Troubleshooting PC Hardware

Troubleshooting PC Hardware Objectives

• Apply troubleshooting methodology.
• Configure BIOS/UEFI.
• Troubleshoot power and disk issues.
• Troubleshoot system and display issues.

Troubleshooting Methodology

• Develop general troubleshooting skills to confidently approach new and unexpected issues.
• Troubleshooting begins with problem-solving.
• Problems have causes,symptoms, and consequences.

CompTIA's A+ Troubleshooting Model

• Identify the problem, gather information from the user, identify user changes, and perform backups
• Inquire about environmental/infrastructure changes
• Establish a theory of probable cause and question the obvious.
• Conduct external/internal research based on system failure symptoms:
• Test your theory to determine the cause.
  • If theory is confirmed, then determine next steps to resolve problem
  • If theory is not confirmed, re-establish a new theory or escalate.
• Establish action plan to resolve problem, implement solution and refer to the vendor's instructions for guidance.
• Verify full-system functionality and implement preventative measures.
• Document the findings, actions, and outcomes.

Configure BIOS/UEFI

• Firmware is specialized program code stored in flash memory.
• Firmware is closely tied to a specific hardware device type/model and its basic functions.
• PC or system firmware provides low-level code and permits PC components installed on a motherboard to be initialized, so they can load the main operating system software.
• The system firmware for a PC used to be called the Basic Input/Output System (BIOS).
• BIOS supports 32-bit operation and limited functionality.
• Newer motherboards use a different firmware called Unified Extensible Firmware Interface (UEFI).
• UEFI provides support for 64-bit CPU operation at boot, a full GUI and mouse operation at boot, networking functionality at boot, and better boot security.
• A computer with UEFI may also support booting in a legacy BIOS mode.
• System settings can be configured via the system firmware setup program.
• The system setup program is accessed via a keystroke during the power-on (boot) process, typically when the PC vendor's logo is displayed.
• Key combinations vary; typical examples are Esc, Del, F1, F2, F10, or F12.
• Options within the BIOS include:
  • Boot and device options
  • USB permissions
  • Fan considerations
  • Boot passwords and secure boot
  • Trusted platform modules – look at encryption
  • Hardware security modules

Troubleshooting Power and Disk Issues

Troubleshoot Power Issues

• PC components need a constant, stable power supply to run.

• If the computer will not start, there is likely a power problem.

• If the PC suddenly turns off/restarts, power could be a common cause.

• To diagnose no power, check if the LEDs on the system case front panel are lit up and whether you can hear the fans.

• A power issue can be from a fault in the PSU, incoming electricity supply, power cables/connectors, or fuses.

• To isolate the cause of no power:

  • Check that other equipment in the area is working; there may be a fault in the power circuit or wider failure.
  • Try plugging in a known-good basic electrical equipment, into the wall socket.
  • Check that the PSU cabling is connected to the PC and the wall socket correctly and that all switches are in the “on” position.
  • Try another power cable; there may be a problem with the plug or fuse.
  • Try disconnecting extra devices, such as a plug-in graphics card.
  • If this solves the problem, the PSU may be underpowered or one of the devices is faulty
    • Test the PSU using a multimeter or power supply tester in a safe working environment.
    • The problem is likely with a faulty motherboard or power supply and should be looked at by an electrician.

• If you suspect that a power supply is faulty, do not leave unattended and do not leave it turned on for longer than necessary.

• Look out for external signs of a problem like smoke or fire.

• If there are any unusual sights, smells, or noises, turn off immediately.

Troubleshoot POST Issues

• Once the CPU has been given the power good signal, the system firmware performs a POST (power-on self-test).
• POST is a diagnostic program in the system firmware that checks the hardware to ensure PC components required to boot are present and correctly function.
• If power is present and you hear the fans spinning, but the computer won't start, there is a black screen, and there are no beeps from the internal speaker.
  • The issue is likely that either the display is faulty or the POST procedure is not executing.
• Assuming you can rule out the display issue, try troubleshooting using the following solutions:
  • Verify system firmware is up to date
  • Check cabling and connections, especially if maintenance work was performed on the PC.
• An incorrectly oriented storage adapter cable or a badly seated adapter card can stop the POST from running
• Correct any errors, reset adapter cards, then reboot the PC
• Check for faulty interfaces and devices; faulty adapter card/device may halt the POST
  • Try removing devices one at a time to see if this solves the problem/remove all non-essential devices, then add them back.
• Check the PSU; there may be a fault preventing the power good signal from being sent to the CPU, preventing POST.
• Check for a faulty CPU or system firmware (if possible, replace the CPU chip), then update the system firmware.
• After a POST error is detected, an error message is generated as a beep code.

