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:
Estimated lesson time: 20 minutes
- 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.
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.
The following list provides examples of the types of documentation you should assemble before you begin a repair.
Carefully consider the following questions before you open the case of any computer:
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.
|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.|
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.
You'll want to compile and carry bootable floppy disks for each operating system that you encounter. These should contain the following files:
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.
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.
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:
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:
The following points summarize the main elements of this lesson: