Computer Troubleshooting and Repair [Troubleshooting and Repairing Commercial Electrical Equipment]

The familiar desktop or laptop computer incorporates two distinct areas-software and hardware. Software is a broad and somewhat diverse term, so to begin on secure footing we will consider hardware first. We all know what that means. Hardware is made up of the physical components including the central processing unit (CPU) plus all peripherals such as printer, keyboard, monitor, speakers, and so on. Also included are cabling, satellite dish if used for Internet connection, and so on. What these all have in common is a physical reality. A compact disc (CD) is a piece of hardware, while the information it contains is within the category of software, whether or not it is used for programming.

When it comes to computers, everything falls into one of these two categories. When a problem arises, it is generally useful to ask, "Is it a hardware or a software problem?" Since the two are interrelated, it is possible for the damage to be in both areas simultaneously, and indeed these problems may feed off one another.

Of course, there are instances where it is an obvious hardware problem. When the computer does not power up at all, begin by checking the branch circuit supply and the power cord. If they are not at fault, go on to measure voltages at the power supply, input and output. If there is a blown fuse, proceed to check the downstream components carefully before throwing in another fuse.

In addition, it often happens that the cooling fan stops working. (There may be more than one fan.) The fan is usually audible from the outside. If it is making an unusually loud or altered sound or no sound at all, power down the computer, check the supply voltage to the fan, and if the fan is at fault, replace it. Some computers shut down in response to a perceived temperature rise while others continue to run, rapidly frying valuable microchips.

Fans are very inexpensive, so do not bother trying to oil the bearings.

BIOS Start-Up

If the CPU power light goes on, but the monitor remains dark, it could be strictly a monitor problem. It is also possible that the monitor is good, but the computer is not telling it what to do. This is where the basic input/output system (BIOS) comes in.

As most schoolchildren understand these days, a computer contains two separate types of memory. Primary memory refers to the systems that operate more or less instantaneously, this being within microchips. This random access memory (RAM) is further subdivided into volatile and nonvolatile memory. Nonvolatile memory is permanently wired into semiconductors, while volatile memory is available for both computer access and manipulation.

The other broad category of computer memory is the hard drive. This is a mechanical device in which information is recorded, retrieved, rearranged, and erased as needed. It is much slower but has vastly more capacity than the semiconductor based memory. It is instructive to take a discarded computer apart, see how the hard drive is constructed, and how it is cabled into the logic board and, ultimately, the outside world.

When a computer is first turned on, the BIOS function comes into play. This is a type of firmware that is built into the computer in the form of a specialized nonvolatile microchip located on the motherboard. There are different BIOS chips for each type of computer, and they are designed to wake up the computer before the hard drive enters the picture.

BIOS performs several functions, typically configuring hardware, setting the system clock, enabling or disabling system components, selecting devices for booting, and initiating password prompts. This means that if the monitor fails to come up, it could be a hardware problem in the monitor itself, in the CPU BIOS chip, or in associated circuitry.

Computer monitors are a bit more complex than TVs as far as servicing is concerned.

They are similar, but computer monitors have auto-scan, high scan-rate deflection electronics, and more elaborate power supplies. An auto-scan monitor automatically determines the input scan rate and chooses the correct horizontal and vertical deflection and power supply voltages as needed.

As for monitor repair, beware of high voltages. Like a TV, a computer monitor retains for a long time a large amount of electrical energy even when turned off and disconnected from the power source. Please review the cautionary material in Section 7 for information on protecting yourself from this hazard.

When installing a submersible well pump of 1 horsepower or less, you can dispense with the pull rope. It is just in the way and the pipe-wire combination is capable of pulling up the pump if that ever has to be done. Some installers leave out the torque arrestor, but that is a bad practice because reverse torque when the motor starts and stops can lead to a chafed wire and ground out one of the conductors.

Used monitors are abundant because outdated or nonfunctional computers are frequently discarded along with good monitors. Check with large office buildings and businesses. There is high interchangeability for monitors if the cabling is compatible; so, many times an extensive monitor repair procedure is not warranted. However, if you are interested, here are some monitor symptoms with remedies:

• If color or brightness is seen to be variable, or if there are problems with size or position, look for bad connections. They may be either inside the monitor or at cabling terminations, including inside the computer.

