Troubleshooting Flashcards
laptop with inadequate airflow
What to look for
intermittently shuts down at random times
capacitor
What to look out for
- If swollen it will have foul odor coming from the motherboard
- Capacitors are tiny electrical components that are soldered onto the motherboard and aid in the storage and use of DC voltage
CMOS battery
What to look out for
- Used to maintain date/time settings
- if fails the date/ time settings wont save when powered down
Overheating Workstation
What to look out for
- it will shut down or reboot itself to protect the processor
- This can occur if the case fans are clogged with dust or become unplugged
- By checking and reconnecting the case fans, the technician can rule out an overheating issue causing this problem
If the motherboard power cable was not connected
What to look out for
- motherboard’s LED would not be lit.
- Case fans wont spin (they receive power from the motherboard)
- Without the connection to the power, the computer couldn’t complete its POST.
- The hard drive will not spin since it receives the wake-up command from the motherboard through a SATA data cable.
SATA 15-pin power cable hadn’t been connected
What to look out for
- the LED would have lit up
What are the 6 steps in theTroubleshooting Methodology
(1) Identify the problem
(2) Establish a theory of probable cause
(3) Test the theory to determine the cause
(4) Establish a plan of action to resolve the problem and implement the solution
(5) Verify full system functionality and, if applicable, implement preventive measures
(6) Document findings, actions, and outcomes.
Identify the problem
gather more information about the problem and its symptoms for you to identify the problem
Question user
- What happened
- What was the status before
- What was the status after that
- Are there any changes in the system
Establish a theory of probable cause
- Probable cause
- Most likely
make physical inspection - sound
- smell
- touch
- behavior
Test the theory to determine the cause
- Theory is confirmed
- theory is not confirmed
- lack skills or authority
- Unable to solve
- escalate
Establish a plan of action to resolve the problem and implement the solution
- repair
- replace
- workaround
- How many are the resources
- how much time does it take
- how much does it cost
- impact on the users and system
- a change of plan needs to get the authorization again
Verify full system functionality and, if applicable, implement preventive measures
Document findings, actions, and outcomes.
Hard Disk Drive
What to look out for
- Loud clicking noises are usually indicative of a hard drive failing
Case Fan
What to look out for
- Loud clicking noises caused by dirt
- if overheating b/c of case fan the computer will usually reboot itself after running for 15-20 minutes (once enough heat is built-up)
- The best step would be to apply a small amount of oil to each of the fan’s bearings, as this will eliminate the noise. If the fans had been dusty, you would instead apply compressed air or clean the fan blades using a damp cloth. Since there was no dust noticed, this cannot be the whining source, and instead, you should apply oil to the bearings. Over time, dust can get into the fan bearings, causing increased friction when spinning and creating a whining sound. If this doesn’t solve the noise, then you would replace the case fans.
BIOS
Basic Input Output Settings
- Program that a CPU uses to start the computer system
▪ BIOS serves as a method of configuring the motherboard using a textbased interface
o Firmware
▪ Software on a chip and contains BIOS program code in the flash memory
of a motherboard
● Power-on self-test
● Hardware configuration
● Boot order setup
- Computers that rely on BIOS use MBR to hold the boot information
- If the system still fails to boot up from the correct drive, then go into the BIOS/UEFI setup program and check the existing boot order settings.
- If they are in the wrong order, reconfigure them to ensure the usual boot device is listed first in the list and then restart the computer
Unified Extensible Firmware Interface (UEFI)
- Supports 64-bit processors
● Supports larger HDDs and SSDs
● Supports the new GUID Partition Table (GPT) format
● Faster boot-up system
● Uses a larger ROM size - Secure Boot
- Computers that rely on UEFI use GPT to hold the boot information
BIOS/UEFI Security
o Supervisor/Administrator/Setup Password
o User/System Password
o Storage/Hard Drive Password
o Secure Boot - settings and is not supported by BIOS
o Modern systems are configured to enable or disable the USB ports on the motherboard
o Disable the ability of USB to read and write from mass storage devices
▪ Set passwords
▪ Enable secure boot
▪ Restrict or disable USB ports
Root kit
a special type of malware
Flashing
- Performed during upgrades, security fixes, or feature improvements
Firmware
- Software on a chip - contains BIOS program code in the flash memory of a motherboard
- BIOS is an example of firmware
What button will allow the user to choose to boot into Windows in regular or safe mode.
