CIS 107a: Introduction to Hardware Concepts

Chapter 16: Troubleshooting and Maintenance Fundamentals

 

Objectives:

This chapter is about troubleshooting guidelines. The objectives important to this chapter are on page 647:

  1. How to protect yourself, your hardware, and your software while solving computer problems
  2. What tools are needed to support personal computers
  3. How to isolate computer problems and devise a course of action
  4. The importance of good recordkeeping
  5. How to take a computer apart and put it back together
Concepts:

The chapter begins with a description of four different jobs that a technician might have:

  • support technician - this job is stationed at the same work site as the users who you try to help
  • service technician - this job entails travel to different sites, to handle problems as they arise
  • bench technician - this job is located in a lab setting, and provides help to users indirectly
  • help-desk technician - this job requires telephone contact with users at various locations

Each type of job will use different tools and techniques. The text explains that this chapter is mostly about the work of a support technician, the on site technician who will have to interface most directly with users, and who is in the best position to be proactive about avoiding trouble.

The text presents a list of equipment in terms of need. For all tools listed, do not use magnetic tools. These can cause damage to computer equipment and media.The most needed equipment: (Some items are shown in the picture on the right. Hover over the items with your mouse for the items' names.)

  • Phillips-head screwdriver - a couple of sizes here are a good idea
  • Extractor, a spring-loaded device that looks a bit like a hypodermic syringe. Press the plunger and wire prongs come out the other end, that can be used to pick up fallen objects. Sometimes you need this, sometimes you need the tweezers. Sometimes you need the much longer version that is available in automotive stores.
  • Tweezers - for picking pieces of paper out of printers or dropped screws from tight places. Surgical forceps are also good.
  • Flathead screwdriver - a wide blade and a narrow blade are useful.
  • Chip extractor to remove chips - this is not done very often. I would put it in the second list
  • Socket drivers for hex nuts and hex screws
  • Bootable rescue disk - this is not as practical if your users use NT or XP workstations. Typically, these OSs require an individual rescue disk for each workstation. (Not shown in this picture.)
  • Ground bracelet and/or ground mat - a good idea, but not used much in the real world. (Not shown in this picture.)
  • Torx screwdrivers - unfortunately, these come in several sizes, and none can be substituted for each other. A good set of them is desirable. (Not shown in this picture.)

If you do not have a tool set, and can only get one, the best thing to have is a Swiss Army Cybertool. I took apart a hard drive with one to make the point that it could be done. Follow the link to see features of one model. Mouse over the components for a description of them.

Handy equipment that it would be good to have:

  • Multimeter to check the power supply output. Can also be used to check circuit continuity.
  • Needle-nose pliers for holding objects in place
  • Flashlight to see inside the PC case (A small Maglite® is handy, because they are durable and you can focus them.)
  • AC outlet ground tester
  • Small cups or bags to help keep screws organized as you work
  • Antistatic bags to store unused parts. Static shielding bags would be better.
  • Pen and paper for taking notes
  • Diagnostic cards and diagnostic software
  • Utility software
  • Virus detection software on disks or CD. If Internet connectivity is working, try online scanning instead. (Trend Micro, the maker of PC-cillin. Symantec, the maker of Norton AntiVirus.)

The text recommends some diagnostic hardware and software. It is unlikely that the hardware will be of any use to you, unless you are actually working as a lab or bench technician. A support technician will find the software of more use.

Note that the text suggests several software packages, among them two by Windsor Technologies, Data Lifeguard by Western Digital, Symantec's Norton Utilities, Smith Micro Software's CheckIt, and others. These are all fine products. The software we used for testing in the classroom, Sandra, is an improvement over diagnostic software used in class previously.

Virus detection software is not discussed in this edition of the text. A few words are needed. Viruses can come in many forms, and by many methods. It is common to receive viruses by e-mail, but it need not be a disaster if you have a good anti-virus program running at all times, and if you receive regular updates to that program. I use Norton AntiVirus at home and at work. My system at home is configured to contact Symantec (Norton's publisher) regularly, and to download updates as they become available. This is a recommended configuration.