• If ghosts, streaks, or shadows are observed, check the input signal. They may also be caused by bad or excessively long cables, connections to other monitors, or other types of cabling design or installation flaws.

• Electromagnetic interference (EMI) or line interference is caused by nearby motors, nonlinear loads, or bad utility power. The solution is to relocate equipment or wiring that is problematic, or construct grounded shielding.

• Reduced brightness is a chronic problem for a monitor as it ages. Internal or external adjustments often but not always provide a solution.

Sometimes, ascertaining whether a fault is in the software or hardware can be difficult.

If intermittent freezing takes place, it could be due to overheating, a hardware fault. Look to the power supply or the fan.

Alternatively, it could be due to a software failure, and there may be no immediate way to determine where the fault lies. However, if you keep thinking about it and performing standard troubleshooting procedures, you should be able to come to an understanding of the machine status, and find whether it is capable of being repaired.

If there are intermittent freeze-ups that require rebooting, notice whether they take place when the temperature in the room is excessively high. Try placing a small electric heater near the computer and see if that brings out the malfunction. If so, try using the heat gun very gently on various components to locate an intermittent defect.

Hardware versus Software

If, despite your best efforts, a hardware-based fault does not seem to emerge, you will need to take a second look at the software side of the picture. Recall the history of the malfunction, conferring with users of the computer. Did the problem arise immediately after a new program was installed? Some programs in conjunction with other programs give rise to conflicts, and they may cause the computer to crash. Use a half-splitting troubleshooting technique to localize the application that is causing the problem. You can temporarily disable programs to see which one is responsible. If one of the two that is causing the conflict is expendable, that is the end of the story. If not, see if there is a newer version available.

Otherwise, simply removing it and reinstalling it may rectify the situation.

If this does not work, try a PC or Mac repair program, found under utilities or a similar menu entry. Do not be afraid to defragment the hard drive, as this should be done from time to time and may solve chronic memory shortages.

If all else fails, it is possible that the operating system has lost data or acquired one or more corruptions. Use the restore disc that came with the computer.

As a diagnostic procedure, safe mode is useful. For a windows-type computer, it is instituted by holding down the F8 key as the system boots up. For a Mac, hold down the Shift key while booting. This results in a start-up with no extensions, and is useful if a conflict is suspected. For a Mac, begin by shutting the computer down. Then press the power button. After but not before you hear the start-up tone, depress the Shift key. When the gray apple icon appears, release the Shift key. To come out of safe mode, restart the computer in the normal fashion, without holding down the Space Bar.

When repairing an amplifier or similar equipment and you cannot find the problem, try going over all the solder joints with a hot soldering iron. With time, one or more of them may have oxidized at a cold joint making a high-resistance connection. Another possible remedy is to separate and reconnect all the ribbon connectors, which polishes and restores the contacts.

Laptops constitute a special case of computer repair, not because the operating system or electronics is appreciably different, with the exception of the battery and battery charger, but because opening up the laptop and access to sections within are more acute, due to efforts by the manufacturers to make them slimmer and more compact. This impulse is, in my view, misguided. Who cares if the laptop weighs a few ounces less or is a fraction of an inch thinner? It is very easy to carry around anyway unless you are planning to take it with you on an ascent of the Mount Everest.

The MacBook Pro with Retina Display carries this trend to such an extent that, although it is a beautiful human artifact, it is virtually un-repairable outside of a specialized shop. It takes special tools and procedures to open it up. To change the hard drive or battery is difficult beyond description. (The battery is cemented in place!) In contrast, the previous MacBook Pro 15 in. is robust with bountiful memory and advanced features, yet battery, trackpad, RAM, hard drive, optical drive, airport card, magsafe board, and fan are all easily accessible.

Apple introduced the MacBook Pro in 2006. Externally, it resembles its predecessor, the Powerbook G4 Apple laptop. The changes to the casing are minor, but inside it is a completely new computer with a large capacity hard drive and a lot of RAM.

When working on this computer, as with any sensitive electronic equipment, take whatever measures are possible to guard against static electricity damage to semiconductors.

An antistatic bracelet attached to a grounding terminal will work. If this is not available, touch a grounded metal surface periodically in the course of your work. Hold printed circuit boards at the edges and keep replacement semiconductors in their original conductive foam packing, which keeps the leads shunted together so that they cannot be at different voltage levels.

