Lesson 1: Computer Disassembly and Reassembly

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In this lesson, we look at the tools and practices required by a computer technician to physically take apart a computer and successfully put it back together. Although this lesson mentions software that you should have and know how to use, software is covered more deeply in Chapters 15, "Software: MS-DOS and Windows 3.x," and 16, "Windows 95 and Beyond."

After this lesson, you will be able to:

  • Develop a systematic and logical approach to repairing a computer.
  • Identify and describe the basic tools and procedures for working on a computer.
  • Identify basic procedures for adding and removing computer components.
Estimated lesson time: 20 minutes


Knowledge and preparation are the primary ingredients for a successful, efficient, and profitable upgrade or repair. Before attempting any work on a computer, it is wise to know what you are working with and to have a good understanding of the problem, or task, at hand. Ten minutes to an hour of preparation can save hours of endless guessing and frustration.

Documentation is the key to preparation. If adequate documentation is not readily available, your first step is to collect or create it. When you finish a job, don't forget to save the documentation, including an account of what you did and any problems you encountered.

Documentation to Collect Before Starting the Job

The following list provides examples of the types of documentation you should assemble before you begin a repair.

  • A computer configuration sheet. A sample computer configuration sheet is shown in Figure 14.1 in Lesson 2 of this chapter.
  • Copies of the computer and/or motherboard documentation.
  • A list of all installed expansion cards. If possible, include the date on which they were originally installed.
  • Copies of the operating-system documentation (especially if you are not familiar with the system).
  • A plan of action. Writing down a checklist of tasks and related tools and parts before starting a project can help you keep focused and stay on target. Remember, plans can always be changed; but without a plan, you could find yourself wandering aimlessly through the project and perhaps getting sidetracked or lost.

Questions to Ask Yourself Before Starting the Job

Carefully consider the following questions before you open the case of any computer:

  • Is this the right computer?
  • Why am I taking it apart?
  • Do I have everything necessary to do the job?
  • Do I need more information before starting this job?
  • Might any components of this machine be proprietary hardware? If so, do I have the right tools and parts to do the job?
  • Do any of these tasks require the assistance of a third party—for example, monitor adjustment?

Recommended Hardware

A computer professional does not need a large toolbox; only a few basic hand tools, a handful of floppy disks are required to solve most computer problems. Most PCs can be opened and most parts removed and replaced with a pair of screwdrivers. Be careful when working on a proprietary machine, however—special tools are often required. A small canvas bag or a briefcase will generally be sufficient to carry everything you need.

The following table lists and describes the hand tools that will meet most needs.

Tool Description
Screwdrivers Two of each (one large and one small) flathead (regular) and Phillips (sometimes called a cross) screwdrivers are usually sufficient. Avoid magnetic screwdrivers: although they are convenient for picking up lost screws, their magnetism can cause problems.
Torx driver Used to remove the odd star-shaped screws found on some proprietary computers. Sizes T-10 and T-15 should meet the needs of most computers.
Tweezers Very convenient for picking up small parts (for instance,screws). You might consider the long plastic variety; these don't conduct electricity and hence won't create any short circuits.
Needlenose pliers Can be used to pick up dropped items and to hold or loosen screws, nuts, and bolts.
Chip removers Although optional, these are very useful when changing video RAM or other (older) RAM chips that are pushed into a socket.
Tube for small parts A short plastic tube (with caps on both ends) will keep loose screws and small parts from wandering.
Compressed air A can of compressed air is helpful to remove dust.
ESD tools An antistatic wristband is a must. Antistatic mats and antistatic bags are also helpful.
Multimeter A small, digital meter that is capable of measuring volts (AC and DC) and ohms (resistance or continuity) is all that is needed.
Flashlight A small (bright) light for illuminating those hard-to-get-at places.
Nut driver set Sizes 3/16-inch, 7/32-inch, and 1/4-inch.
Hemostats Good for picking up and holding small parts. Straight hemostats will work most of the time. However, curved ones will get into those small places that the straight ones can't reach.
POST Card A POST card can be used to see what the error messages during system start are being sent when no data is being sent to the display.

Recommended Software

Don't feel compelled to carry an entire arsenal of arcane software. A small number of commonly used programs can serve most of your needs.

Bootable Floppy Disk

You'll want to compile and carry bootable floppy disks for each operating system that you encounter. These should contain the following files:

  • EMM386.EXE
  • MSD.EXE (.COM)
  • NOTE
    These files will just barely fit on one 3.5-inch high-density floppy disk. Files listed in bold are essential.

    A Windows 98 startup disk is also a good item to carry. This is a bootable disk that will also load all drivers needed to run a CD-ROM on most PCs.

