourself 1 Are you familiar and practicing occupational health and safety (OHS) when working with computers 2 Do you know how to operate a computer 3 Are you afraid of electricity 4 Do you have the passion to learn on how to fix computers 5 Have you ever tried tinkering or opening an electronic device 6 Are you resourceful enough 7 Do you have patience Asking these questions to yourself gives you a hint of what a computer hardware service technicians attributes are If ever you say no for any of the questions above it is ok Read on and you will know why I am saying it really is ok Safety Is A Priority Working with computers may seem harmless You cant be sure though because


even if you are just sitting and browsing the web with your computer radiation is already softly cooking you Your monitor emits small amounts of radiation tolerable by own body but radiation is still radiation Wonder why your eyes gets tired and sores a little when using computers for some prolonged usage of your computer Safety must be observed Now how about if your are to fix a computer Accidents may happen like electrocution cuts dropping and damaging the tools and equipment blowing or frying the motherboard and other peripherals if safety is disregarded To make things short computer safety must be followed I Know You Can Operate A Computer This might be a silly statement but what I am trying to imply is different Of course I know you can operate a computer that is why you are reading this article But sometimes what we think we already know isnt enough Keyboard shortcuts using process names to open programs use of batch files and the command prompt tweaking using the registry editor and so many things are some of the operation that you should be familiar And I am not saying that you must know everything about operating the computer first before learning how to fix it you must somehow learn by process Learn more computer terms by reading ebooks We will soon be providing ebook downloads soon or just email me to ask for a copy Fear Not For Electricity Is Your Friend During my years as a freelance computer hardware serviceman I often see students having On-the-Job Trainings (OJT)in computer shops just standing by the corner and watching seasoned computer technicians doing something And when a seasoned technician asks for assistance from the trainee it is evident that the trainee shows hesitation with plugging into sockets and molex power connectors It is not good to hesitate in doing things because uncertainty surely leads to disaster Fear of electrocution is common among newbies I could remember during my college days when my Building Wiring and Electricity instructor tried to have us touched a 220 live wire just to let us feel electricity I never touched when he said so but when we were asked to do our practical examination by building a two-way switch on a large dashboard I accidentally touched a bare live wire A shock


was sent up to my armpit and I was so careful about electricity ever since You cant fix a computer without electricity just be very careful in using it Be Passionate About Fixing Or Troubleshooting a Computer Its just like having a girlfriend If you are not dedicated and passionate with her you will be throwing stones at each other by the morning You see if you love what you are doing you can do things right and makes you genuinely happy If you feel that troubleshooting computers is not the thing for you then quit Do other stuff that you feel you love to do and you surely will be good and happy with it Be passionate to troubleshoot and learn computer hardware servicing You can only be a good computer hardware technician if you are passionate on what you are doing Doing things right with eagerness to improve is the key to be a successful learner Tinkering And Being Curious About The Insides Of An Electronic Device If you love to open electronic devices or just anything you are curious at is a good sign that you are an eager learner It also shows that you have interest in the inner workings of a machine and wants to analyse how a thing works In troubleshooting computer hardware it is important that you can analyse how the parts are positioned or being attached to Computer hardware servicing may seem difficult very technical and boring but it is actually easy handy and exciting Be Resourceful Not Everything You Got Is Enough Learning really takes time You just cant just click any links from the web and expect to learn something Sometimes you must choose those which are worth knowing and reading Sometimes clicking some links in a site brings you to good pages and will take away your blues trying to learn So be resourceful dont just get stuck with few resources Research and dont be afraid to learn Experience will also bring more knowledge Try to apply what you have learned and you will surely thank yourself Be Patient At All Times Patience has something to do with time In troubleshooting computer problems


there will be times when you cant fix the machine right away You need to give yourself a time to regroup and think of a better solution Have you thought of these things If you think you have or able to develop the attributes discussed above then you already becoming a good computer technician in the process Learning is a process it takes enormous effort and time So let me give you a draft on what things you should be learning to become full fledged computer hardware servicing technician What You Should Learn About Computer Hardware Servicing 1 Occupational Health and Safety Procedure 2 Basic Computer Operation 3 Understanding Binaries and Logic Gates 4 Introduction To Computers - Components of the IT System 5 The System Unit - Hardware Component Functions and Description - Motherboard - Central Processing Unit - Random Access Memory Read Only Memories and Basic InputOutput System (BIOS) - Storage - Operating Systems Tools and Utilities - Installation - Networking - Troubleshooting Techniques TROUBLESHOOTING PROCEDURE Before testing the system unit we must first ask few questions to the owner of the system unit to give us some clues on what and whens regarding the computer problem encountered Remember that first hand information about the computer problem encountered by the owner or user is the most near-reliable source of idea on what really is the problem of his or her computer But be warned I have had said near-reliable because most users being asked lies on the details fearing that the blame is on them You must ask them in low tone soft non-vindictive and non-agitating manner The details they give might be useful for your approach introubleshooting After gathering the information provided by the user you must verify it by


checking and testing the system unit Be sure to physically check the peripherals first before testing Try to see if there are missing blown or poorly attached cables and peripheral cards Then after a thorough check test the system unit and do a detailed observation

SAFETY PROCEDURES There are certain procedures you should follow when you are installing items in your system Below is information to avoid damage to your system orand yourself

Before entering the computer move computer off the carpet (for static purposes) If your not able to then try not to move on the carpet to keep the static from building

Disconnect all cables including power cord I cant stress this enough Remove the power cord monitor keyboard mouse phone line network cable speakers printer scanner USB cables cable modem DSL modem and anything else that is connected (it should look similar to the picture below)

With everything disconnected push the power button for 5 seconds (with power cord disconnected) The computer can store power even with the power cord disconnected Pushing the power button drains that power (only if the power cord is disconnected) VERY IMPORTANT

Touch something metal on the case of the system to release any static build up in your body

Computers are the best dust collectors Do not blow on the dust with your breath Your breath has moisture and electronics hate moisture

If you want to clean the inside of the system of dust use compressed air that is designed for electronics

While using the compressed air do not hold down the button Not only will the can get cold moisture will also form Use quick short bursts

When handling parts do not touch the bronze teeth Hold the parts on the edges if at all possible

If you are troubleshooting noise issue some people will stick a pencil or other objects in the fan to stop the fan from turning to see if the noise goes away DONT DO THAT The fan might shatter the pencil cause a fire cause electrical shock or short

If you disconnect the cable that goes to the processor fan to check for noise do not leave system on for long with it disconnected


