12 Hardware and Network Troubleshooting Flashcards
Troubleshooting Storage Drives and RAID Arrays
storage system problems usually stem from one of the following three causes:
The adapter (that is, the SATA, PATA, or other interface) is bad.
The hard drive (or optical disc) is bad or failing.
The adapter and disk are connected incorrectly.
If the problem is a bad or failing disk drive, the symptoms aren’t always as obvious.
Hard Drive Lights and Sounds
Storage systems usually have some sort of activity indicator that blinks when the drive is busy either reading or writing data. If the light never comes on, or if the light is on constantly without flickering, there could be a problem. External network attached storage (NAS) and redundant array of independent (or inexpensive) disks (RAID) storage enclosures have lights. Many RAID arrays have a light that only illuminates if a drive has failed and needs to be replaced.
Storage devices that have moving components will make sounds. Mechanical HDDs have a whirring sound as the platters spin, and an irregular ticking or clicking sound when reading and writing. An optical drive spins up when a disc is inserted, and it too will whirr. A grinding noise from a storage device means there is a failure in the motor or spindle, or if it sounds more like fingernails on a chalkboard, it means the read/write heads have crashed into the platter and are cutting grooves into it. A regular, rhythmic ticking or clicking sound is bad usually means the drive is failing or has failed.
Devices Not Found
If a storage device is plugged in and working, the BIOS/UEFI should detect it first, and then as the operating system loads, it will recognize the drive as well. If someone gives you the symptom that their hard drive isn’t being found, the first thing to do is clarify where it’s not being found. Is it the BIOS/UEFI, or in the operating system? Bootable Device Not Found This could manifest itself in a few different ways, such as a complete failure to boot, the hard drive not being recognized by the BIOS/UEFI, or the OS not being found. Failure to boot at all likely means the drive is not properly connected or it’s dead. Do your due diligence and reseat your connections and try different cables, or try the drive in another machine if possible. Most BIOSs/UEFIs today auto detect the hard drive. If that auto-detection fails, it’s bad news for the hard drive, unless there’s a cable or connection issue. Finally, a system that boots fine but can’t find the OS could indicate a problem with the master boot record (MBR) or boot sector on the hard drive. To fix this in any current version of Windows, boot to bootable media (USB or optical disc) and enter the Windows Recovery Environment (WinRE). In WinRE, you can get to a command prompt and use bootrec /fixmbr to fix the MBR and bootrec /fixboot to fix the boot sector.
Missing Drives in OS
Sometimes you have a storage device installed, but you are unable to find it in Windows File Explorer or the Finder in macOS. This could be a connection issue, or perhaps the drive hasn’t been properly set up for use. Windows comes with a utility called Disk Management, and Macs have Disk Utility to perform storage device management. If those utilities don’t see the drive or mark it as unusable, there are a few things to try:
Check the connections and try a new cable or port.
Double-check that the drive is found by the BIOS/UEFI and enabled. If the BIOS/UEFI doesn’t see it, the OS won’t either.
Ensure that the drive is found in Disk Management or Disk Utility. If the BIOS/UEFI sees the drive, then the disk utilities should too—but that doesn’t necessarily mean the drive is ready for use by File Explorer or the Finder.
Prepare the drive by initializing it (if needed), allocate space by creating a partition, and assign a drive letter. Without a partition and drive letter, File Explorer and the Finder won’t be able to use the space.
Update the storage device’s driver, if possible. This is admittedly a long shot, but it could work, particularly if you’re dealing with older hardware.
Check the drive for bad sectors or other damage. If enough sectors are damaged, the operating system may deem the drive unreadable.
Hard Drive Performance Issues
Data loss/corruption
Extended read/write times
Input/output operations per second (IOPS)
A failing hard drive might exhibit data loss or corruption or very slow (extended) read/
write times. They can also be a symptom of the hard drive being too full. If the drive doesn’t have enough free space (at least 10 percent), it can slow down dramatically. The solution here is to remove files or old applications to free up space and look at defragmenting the hard drive. If problems
persist, consider formatting the hard drive and reinstalling the OS. If the issues don’t go
away, assume that the hard drive is on its last legs. Input/output operations per second (IOPS), pronounced eye-ops, is an industry standard for how many reads and writes a storage unit can complete. IOPS is frequently quoted on dedicated storage systems such as NAS and RAID devices. If a device’s IOPS steadily declines over time or is no longer fast enough to service the user’s (most likely the network’s) needs, it could be time to replace the device. The most popular tool used to measure IOPS is Iometer. Iometer runs simulated disk reads/writes and provides results in a graphical interface and a CSV file.
