Troubleshooting Computer Hardware

How do you delete the recovery partition?

1.Confirm the presence of the recovery partition. Open Terminal.app and enter diskutil list to do that. 2.Assuming you see a recovery partition listed on the screen that appears, go back to Ter-minal.app and enter the following:defaults write com.apple.DiskUtility DUDebugMenuEnabled 1 3.Open the Disk Utility app. Now, in the menu bar at the top, select Debug ➢ Show Every Partition. 4.Select Recovery HD and click the Mount icon to make it active. 5.Once the option Recovery HD is no longer grayed out, you can right-click to delete it or use Control+click and select Erase. 6.There is still an empty partition, so select the Partition tab and click the Recovery HD partition to select it. Then click the minus sign to remove it.

How do you clear the dynamic link editor cache?

1.Launch Terminal, located at /Applications/Utilities/. 2.At the Terminal prompt, enter the following command. Please note this is a single line; some browsers may show this command spanning multiple lines.sudo update_dyld_shared_cache -force 3.Press Enter or Return. 4.Enter the administrator account password. 5.Terminal may display warnings about mismatches in the dlyd cache. These are normal, and you can proceed.

What should be done to troubleshoot a PC that has distended capacitors?

A swollen or distended capacitor on the motherboard does not always indicate a failed or failing capacitor, but at the least it indicates one that is in poor health and should be replaced. A distended capacitor will look normal on the side, but the top of it will be swollen a bit, and there may be brown residue coming out of the top of the capacitor. The symptoms of this are a system that reboots intermittently and will start only intermittently or not at all. To replace a capacitor, follow these steps: 1.Locate the failed capacitor. Look for those that exhibit any of the physical symptoms. 2.Procure a replacement capacitor. It should have the following:■The same voltage■The same or larger capacity■The same external sizeWhile you can use a capacitor that has a higher voltage or a larger capacity, it is best to use one that matches the one you are replacing. 3.Remove the battery from the board. 4.Use a soldering iron to heat the connection to the board until you can remove the old capacitor. Be careful not to heat the board so much that you damage the connections of other components. 5.Clean the remaining hole, and if necessary, use a pin to enlarge the hole for the new capacitor. 6.Insert the new capacitor. Heat some solder and allow it to flow into the hole to seal. Try to keep the remaining drop on the outside as small as possible. This should be performed only by an experienced technician. Soldering incorrectly can ruin the motherboard.

What should be done to troubleshoot a PC that is failing to boot after having tried to boot it to the correct location for the boot files?

Boot problems can also occur with corruption of the boot files or missing components. During the installation of the OS, log files are created in the specific OS. If you have a puzzling problem, look at these logs to see whether you can find error entries there. For routine troubleshooting, you can activate boot logging by selecting Enable Boot Logging from the Windows ➢ Advanced Options menu to create an ntbtlog.txt log file in the %systemroot% folder.

What should be done to troubleshoot a PC that is overheating?

Chip creep—the unseating of components—is one of the more common byproducts of a cycle of overheating and cooling of the inside of the system. Take care to keep the air around the PC within normal ranges (approximately 60-90 degrees Fahrenheit) and at a constant temperature. Replacing slot covers is vital. Leaving slots on the back of the computer open alters the air circulation and causes more dust to be pulled into the system. Note whether the fan is working; if it stops, that is a major cause of overheating.

What should be done to troubleshoot a PC that is having POST code beeps?

During the bootup of the system, a power-on self-test (POST) occurs, and each device is checked for functionality. If the system boots to the point where the video driver is loaded and the display is operational, any problems will be reported with a numeric error code. If the system cannot boot to that point, problems will be reported with a beep code. Although each motherboard manufacturer's set of beep codes and their interpretation can be found in the documentation for the system or on the website of the BIOS/UEFI manufacturer, one short beep always means everything is OK. During startup, problems with devices that fail to be recognized properly, services that fail to start, and so on, are written to the system log and can also be viewed with Event Viewer in Microsoft or in the Console in Mac. You can access it through Computer Management, or you can access it directly from the Administrative Tools in Control Panel.

What should be done to troubleshoot a PC that is experiencing continuous reboots?

If the system reboots on its own, consider the following possibilities: ■Electrical problems such as brownouts (not a total loss of power but a sag in the power level) or blackouts can cause reboots. ■Power supply problems can cause reboots as well. The power supply continually sends a Power_Good signal to the motherboard, and if this signal is interrupted, the system will reset. ■Overheating is also a big cause of reboots. When CPUs get overheated, a cycle of reboots can ensue. Make sure the fan is working on the heat sink and the system fan is also working. If required, vacuum the dust from around the vents. Because overheating plays a large role in reboots, ensure that a laptop is sitting on a flat surface that allows for proper cooling (not on a bed, pillow, or other soft surface).