Be careful while inside system the system has sharp edges Never put your hands inside system when the system is either plugged in or

turned on Some computer desks have a compartment that you can put your

computer in Make sure that compartment is well ventilated If it is not ventilated it can fry the system If it is not well ventilated you can drill holes in the desk to give it ventilation or you can install a small fan in the desk that will circulate air

Do not connect or disconnect cables while the system or device is turned on (unless it is USB USB can be disconnected or connected while system is on) Equipment can be damaged by this

Keep these important tips in mind as you work inside your computer Remember to Flip the Switch Always always always remember to turn the power off before servicing anything This should always be your first step Do not even open the computer case unless the power is turned off Many computers have a number of lights inside that serve certain functions so check to see that no lights are on If any are still on then the power is probably not completely off Many power supply units have a switch on the back killing power to the device and ultimately the rest of your PC If your PSU has one be sure to turn it to the off position Unplug for Extra Safety As a second precaution it is wise to unplug the computer from the wall or power strip If there was any doubt as to whether the computer was off before its settled now Avoid Smoke and Smells See smoke coming from the power supply or inside the case or smell a burning or solder scent If so

1 Stop what youre doing immediately 2 Unplug the computer from the wall 3 Allow the PC to cool or discharge unplugged for at least 5 minutes

Finally if you know which device was generating the smoke or smell remove and replace it as soon as you can Dont try to repair a device thats been damaged to this extent especially if its a power supply


Remove Hand Jewelry An easy way to get electrocuted is to work around a high voltage device like a power supply with metal rings watches or bracelets on Remove anything conductive from your hands before working inside your computer especially if youre doing something like testing your power supply Avoid Capacitors Capacitors are miniature electronic components contained in many of the parts inside a PC Capacitors can store electric charge for a short while after the power is turned off so its a wise decision to wait a few minutes after pulling the plug before working on your PC Never Service the Non-Serviceable When you come across labels that say No serviceable components inside dont take it as a challenge or even a suggestion This is a serious statement Some parts of a computer are just not meant to be repaired even by most professional computer repair persons You will usually see this warning on power supply units but you may also see them on monitors hard drives optical drives and other dangerous or highly sensitive components Help your computer live longer perform better and avoid debilitating crashes

INTRODUCTION TO PC COMPONENTS Here you will learn computer hardware tutorials introduction basic pc components networking devices ram vga monitor and printer etc Computer hardware is the physical part of the computer including the digital circuits inside the computer as opposed to the software that carry out the computing instructions The hardware of a computer is unlikely to change frequently unless due to the crash or for upgrading them The devices that is capable of storing executing system instructions and controlling other logical outputs Hardware comprises all of the physical part of the computer such as Monitor CPU motherboard ram CD-Rom printer scanner hard disk flash drive (AKA pen drive) processor pci buses floppy disk power supply VGA card sound card network interface card peripherals joystick mouse keyboard foot pedal computer fan camera headset and others On the other hard software is a logical part of a computer and is used to carry out the instructions storing executing and developing other software programs A


typical PC consists of a case or chassis in the desktop or tower case and these components

CHAPTER 1 INTRODUCTION Your PC (Personal Computer) is a system consisting of many components Some of those components like Windows XP and all your other programs are software The stuff you can actually see and touch is hardware Hardware The hardware are the parts of computer itself including the Central Processing Unit (CPU) and related microchips and micro-circuitry keyboards monitorscase and drives (hard CD DVD floppy optical tape etc) Other extra parts called peripheral components or devices include mouse printers modemsscanners digital cameras and cards (sound colour video) etc The devices which are Necessary to assemble a computer bull Motherboard bull Processor bull Memory bull Hard Drive bull Video Card (if motherboard didnt come with it) bull Sound Card (if motherboard didnt come with it)

bull Modem andor Network Card bull Floppy Drive bull CD-Rom bull Keyboard and Mouse bull Case And Power Supply bull Monitor

CHAPTER 2 PROCESSOR

The Central Processing Unit Which is often referred to as the ldquoProcessorrdquo is the brain of the computer The chip that performs the majority of calculations and


instructions needed to make your computer run Without this chip no other function of the PC is possible The processor is attached to the motherboard (Processor slot) The speed of the CPU The computers speed or clock rate is integral to its overall design The computers clock rate is the frequency at which it can execute a set of instructions Computer clock rates are measured in Megahertz (million of clock ticks per second) There are two types of speeds that should be considered when evaluating the system performance Internal clock speed ndash Is the speed at which the processor can obtain information within itself like with internal cache and registers (Pentium III 800 MHz the 800 MHz is the internal clock speed) External clock speed ndash Is the speed at which the CPU communicates with components outside itself Some commercially available processors bull Pentium I-IV bull Celeron bull Athlon

bull Duron bull Cyrix C3 bull Itanium (64 bit)

bull Opteron (64 bit)

How to Choose a CPU When you are choosing one CPU always consider your computing needs when selecting a CPU If you want to do simple word processing or general computer tasks go for the budget or low end processors If you are more into gaming or do CPU intensive work like video editing go for a mid-range or high-end processor

CHAPTER 3 MOTHERBOARD Chapter 31 Motherboard The motherboard is the main circuit board inside your PC Every components at some point communicates through the motherboard either by directly plugging into it or by communicating through one of the motherboards ports The motherboard is one big communication highway Its purpose inside your PC is to


provide a platform for all the other components and peripherals to talk to each other

Motherboard

MOTHERBOARD COMPONENTS The motherboard holds all the major logic components of the computer Here we are going to see with no particular order some of those major motherboard componets and their function in a computer or to be more precise in your computer A core 2 Duo Intel Processor

CPU- Central Processing Unit It is also known as the microprocessor or the processor It is the brain of the computer and it is responsible for fetching decoding and executing program instructions as well as performing mathematical and logical calculations


The processor chip is identified by the processor type and the manufacturer and this information is usually inscribed on the processor chip eg Intel 386 Advanced Micro Devices (AMD) 386 Cyrix 486 Pentium MMX (old processor types) Intel Core 2Duo etc If the processor chip is not on the motherboard you can identify the processor socket as socket 1 to Socket 8 LGA 775 etc This can help you identify the processor that fits in the socket For example a 486DX processor fits into Socket 3