S.M.A.R.T. Diagnostics
As of 2004, nearly every hard drive has been built with Self-Monitoring, Analysis, and
Reporting Technology (S.M.A.R.T.) software installed. S.M.A.R.T. monitors hard drive reliability and theoretically can warn you in the event of an imminent failure. Helping hard drive manufacturers do a better job isn’t a bad thing, but S.M.A.R.T. hasn’t enjoyed widespread commercial success with end users. This can largely be attributed to the following three factors:
Windows OSs don’t come with a built-in
graphical utility to parse the data.
The 70 metrics provided by S.M.A.R.T. aren’t always easy to understand, and there has been little guidance as to which metric or metrics are most closely associated with
impending drive failure.
Manufacturers have not consistently defined the metrics among themselves; there are no
industrywide analysis applications or standards for this technology.
The safe conclusion is that S.M.A.R.T. can provide useful diagnostics on a hard drive’s health, but it’s by no means a guaranteed problem finder.
S.M.A.R.T. metrics most correlated with hard drive failure
ID Attribute name Description
05 Reallocated sector count
The number of bad sectors that have been found and remapped during read/write processes. Any nonzero number could indicate a problem.
187 Reported uncorrectable errors
The number of errors that could not be recovered using hardware error correction
188 Command timeout The number of failed hard drive read/write operations due to disk timeout
197 Current pending sector count
The number of unstable sectors waiting to be remapped
198 Uncorrectable sector count
The total number of bad sectors when reading from or writing to a sector
RAID Issues
If you are using a redundant array of independent (or inexpensive) disks (RAID) system, you have more disks, so the chance of having a single failure increases. You more than likely have one or more additional hard disk controllers, so again you introduce more parts that can fail. There will likely be a software component that manages the RAID array. If your RAID array isn’t found or stops working, try to narrow down the issue. Is it one disk that’s failed, or is the whole system down, indicating a problem with a controller or the software? Most external RAID systems have status indicators and troubleshooting utilities to help you identify problems. Definitely use those to your advantage.
Finally, the problem could be dependent on the type of RAID you’re using. If you are
using RAID 0 (disk striping), you actually have more points of failure than a single device,
meaning that you’re at a greater risk of failure versus using just one hard drive. One drive failure will cause the entire set to fail. RAID 1 (disk mirroring) increases your fault tolerance; if one drive fails, the other has an exact replica of the data. You’ll need to replace the failed drive, but unless both drives unexpectedly fail, you shouldn’t lose any data. If you’re using RAID 5 (disk striping with parity), a minimum of three drives are needed and a single drive failure usually means that your data will be fine, provided that you replace the failed drive. If two or more drives fail, the RAID 5 array will be lost and you will need to fix the array and then restore the data from backup. RAID 10 is a mirrored striped set that requires at
least four drives. As long as one drive in each mirrored pair is functional (just like in RAID
1), you shouldn’t lose any data.
Optical Drive Issues
Optical drive (CD, DVD, and Blu-ray)
problems are normally media-related. One factor to consider is the cleanliness of the disc. On many occasions, if a disc is unreadable, cleaning it with an approved
cleaner and a lint-free cleaning towel will fix the problem. The next step might be to use a
commercially available scratch-removal kit. If that fails, you always have the option to send the disc to a company that specializes in data recovery. If the operating system doesn’t see the drive determine if the drive is receiving power. If the tray will eject, you can assume the drive has power. Next, check BIOS/UEFI Setup (SATA or PATA drives) to make sure that the drive has been detected. If not, check the primary/secondary jumper on the drive, and make sure that the PATA adapter is set to Auto, CD-ROM, or ATAPI in BIOS/UEFI Setup. Once inside the case, ensure that both the drive and motherboard ends are securely connected and, on a
PATA drive, that the ribbon cable is properly aligned with pin 1, the edge that has the red or pink stripe, being closest to the power connector. To play movies, a DVD or Blu-ray
drive must have Moving Picture Experts Group (MPEG) decoding capability. This is usually built into the drive, video card, or sound card, but it could require a software decoder. If DVD or Blu-ray data discs will read but not play movies, suspect a problem with the MPEG decoding. If an optical drive works normally but doesn’t perform its special capability (for example, it won’t burn discs), perhaps you need to install software to work with it. For example, with CD-RW
drives, unless you’re using an operating system that supports CD writing (and nearly all OSs today do), you must install CD-writing
software in order to write to CDs.
Troubleshooting Video, Projector, and
Display Issues
There is either no video or bad video.
The video card or the monitor/projector/display/cable is to blame.