As with any laptop, during a repair you want to remove the battery at the earliest opportunity. For this model, there is nothing to it. Just turn the laptop over, and rest it on a clean cushioned surface. There are two latches at the bottom of the case near the middle.

Slide them toward the back, and then the battery will pop out. After the battery has been removed, five screws are visible. Of these, three screws with large heads hold the memory bay cover in place. Remove all of these screws, noting where each type goes. Take copious notes at each step of the teardown process, so that there are no questions during re assembly. Note that three of the screws are shorter than the others.

After the screws are removed, take off the memory bay cover by sliding it toward the front of the computer. Once the memory bay cover has been removed, you will see two RAM slots. They will contain whatever memory was included when the laptop was originally purchased or installed in the course of an upgrade. There will be either one or two memory modules, held in place by metal clips. Move them out of the way and slide the modules out.

Reverse the process to reinstall the memory modules or replace them with new modules. The maximum upgrade involves two 1-GB memory modules for a total of 2 GB of RAM-that is a lot of memory.

The last article of the National Electric Code covers Network-Powered Broadband Communications Systems. "Network-powered" means that in addition to a data signal for telephone, cable TV, or interactive services, the line also carries a dc or ac voltage which is used to power any electronic components such as required for amplification along the way. In the early years of telephone technology, each phone contained its own batteries. If you look inside a modern phone, you will see solid-state components for amplification, but no power supply or rectifier. A dc voltage is provided by the utility and accompanies the voice signal on a single pair of conductors.

Next on the agenda is to remove the top case. There are 10 screws altogether. After they are removed (using a Torx TR tool), pull out the top case enough to reveal the cable that connects it to the main logic board. Sometimes the top case is reluctant to separate at first. The perfect tool to aid in this is a plastic guitar pick, which will slide in gently and not mar the edges. Disconnect the top case. Now the hard drive is accessible. If the object of this repair is to replace the hard drive, disconnect the hard drive cable from the main logic board. Pull the cable evenly and it will come free. On the right side are two screws holding the hard drive bracket. Remove the Bluetooth module and the bracket.

Everything comes apart easily. Remove the hard drive and disconnect the main interface cable.

To install a new hard drive, simply reverse the steps above. That is it, as far as the hardware is concerned. It will still be necessary to format the new disc and install the operating system. Directions for doing this are on the Internet, and are not overly difficult.

More Mac Subsystems

Going deeper into the MacBook Pro, it is feasible to replace the Bluetooth module, the Superdrive, Airport Express including antenna cables, keyboard, speaker assembly, Magsafe board, logic board, display, inverter board, and other components.

General troubleshooting techniques apply to both hardware and software problems.

Hardware defects are easier to pin down, but the parts may be more expensive. Software troubleshooting requires a measure of expertise, but the overhead is often zero.

In looking for the source of hardware problems, an important clue is provided when you think back (or discover from the user interview) to determine if a specific event initiated it. Did it first occur when a new cable or peripheral device was installed? If so, check the integrity of connections.

If a computer boots up successfully, but a hardware device or software program fails to perform, there is reason to suspect that it is a driver problem. A driver is a small application that controls a device, mediating between it and the operating system. All devices have drivers. Devices, in this context, are units of hardware including printers, keyboards, disc drives, etc. The computer's operating system contains the driver for the keyboard, but other devices need to have their specific drivers installed in the computer. A printer, to take one example, usually comes with a CD containing the driver. If the CD is not available, the driver can be obtained as a free download from the Internet. Type the make and model of the device, the computer platform (Mac or PC), and "download driver" into the search engine.

Very frequently, a device will exhibit erratic behavior or cause the computer to crash. By downloading a new driver, you can often resolve the problem.

There is a very powerful tool for diagnosis of computer problems. You have undoubtedly noticed that when a computer starts up, there is a characteristic chime or tone.

It is initiated by the BIOS application and indicates that diagnostic tests have not detected hardware or software problems. The PC terminology is POST. This means Power-On Self Test. Depending upon the computer and type of BIOS chip that it contains, the error codes will vary, as will the amount of information available to aid in troubleshooting. As an example, the following is a list of the standard original IBM POST error codes:

• A single short tone: System is good.