Memory Modules Main Memory Random Access Memory (RAM) Random access memory or RAM most commonly refers to computer chips that temporarily store dynamic data when you are working with your computer to enhance the computer performance In other words it is the working

place of your computer where active programs and data are loaded so that any time time the processor requres them it doesnt have to fetch them from the hard disk which will take a longer access time Random access memory is volatile memory meaning it loses its contents once power is turned off This is different from non-volatile memory such as hard disks and flash memory which do not require a power source to retain data When a computer shuts down properly all data located in random access memory is returned back to permanent storage on the hard drive or flash drive At the next boot-up RAM begins to fill with programs automatically loaded at startup and with files opened by the user a process called booting

BIOS Chip BIOS- Basic Input Output System BIOS is a term that stands for basic inputoutput system which consists of low-level software that controls the system hardware and acts as an interface between the operating system and the hardware Most people know the term BIOS by another namemdash

device drivers or just drivers In other words the BIOS is drivers meaning all of them BIOS is essentially the link between hardware and software in a system All motherboards include a small block of Read Only Memory (ROM) which is separate from the main system memory used for loading and running software


On PCs the BIOS contains all the code required to control the keyboard display screen disk drives serial communications and a number of miscellaneous functions The system BIOS is a ROM chip on the motherboard used by the computer during the startup routine (boot process) to check out the system and prepare to run the hardware The BIOS is stored on a ROM chip because ROM retains information even when no power is being supplied to the computer

CMOS Battery CMOS-Complimentary Metal Oxide Semiconductor Motherboards also include a small separate block of memory made from CMOS RAM chips which is kept alive by a battery (known as a CMOS battery) even when the PCrsquos power is

off This prevents reconfiguration when the PC is powered on CMOS devices require very little power to operate The CMOS RAM is used to store basic Information about the PCrsquos configuration eg

Floppy disk and hard disk drive types CPU RAM size Date and time Serial and parallel port information Plug and Play information Power Saving settings

The Other Important data kept in CMOS memory is the time and date which is updated by a Real Time Clock (RTC)

L2 Cache on an old Motherboard Cache Memory It is a small block of high-speed memory (RAM) that enhances PC performance by pre-loading information from the (relatively slow) main memory and passing it to the processor on demand Most CPUS have an internal cache (in-built in


the processor) which is referred to as Level-I cache memory or primary cache memory This can be supplemented by external cache memory fitted on the motherboard This is the Level-2 Cache memory or secondary cache Some CPUs have both L1 and L2 cache built-in and designate the separate cache chip as Level 3 (L3) cache

PCI Slots Expansion Buses An inputoutput pathway from the CPU to peripheral devices typically made up of a series of slots on the motherboard Expansion boards (cards) plug into the bus PCI is the common expansion bus in a PC and other hardware platforms Buses carry signals such

as data memory addresses power and control signals from component to component Expansion buses enhance the PCs capabilities by allowing users to add missing features in their computers in form of adapter cards that are slotted in expansion slots The different types of buses include PCI ISA and EISA expansion bus Chipset A chipset is a group of small circuits that coordinate the flow of data to and from key components of a PC This includes the CPU itself the main memory the secondary cache and any devices situated on the buses The chipset also controls data flow to and from hard disks and other devices connected to the IDE channels A computer has got two main chipsets-

The NorthBridge (also called the memory controller) is in charge of controlling transfers between the processor and the RAM which is way it is located physically near the processor It is sometimes called the GMCH for Graphic and Memory Controller Hub

The SouthBridge (also called the inputoutput controller or expansion controller) handles communications between peripheral devices It is also called the ICH (IO Controller Hub) The tem bridge is generally used to designate a component which connects two buses

Chipset manufacturers include SIS VIA ALI OPTI etc Interesting hubs


Motherboard Form Factors The motherboard form factor describes its general shape the type of case and power supply it can use and its physical organization (layout of the motherboard) It is what we are going to have a look at in this hub

Computer Bus Architecture Types A bus is a common pathway through which information is connected from one component to another This pathway is used for communication and can be established between two or more computer components

DDR1 DDR2 DDR3 Navigating The RAM Maze Choosing the proper DDR-type for your PC is critical The wrong choice can drastically bottleneck your system Here is a full guide to picking the right DDR for your CPU

Cpu Clock The clock synchronizes the operation of all parts of the PC and provides the basic timing signal for the CPU Using a quartz crystal the CPU clock breathes life into the microprocessor by feeding it a constant flow of pulses For example a 200 MHz CPU receives 200 million pulses per second from the clock A 2 GHz CPU gets two billion pulses per second Similarly in a communications device a clock may be used to synchronize the data pulses between sender and receiver A real-time clock also called the system clock keeps track of the time of day and makes this data available to the software A timesharing clock interrupts the CPU at regular intervals and allows the operating system to divide its time between active users andor applications

Dip switch on an old motherboard Jumper pins with a cap on Switches and Jumpers


DIP (Dual In-line Package) switches are small electronic switches found on the circuit board that can be turned on or off just like a normal switch They are very small and so are usually flipped with a pointed object such as a screwdriver bent paper clip or pen top Care should be taken when cleaning near DIP switches as some solvents may destroy them Jumper pins Jumpers are small pins on the board with plastic or metal devices that go over the pins This device is called a bridge or a jumper cap When the bridge is connected to any two pins via a shorting link it completes the circuit and a certain configuration has been achieved Jumper cap A metal bridge that closes an electrical circuit Typically a jumper consists of a plastic plug that fits over a pair of protruding pins Jumpers are sometimes used to configure expansion boards By placing a jumper plug over a different set of pins you can change a boards parameters Modern motherboards come with the following features

Processor slot Processor slot is used for processor Memory banks Memory banks are used for RAM modules AGP slot AGP slots are used for graphics accelerators PCI slots PCI slots are used to provide connectivity for PCI cards such as

modems and sound cards IDE IDE are used to connect and control IDE devices such as hard drives

and CD-ROM drives USB ports USB ports are used to connect USB devices

These are just some of the features that a motherboard may have as standard some motherboards come with integrated components such as a sound card graphics card modem NIC (Network Interface Card) and more Types of Motherboards The type of motherboards depends on the CPU it was designed for You can therefore categories motherboards by which socket type they have eg Socket A Socket 478 etc The Type of motherboard you buy is very important as it will need to house your CPU and they are not interchangeable When buying a motherboard it will always tell you what socket type it has