In the majority of cases when you have a video problem on a desktop computer, a good troubleshooting step is to check the monitor by transferring it to another machine that you know is working. See if it works there. If the problem persists, you know it’s the monitor. If it goes away, you know it’s the video card (or possibly the driver). Is the video card seated properly? Is the newest driver installed?
Video Input Issues
Try these three steps:
- Check the obvious. Is everything plugged in and powered on? Look for indicator lights on the projector or external monitor to be sure.
- Make sure the laptop is set to output video to the right device. On most laptops, you
need to press the function key and another key known as the LCD cutoff switch (such
as F4 or F8) to direct the video output to an external monitor. This is called toggling the display. You might need to do this a few times. - Verify that the monitor or projector is configured for the correct data input source.
Having an incorrect data source means that the device won’t display anything. Most
monitors and projectors have multiple inputs, such as three or four HDMI, DisplayPort, and possibly even VGA ports. There may be a button on the monitor or projector to bring up an onscreen menu and configure the correct source, or you may need to use the device’s remote control.
If everything checks out, it’s possible there could be physical cabling issues. You can try
disconnecting and reconnecting the video cables or another cable if possible.
Video Image Problems
This group of symptoms deals specifically with the image on the screen, or the lack thereof. Here are the ones you should know:
Burned-Out Bulb
This is a projector-specific issue. Projector bulbs have a limited shelf life, and the heat produced by a projector and its bulb can shorten it even further. If the bulb burns out, then clearly there will be nothing displayed. The only resolution is to replace the bulb.
Fuzzy Image
Projectors have focus mechanisms that allow them to produce images on screens at different distances. A lot of projectors will try to autofocus but will also have onscreen menu options or a knob around the outside of the lens to manually adjust the focus. A fuzzy image on an LCD screen could be caused by external interference such as fluorescent lights, magnetic devices, and electrical devices such as fans, lamps, and speakers. If the display uses a cable, it could also be a loose or bad cable. Finally, it could be that the resolution is set for something that the display can’t handle well. Change the display resolution or Custom scaling features
Display Burn-In
When this happens, no matter what you have on your screen, you can still see the outlines of a different image. That image has been “burned” into the monitor (sometimes simply referred to as burn-in) and isn’t going away. The only solution is to replace the monitor.
Dead Pixels
Dead pixels are spots on the screen that never light up. You can check for these by setting the background to white and seeing if any spots don’t light up. The only solution for dead pixels is to replace the monitor. Flashing Screen Sometimes a display will either subtly flicker or flash off and on. Flickering screens are most commonly caused by the backlight starting to fail. In those cases, replace the backlight. Flashing off and on could be the backlight, but it could also be a loose cable or an unsupported resolution. Try the usual fixes, including checking the cables (if applicable),
changing the resolution, or reinstalling the video card driver.
Incorrect Color Display
This can happen when the LCD monitor’s controller board starts to fail and doesn’t perform color mapping correctly. To fix it on an old CRT display, you use a process called degaussing (decreasing or eliminating an unwanted magnetic field), which is done through a utility built into the menu on the monitor. Finally, this can also happen if the pins on the connector are damaged or if the connector isn’t plugged in all the way. If switching the monitor makes the problems go away, it’s probably time to replace the monitor.
Dim Image
If this is a problem with the monitor itself, it’s most likely caused by a failing backlight. However, it could also be a configuration setting. On an external monitor, open the onscreen menu and try adjusting the brightness. If no amount of adjustment makes the image bright enough for
normal use, then replace the backlight.
Other Display Issues
Audio Issues
Many display units today have built-in
speakers. The most common reason people have audio problems is because something is muted, but it could also be a cable or connection issue. Check to ensure that the computer’s audio output is set to the correct device. In Windows, right-click the speaker icon on the taskbar, then choose Open Sound Settings.
Intermittent Projector Shutdown
When a projector overheats, it will shut itself off to avoid frying components or the
bulb. This is the most likely cause of intermittent shutdowns. Perform a little maintenance cleaning. Most projectors have an air filter to keep dust and debris out of it. Check to make sure the cooling fan is operational and blowing out warm air.
Monitors can shut down intermittently as well due to overheating. Be sure the air
vents on the back of the display unit are clear from dust and debris. If the problem persists, it’s best to replace the monitor.
Booting into Low-Resolution Mode Sometimes an operating system refuses to boot into its normal mode and instead boots into a basic video mode. Newer versions of Windows call this “low-resolution” mode, whereas older versions called it VGA mode. This is normally caused by one of two things: the video card was set to a resolution
it can’t handle / there’s something messed up with the video card driver. After the OS boots, try reducing the resolution and reboot. If it’s still a problem, reinstall the
video card driver. If new drivers don’t help, consider that the video card is failing.