• Two short tones: Error is shown on screen.

• No tone: System board or power supply malfunction.

• Continuous tone: Keyboard, power supply or system board malfunction.

• One long and one short tone: System board failure.

• One long and two short tones: Display adapter malfunction.

• One long and three short tones: Enhanced graphics adapter malfunction.

• Three long tones: Keyboard card failure.

These error codes can take you directly to the problem. To decode tones (or flashing lights), type the computer make and model along with the appropriate query into the search engine and you will find the answer.

CATV cable typically has an ac voltage of approximately 60 volts, which can be introduced at any point along the line. The amplifiers, which may be every 400 ft along the line, contain transformers and rectifiers, which power the solid-state amplifiers. The ac is blocked so that it does not reach the TV.

A common reason for a TV cable system to go down is loss of ac power at the service, and the repair can be as simple as resetting a breaker. An important troubleshooting technique is to take voltage measurements at the input and output of each amplifier along the line. These amplifiers are in weatherproof gasketed boxes, which can be opened to change modules. Also, look for problems with the connectors.

Most electricians and electronic technicians are computer literate. They have no problem configuring Internet connections, working with advanced preferences, going into the MS DOS or command line mode to ping an external device, or performing other troubleshooting tasks. Any of these things should be easy for you and if you do not know how to do them, you do know how to go into an Internet information-gathering mode and get on with the task in short order.

However, programming is a different matter altogether. If you have looked into this field at all, you may have been overwhelmed and come to regard it as akin to learning a foreign language, the only difference being that everything has to be letter perfect just to be acceptable.

Excellent online programming courses, free of charge, may be found at www.codeacademy.com. It is a remarkable interactive site that will have you actually writing lines of programming code immediately.

A good, user-friendly entry into computer programming is learning to write hypertext markup language (HTML). It is easy and you can get results right away. HTML is used to compose web pages. You can make a complete 50-page website right on your computer and, if you have a browser such as Internet Explorer or Safari, you can display the finished product complete with color graphics, sound, video, and so on. You can compose any number of websites and save them on your hard drive, even if you do not have an Internet connection.

There are quite a number of web-authoring programs available. Some are free and others are expensive. The idea with these programs is that you can compose a web page using an interface that displays the finished product as it will appear online. Then, the program converts your work into HTML and with a click of the mouse the site will be uploaded to the web host you have chosen and instantly your work is published on the web.

HTML Coding I have tried some of these web-authoring programs and find that they are more bother than they are worth. It is easier to simply use HTML coding and make the website that way. You do not need to learn the HTML tags; just refer to a chart as needed. Soon you will learn the tags you use most, and the process of making a web page will become logical and spontaneous.

To compose a single web page, use the text editing program that came with your computer. For Mac it is TextEdit and for PC it is NotePad or some successor. Open a new document in that program and start typing the HTML for the web page you want to make.

Anytime you connect to the Internet and, via your browser, you have a web page on screen, it is possible to view the HTML that created that page. Click on VIEW SOURCE or DOCUMENT SOURCE, and the HTML for that page will appear on your screen. This is a great way to get a feel for how HTML coding corresponds to a finished web page. You can copy and paste part or all of these documents into your text editor, change wording, colors, graphics, fonts, page layouts, etc. and customize your own web pages in no time.

A useful item in an electrician's toolbox is the neon test light. It is good for taking readings to determine presence or absence of voltage when the exact number is known anyway. You can determine whether a conductor is grounded or ungrounded where the system is no greater than house current by putting one probe on the conductor in question and touching the other probe to the grounded chassis. The neon bulb will glow if you have the hot wire. The resistance of the bulb and series resistor, which is inside, is so high that a negligible current flows to ground.

Make a folder with all the text editor documents and graphics pertaining to each website that you create. That way, if the web host crashes and loses your data, you will not have to start all over.

Double click on the icon for one of your text editor documents, finished or in progress, and it will be displayed on the screen. Right click (for Mac, Control click) on that icon and a contextual drop-down window will appear. One of the choices will be Open With. Follow that alternative and there will be a list of applications. Click on your preferred browser and the finished or in-progress web page will be displayed just as it would appear on the web. You can put that and the HTML document on screen side by side to see how changes you make in the HTML will affect the web page. Every time you make a change in the HTML, it has to be saved before it can be viewed in the browser as a web page. All of this can be done without publishing any of it on the web, and indeed without even having an Internet connection.