Chapter 32 How to Choose a Motherboard As everything you have on the PC at some point needs the motherboard you need to consider these components when buying a motherboard For example if you have a lot of devices with a PCI interface that you wish to use there is little point buying a motherboard that only offers you 3 PCI slots Like wise with memory you have to make sure that there are enough slots for the amount of memory you have or wish to have The motherboard also needs the correct type of interface for your Memory Graphics card Hard disks and other items as well You will find that most motherboards offer everything you need however it needs checking on when buying Its especially important to pay detail to your motherboard if you want to use older components which a new motherboard may or may not support The major difference between motherboards that support the same CPU is the model of the chipset (more on the chipset later) Different chipsets offer different performance and different features in terms of memory support AGP port speed Multiplier numbers Bus speeds and much more When you are choosing one motherboard you have to consider Whats Your Processor First and most important thing to consider when buying your motherboard - what CPU or processor are you using Motherboards are made differently not all motherboards will support all CPUs What CPU you select will determine the type of motherboard you get For example if you want to use an Intel Pentium 4 CPU the motherboard you select must be able to support that brand and model of CPU The motherboards are also designed to support specific speeds for a CPU so make sure it can support the speed of the processor as well Choose Your Chipset What is a chipset Well chipsets are the main controllers on the motherboard - they allow the CPU to interface with the various components and expansion cards installed When choosing your chipset always bear in mind the type of memory supported by the motherboard Make sure that the board supports the type and amount of RAM you need Generally choosing a chipset that supports high speed memory will allow your system to perform better


What is a Motherboard Chipset A motherboard chipset controls all the data that flows through the data channels (buses) of the motherboard The primary function of the motherboard chipset is to direct this data to the correct areas of the motherboard and therefore the correct components Expansions Slots and Connectors If you intend to various peripherals to the computer then the number and type of expansion slots and connectors is important By default most motherboards these days have USB 20 ports incorporated into their design If you intend to buy expansion cards make sure the board comes with an ample number of PCI slots Other Features These days most motherboards have a whole host of extra features loaded into them These can include things such as on-board VGA audio a RAID controller Modem or Network Card

CHAPTER 4 RAM RAM (Random Access Memory) is the basic working memory of your computer system A computer used RAM to hold volatile (Temporary) instructions and data needed for processing Volatile simply means that it is not permanent which means anything written to RAM

will be loses if the machine loses power or if its turned off Another key point about RAM is that data stored init can be accessed much more quickly than data retrieved from the hard disk Theoretically data retrieved from RAM is accessed 100 to 300 times faster then the same information from a hard disk optical drive or a floppy Memory is measured in bytes so youll often encounter the terms megabyte (MB) and gigabyte (GB) in describing RAM sizes (a megabyte is a million bytes a gigabyte a billion) RAM is something that you do not want to skimp on You can choose a slower processor but with RAM you want as much as you can get Types of RAM

SDRAM DDR

DDR2 DDR3


SDRAM Almost all systems used to ship with 33 volt 168-pin SDRAM DIMMs SDRAM is not an extension of older EDO DRAM but a new type of DRAM altogether SDRAM started out running at 66 MHz while older fast page mode DRAM and EDO max out at 50 MHz SDRAM is able to scale to 133 MHz

(PC133) officially and unofficially up to 180MHz or higher As processors get faster new generations of memory such as DDR and RDRAM are required to get proper performance DDR Memory (184-pin DIMMS) These were introduced in 2002 to replace the earlier SDRAM format To use this

type of memory you need a 184-pin socket for the module to fit into DDR Memory is available in different speeds of PC2100

PC2700 PC3200 (DDR400) and PC4000 (DDR500) The modules can be used singly or how desired however you cannot mix different speeds together DDR2 Memory (240-pin DIMMS) This format builds on the technology of DDR This standard has more pins and its main developments are the ability to run faster whilst consuming less power

To use DDR2 memory you need a 240-pin socket for the module to slot on your motherboard DDR2 Memory is available in many different speeds including PC2-3200 (DDR2400) PC2-4200 (DDR2533) and PC2-5300 (DDR-667) The modules can be used singly or you can

install different speeds of DDR2 memory together if your motherboard supports the faster speed however faster modules will perform at the lower speed


This may be worth considering if you want to run Dual-Channel memory where you must use the same speed and ideally matching pairs to ensure compatibility

DDR3 Memory (240-pins) THIS is the latest memory standard (2008 onwards) taking over from the previous DDR and DDR2 standards Although

DDR3 comes with 240-pins the same as DDR2 the notch is in a different place so people can not install the wrong type DDR3 is not backward compatible with DDR2 in addition to the notch the voltage runs at a lower 15V than DDR2 18V DDR3 memory will not fit into a standard DDR2 DIMM socket or an earlier DDR memory socket To use DDR3 memory your system motherboard must have 240-pin DIMM slots and a DDR3-enabled chipset

CHAPTER 5 HARDDISK The hard disk (or hard drive) is the permanent storage area of your computer It stores information whether the computer is on or off A hard drive is a mass storage device found in all PCs (with some exclusions) that is used to store permanent data such as the operating system programs and user files The data on hard drives can be erased andor overwritten the hard drive is classed as a non-

volatile storage device which means it doesnt require a constant power supply in order to retain the information stored on it (unlike RAM) Inside every hard drive are small round disk-like objects made of either an aluminumalloy or a glassceramic composite these are called platters each platter is coated with a special magnetic coating enabling them to store data magnetically Hovering above these platters are readwrite heads that transfer data to and from the platters Hard drives come with many different storage capacities hard drive capacity is measured in bytes with common capacities being stated in MB (Megabytes) and GB (Gigabytes)


Hard Drive RPM Speeds You will often see hard drives advertised as being capable of a certain RPM (Revolutions Per Minute) this figure (as the name suggests) refers to how many times the spindle makes a complete 360 turn in any single minute RPM values range from about 5400RPM to 12000RPM and above How to Choose a Hard Drive When you are choosi ng one Hard Drive you have to consider ATA and SCSI In the hard drive world there are two data access standards ATA and SCSI (pronounced Scar-Zee) Most of normal hard drives were used to rely on the PATA standard Some newer hard drives use the SATA standard SATA allows transfer speeds of up to 150 MBs while PATA gives up to 133 MBs However to use SATA youll need a Serial ATA controller a SATA drive and a SATA power cable The speed difference between PATA and SATA is also not significant unless you have a high-end SATA drive The SCSI standard is a very fast hard drive standard used for professional computer systems which demand extremely fast data access SCSI drives provide an access time of about 95ms - which I feel is really not needed for average home use Disk Space vs Price An important factor to consider is the disk space versus price ratio When you look at the 30 GB 40 GB and 80 GBPATA hard drives youll find they are very close in price For the average home user however 40 GB to 80 GB of disk space is plenty Drive Speed If data access speed is important to you you can go for faster SATA drives or SCSI drives But remember that these drives come at a price premium and may not be necessary for average home use