What should be done to troubleshoot a PC that is experiencing BIOS time and setting resets?

If you find that you are continually resetting the system time, it could be that the CMOS battery is dying. Sometimes a symptom of this is that the hard drive and other settings stored in the BIOS are lost. In the absence of an external time source, the time in the BIOS is where the system gets its cue for the date and time. Change the CMOS battery and the problem should be solved.

What should be done to troubleshoot a PC that is experiencing the PWOD?

In many cases, the situation may not be as dire as it appears. It can be that a single application is holding the device captive. If this is the case, either clicking the desktop or bringing another application to the front will return control to the user. While that will solve the issue for the moment, there was some reason why that application caused the lockup, and it will probably occur again. Two things can be done to prevent a problem from recurring. First, it could be that the system permissions associated with the application and the files it uses have gotten corrupted. You can use Disk Utility to perform a "permissions repair," which restores file or folder permissions to the state the OS and applications expect them to be in. Second, it may help to clear the dynamic link editor cache. This is a cache of recently used entry points to the dynamic link library. If this cache gets corrupted, it can cause the PWOD. On the other hand, if you are experiencing this spinning wheel at startup, the problem is more severe. It means that the system is corrupted. The recovery options will be found by booting to the recovery hard drive. To do this, start the device, and after the chime, press and hold Command+R until a menu appears. Then select to boot to the recovery partition.

What should be done to troubleshoot a PC that had an unexpected shutdown?

In some cases, a blue screen on the display with a lot of text precedes this shutdown. If that occurs, the problem is related to the operating system and may not involve a hardware issue. One common reason for shutdowns is overheating. Often when that is the case, however, the system reboots itself rather than just shutting down. Always check the obvious, such as the power cable and the source of power. Check to see whether a breaker flipped in the power box as well.

What should be kept in mind when it comes to the indicator lights when troubleshooting?

Many of the components in the system have an indicator light that should be in a specific state during normal operation. Status lights are often found on the network interface card (NIC) as well as on the front of a desktop model and in the display area of a laptop. On the NIC, a display other than a green light can indicate that there are problems with the network; more important, though, the lack of any light can indicate that the card itself has gone bad. The hard drive, CD-ROM, and tape or DVD drive lights will be on when activity is occurring and will blink accordingly. The power light should be a steady green.

What is BSOD and what is the troubleshooting process?

Once a regular occurrence when working with Windows, blue screens (also known as the Blue Screen of Death) have become much less frequent since Windows 2000. Occasionally, systems will lock up, and you can usually examine the log files to discover what was happening when this occurred and then take the necessary steps to correct it. The details included in the BSOD error that comes up can help in troubleshooting the problem. It is often easy to query Microsoft's Knowledge Base with the first part of the BSOD error to discover the component causing the problem. Often, the Knowledge Base article gives a detailed explanation of how to fix the problem as well.

What should be done to troubleshoot a PC that is smoking or has a burning smell?

Smoke is never a good thing. Shut the system down immediately to prevent further damage. This is usually a burning or overheating component, usually the CPU. A burning smell usually accompanies smoke but could be present after the smoke has ended because the burning component is now dead. Try to identify the damaged component through a visual inspection; if that is not possible, try to determine the damaged component by replacing parts one by one until functionality returns.

What are proprietary crash screens?

Some operating systems have a proprietary method of notifying the user that the worst may have just happened. The most common are the BSOD (windows) or PWOD (Mac).

What should be done to troubleshoot a PC that had its system lockup?

Sometimes the system just freezes up and will not respond to any keyboard input or mouse clicks. The difference between a blue screen and a system lockup is whether the dump message that accompanies a blue screen is present. With a regular lockup, things just stop working. If lockups occur, you can examine the log files to discover what was happening (such as a driver loading) and take steps to correct it. From a hardware standpoint, freezes or lockups can be caused by the following: Memory Problems: Memory problems include a bad or failing memory chip, using memory that's too slow for the system, or using applications that require more memory than is present in the computer. Replace and upgrade the memory as required. Too little memory can also be an issue when more is required for an application. Virus or Malware: If the system freezes and there is still significant hard drive activity occurring, a virus could be present. Scan the system, preferably from an external source such as a flash drive or CD. Video Driver: Bad video drivers can sometimes cause a lockup. Update the video driver. In the case of a driver you just updated, you can roll back the driver to the old driver until you can obtain a new version of the driver that does not cause issues.