Some symptoms that might point to a virus having infected a computer:

  • A program takes longer than normal to load.
  • Disk access times seem excessive for simple tasks.
  • Executable files that once worked no longer work and give unexpected error messages.
  • Unusual error messages occur regularly.
  • Less memory than usual is available.
  • Files disappear mysteriously.
  • There is a noticeable reduction in disk space.
  • Executable files have changed size.
  • The access lights on hard drives and floppy drives turn on when there should be no activity on those devices.
  • You can’t access a drive. This can be a hard drive, CD-ROM drive, Zip drive, or floppy drive.
  • The system won’t boot.
  • Print services are not working properly.

Unfortunately, this list is neither exhaustive, nor definitive. Each of these problems could be caused by something other than a virus, and viruses are not limited to these behaviors. The best procedure to follow when a virus is suspected is to scan the machine with an updated copy of a good anti-virus program. It is often possible to scan the machine across the Internet, which assures you of getting the most current protection available from the anti-virus software publisher. (Trend Micro, the maker of PC-cillin. Symantec, the maker of Norton AntiVirus.)

Some simple precautions will keep you safe from most virus infections:

  • Don't download files except from trusted sources.
  • Scan all files before opening. (Good anti-virus software will do this.)
  • Don't pass floppy disks between users, unless necessary. When you must use floppies, scan them before use.

The text offers a systematic approach to troubleshooting problems. In fact, it is repeated several times in the chapter, so I will try to condense it here.

  • Approach every problem systematically. Be careful, check what you think you know, and don't assume anything.
  • This appears later in the list in the book, but it belongs here: interview the user. Be polite, be helpful, and confirm with the user that you understand their report before moving on. Emphasize that you are collecting the facts, not placing blame. Your duty is to find the truth. What did the user do? How was the system changed since it last worked? Did it ever work? Who else could have used or changed the system?
  • Simplify the problem into components. Check each component, one at a time. For instance, if the user is having a problem, ask what software was running at the time. Remove the programs, one at a time, to test for a conflict or an out-of-memory problem. Alternatively, remove all programs, and add them to the mix, one at a time.
  • Check everything, especially simple things like the computer being turned on and plugged in.
  • Check the simple things first. If you have three things to check, and two will take much less time than the third, save the third for last, unless you really believe that the third item is the real problem.
  • Research for an answer. The Internet has made a lot of difference in what companies offer in terms of support and online documentation.
  • Keep notes about what you do and what you learn. This is for you and for those who follow you. You may need to undo what you try, or you may need to repeat the process.

When testing the problem, some general advice applies to most situations:

  • To test hardware, swap known good for suspected bad. This can backfire: if the problem is the power source and you swap out a damaged component, you may damage the good component. Example: a talented student had a problem with a motherboard. He replaced it with a new one. He neglected to properly insulate it from the metal case of the system unit. The mistake resulted in another lost motherboard.
  • It may be safer to try the alternative version of the advice above: swap suspected bad for known good. If you think a hard drive is bad, put it in place of a good one in another computer. This may prove that the hard drive is not functioning. This technique is less likely to result in damaging good equipment.

Some tips are offered in the chapter for specific troubleshooting.

It is possible that a system problem may come from bad connection of some component. The text recommends removing and replacing components, like expansion cards, making sure that the contacts where they attach are not corroded and that no contact pins are bent or missing. Contacts on expansion cards may be cleaned with a pencil eraser, but care must be taken not to leave bits of rubber on the contacts or in sockets.

It is recommended that you become familiar with the Startup Menu of Windows 9.x and later. Most users never see this menu until something goes wrong with Windows. It is possible to force the menu to appear when Windows boots up by pressing the F8 key while the screen is still black. From the Startup Menu, you may start Windows in Safe Mode, with or without network support, which will be useful in troubleshooting settings in Windows itself.

It is often expedient, when having problems with specific software, to reinstall the software. It may be useful to uninstall the software first, because some installation programs check for installed components, and will not necessarily overwrite a bad or corrupted program file. You are cautioned to back up the user's data first, if at all possible.

It has been common for one Windows program to cause problems with another, because such programs often install components of themselves in the Windows\System directory (or the WinNT\System32 directory, if running Windows NT). The installed components are often DLL files. DLL stands for Dynamic Link Library. A DLL file is like a collection of functions that another program can call. The problem is that one program may install its own version of a DLL file that has the same name as a DLL belonging to another program. It is more common currently for programs to install such files in their own directories, but this problem still comes up.