F8 key
Power Supply
What to look out for
- How much power is being drawn out of a wall outlet?
▪ A 500-watt power supply that is 70% efficient will draw 714 watts
▪ A 500-watt power supply that is 80% efficient will draw 625 watts
o Power supplies are not 100% efficient
- Buy power supply that is bigger than calculated. If the power supply is faulty, the computer will reboot itself
- When a power supply fan creates a grinding sounds, this is evidence of an impending failure
- Replace the entire power supply if the fan is faulty or makes grinding noises.
- Do not attempt to repair or fix a power supply due to high voltage risks.
- Never open a power supply or replace its internal components.
- A burning smell is indicative of a bad power supply
The Blue Screen of Death (BSOD)
What to look out for
- is a “stop screen” that appears when the Windows operating system detects a critical error and literally stops the system so that the error doesn’t cause any loss of data.
- a screen with a full blue background and white text containing troubleshooting information and error codes.
“Pinwheel of Death”
On a Mac (OS X) system “stop screen’ is called the “Pinwheel of Death,” which is an endlessly spinning mouse pointer displayed on the screen.
Kernel panic
On a Linux system “stop screen’ is called the “Kernel Panic,”
multimeter
What to look out for
- can measure the voltage, amperage, and resistance of a circuit
- can be a hand-held device useful for basic fault finding and field service work or a bench instrument that can measure electricity with a high degree of accuracy
- you can determine the exact voltage being supplied to the motherboard from the workstation’s power supply
-
POST card
a plug-in diagnostic interface card that displays progress and error codes generated during the power-on self-test of a computer
loopback plug
- used to test a port
- When you connect a loopback plug to a port, you should see a solid connection LED
- You can also use the loopback plug in conjunction with diagnostic software
cable tester
- used to ensure a cable is properly created as a patch cable (straight through) or a crossover cable.
- Cable testers provide detailed information on the physical and electrical properties of the cable.
- For example, they test and report cable
conditions, crosstalk, attenuation, noise,
resistance, and other cable run
characteristics.
- For example, they test and report cable
Denial of Service ( DoS)
- cyber attack
- Involves a continual flooding of victim systems with
requests for services, causing the system to crash (single
attacker)
Power-on Self-Test (POST)
- During the bootup process, a power-on self-test (POST) is performed. A single beep is commonly used to indicate the successful completion of the POST.
- Based on the POST results, different series of beeps may be played to indicate the status of the system
Continuous reboot
Hardware failure or system instability can cause the computer to reboot continuously.
blank screen during boot up. You decide to plug in an external monitor to the laptop and reboot it again
Many laptops have a series of keystrokes such as FN + F8 to switch from the internal display to an externally connected screen. Since the internal display is not working, rebooting again or trying to navigate the BIOS without seeing the screen would be ineffective. Instead, trying the function key toggle that switches to an external monitor may resolve the issue temporarily while you begin to look for a long-term solution. Different manufacturers use different keystrokes, but FN + F8 is an example of the keystroke used in Dell laptops.