Other graphics issues can be attributed to the memory installed on the video card. Certain unacceptable video-quality issues, such as jerky refresh speeds or lags, can be remedied by adding memory to a video card (if possible). Doing so generally results in an increase in both quality and performance. If you can’t add memory to the video card, you can upgrade to a new one with more memory.
Mobile Device Issues: Power and Heat Issues
Battery and Charging Issues
If the device works when it’s plugged in but not unplugged, you’ve narrowed down the problem. Always check power and connections first!
Poor Battery Health
If the laptop works while it’s plugged in but not while on battery power, the battery
may be the culprit. As batteries get older, they are not able to hold as much of a charge and, in some cases, are not able to hold a charge at all. Another issue that small devices can have is an extremely short battery life. If it’s a laptop, you can try to perform a battery calibration. For all mobile devices, you can try to drain the battery completely and then charge it fully
before turning the device back on. If these options don’t work, then it’s likely that the battery needs to be replaced.
Swollen Battery
Battery physically swells in size. It can be caused by a number of things, including manufacturer defects, age, misuse, using the wrong adapter for charging, or leaving the laptop constantly plugged into a wall outlet. Inside the battery, the individual cells become overcharged, causing them to swell. Sometimes the swelling is barely noticeable, but it can cause the device case to crack or pop apart. If you have a swollen battery, turn the device off immediately and make sure that it’s not plugged into a charger. If the battery is removable, you can try to remove. Swollen batteries are more prone to explosions than normal batteries because the casing is already compromised.
Overheating
Smaller devices have greater potential to overheat, all the components are packed tightly together, which means less room for each component to breathe. Manufacturers use components that generate less heat. It could be from overuse, or perhaps it did not
have proper ventilation. On laptops, check to ensure that the cooling fan is working and not full of dust or debris. If the overheating is persistent test or replace the battery. If overheating still happens, you may have to replace the device.
Connectivity Issues
If your wireless networking isn’t working on a laptop, do the following:
- Ensure that the network card is turned on. Most laptops have an external switch or
button on the front or side or above the keyboard that can toggle the network card on and off. In some cases, it will be a function key. Be sure that this is set to the On position. - Next, make sure the wireless card is enabled through Windows.
- Check the strength of the signal. A weak signal is the most common cause of intermittent wireless networking connection
problems. If you have intermittent connectivity and keep getting dropped, see if you can get closer to the wireless access point (WAP) or remove obstructions between you and the WAP. Failing network cards and connectivity devices can also cause intermittent wireless networking connection failures.
Physical Device Damage
A device can become damaged in many ways, dropping being the most common. Liquid can damage as well. If a laptop gets doused in a liquid, turn it off and let it dry out. For significant liquid damage, the laptop can be taken apart and the components—even circuit boards such as the motherboard—can be cleaned with demineralized water and a lint-free cloth. Reassemble, and see if it works.
Many phones and tablets today are water-resistant / entirely waterproof. Every smartphone that is considered water-resistant will have an ingress protection (IP) rating, such as IP67 or IP68. The first digit, which will be from 0–6, represents the device’s ability to withstand solid foreign material such as dust. The second digit, which will be from 0–8, shows its moisture resistance. A rating such as IPX6, which means the device has not been tested for dust resistance and has a moisture resistance rating of 6. For a device to be considered waterproof, it needs to have a moisture resistance rating of 7 or 8. A 7 rating means the device is protected from damage from immersion in water with a depth of up to 1 meter (3.3 feet) for up to 30 minutes. An 8 rating is given to devices that can withstand greater depth and time of immersion.
If a mobile device has suffered water damage, turn it off. Remove the case, SIM card and battery. Dry everything you can with a lint-free cloth. Let it air dry for at least 48 hours. Sometimes the ports can be damaged or simply fail to work. The only remedy is to replace the port, which usually means replacing several components,
including the motherboard on a laptop, or replacing the entire mobile device.
Laptops and Malware
To help guard against malware, install antimalware software. Four main classes of applications to help protect your system against malware and hackers:
Antivirus software defends against viruses, worms, and Trojan horses.
Antispyware software defends against adware and spyware.
Antispam software reduces the amount of junk email you receive.
Software firewalls block potentially dangerous network traffic.
When a system is infected with a virus, a worm, a Trojan horse, or other malicious software, you need to remove it immediately. Here are the five steps to take to remove malware:
- Identify malware symptoms.