CHAPTER 6 CARD 61 Video Card VGA Card is the one sending the monitor signal to the monitor A computer video card is placed in the motherboard where it transfers video signals through a cable to your monitor The video card can either be built into


the motherboard or be a separate card that is placed in either the AGP or PCI-Express Slot

The computer graphics cards major job in a computer is to convert graphic patterns into signals for the monitors screen However in recent times as the graphics card has become more advanced it has taken

some of the jobs previously assigned with the CPU and through a graphics pipeline adds 2D and 3D effects and it also adds textures How to Choose a Video Card The VGA Card price will change on

1 VGA Card Processor 2 VGA Card Ram capacity 3 Ram type of VGA Card

When you are choosing one Video Card you have to consider The best way to see what video card to buy is to consider how youre using your computer now There are several categories Server If youre using your computer as a mail server FTP server print server or even a game server you definitely do not need a high-end video card What you need is a simple no-frills low-end video card Simple Applications Say youre using the PC for simple applications only for example word processing email or web surfing Again you do not need the best video card out there A cheap and decent one will do the trick Complex Applications If you need to perform more complex tasks like 3D computer aided design or video editing it will make more sense to go for a heavy duty card Screen


resolution and image quality tend to be important factors for this type of work Look for a video card whose processor which supports a high screen resolution with ample graphics memory General Games If youll only play simple games like Minesweeper Reverse or Backgammon then my advice is to save your money and just get a simple video card No need for the latest 3D graphics gizmo

62 Sound Card Sound Card

The sound card is an essential component in the PC since it translates digital signals into analog audio for your listening pleasure Well thats true if you want to play games or run multimedia applications in your PC

Otherwise it may not be necessary especially in business environments Sound card ports


A computer sound card is used by a computer for music sounds during applications and entertainment (TV movies and games) A typical sound card usually has four ports The largest port is the MidiGame port which is used for connecting a joystick or gaming controller to The other three ports look similar and are generally green pink and blue Underneath each port will be a small engraving of what each port does The pink port is for a microphone which can record sound to the computer The green port is line out and this is where the speakers are connected to produce sound from the computer The blue port is line in and this is for connecting a CD-player or cassette tape to the computer

Remember a sound card by itself is not enough to hear sound You will still need to purchase some computer speakers or a headphone set If you want to make use of the microphone feature then you will need to buy a computer microphone and you should then be able to record sound to your computer How to Choose a Sound Card When you are choosi ng one Sound Card you have to consider

First thing to consider here is your intended usage of the sound card If all you want is basic sound support and not spectacular 3D surround sound Id say go buy a cheap simple card or even rely on your motherboards on-board sound

If you want great surround sound and better speaker connectivity options then youll want to consider a dedicated sound card

63 Modem Card

A device that translates data from your PC into a form that can be sent to other computers over regular phone lines The modem also receives signals from other


computers and converts it into something your computer can understand A modem is the device most home computers use to connect to the Internet A Modem converts digital information into sound so that it may be transmitted over telephone lines When the modem hears this sound on the other end it converts the sound back into digital information There are two types of modems bull INTERNAL bull EXTERNAL

External modems are slightly more expensive than internal modems and are housed in an external box or enclosure External modems require a socket on the computer or port (usually the serial port on the back of your computer) The serial port is also called a COM port com for communications

64 Network Card A network interface card more commonly referred to as a NIC is a device that allows computers to be joined together in a LAN or local area network Networked computers communicate with each other using a given protocol or agreed-upon language for transmitting data packets between the different machines known as nodes The network interface card acts as the liaison for the machine to both send and receive data on the LAN The most common language or protocol for LANs is Ethernet sometimes referred to as IEEE 8023 A lesser-used protocol is Token

Ring When building a LAN a network interface card must be installed in each computer on the network and all NICs in the network must be of the same architecture For example all must either be Ethernet cards Token Ring cards or an alternate technology An Ethernet network interface card is installed in an available slot inside the computer The NIC assigns a unique address called a MAC (media access control) to the machine The MACs on the network are used to direct traffic between the

COMTECH Page 35 of 55 pages

computers The back plate of the network interface card features a port that looks similar to a phone jack but is slightly larger This port accommodates an Ethernet cable which resembles a thicker version of a standard telephone line Ethernet cable must run from each network interface card to a central hub or switch The hub or switch acts like a relay passing information between computers using the MAC addresses and allowing resources like printers and scanners to be shared along with data A network interface card does not have to be hard wired with physical cable Wireless Ethernet cards are installed like their wired counterparts but rather than a port for an Ethernet cable the card features a small antenna The card communicates with the central wireless switch or hub via radio waves Wireless LANs may have some restrictions depending on the material the building is made from For example lead in walls can block signals between the network interface card and hub or switch When buying components for a LAN make sure the NICs and hub or switch have the same capabilities The entire network must be either wired or wireless so a wireless network interface card cannot talk to a wired switch or hub In addition newer versions of hardware will likely support more features andor greater speeds than older versions Make sure your central switch or hub can utilize the highest capabilities of the network interface card under consideration

CHAPTER 7 PERIPHERALS Chapter 71 Keyboard and Mouse These two input devices are obviously needed otherwise you cant interact with the computer system These components are fairly standard stuff and can be purchased at pretty cheap prices Keyboards

The keyboard is the main input device for most computers There are many sets of keys on a typical ldquowindowsrdquo keyboard On the left side of the keyboard are regular alphanumeric and punctuation keys similar to those on a typewriter These are used to input textual information to the PC

A numeric keypad on the right is similar to that of an adding machine or calculator Keys that are used for cursor control and navigation are located in the


middle Keys that are used for special functions are located along the top of the keyboard and along the bottom section of the alphanumeric keys Keyboards are mainly divided into two types 1Multimediakeyboard 2OrdinaryKeyboard Mouse

Mouse is another input device used in computer Mouse is a device that controls the movement of the cursor or pointer on a display screen A mouse is a small object you can roll along a hard flat surface Its name is derived from its shape which looks a bit like a mouse its connecting wire that one can imagine to be the mouses tail and the fact that one

must make it scurry along a surface As you move the mouse the pointer on the display screen moves in the same direction Mouse contain at least one button and sometimes as many as three which have different functions depending on what program is running Some newer mouse also includes a scroll wheel for scrolling through long documents