What should be done to troubleshoot a PC that is making a loud noise?

The most common are the fan and the hard drive (except for solid-state drives, which make no such noises). No matter what is responsible, you will want to take immediate steps to shut down the machine and start the replacement process. When you remove the cover, see whether you can tell which component the noise is coming from. Change each component you suspect with a known good replacement until the noise stops.

What is the PWOD?

The pinwheel of death is a multicolored pinwheel mouse pointer that signifies a temporary delay while the system "thinks."

What is an Unexpected_Kernel_Mode_Trap error?

This error is described on the Microsoft website: "If hardware was recently added to the system, remove it to see if the error recurs. If existing hardware has failed, remove or replace the faulty component. Run hardware diagnostics supplied by the system manufacturer, especially the memory scanner, to determine which hardware component has failed. For details on these procedures, see the owner's manual for your computer. Setting the CPU to run at speeds above the rated specification (known as overclocking the CPU) can also cause this error."

What is a Data_Bus_Error?

This error is described on the Microsoft website: "The most common cause of this error message is a hardware problem. It usually occurs after the installation of faulty hardware, or when existing hardware fails. The problem is frequently related to defective RAM, L2 RAM cache, or video RAM. If hardware has recently been added to the system, remove it and test to see if the error still occurs."

What is a irq1_not_less_or_equal error?

This error is described on the Microsoft website: "This Stop message indicates that a kernel-mode process or driver attempted to access a memory address to which it did not have permission to access. The most common cause of this error is an incorrect or corrupted pointer that references an incorrect location in memory. A pointer is a variable used by a program to refer to a block of memory. If the variable has an incorrect value in it, the program tries to access memory that it should not. When this occurs in a user-mode application, it generates an access violation. When it occurs in kernel mode, it generates a STOP 0x0000000A message. If you encounter this error while upgrading to a newer version of Windows, it might be caused by a device driver, a system service, a virus scanner, or a backup tool that is incompatible with the new version."

What is a Page_Fault_in_nonpaged_area error?

This error is described on the Microsoft website: "This Stop message usually occurs after the installation of faulty hardware or in the event of failure of installed hardware (usually related to defective RAM, either main memory, L2 RAM cache, or video RAM). If hardware has been added to the system recently, remove it to see if the error recurs. If existing hardware has failed, remove or replace the faulty component. Run hardware diagnostics supplied by the system manufacturer. For details on these procedures, see the owner's manual for your computer."

What should be done to troubleshoot a PC that has its fans spinning even though there is no power reaching the other devices?

This issue can be caused by an external device requiring more than the available power being supplied. Ensure that you are not requiring more power than the power supply can provide.

What should be done to troubleshoot a PC that is attempting to boot to incorrect devices?

When multiple volumes or partitions exist on the computer or there are multiple hard drives and maybe CD/DVD and flash drives as well, there are multiple potential sources for the boot files. If the system delivers an "operating system not found" message, it could be that the system is looking in the wrong location for the boot files. The boot order is set in the BIOS/UEFI. Check the boot order and ensure that it is set to boot to the partition, volume, and hard drive where the boot files are located.

What should be done to troubleshoot a PC that has a blank screen on bootup?

When the screen is blank after bootup and there are signs that the system has power and some functionality (perhaps you can hear the fan or see lights on the system), the problem could lie in several areas. Consider these possibilities: ■ Make sure the monitor is on. It has a power switch, so check it. ■ If you hear the fan but the system doesn't boot, it could be the power to the mother-board. Check and reseat the power cable to the motherboard. ■ Make sure the cable from the monitor to the system is connected properly and try changing it out with a known good cable. ■ Try a known good video card to rule out a bad card. ■ Ensure that the brightness setting is set high enough. ■ In cases where a laptop has been used to direct output to a second display, ensure that the image is being sent to the main display and not just to the external monitor. ■ As a last solution, try replacing the monitor.

What should be done to troubleshoot a PC that has no power?

■Check the power cord, and if it's plugged into a power strip or UPS, ensure that the strip is plugged in (and if it has a breaker, check to see whether it was tripped by a surge or whether the switch that turns off the entire strip has been inadvertently turned to the off position). In the case of a UPS, check whether the UPS battery is dead. If the cord and UPS are OK, also try a second wall outlet. ■Try replacing the power supply with a known good unit to see whether the power supply failed.

What should be done to troubleshoot a PC that is experiencing intermittent device failures?

■Try replacing the problem component with a known good one. ■A bad motherboard can cause these types of problems when there are issues with its circuitry. Try replacing the motherboard with a known good motherboard.