- Quarantine the infected system.
- Remediate infected systems.
- Schedule scans and updates.
- Educate the end user.
Mobile Devices and Malware
Four most common ways mobile devices can contract malware:
Malicious Apps
The most common way that malware ends up on mobile devices is through downloading malicious apps. If someone has jailbroken their phone and is downloading apps from random places this is a risk to contract a malware infection.
Operating System Vulnerabilities
A general rule of thumb is to always update to the newest version of the mobile
operating system that you can.
Suspicious Links
Clicking it can install malware on your
device without your knowledge.
Unsecure Networks
Using an unsecure network doesn’t risk downloading malware, but it could allow a hacker to read the data transmitted to or from your device. A VPN can help eliminate these issues on unsecured public networks.
Don’t jailbreak mobile devices. This compromises built-in security mechanisms.
Download apps only from official app stores.
Always update the OS to the most current version.
Avoid clicking links if you are unsure of the source.
Use a VPN when on public networks.
Impact Printer Problems
Impact printers are relatively simple devices; therefore, only a few problems usually
arise. Common impact print quality problems:
Consistently faded or light characters /
Worn-out printer ribbon / See if you can adjust the print head to be closer to the ribbon. If not (or if it doesn’t help), replace the ribbon with a new, vendor recommended ribbon.
Print lines that go from dark to light as the print head moves across the page /
Printer ribbon-advance gear slipping /
Replace the ribbon-advance gear or mechanism.
A small, blank line running through a line of print (consistently) / Print head pin stuck inside the print head / Replace the print head.
A small, blank line running through a line of print (intermittently) / A broken, loose, or shorting print head cable / Secure or replace the print head cable.
A small, dark line running through a line of print / Print head pin stuck in the out position / Replace the print head. (Pushing the pin in may damage the print head.)
Printer making a printing noise, but no print appears on the page / Worn, missing, or
improperly installed ribbon cartridge / Replace the ribbon cartridge correctly.
Printer printing garbage, such as garbled characters / Cable partially unhooked, wrong driver selected, or bad printer control board
(PCB) / Hook up the cable correctly, select
the correct driver, or replace the PCB
(respectively).
Printout Jams inside the Printer
A paper jam happens when something prevents the paper from advancing through the printer evenly. There are generally
three causes of printer jams:
an obstructed paper path
stripped drive gears
using the wrong paper
Obstructed paper paths are often difficult to find. A common obstruction is a piece of the “perf”—the perforated sides of tractor-feed paper—that has torn off and gotten crumpled up and then lodged in the paper path.
Stripped drive gears cause the paper to feed improperly, causing it to crinkle and cause
jams. Using the wrong paper, such as thick paper when the platen has been set for thin
paper, can also cause jams. When loading new paper, always be sure that the platen is properly adjusted.
Impact printers are used for multipart (or multipage) forms. Those forms are typically
three or more sheets of paper thick. If the multipage forms are not feeding properly, it could be that the printer is set to receive paper that is too thin or too thick.
Stepper Motor Problems
Printers use stepper motors to move the print head back and forth as well as to advance the paper. The carriage motor is responsible for the back-and-forth
motion while the main motor advances the paper. These motors get damaged when they are forced in any direction while the power is on. This includes moving the print head over to install a printer ribbon as
well as moving the paper-feed roller to align paper. These motors are very sensitive to stray voltages. If you are rotating one of these motors by hand, you are essentially turning it into a small generator and thus damaging it. A damaged stepper motor is easy to detect. Damage to the stepper motor will cause it to lose precision and move farther with each step. If the main motor is damaged (which is more likely to happen), lines of print will be unevenly spaced. If the print head motor goes bad, characters will be scrunched together. If a stepper motor is damaged badly enough, it won’t move at all in any direction; it may even make grinding or high-pitched squealing noises. If any of these symptoms appear, it’s time to replace one of these motors. Stepper motors are usually expensive to replace—about
half the cost of a new printer! Damage to them is easy to avoid; the biggest key is to not force them to move when the power is On.
Inkjet Printer Parts:
The parts on an inkjet can be divided into the following four categories:
Print head/ink cartridge
Print head carriage, belt, and stepper motor
Paper-feed mechanism
Control, interface, and power circuitry
Biggest difference between inkjet and impact printers is that impact printers often use tractor-feed paper, whereas inkjets use normal paper. Inkjet printers work by spraying ink (often in the form of a bubble) onto a page. The pattern of the bubbles forms images on the paper. Inkjet printers are the most common type of printer found in homes because they are inexpensive and produce good-quality images.
