A POST card is a diagnostic and troubleshooting device that is plugged into the expansion slots and tests the operation of the system as it boots up. These cards can be as direct memory access or they can be complex as ROM BIOS diagnostic tools that perform the advance level diagnostic tests. POST cards are generally used when the computer systems appear to be dead or the system is unable to read from the floppy or hard disk. The POST routines generally report two types of errors fatal and non fatal.
The fatal error stops and system and when the POST card observes non fatal errors, they should be read very carefully because the error code, which is indicated must be coordinated with the timing of the error message or beep code produced by the BIOS routines. Normally POST cards come with the LEDs (light-emitting diodes that produces code error signals and they identify any kind of problem.
Monday, February 8, 2010
Troubleshooting with Cable Testers
The most common hardware related compute networking problem is the bad cabling and RJ-45 connectors. There are a number of devices, designed for testing the network communication cabling. These devices include continuity tester, time domain reflectometer and cabling testers. Data cabling testers are designed to perform a number of different types of tests on the UTP/STP and coaxial cables. The master end of the cable tester is attached to one end of the cable and the load unit of the cable tester is attached to the other end of the cable. The master unit sends the signals through the cable and reads them from the load unit. When testing the cables, these devices normally detect the problems such as crossed-over wiring, broken wires, short connections and the cable connections that are improperly impaired.
Troubleshooting with Multimeter
Testing tools can help in isolating the hardware or software problems and digital multimeter is a most important tool for the electronic troubleshooting. Digital Multimeter and other electronic test instruments are available in analog and digital form and these instruments can be used to measure the electrical values of the voltage, current in miliamperes and resistance in ohms. These devices are known as Volt-ohm-milimeters (VOMs) for the analog signals and digital millimeters (DMMs) for the digital types. You can also check the transistors, capacitors, motor windings and diodes with the digital multimeter. In computer troubleshooting, most of the tests of the digital multimeter are to check the DC readings.
Software Diagnostics Routines
Many disk based diagnostic methods can check the system and identify the problems by running the number of tests on the different areas of the system hardware. These tests produce the visual reports and error messages to identify the nature of the problem. The most common software troubleshooting routines check the computer’s memory, keyboard, monitor, system processor, and hard disk’s speed. If the system CPU, hard disk and system clock is working properly, then you will be able to localize the problem by targeting the other points in the system. If the diagnostic tools/routines identify a number of defective software/hardware then you should replace one defective unit a time.
PC Hardware Troubleshooting Tools
Due to the low cost of the some of the hardware components, it’s usually not advisable to repair the IC level problems of the components, instead they should be replaced. The repair cost of the component will most likely be high as compared to the actual cost of the component. There are some very excellent hardware problem detection tools that are very helpful in identifying and isolating the problems. These tools included Multi meter, Cable Tester, POST card and software diagnostic disk.
Configuration Error Messages and Meanings
Press F1 to continue Invalid configuration
CMOS time and date not set CMOS battery error
CMOS memory size mismatches System configuration and setup failure
CMOS system option not set CMOS battery failure or CMOS checksum
After the beep tones occur during the startup process, the system now looks and loads the operating system. The errors that occur between the beeps and initializing the operating system can be categorized into the following categories.
• Hardware failure ( due to the physical problem with the booting drive)
• General Failure Error Reading Drive x
• Bad or Missing Command Interpreter
• Non system Disk or Disk Error
• Bad File Allocation Table
• Corrupted or missing operating system files
• Corrupted or missing boot files
The configuration or boot up problems can be occurred to the hardware or operational function’s failure and if the configuration is correct and these error appears this means there is some problems in the hardware and boot up problems are normally linked with the operating system.
CMOS time and date not set CMOS battery error
CMOS memory size mismatches System configuration and setup failure
CMOS system option not set CMOS battery failure or CMOS checksum
After the beep tones occur during the startup process, the system now looks and loads the operating system. The errors that occur between the beeps and initializing the operating system can be categorized into the following categories.
• Hardware failure ( due to the physical problem with the booting drive)
• General Failure Error Reading Drive x
• Bad or Missing Command Interpreter
• Non system Disk or Disk Error
• Bad File Allocation Table
• Corrupted or missing operating system files
• Corrupted or missing boot files
The configuration or boot up problems can be occurred to the hardware or operational function’s failure and if the configuration is correct and these error appears this means there is some problems in the hardware and boot up problems are normally linked with the operating system.
PC Hardware Troubleshooting Techniques
Here you will learn about computer hardware troubleshooting techniques, cable testers, software diagnostic routines, POST cards, error diagnostic methods. Computer hardware is the physical part of a computer and it is frequently changed as compared to the software. Most computer hardware is inside the computer and cannot be seen by normal users. There are a large number of the computer hardware devices including Hard disk, CD-Rom, RAM, Motherboard, Monitor, printer, peripheral devices and other devices. One of the first steps in the troubleshooting is to sort out the hardware and software problems. You can use the event viewer utility in the Windows operating systems to identify the nature and cause of the hardware or software problem. Also you can identify the hardware problems by identifying the initial start up beeps.