It is suggested that the most difficult problems to solve are those that are intermittent. Neither you nor the user can predict when the next instance will be, so it is impossible to predict when to be at the user's workstation to diagnose the problem. In such cases, it may be useful to instruct the user in the proper procedure to get a screen dump of any error message he may get. If possible, the screen dump should be sent to a printer, or saved as a file.

Some observations are made about keyboards. Often, a bad keyboard should simply be replaced. If necessary, the text suggests that you can rinse off spilled soft drinks, but the keyboard should dry for a couple of days before you try to use it again. I once turned a keyboard upside down, and not only did spilled coffee drip out of it, but I also saw cigarette ashes and paper clips fall onto the desk. It was a wonder that it worked at all.

Several observations are made about monitor trouble. Often, the user has selected a driver or a combination of settings that do not work with with the monitor and/or video card. Starting a Windows system in Safe Mode will let you load a "plain vanilla" video driver that will work with most monitors and video cards. This will let you test possible combinations of color density, screen resolution, refresh rates, etc. You should be familiar with the procedure to change each of these settings in Windows.

Printer problems are often reported by users. The problem they are having could be an incorrect driver, a printer that needs paper or toner, or a simple jam in the paper path in the printer. Some tips from this section:

  • a printer may give an error message (such as "paper out") if the paper tray is not correctly inserted, or if the sensor for the paper is bent, misaligned, etc.
  • a printer may function improperly if a setting on the tray or in the software does not match the paper size actually being used
  • toner for laser printers may not be totally gone when the printer says it is. You may be able to continue using the same toner cartridge by removing it, shaking it to distribute any existing toner, and replacing the cartridge
  • paper jams can be caused by shreds of paper, labels, or glue that are hidden behind rollers in the printer. Check carefully for debris. Also check for the wrong kind of paper. Paper should generally be 20 pound, and the proper sort for the printer: laser or ink jet type.

A technician is cautioned to keep documentation about equipment. Not only the documentation that comes from the manufacturer, but notes about how the equipment has been configured for the worksite.

It is recommended at the end of the chapter to have backup copies of both your system (and application) software, and your data files. Storing these two kinds of files on different drives is a good idea. Storing data on network servers makes sense, because the data may be backed up centrally instead of relying on a user to make copies.

Fire Extinguishers - The text discusses use and classes of fire extinguishers. Fire extinguishers are classed by the kind of fire they are able to put out. Your book's information is correct, but dated. The links below will take you to sites with more information about fire classes and extinguishers. In surveying several sites, I found that there are currently at least four classes of fires, and that the symbols for them have been updated to use pictures instead of letters. Some sites list a Class K for cooking oils (Kitchen fires), but this does not seem to be universal.

Description of Extinguisher Class
Letter and Shape Symbol for Class
Picture for Class
Class A: paper, cloth, wood.
Class B: oil, gasoline, kerosene, propane.
Class C: electrical
Class D: combustible metals, such as magnesium, potassium, sodium
Class K: combustible cooking oils

Information from FEMA

Information from Underwriters Laboratories

Information from the University of Oklahoma Police Department

In most cases, a multiclass extinguisher is preferred. On extinguishers I examined at my workplace, multiple picture symbols were used, showing the pictures for class A, B, and C. (Although they were black and white, not blue, the pictures were the same as those above.)

If the extinguisher is not rated as being effective for a particular class, the symbol or picture will either be missing, or will have a diagonal line drawn through it. Water extinguishers, for example, are not effective against flaming liquids, because the flaming liquid spreads instead of being covered by the water.

While your book does not discuss it, several web sites I encountered discuss a classic explanation of fire. It may be helpful to understand this, the next time you have to put a fire out. For a fire to exist, three factors are needed:

  • oxygen
  • fuel
  • heat

If you can eliminate any one of these factors, the fire will go out. This is why Carbon Dioxide extinguishers work: the CO2 replaces the oxygen in the immediate vicinity of a fire, and the fire stops. Smothering a campfire works about the same way.

A fire break is an example of fighting a fire by depriving it of fuel. Forest fires can be fought this way. Somewhat similarly, I once walked into a rest room in an office and found that someone had placed a roll of toilet paper on top of the light fixture over the sink. I noticed it because it was on fire. I grabbed the roll of paper and tossed it into the sink. This established a fire break. I then put out the fire on the roll of paper with water.

Keeping your computer system cool, so that a fire will not ignite, is your most effective form of firefighting: don't let it start.