Hardware Root of Trust (RoT)
- Hardware RoT is the foundation of all secure operations of a computing system
- A hardware RoT is used to scan the boot metrics in the OS files to
verify signatures and then use them to sign the report
Trusted Platform Module (TPM)
- Secured boot-up
- Provides encryption
- TPM is a hardware RoT
Hardware Security Module (HSM)
Appliance for generating and storing cryptographic keys that
is less susceptible to tampering and insider threats
Overclocking the processor
generates excess heat
Distributed Denial of Service (DDoS)
Multiple machines simultaneously launch attacks on the server to force it offline (multiple attackers)
Blackholing/Sinkholing
Identifies any attacking IP addresses and routes their
traffic through a null interface
Access Control List (ACL)
Rule sets placed on the firewalls, routers, and other network devices that
permit or allow traffic through a particular interface
▪ The actions are performed top-down inside of an ACL
Self-Monitoring, Analysis, and Reporting Technology (SMART)
▪ Self-diagnostic program that alerts the OS if there is a failure
- SMART utility is monitoring input/output operations per second (IOPS)
▪ SMART monitors the hard drive and understands the health status of the
drive
● Read Error Rate
● Spin-Up Time
● Reallocated Sector Count
● Seek Error Rate
● Power-On Hours
● Temperature
Single disk failure
▪ If a RAID loses a disk, it will continue to operate as normal but at a slower
speed
▪ RAID rebuild is the utility used to rebuild the RAID
Full Raid Failure
▪ Entire array or volume stops working
▪ When the RAID fails, restore from backup, reconfigure, and rebuild using
new disks
Projector Issues
o Dim images
o No images
o Shut down or restart
o Burned-out bulb is when the projector bulb has no light and cannot send an
image
o Projector bulb has a lifespan of about 500-2000 hours
o Use gloves to protect the life of the bulb
o Cool down the projector for 15 to 30 minutes before removing the bulb
o The projector without the source input will shut down
Network Performance Issues
▪ Manifesting the slowdown of network
o Half Duplex
▪ Network that sends or receives information
▪ Half duplex is the standard in hubs and network
o Full Duplex
▪ Network that sends or receives information at the same time
▪ Network interface cards are set to auto negotiation
o Data exfiltration is sending data in the background without the user seeing it
1. Mismatch in the duplex setting
2. Mismatch in the speed setting
3. Network adapter drivers are out of date
4. Malware infection
Wireless Connectivity Issues
o Intermittent wireless connectivity
o Signal interference
o Low signal strength
o Standards mismatch
Mobile Malware Infections
o Antivirus or anti-malware solution
o Excessive power drain
o Significant data transmission
o Camera and microphone
o Asking for additional permissions
o Back up the data
o Format the device and re-install the base operating system
Faded printout
Faded printout is caused by the running out of ink inside of a printer ink
cartridge or toner
Blank pages
Blank page is caused by a software issue
White stripes
▪ White stripes in laser printers are caused by an issue with the toner
cartridge or the drum
▪ The uniform white stripe on the page indicates a problem with the drum
Black stripes
▪ Indicates the primary charge roller is dirty or damaged, or the high
voltage power supply to the developer unit is malfunctioning
▪ To fix the black stripes issue, troubleshoot the corona wire
or replace the drum and the toner cartridge
Speckling output
Clean the printer using an approved toner vacuum
Vertical or horizontal lines
▪ The vertical or horizontal line is caused by dirty feed rollers
▪ Dirty photosensitive drum can create vertical or horizontal lines
Toner does not fuse
Check the voltage of the fuser and get the proper input voltage
Double or echo image
A double/echo/ghost/shadow image indicates a drum issue
Incorrect chroma display
Software or printer driver issue could be causing the incorrect color
Missing color
▪ Use rubbing alcohol to clean the contacts between the printer and the
cartridge
▪ Consistent white line indicates a blocked or clogged inkjet nozzle
▪ Replace the printhead and this will replace the dots inside of it
▪ Platen adjusts the gap between the paper and the printhead
to different paper sizes
Print Finishing Issues
o Incorrect page sizes
o Incorrect page orientations
o Issues with stapling
o Issues with hole punching
o Use the right paper size to print
o Word processor sets portrait as the default
o Slide presentation sets landscape as the default
o To solve staple jams, remove the staple cartridge and replace it
Print monitor
Software program used to transmit the print job and provide status
information
Print monitors look at toner and ink cartridge levels and notify when they
get low
Print queue
Software that collects all the print jobs and manages them
Print spooler
Manages the paper printing jobs sent from a computer or a printer server
● Print Queue
Pending
● Print Spooler
Active
Garbled Print Job
Print driver
● Any output that is scrambled or encrypted
● Garbled printouts are a driver issue
● A font can cause a garbled printout