Errors that occur before the initial beep shows that there is some kind of hardware problem exists in the system. At the POST stage, only the BIOS of the system and basic hardware is active and operating system does not starts to initialize at this stage until a final beep occurs. If a computer produces an error (“The system has detected Unstable RAM”) or a beep code appears, this means that system and found a problem with the devices and system RAM should be changed. Additionally, if the system starts up process reaches the point where CMOS configuration information is displayed on the screen this means that there is no problem detected with the basic hardware of the system. After this point, the system starts to load the device drivers and operating system.
You can categorize the system configurations errors and components failure errors. Sometimes configurations or setup problems occur when a new hardware is installed and used in the system for the first time. These problems occur due to the mismatches of the CMOS memory information and component's configuration information. It is usually advisable to access the system CMOS when the system is first time prepared, when it is necessary to replace the CMOS battery and when a new device such as hard disk, CD-Rom, RAM, Video adapter etc added to the system. In most of the computers, the BIOS use plug and play techniques to detect most of the devices. These components provide system resources to the newly added device. When you are installing a new devices or software, you may notice some configuration errors.
If you face the configuration errors, you should see the installation manual that comes with the new computer device. If you cannot confirm configuration problems and the device is not working properly, this means that there must be some defect in the hardware. The symptoms and errors can be divided into the three parts such as boot up problems, configurations problems and operational problems. First of all system’s configurations settings are checked. The error messages that occur during or after the end of the POST are reported so it is important to observe that where the problem is actually occurred.
Errors that occur before the initial beep shows that there is some kind of hardware problem exists in the system. At the POST stage, only the BIOS of the system and basic hardware is active and operating system does not starts to initialize at this stage until a final beep occurs. If a computer produces an error (“The system has detected Unstable RAM”) or a beep code appears, this means that system and found a problem with the devices and system RAM should be changed. Additionally, if the system starts up process reaches the point where CMOS configuration information is displayed on the screen this means that there is no problem detected with the basic hardware of the system. After this point, the system starts to load the device drivers and operating system.
You can categorize the system configurations errors and components failure errors. Sometimes configurations or setup problems occur when a new hardware is installed and used in the system for the first time. These problems occur due to the mismatches of the CMOS memory information and component's configuration information. It is usually advisable to access the system CMOS when the system is first time prepared, when it is necessary to replace the CMOS battery and when a new device such as hard disk, CD-Rom, RAM, Video adapter etc added to the system. In most of the computers, the BIOS use plug and play techniques to detect most of the devices. These components provide system resources to the newly added device. When you are installing a new devices or software, you may notice some configuration errors.
If you face the configuration errors, you should see the installation manual that comes with the new computer device. If you cannot confirm configuration problems and the device is not working properly, this means that there must be some defect in the hardware. The symptoms and errors can be divided into the three parts such as boot up problems, configurations problems and operational problems. First of all system’s configurations settings are checked. The error messages that occur during or after the end of the POST are reported so it is important to observe that where the problem is actually occurred.
Device Manager
If you're running Windows 95, 98, or ME, your first stop after the computer finishes the startup process should be the Device Manager, a piece of operating system software that helps you manage the various pieces of your PC. You can get to the Device Manager in several different ways: the two easiest are right-clicking on the My Computer icon on your desktop and selecting Properties from the context menu that pops up when you do this, or by going to the Start menu, going up to Settings, selecting Control Panel from the list of choices and then double-clicking on the System control panel. Either way, you’ll be presented with a tabbed dialog box; click on the tab that says Device Manager, and you’re there.
The first thing to look for is a yellow exclamation point or red international no sign (you know, the circle with the slash through it) next to one of your devices. You may need to click on all the little plus signs next to each category of devices to see the full outline-like list of everything in your computer. If you see the yellow or red symbol, you know something is amiss. My first suggestion is to highlight the offending device and click on the Remove button. What this does is essentially erase the driver software associated with the device as well as references to it within the Windows 95/98/ME Registry. (The Registry tracks all the hardware and software you install, the preferences you set for each, as well as lots of other stuff). The fancy term for this is "logically" removing the device because, even though it may still be physically attached, the computer no longer has any record of its presence.
Next, you should restart your computer, let Windows' Plug-and-Play feature "find" the device again, and redo the driver installation process by either using the driver suggestions that Windows finds and makes or clicking on the Have Disk button and using the installer disks that came with the device. (If both options are possible, I’d go with the disks that came with the hardware—unless you’re sure they are an older version.) If the computer doesn’t find the device, then I would suspect the connections or the device itself. Buy another cable, unplug and re-plug the connectors, remove and then physically reinstall any new plug-in cards or do whatever you have to to ensure that the connection is solid. Once you’ve done that, you’ll find that many times, simply reinstalling the drivers solves the problem.