Chapter 72 Floppy Drive and CD-Rom Floppy Drive A 35rdquo square holding a flexible magnetic disc that holds information or data You need a floppy drive to read the floppy A floppy disk can hold only 144 megabytes but it is portable and allows you to make copies of your files

CD-Rom A CD-ROM drive used to be an optional extra in computers - it is no longer so Most software packages come in CD format so you must have a CD-ROM drive to read them Typically CD-ROM drives today need to be at least 24X speed to keep up with the newer software applications out there


A CD drive connects to the computer motherboard through two types of cables The older and more common connection is through the IDE Ribbon cable Recently SATA (Serial ATA) drives have been produced and will gradually become more common The benefits of having SATA cables is that they are smaller and the transfer rate is higher Floppy drives were the main source of data transfer and files were small enough to fit on them However today even CD drives are getting out of date and are fast being replaced by the DVD ROM and DVD RW Drives

CD-RW CD writer is used to write CD It can also used as a CD drive CD can be able to write with different formats By using CD writer we can able to write with different speeds There are different types of writers are available in the market with different writing speeds On a CD drive there is usually some numbers with a x symbol after it This stands for times for example common speeds are 4x 8x 16x 18x 24x 32x 40x and 52x CD RW drives have speeds like 24x-10x-40x or 52x-32x-52x

How to Choose a CD-RW When you are choosing one CD-RW you have to consider Drive Speed For CD writers you should generally look for a 40X record speed or faster If you buy anything that is slower it will definitely waste a lot of time when youre burning CDs

Chapter 73 Monitor Monitor

Monitor is the display device Many times per second the video card sends signals out to the monitor The information video card sends controls which dots are lit up and how bright they are which determines the picture you see


Color monitors can display anywhere from 16 to over 1 million different colors Color monitors are sometimes called RGB monitors because they accept three separate signals -- red green and blue The resolution of a monitor indicates how densely packed the pixels are In general the more pixels (often expressed in dots per inch) the sharper the image Most modern monitors can display 1024 by 768 pixels the SVGA standard Some high-end models can display 1280 by 1024 or even 1600 by 1200 How to Choose a Monitor If youre a graphics professional you may prefer a CRT monitor because they are said to show more realistic colors However the latest high-end LCDs can also give equal color quality If you with text most of the time a LCD is a good choice because the various pixels that you find on a LCD will have nicely defined edges This gives sharp and focus letters on the screen

CHAPTER 8 CASE AND POWER SUPPLY

Chapter 81 Case

Computer Case

The computer case is your computers housing You need this to store your components the largest of which is your motherboard


Types of Case Mini Tower

Advantages Excellent size which can be placed on top ofbelow of a computer desk Disadvantages While this case does offer upgradeability it can be filled up much faster then the Mid-Sized tower Recommendations Great PC for end-users and small businesses Mid-Size Tower

Advantages Excellent case which can fit below and on top of your computer desk Plenty of expandability for new devices for businesses end-users and advanced users One of the most used computer cases found today Disadvantages None

Full-Size Tower

Advantages Excellent computer for upgradeability Excellent case for a server machine Disadvantages Cost is going to be a lot more then a standard case Generally A large case which cannot be placed on top or beneath a desk Recommendations This case is an excellent choice for all users and businesses


Desktop Advantages Excellent desk computer Great use of desk space when monitor is placed on top of the computer Disadvantages With some types of desktop cases can be very difficult to upgrade Does not

really work on the floor Recommendations We recommend that this type of case be purchased by advanced users or users who plan to have a stand alone machine as a server

Chapter 82 How to Choose a Case Choosing a computer case can be difficult if you dont know what your looking for The range of computer cases is huge and bigger then its ever been So how do you find one that suits you This guide will explain how to choose a computer case that suits your needs Whats your budget The first step in choosing a computer case is working out how much you are willing to spend on a case If you would like to save money then dont spend a fortune on your case Whats your needs The second step in choosing a computer case is making sure that it has enough room to house all your components If you have two CD drives then get a case that has room for the three drives Put one at the top and one at the bottom leaving space in between for cooling Do the same for your hard drives and floppy drives Also make sure that your motherboard can fit inside the case Some cases are smaller then others and some motherboards are bigger then others so make sure your motherboard will fit Next make sure that there is at least one fan built into the case I would recommend two fans at least and if you are really worried about your equipment over-heating then get another fan


I have a friend who is very worried about over-heating He has about 6 fans inside his computer and when he turns it on it sounds like an airplane taking off and all the lights in his house go dim So if your prepared for a little more noise then its a good idea to get an extra fan to cool your equipment down However dont get paranoid about fans one or two should be fine and unless there is no circulation your hardware should survive Computer Case Style The last thing to do in choosing a computer case is to choose what you want the case to look like Do you want a black or white case a fancy or plain case The range of computer cases on the market is huge so select one that you like If you would prefer a cheap computer case then choose a plain one Many computer cases come with extras at the front like USB and ports for a headset These can be very useful and are worth it for the extra money When you are choosing one Case you have to consider External Space The first factor to consider is how much space your PC case is going to take up Are you placing it on a tight crammed desk Or on a large desk If you have the space tower PC cases are a good choice If youre short of space you may wish to consider smaller mini PC cases which are getting more popular these days Internal Space Another factor to consider is how many components you wish to fit in your PC case If youre a computer nut like me youll want to fit in a good motherboard CPU a couple of hard drives video card LAN card cooling fans a CD-ROM drive and a DVD writer Thats a lot of components to be cramming into a PC case Again a good choice would be a tower PC case However with so many components you have to watch out for overheating problems - make sure you deck out the system with a couple of good fans Motherboard Support Check that your motherboard can fit into the case Some cases are flexible enough to support AT ATX and Baby-AT boards but others only support one of these sizes Even then you need to be careful - some cheaper ATX cases dont


really fit ATX motherboards I remember buying a wonderful ATX motherboard and it couldnt fit into my PC case Imagine my frustration Power Supply Most PC cases come with power supplies With more and more components being fitted into a PC you will certainly need enough juice to power them Cooling If youre a over clocker or have many system components youll need to ensure youve got enough fans in that case to cool the system Good PC cases allow multiple (4 or more) cooling fans to be installed ensuring good ventilation Looks Just a few years back PC cases were boring white boxes These days you can find a plethora of colorful PC cases - if youre concerned about your PCs look Many PC enthusiasts I know go for good looking PC cases that come in a variety of colors - red black green blue and what not