Common Beep Codes

• 1 Short Beep: Normal POST (system is OK); most modern PCs are configured to boot silently, however.
• 2 Short Beeps: POST error; error code shown on screen.
• No Beep: PSU, motherboard problem, or faulty onboard speaker.
• Continuous beep: Problem with system memory modules or memory controller.
• Repeating Short Beeps: PSU fault or motherboard problem.
• 1 Long, 1 Short Beep: Motherboard problem.
• 1 Long, 2 or 3 Short Beeps: Video adapter error.
• 3 Long Beeps: Keyboard issue (check that a key is not depressed).

Troubleshoot Boot Issues

• After the POST tests are complete, the firmware searches for devices as specified in the boot sequence.

• If the first device in the sequence is not found, the system attempts to boot from the next device.

• If there is no fixed disk, the boot sequence checks for a USB-attached drive.

• If no disk-based boot device is found, the system might attempt to boot from network.

• If no boot device is found, the system displays an error message and halts the boot process.

• If the system attempts to boot from an incorrect device, check removable drives do not contain interfering media and that the boot device order is correctly configured.

• If a fixed disk is not detected at boot, try checking that it is powering up.

• Drive activity is usually indicated by an LED on the front panel of the system unit case.

• If the LED is inactive, check that the drive has a power connector attached.

• If there are no LEDs or they are faulty, you can hear a hard disk spinning up.

• After determining the drive is powering up:

  • Check data cables have no damage and are correctly connected to the drive.
  • If the drives connect to a motherboard port, check that is enabled.

• There are two ways of formatting the boot information: MBR and GPT.

• In the legacy master boot record (MBR) scheme, the MBR is in the first sector of the first partition.

  • Partitions allow a single disk device to be divided into multiple logical drives.

• First sector contains information about the partitions on the disk plus code,pointing to the location of the active boot sector.

• The boot sector is located either on the sector after the MBR or the first sector of each other partition.

  • It describes the partition file system and contains the code that points to the method of booting the OS.

• Typically, it will be the Boot Configuration Data (BCD) store for a Windows system or GRUB/LILO Linux boot managers.

• Each primary partition can contain a boot sector; only one of them can be marked active.

• With the modern globally unique ID (GUID) partition table (GPT) boot scheme:

  • Boot information is not restricted to a single sector but still serves the same basic purpose of identifying partitions and OS boot loaders.

• If the disk uses an MBR/GPT partitioning scheme, damage to these records results in boot errors (i.e., "Boot device not found").

• If a boot device is located, code is loaded from the boot sector on the selected device into memory and takes over.

• The boot sector code loads the rest of the operating system files into system memory.

• Error messages received after this point can usually be attributed to software or device driver problems rather than physical issues.

• If there is a serious fault, a Windows system shows a blue screen of death (BSOD).

  • It typically indicates a system memory fault, a hardware device/driver fault, or corruption of operating system files.

• Errors displayed on the fault screen can be looked up via online resources.

• The system generates a memory dump that you can forward for analysis if you have a support contract.

  • Symptoms of a failing fixed disk include:
  • Unusual noise
  • No LED status indicator activity
  • Constant LED activity
  • Bootable device not found
  • Missing drives in OS
  • Read/write failure
  • Blue screen of death (BSOD)

• An HDD fails from mechanical problems within the first few uses, or after a few years.

• An SSD is typically more reliable but has a maximum expected lifetime.

• Sudden loss of power can damage or corrupt any fixed disk, especially if it occurs mid-write.

• In addition to symptoms, many fixed disks have a self-diagnostic program (Self-Monitoring, Analysis, and Reporting Technology, known as SMART).

• SMART can alert the OS if there is a failure.

• You can also run advanced diagnostic tests on the drive for suspected failures or performance issues, such as extended read/write times.

• Many fixed disk vendors provide utilities for testing drives, same with the system diagnostics program.

• These tests can detect any damage to the device's storage mechanisms and can report statistics such as input/output operations per second (IOPS).

• If performance is reduced from the vendor's baseline measurements under test conditions, the device is likely faulty.

• If performance metrics are similar to the device's benchmark under test conditions, slow read/write access observed during operation is due to a more complex system performance issue.

• File fragmentation, application load, and general system resource issues, as well as limited remaining capacity, can be possible causes.

• Extended read/write times can also occur if particular sectors (HDDs) or blocks (SSDs) fail ("go bad").

• Data loss/corruption means that files stored in these locations cannot be opened or simply disappear.

• Disk firmware marks bad sectors/blocks as unavailable for use.

• Attempt to recover corrupted data from the device using a recovery utility in the absence of a backup.