Let us get started. All HTML tags are enclosed in angle brackets: <HTML>. The angle brackets tell the browser that what is inside the brackets is an HTML tag. Without the angle brackets, nothing is going to happen.

There are two kinds of tags-container tags and open tags. A container tag has to be initiated and, following the material that is affected by the tag, it has to be closed. The characters that are within the two pairs of angle brackets comprise the tag. The opening tag initiates the HTML action and the closing tag concludes it. The character that denotes a closing tag is a forward slash. For example, <html> starts an HTML document and </html> closes it. Everything between these two tags is recognized by all browsers as the source code for a web page. If it is not opened and closed in a letter-perfect manner, the web page will not be displayed properly. All container tags have to be opened and closed.

There can be any number of tags within tags. Be sure to close them in the reverse order in which they were opened.

For troubleshooting receptacles, use an appliance bulb screwed into a plug-in socket.

This is easier than using a meter, where you never know if the test leads are making contact. If the receptacle is within sight of the panel, leave it plugged in while you locate the breaker. If it is not in sight, use a radio turned up loud.

The other type of tag is known as an open tag. It does not have to be closed-it is just a one time entry. An example of this type of tag is <hr>. It directs the browser to make a horizontal line across the width of the web page. If you used your keyboard to make a horizontal line across the text editor document, it would not display properly in the web page. Similarly, you could hit the return key on your keyboard as many times as you wanted and it would have no effect on the web page. Instead, use this tag: <br>. It stands for break. In addition, you cannot make a paragraph break by pressing the TAB key as you would in a word processing program. This would appear in the text editor but not on the web page, where a continuous paragraph would be seen. To make a paragraph, use this tag:

<p>. It is a container tag, but by convention the closing tag may be omitted.

A great many tags are recognized by all browsers. Each browser, however, may display them somewhat differently. Serious web composers have the major browsers in their computers and view a proposed web page in each of them before publishing it.

Principal HTML Tags Here are some of the principal HTML tags. You can compose a sample web page using some or all of them and see how it looks.

<html> Begin html document.

<head> Begin heading.

<title> Begin title. It appears in the web page title bar and when the page is bookmarked.

<body> Begin web page material.

<h1> Largest type for heading </h1> (<h2> through <h6> are the tags for successively smaller headings).

<p> Begin new paragraph. (Closing is optional.)

</body> Close body.

</html> Close html document.

<br> Break in line.

<center>Begin centered material.

<hr> Horizontal line.

<strong> Bold text.

<em> Italics.

<a href="http://www.electriciansparadise.com"> Outside link.

</a> Hot link.

<a href="mailto: email@extension">Email@extension</a> Email link.

<blockquote>Insert material to be blocked between these tags</blockquote> Indent for long quotes.

<img src="picture.jpg" align=left> Insert graphics.

<table> Open table.

<tr> Open table row.

<td> Open table data.

</td> Close table data.

</tr> Close table row.

</table> Close table.

You can make an HTML template and use it every time you want to do a new page. This saves time and ensures that no items will be omitted.

If you make a website for yourself or someone else, you will need to publish it on the Internet. Web hosts, of course, have their own websites, which include a facility for checking to see if a universal resource locater (URL) is already taken. When you find an available URL that is satisfactory to you, you can pay for the service and after a short time, typically 24 hours, you can publish your site and thereafter make changes as often as you desire.

The web host will give you instructions for uploading HTML files, and its tech help will provide guidance if you experience problems.

Interestingly, HTML files do not contain graphics. They have text that refers to the graphics files, which are uploaded separately.

Typically, your homepage takes this form:

http://www.electriciansparadise.com/index.html.

Individual pages within the site take this form:

http://www.electriciansparadise.com/capacitance.html.

The final characters in each of these URLs are required to let the web host know what is going on.

You might be puzzled at the cryptic-sounding language at the top of the page, above the

<HTML> tag. This is not part of the HTML. It is called the "declaration" and it is a statement of the type of HTML coding that is being used. It is optional and not necessary for the page to be displayed. However, it is believed that inclusion of the declaration makes the web page more search-engine friendly and will result in a higher search engine ranking.