PC Construction and Maintenance

1. PC Construction and Maintenance Week 2 The Prerequisites: Monitors, Mice, Keyboards and Cases Tools for the Job, and Tips http://www.cms.livjm.ac.uk/cmspcar1/pc_construction

2. Monitors • There are several different types of computer monitor available • TFT (Thin film Transistor) screens are very thin and save a lot of space. • CRT based monitors are the current standard

3. Monitors • All CRT monitors have common set of parameters • They are Screen size, Resolutions, Refresh Rate, Dot Pitch • Recommended minimum size for a monitor is 15” • Screen size is often smaller than quoted size. Depends on brand

4. Monitor Resolution • Resolution of monitor specifies how many pixels can be displayed on screen • Resolution is expressed as a horizontal and vertical measurement • Most Modern monitors can do a resolution of 1024x768 • 800x600 is often adequate for windows-based systems, but Linux often needs higher

5. Dot Pitch • The screen consists of phosphor dots that emit red,green or blue light, providing colour • The Dot Pitch is a measurement of the size of these dots • Smaller dot pitch is better • Dot pitch becomes limiting factor of true resolution for hi-res modes

6. Refresh Rate • The refresh-rate is the number of frames per second that can be displayed by the monitor • In practice, the available refresh rates will depend on the current resolution • 60Hz or above is recommended • Screen mode can be interlaced or non-interlaced • Non-interlaced mode is recommended

7. Monitor Standards • Monitors comply to a standard known as SVGA • All SVGA monitors will plug into a standard PC graphics adapter (15 pins) • Older 9-pin VGA monitors are now obsolete • Power to monitor is standard “kettle lead” • Power may be supplied directly from outlet, or from base unit via connecting lead

8. Mice • A mouse is an essential part of the computer • 3 types in common use are:- Serial, PS/2 and USB • Most new computers use PS/2 • Standard mice use a ball and rollers, and are cheap • Optical mice need a special mat and are very smooth to use

9. Mice • A two button mouse is adequate • Three button mice have uses under Linux, but the middle button is rarely, if ever used under windows • Standard ball and roller mice need regular cleaning, otherwise, become unresponsive • Adapters are available to plug old mice into newer computers and vice versa

10. Keyboards • Three types of keyboards in common use – PS/2, AT and USB • Most new computers use PS/2 keyboards • Unfortunately, PS/2 keyboards and mice have the same type of socket and plug. Sockets situated right next to each other. • Usually, the keyboard plugs nearer to the edge of the case

11. Types of Case • AT and ATX cases are the most commonly in use • Practically all new cases are ATX • All ATX compliant motherboards will mount inside an ATX case • ATX defines plan for positions of motherboard mounting holes • ATX allows spaces for on-board peripheral devices such as graphics,sound network etc

12. Shapes and Sizes of cases • The four common sizes of cases are, Desktop, Mini-Tower, Midi-Tower, Full-Tower • Desktop allow the monitor to be situated on top of the case, and save a lot of room • The Tower cases are very similar. They merely have different numbers of drive bays • Approx number of drive bays as follows desktop=2, mini-tower=2, midi-tower=3 or 4, full-tower=5 or 6

13. Other types of cases • Often, machines purchased from high-street outlets can have non-standard cases • Slimline cases are often cheaper to make • Daughterboards are often used to fit peripheral cards into slimline cases • Non-standard cases are difficult to upgrade, and so are best to be avoided

15. Drive Bays • The standard PC drive bay is known as a 5¼” bay • Standard Drive bay is used for mounting DVD/CD-ROM drives, ZIP drives, or even hard drives • In addition there are usually one or two 3½” bays for mounting floppy drives

16. Screws used in PC building • All screws of the Phillips type • One screwdriver usually fits every screw • Screw not exactly standardised • 4 different important types • PC screws are made from soft metal • Care must be taken not to round the head

18. Motherboard mounting • When building a PC, mount the motherboard into the case first • A mixture of brass and plastic spacers are often used • Must ensure that the position of all the spacers lines up with motherboard • Short circuits can be caused by brass spacers in the wrong place

19. Installing a motherboard • Ensure there are at least 2 (preferably 3 or more) brass or similar spacers installed into the case • Ensure that the position of brass spacers corresponds to holes on motherboard • Where there are no brass spacers, use plastic spacers where possible

20. Installing a motherboard • Carefully hold motherboard, and double check its alignment relative to case • Slide motherboard into position • Carefully tighten screws into brass spacers • Use washers with screws if available, though you can do without • Check motherboard is firmly seated

21. Order of component installation • Often, the CPU and RAM are installed onto the board, before installing the board into the case • However, often upgrading of CPU and RAM can be done without removing the motherboard • It all depends on the layout of the board, and the shape and size of the case

22. Connecting up the board power • Plug the ATX power connecter lead from PSU into board power receptacle. It only fits one way round. • For old AT boards, there are two power plugs that plug into one long socket. The two sockets must be connected up correctly. In this case, the black wires of each plug must be adjacent, in the centre of the socket.

23. Connecting up the case features • The case power switch, reset switch, HDD LED, power LED and speaker should all be connected to the board • The LEDs only work when plugged in the correct way round • Sometimes you have to use trial and error to get this right. Its O.K. no damage can result

24. Connecting up the case features • The speaker is historically a four-pin wide socket. The plug can fit either way • The speaker is important, as it is often used to diagnose basic faults • Some cases feature a turbo LED • Turbo feature not generally used anymore • Reset and Power switches can go either way round

25. Powering up the board • The board must be capable of displaying output to a monitor before it can initialise, and be tested • Boards which do not have on-board video must have a video card plugged in, before they can be used • A keyboard must also be plugged in for setting up the system

26. POST Codes • The Power On Self Test codes use the PC speaker to report errors • POST codes are represented by a specific number or pattern of speaker beeps • POST codes usually mean that there is a configuration error, or something physically wrong with the set-up • Motherboard manuals usually contain a list of the POST codes for a particular board

27. Additional Tools • A nut spinner is a device that comes in very handy for tightening and freeing brass spacers • Long nosed pliers are handy for releasing plastic spacers from motherboards • Tweezers can come in handy for changing motherboard jumpers, and retrieving awkward dropped screws

28. Static Damage • Computer components can be damaged by static electricity • People normally carry a static charge • Static damage is in practice, very rare • Certain carpets, clothing materials pose much greater risk than others • Stepping out of a car can cause great static charge

29. Preventing Static Damage • Anti-static wristbands are available • Often just necessary to touch earthed case or metal pipe before starting work • Minimise handling time of electronic components • Avoid touching metal contacts of components

30. Tips • Earth yourself before touching components, in particular – chips • Use a magnetised screwdriver if available • Try not to tighten screws too hard. PC screws are made from relatively soft metal • Check for foreign objects (dropped screws etc..) around and underneath the motherboard, before powering on the system