• Redundant Array of Independent Disks (RAID) is a means of protecting data against a single fixed disk failing.

• The data is copied to a second drive (mirroring) or additional information is recorded on multiple drives to recover from a device failure (parity).

• RAID can be implemented using hardware or OS features.

• The redundant storage is made available as a volume, which can be partitioned and formatted in the OS as one or more drives.

• RAID failure scenarios include a device failure within the array and the failure of the whole array or volume.

  • The volume will be listed as "degraded" when one of the underlying devices fails, but the data is still accessible.

• Most desktop-level RAID solutions tolerate the loss of one disk and should be replaced soon as possible.

• The new disk can be inserted into the computer chassis or a disk chassis if the array supports hot swapping.

• After this is done, the array can be rebuilt using the RAID configuration utility (if a hardware RAID controller is used) or an OS utility (if you are using software RAID).

• Rebuilding the process is likely to affect performance because the controller is probably writing multiple gigabytes of data to the new disk.

• If a volume is unavailable, more than the tolerated number of disks has failed, or the controller has failed.

• If the boot volume is affected, the operating system will not start.

Troubleshooting Component Issues

• There are symptoms such as the system locking up, intermittent shutdowns, continuous rebooting, OS blue screen/Kernel panic errors, and application crashes.
• Intermittent shutdowns, continuous rebooting, and OS blue screen/kernel panic/application crashes are difficult to diagnose.
• Likely causes are software, disk/file corruption problems, or malware.
• Attempt to establish whether the problem is intermittent or whether there is a pattern to the errors can discount these.
• It could be a thermal issue if the PC has been running for a long time.
• The vendor may supply a diagnostic test program which can identify hardware-level errors.
• These programs are run from the firmware setup utility, as opposed to the OS.
• Without using diagnostic utilities, motherboard, RAM, or CPU hardware issues can be identified, by observing physical symptoms.

Overheating

• Excessive heat can easily damage sensitive circuitry in a computer.
• Check for overheating if a system feels hot to the touch.
• If a system feels overly hot or an unknown smell is detected in the area, the system should be shut down immediately and the problem should be investigated.
• Burning smells indicate something (probably the power supply) is overheating or the case and/or fan vents are clogged.
• Actual physical damage to a computer system is usually caused to peripherals, ports, and cables.
• Damage to other components is only likely if the unit has been in transit. Inspect a unit closely for damage to the case; even a small crack/dent indicates worse damage to the internal components.
• If the peripheral device does not work,examine the port and cable ends, looking for bent, broken, or dirty pins/connectors, and damage to the cable itself.
• Performance issues are one of the hardest problems to diagnose/troubleshoot with poor varied of symptoms.
• Have a structured approach with any issues to compartmentalize the source, verify the problem is there, and rule out issues with operating system.
• Check for overheating, misconfigurations, or networking

Inaccurate System Date/Time

• It is important for computers to keep time accurately.
• If the date/time are not correctly synchronized with computers on the network/internet, security systems will not work, and utilities like backup programs will be unreliable.
• The real time clock (RTC) is a part of the chipset that keeps track of the calendar date/time.
• This component is run from a coin cell lithium battery when the computer is turned off.
• It can be a sign that the RTC battery is failing if the date/time is inaccurate in the system firmware setup program.
• Replace it with the same size and type.

Missing Video Issues

• If there is no image displayed on the monitor/projector: ensure the display device is plugged in and turned on and that the monitor is not in standby mode.
• Use controls on the monitor to adjust the image/select the appropriate data source or input channel.
• If the display is powered on and input source has been ruled out:
  • Check the cable between the video card and monitor.
  • Make sure the cable is connected securely at both ends and is not loose.
  • Verifiy the cable has not been stretched or crimped.
  • Verify the cable specification is valid for the application.
• A video project is is good for use in a presentation.
• The image is shown on a screen using a lens system.
• display monitors, projectors use different imaging technologies (i.e., CRT, LCD, and DLP).
• A PC display uses a small backlight/LED array, projector uses a very strong bulb to project onto a screen/backdrop.
• Projector bulbs have a limited lifetime and will often need to be replaced/dimming.
• There may also be a bulb health warning indicator light.
• A bulb that fails completely is a burned-out bulb.

Intermittent Projector Shutdown Issues

• Usually caused by overheating.
• Check that the projector's fan is working and that vents are not obstructed, and that the ambient temperature is not too high.
• Check for connector troubles or that the bulb is properly secured after overheating is completely ruled out

Video Quality Issues

• Can be caused by something wrong within the display itself, or within the signal itself
• These faults include:
  • Dim image
  • Fuzzy image
  • Flashing screen
  • Dead pixels
  • Burn-in
  • Incorrect colour display