    The utility MSD.EXE is a good diagnostic tool that can determine which hardware options are installed on a computer system without the need for you to remove the case. MSD.EXE is also a great tool for diagnosing software conflicts.

    Operating-System Disk

    Make sure copies of the original operating-system disk (or CD) are available. If it becomes necessary to install one or more components that were left out during the original installation, the computer might require verification of serial numbers (the original disk #1) before any additional files can be installed. Windows 95 and 98 and Windows NT strongly recommend that you create a rescue disk in case there are any problems with corrupt files in the operating system. It is a good practice to ensure that you have this disk available.

    A rescue disk is unique to the computer for which it was created. Therefore, a new one must be made for each computer in service.

    Software Utilities

    There are many good-quality utility programs available today. These programs allow the experienced user to find and correct a multitude of problems. However, caution should be used when "correcting" a problem that has been identified by the software. The software might consider something a problem simply because it does not recognize it. ("If I don't know what it is, it must be bad.") In some cases, the cure is worse than the disease. Also, keep in mind that one utility will not solve every problem. As a computer professional, you will do far better to master one good software system than to have a box full of utilities that you don't know how to run effectively. Don't forget good old MS-DOS; it is full of commands that are usually forgotten or never used.

    Older versions of utility programs are designed to work with MS-DOS and Windows 3.x. They can wreak havoc on a Windows 95 or Windows 98 system. You must also be especially careful if you're running later versions of Windows 95 or Windows 98 that use the FAT32 file system, because most utilities are designed to handle the traditional FAT16.

    You should never run any application to "tune" a system that is not specifically designed for that version of the operating system. That applies triple to advanced 32-bit operating systems such as Windows 98 and Windows 2000.

    Among the handiest utilities have around are virus-checking programs that are compatible with each operating system you work with, such as disk and video display diagnostic programs.


    Disassembling a computer is a straightforward task. In most cases, you will need to remove little more than the outer cover or shroud of the case to gain access to the memory, expansions slots/cards, and the CPU. Because there are many manufacturers, each seeking to establish its own unique marketing identity, each brand has some custom components or layout. The best strategy for efficient disassembly is to locate and use the manual that came with the computer.

    Often, manuals don't provide a lot of technical information, but they usually tell you how to remove the cover. The extent to which you will have to disassemble a computer depends on the specific problem or repair. Following the following procedure will help you establish a routine for completely and efficiently disassembling most computers:

    1. Make a complete backup of necessary operating-system and working files.
    2. Document the system (hardware and software).
    3. Create a clean work area with plenty of room and light.
    4. Gather all the necessary tools for the job.
    5. Implement safety procedures. (See Chapter 13, "The Basics of Electrical Energy," and Chapter 19, "Maintaining Computer Hardware," for details.)
    6. Turn off the computer.
    7. Disconnect the power cables.
    8. Wear an antistatic wrist strap.
    9. Locate the screws for the cover—check the manual to discover the location of the screws (sides or back).
    10. Remove the screws. It's a good idea to store them in a box or plastic tube to keep them from getting lost.
    11. Remove the cover from the computer.
    12. Document the location of expansion cards and drives.
    13. Remove all the cards and place them in antistatic bags.
    14. Document the location and connections for each drive (pay special attention to the red wire on the data cables—this identifies the location of pin 1 on the device and driver).
    15. Remove the data and power supply cables.
    16. Remove the drives from their appropriate bays—look on their sides for the screws (check the manuals).
    17. Remove the motherboard.


    Run the preassem video located in the demos folder on the CD accompanying this book to view a presentation of all the hardware components that go into a personal computer.

    To reassemble a computer, you simply follow the same procedures as for disassembly, but in the reverse order. When installing components, remember the following:

    • Do not force connectors into place—if they don't fit easily, they are probably in the wrong place.
    • Expansion cards often require some force or side-to-side movement to fit into place, but do not force them.
    • When removing cables, remember the pin 1 locations. Check notations on the circuit boards, and look for the red wire on the ribbon cables.
    • Connect the cables to the drives before installing them in the bays.
    • Test the system before replacing the cover.

    Lesson Summary

    The following points summarize the main elements of this lesson:

    • By following a systematic plan, you can simplify the process of disassembling and reassembling a computer.
    • Establishing and maintaining good documentation and having the right hardware and software tools are the keys to a successful upgrade.
    • Following safety procedures will ensure that no damage is done to you or the computer.

    Microsoft Corporation - A+ Certification Training Kit
    Microsoft Corporation - A+ Certification Training Kit
    ISBN: N/A
    EAN: N/A
    Year: 2000
    Pages: 127

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