Chapter 83 Power Supply A computer power supply is a compulsory unit to a computer Without the power supply a computer is useless as it is just a case full of metal and plastic This page will explain the different power cables and connectors and how they work inside your computer A power cable connects from the power point to the power supply where it supplys the motherboard and other components with power Often there is a power

switch on the back which can be switched off to stop the power current If this is not switched off and even though the computer is off power will still be drawn out of the power point (very small amount) The most common power supply that we have in our computers today are the ATX Power Supply The AT Power Supply was found in many computers a few years ago but this has become less common The graphic below shows each power cable and its name


The computer power supply is placed inside the computer case generally near the top of the case It is sometimes necessary to buy a mini power supply for some cases are so small that they need one Most computer cases when bought come with a power supply that is suited to its case There are usually power ports on the motherboard for the fans in the case but if not it is possible to buy an adapter that will convert power from the 4-pin power cable to a fan power cable

RJ45 COLORS AND WIRING GUIDE DIAGRAM TIA EIA 568 A B

The information listed here is to assist Network Administrators in the color coding of Ethernet cables Please be aware that modifying Ethernet cables improperly may cause loss of network connectivity Use this information at your own risk and ensure all connectors and cables are modified in accordance with TIA standards BASIC THEORY


By looking at a T-568A UTP Ethernet straight-thru cable and an Ethernet crossover cable with a T-568B end we see that the TX (transmitter) pins are connected to the corresponding RX (receiver) pins plus to plus and minus to minus You can also see that both the blue and brown wire pairs on pins 4 5 7 and 8 are not used in either standard What you may not realize is that these same pins 4 5 7 and 8 are not used or required in 100BASE-TX as well So why bother using these wires well for one thing its simply easier to make a connection with all the wires grouped together Otherwise youll be spending time trying to fit those tiny little wires into each of the corresponding holes in the RJ-45 connector

T-568A Straight-Through Ethernet Cable

The T-568A standard is supposed to be used in new network installations Most off-the-shelf Ethernet cables are still of the T-568B standard however it makes absolutely no functional difference in which you choose


T-568B Straight-Through Ethernet Cable

Both the T-568A and the T-568B standard Straight-Through cables are used most often as patch cords for your Ethernet connections If you require a cable to connect two Ethernet devices directly together without a hub or when you connect two hubs together you will need to use a Crossover cable instead

RJ-45 Crossover Ethernet Cable

A good way of remembering how to wire a Crossover Ethernet cable is to wire one end using the T-568A standard and the other end using the T-568B standard Another way of remembering the color coding is to simply switch the Green set of wires in place with the Orange set of wires Specifically switch the solid Green (G) with the solid Orange and switch the greenwhite with the orangewhite HOW TO BUILD AN ETHERNET CABLE INSTRUCTIONS

1 Pull the cable off the reel to the desired length and cut using wire cutters or scissors If you are pulling cables through holes its easier to attach the RJ-45 plugs after the cable


is pulled The total length of wire segments between a PC and a switch or between two PCs cannot exceed 100 Meters (328 feet) for 100BASE-TX and 300 Meters for 10BASE-T

2 Start on one end and strip the cable jacket off (about 1) using a wire stripper or a knife Be extra careful not to nick the wires otherwise you will need to start over

3 Spread untwist the pairs and arrange the wires in the order of the desired cable end Flatten the end between your thumb and forefinger Trim the ends of the wires so they are even with one another leaving only 12 in wire length If it is longer than 12 it will be out-of-spec and susceptible to crosstalk Flatten and insure there are no spaces between wires

4 Hold the RJ-45 plug with the clip facing down or away from you Push the wires firmly into the plug Inspect each wire is flat even at the front of the plug Check the order of the wires Double check again Check that the jacket is fitted right against the stop of the plug Carefully hold the wire and firmly crimp the RJ-45 with the crimp tool

5 Check the color orientation check that the crimped connection is not about to come apart and check to see if the wires are flat against the front of the plug If even one of these are incorrect you will have to start over Test the Ethernet cable

What is an IP address Every machine on a network has a unique identifier Just as you would address a letter to send in the mail computers use the unique identifier to send data to specific computers on a network Most networks today including all computers on the Internet use the TCPIP protocol as the standard for how to communicate on the network In the TCPIP protocol the unique identifier for a computer is called its IP address There are two standards for IP addresses IP Version 4 (IPv4) and IP Version 6 (IPv6) All computers with IP addresses have an IPv4 address and many are starting to use the new IPv6 address system as well Heres what these two address types mean

IPv4 uses 32 binary bits to create a single unique address on the network An IPv4 address is expressed by four numbers separated by dots Each number is the decimal (base-10) representation for an eight-digit binary (base-2) number also called an octet For example 2162761137

IPv6 uses 128 binary bits to create a single unique address on the network An IPv6 address is expressed by eight groups of hexadecimal (base-16) numbers separated by colons as in 2001cdba000000000000000032579652 Groups of numbers that contain all zeros are often omitted to save space leaving a colon separator to mark the gap (as in 2001cdba32579652)


At the dawn of IPv4 addressing the Internet was not the large commercial sensation it is today and most networks were private and closed off from other networks around the world When the Internet exploded having only 32 bits to identify a unique Internet address caused people to panic that wed run out of IP addresses Under IPv4 there are 232 possible combinations which offers just under 43 billion unique addresses IPv6 raised that to a panic-relieving 2128 possible addresses Later well take a closer look at how to understand your computers IPv4 or IPv6 addresses How does your computer get its IP address An IP address can be either dynamic or static A static address is one that you configure yourself by editing your computers network settings This type of address is rare and it can create network issues if you use it without a good understanding of TCPIP Dynamic addresses are the most common Theyre assigned by the Dynamic Host Configuration Protocol (DHCP) a service running on the network DHCP typically runs on network hardware such as routers or dedicated DHCP servers Dynamic IP addresses are issued using a leasing system meaning that the IP address is only active for a limited time If the lease expires the computer will automatically request a new lease Sometimes this means the computer will get a new IP address too especially if the computer was unplugged from the network between leases This process is usually transparent to the user unless the computer warns about an IP address conflict on the network (two computers with the same IP address) An address conflict is rare and todays technology typically fixes the problem automatically Next lets take a closer look at the important parts of an IP address and the special roles of certain addresses