The first thing to look for is a yellow exclamation point or red international no sign (you know, the circle with the slash through it) next to one of your devices. You may need to click on all the little plus signs next to each category of devices to see the full outline-like list of everything in your computer. If you see the yellow or red symbol, you know something is amiss. My first suggestion is to highlight the offending device and click on the Remove button. What this does is essentially erase the driver software associated with the device as well as references to it within the Windows 95/98/ME Registry. (The Registry tracks all the hardware and software you install, the preferences you set for each, as well as lots of other stuff). The fancy term for this is "logically" removing the device because, even though it may still be physically attached, the computer no longer has any record of its presence.
Next, you should restart your computer, let Windows' Plug-and-Play feature "find" the device again, and redo the driver installation process by either using the driver suggestions that Windows finds and makes or clicking on the Have Disk button and using the installer disks that came with the device. (If both options are possible, I’d go with the disks that came with the hardware—unless you’re sure they are an older version.) If the computer doesn’t find the device, then I would suspect the connections or the device itself. Buy another cable, unplug and re-plug the connectors, remove and then physically reinstall any new plug-in cards or do whatever you have to to ensure that the connection is solid. Once you’ve done that, you’ll find that many times, simply reinstalling the drivers solves the problem.
PC Hardware Troubleshooting Tips
Though they tend to cause some of the nastiest symptoms—computers that won't boot, scary and/or confusing error messages, etc.—computer hardware problems are usually the easiest type of problems to solve. The trick, as with all troubleshooting ventures, is to figure out where to start and then focus your efforts.
First, of course, you need to check the stupid stuff. You'd probably be amazed how many "problems" are solved by connecting the cables, or turning on the power switch that you swear you just did. Beyond that, double-check the snugness of your connections—jiggling in a new add-in card or screwing in a cable connection can (and often does) make a difference. You may even want to check the integrity of your cables and connectors. I once solved a baffling SCSI problem by noticing that one of the pins in a miniature 50-pin SCSI-II connector was bent. I had mistakenly presumed, prior to that, that a bent pin would have prevented me from making a connection at all, but it didn't. Unfortunately, as a result, I wasted several hours on something that could've taken two minutes.
Finally, whenever you install something new, whether it's more memory, a new drive, a plug-in card or what-have-you, and something doesn't work, it's more than likely because you made a mistake somewhere in the installation process. Step back through the process again, double- and triple-check your connections, and then try one more time. In the case of RAM that doesn't work or isn't recognized, it could be an incompatibility with the specific manufacturer of the RAM and your motherboard, so see if you can try a different brand before you give up hope. Finally, in some instances installing something new causes a conflict with something else--which is what the rest of this article is all about.
First, of course, you need to check the stupid stuff. You'd probably be amazed how many "problems" are solved by connecting the cables, or turning on the power switch that you swear you just did. Beyond that, double-check the snugness of your connections—jiggling in a new add-in card or screwing in a cable connection can (and often does) make a difference. You may even want to check the integrity of your cables and connectors. I once solved a baffling SCSI problem by noticing that one of the pins in a miniature 50-pin SCSI-II connector was bent. I had mistakenly presumed, prior to that, that a bent pin would have prevented me from making a connection at all, but it didn't. Unfortunately, as a result, I wasted several hours on something that could've taken two minutes.
Finally, whenever you install something new, whether it's more memory, a new drive, a plug-in card or what-have-you, and something doesn't work, it's more than likely because you made a mistake somewhere in the installation process. Step back through the process again, double- and triple-check your connections, and then try one more time. In the case of RAM that doesn't work or isn't recognized, it could be an incompatibility with the specific manufacturer of the RAM and your motherboard, so see if you can try a different brand before you give up hope. Finally, in some instances installing something new causes a conflict with something else--which is what the rest of this article is all about.
Hard Drive Failure Troubleshooting
Students who are still learning the basics of computer repair, like what components are involved in what operation, will frequently assume that all boot issues are due to a hard drive failure. The truth is, of all the four subsystems represented in this table, hard drives are probably the most reliable. I don't mean that hard drives last longer than memory modules or video cards in the pure MTBF (Mean Time Between Failure) sense, I mean they are rarely at fault when you're called in to repair a PC. Hard drive failures are generally pretty easy to troubleshoot, in part because the operating system will include tools to report on the hard drive's reliability when it's accessible.
Motherboard and CPU Troubleshooting
There are very few instances when you'd turn on a PC, have it either power up or not, and be able to say, "Oh, that's a motherboard problem." Motherboard failures usually show up as second level problems, like "I've replaced the video card and the screen is still dead." If you want to learn how to repair PC's without swapping every part, it's critical to know what to look for on a powered up system, like a CPU fan that isn't running, or RAM that stays cold. Sometimes you can spot a blown capacitor on a motherboard, but it's not a common problem.
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