IP Classes Earlier you read that IPv4 addresses represent four eight-digit binary numbers That means that each number could be 00000000 to 11111111 in binary or 0 to 255 in decimal (base-10) In other words 0000 to 255255255255 However some numbers in that range are reserved for specific purposes on TCPIP networks These reservations are recognized by the authority on TCPIP addressing the Internet Assigned Numbers Authority (IANA) Four specific reservations include the following

0000 -- This represents the default network which is the abstract concept of just being connected to a TCPIP network


255255255255 -- This address is reserved for network broadcasts or messages that should go to all computers on the network

127001 -- This is called the loopback address meaning your computers way of identifying itself whether or not it has an assigned IP address

16925401 to 169254255254 -- This is the Automatic Private IP Addressing (APIPA) range of addresses assigned automatically when a computers unsuccessful getting an address from a DHCP server

The other IP address reservations are for subnet classes A subnet is a smaller network of computers connected to a larger network through a router The subnet can have its own address system so computers on the same subnet can communicate quickly without sending data across the larger network A router on a TCPIP network including the Internet is configured to recognize one or more subnets and route network traffic appropriately The following are the IP addresses reserved for subnets

10000 to 10255255255 -- This falls within the Class A address range of 1000 to 127000 in which the first bit is 0

1721600 to 17231255255 -- This falls within the Class B address range of 128000 to 19125500 in which the first two bits are 10

19216800 to 192168255255 -- This falls within the Class C range of 192000 through 2232552550 in which the first three bits are 110

Multicast (formerly called Class D) -- The first four bits in the address are 1110 with addresses ranging from 224000 to 239255255255

Reserved for futureexperimental use (formerly called Class E) -- addresses 240000 to 254255255254

The first three (within Classes A B and C) are those most used in creating subnets Later well see how a subnet uses these addresses The IANA has outlined specific uses for multicast addresses within Internet Engineering Task Force (IETF) document RFC 5771 However it hasnt designated a purpose or future plan for Class E addresses since it reserved the block in its 1989 document RFC 1112 Before IPv6 the Internet was filled with debate about whether the IANA should release Class E for general use Next lets see how subnets work and find out who has those non-reserved IP addresses out on the Internet

Internet Addresses and Subnets


The following is an example of a subnet IP address you might have on your computer at home if youre using a router (wireless or wired) between your ISP connection and your computer

IP address 1921681102 Subnet mask 2552552550 Twenty-four bits (three octets) reserved for network identity Eight bits (one octet) reserved for nodes Subnet identity based on subnet mask (first address) 19216810 The reserved broadcast address for the subnet (last address)

1921681255 Example addresses on the same network 19216811 1921681103 Example addresses not on the same network 19216821 1921682103

Besides reserving IP addresses the IANA is also responsible for assigning blocks of IP addresses to certain entities usually commercial or government organizations Your Internet service provider (ISP) may be one of these entities or it may be part of a larger block under the control of one of those entities In order for you to connect to the Internet your ISP will assign you one of these addresses You can see a full list of IANA assignments and reservations for IPv4 addresses here If you only connect one computer to the Internet that computer can use the address from your ISP Many homes today though use routers to share a single Internet connection between multiple computers Wireless routers have become especially popular in recent years avoiding the need to run network cables between rooms If you use a router to share an Internet connection the router gets the IP address issued directly from the ISP Then it creates and manages a subnet for all the computers connected to that router If your computers address falls into one of the reserved subnet ranges listed earlier youre going through a router rather than connecting directly to the Internet IP addresses on a subnet have two parts network and node The network part identifies the subnet itself The node also called the host is an individual piece of computer equipment connected to the network and requiring a unique address Each computer knows how to separate the two parts of the IP address by using a subnet mask A subnet mask looks somewhat like an IP address but its actually just a filter used to determine which part of an IP address designates the network and node A subnet mask consists of a series of 1 bits followed by a series of 0 bits The 1 bits indicate those that should mask the network bits in the IP address revealing


only those that identify a unique node on that network In the IPv4 standard the most commonly used subnet masks have complete octets of 1s and 0s as follows

2550000 = 11111111000000000000000000000000 = eight bits for networks 24 bits for nodes

25525500 = 11111111111111110000000000000000 = 16 bits for networks 16 bits for nodes

2552552550 = 11111111 111111111111111100000000 = 24 bits for networks eight bits for nodes

People who set up large networks determine what subnet mask works best based on the number of desired subnets or nodes For more subnets use more bits for the network for more nodes per subnet use more bits for the nodes This may mean using non-standard mask values For instance if you want to use 10 bits for networks and 22 for nodes your subnet mask value would require using 11000000 in the second octet resulting in a subnet mask value of 25519200 Another important thing to note about IP addresses in a subnet is that the first and last addresses are reserved The first address identifies the subnet itself and the last address identifies the broadcast address for systems on that subnet See the sidebar on the previous page for a look at how all this information comes together to form your IP address For even more information about IP addresses the Internet and related networking topics head on to the next page

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33 TWEEZER 34 IC EXTRACTOR 35 IC INSERTER

36 LOGIC PROBE 37 LOGIC PULSER+


unit for a few seconds This can significantly dissipate the ESD that you have in your body Also consider using Anti-Static Mat while working your your computer to ensure safety against Static Electricity But again grounding yourself to the computers chassis is enough to drain off the ESDs Since ESDs can damage computer peripherals and components it is best to store your removed components and peripherals in Anti-Static Bags 3 Working Safely with Electricity Whether your home outlet is 110 or 220 volts Alternating Current (AC) it can potentially kill you But before working safely with the insides of your computer let us be familiar first with the outsides of the computer In powerlines the electricity that flows through the lines are not perfectly stable The voltage may rise and fall and this action of the unstable voltage is called a voltage spike Though most devices can operate even with voltage spikes your computer cannot endure this spikes What your computer eats is a stable supply of electrical current The Automatic Voltage Regulator (AVR) does this job It regulates or flattens out the AC flow of electricity to be fed to your computer After the AVR your computer receives the regulated 110 or 220 V AC electricity into your Power Supply Unit (PSU) and converts it into Direct Current (DC) like 12 5 and 33 V respectively So we have in mind that the electricity we get from the outlet is 110 or 220 V unregulated and as it passes though the AVR it is still 110 or 220 V but the spikes are now removed - and still dangerous As the electricity from the AVR is received by the PSU it is converted to DC and is now less dangerous In other words if you are working with your computer turn off your system unit and unplug the power cord from the AVR If you might say that the DC current of the motherboard is small and can not cause you harm consider that the components of your computer are sensitive to electrical shortages































































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