. Flashcards
Types of regulations
Health and safety laws
Building codes
Environmental regulations
Prime example of safety regulations for US- based operations
OSHA
Definition for ground
A safe path for electrical current to flow away in case a device or cable is faulty
Are most pc circuits high or low voltage/current
Low voltage/current
Black box
Power supplies
CRT monitors
LCD display inverter card
Laser printers
Electrical fire safety protocol
Look for fire extinguishers with a K and black label
Cut power supply
Know where master switch is
ESD definition
A situation that occurs when electrons rush from one partially charged body to another with an unequal charge, following the path of least resistance
High voltage, low current
What volts do human feel ESD at
2500V
What Volts does equipment be damaged at
100V
ESD generators
Synthetic clothing
Low humidity
Cool temps
Self grounding definition
The act of touching a grounded object before touching electronic equipment
Have to ground yourself before touching electronic equipment
Protecting components from ESD damage
Drain body and clothing of static electricity before work
Work in an uncarpeted area
Self grounding by placing all fingers on the computer case - drains out ESD
Describe the equipment you should use to prevent static electricity on your body from damaging the equipment on which you are working
Anti- ESD wrist/leg wrap, grounding cord and plug and a conductive mat
In which atmospheric conditions is ESD risk highest
Cool, low humidity conditions.
When humidity is high, static can dissipate through moisture present in the air
Which computer component presents most danger from electrical shock
Power supply
Tower case options and motherboard sizes
Full tower - ATX motherboard
Mid tower- micro ATX motherboard
Mini tower- micro ATX motherboard
Small form factor cases (SFF)
FRU definition
Adapter or component that can be replaced by technician on site. Most laptop and PC components are FRUs, whereas components of smartphones are not
Guidelines for PC disassesmbly
• Back up all data on an interval drive
• have clean work environment
• have necessary tools/equipment
Have camera so you can take pic of state of motherboard so you remember how to put together
• make sure devices are powered off (hold down on power supply which will drain computers power) and take anti static precautions
Motherboard definition
Provides basic foundation for computer’s hardware, including processor, RAM, firmware and expansion cards.
ATX size and no of expansion slots
12X9.6 inches
Up to 7 expansion slots
Micro ATZ size and no of expansion slots
9.6X9.6 inches square
Up to 4 expansion slots
Mini ITX size and no of expansion slots
6.7 X 6.7 square
One expansion slots
Used in SFF PCS
2 forms of CPU
PGA - pins
LGA - pads
RAM
Storage space for computer data and program instructions
Volatile memory that loses data when power is out
Packaged as DIMMS
Main function of chipset
Provides cotrollers for CPU to interface with other components
Controller types
• system memory
I/O
Integrated video, sound network interfaces
Are chipsets upgradeable or ungradeable
Ungradeable
CMOS battery definition
Battery that powers CMOS chip which tracks date and time
RTC Battery
Bus definition
Connections between components on the motherboard and peripheral devices attached to the computer
Traces
Wires etched on to the motherboard to provide electrical pathways
What are the electronic pathways used for
Carries data power and timing signals
Local bus
Internal bus that connects component to processor resulting in high data speed required by components such as video display
• internal bus connects core components
Expansion bus
External bus allows additional components to be connected to computer (peripherals)
Expansion slot
Connection slots on motherboard where adapter cards can be installed to extend the functions the computer can perform
Riser card
Space saving feature for expansion slots
Put it in sideways
System clock
Computers timing mechanism that synchronises the operation of all parts of the computer and provides basic timing signal for CPU
PCIE
Serial communication with point to pink links between I/O controllers
PCIE versions
PCIE 2: 500mbps
PCIE3: 1Gbps per lane
PCIE4: 2Gbps per lane
PCIE5: 4Gbps per lane
Describe how you would open a PC case to access motherboard
Power down PC, remove power cable, hold down power button for few seconds so PC de-energised.
Remove screws holding case cover
What type if socket is used to instal memory
DIMMS
Interface
The point at which two devices connect and communicate with each other
Connection
Physical access point that enables a computer to communicate with internal/external devices
USB - universal serial bus
Hardware interface providing connections for peripheral devices
USB connectors and apeed
USB 1.1 - 12Mbs 5 metres length
USB 2.0 data rate 480Mbs
USB 3.0 - 5 Gbps (blue usb port)
USB 3.1 10Gbps
USB 3.2 20Gbps
Other USB connectors
Type A (4-pin) connects to hosts
Type B (4-pin) connects to devices. Includes B mini and B micro
Type C connects to hosts and devices:
Usb C replaces all of these
Thunderbolt 3 maximum speed and cable length
40 Gbps
Up to 2 metres,
Thunderbolt 2 maximum speed and cable length
20Gbps
Up to 100metres
USB 3.2 maximum speed and cable length
20 Gbps
Up to 1 metre for max speed
USB 3.0 max speed
5 Gbps
Lightning max speed
480 Mbps
Usb 2.0 max speed
480 Mbps
Whats DVI stand for
Digital visual interface
Why would you install an I:O adapter card
To make more/diff kind of ports available
KVM switch
Keyboard video mouse
• a switch supporting one set of input and output devices that control multiple PCs
KVM switch
Keyboard video mouse
• a switch supporting one set of input and output devices that control multiple PCs
Guidelines for installing peripheral devices
• always read the manufactures instructions and check that device is compatible with the PC and operation system
Hold the connector when removing a lead and inspect connector and port for damage
Don’t use excessive force
Check whether device requires external power source
Whats likely cause of keyboard not working properly
Appropriate keyboard layout has not been selected in settings
LCD - liquid crystal display
Digital signalling in the types of flat panel
Liquid crystal elements placed on thin film transistor
Types of LCD
Twisted nematic
In-plane switching
Vertical alignment
Twisted nematic
Original LCD technology
Fast response time (gaming)
Poor viewing angle
In-plane switching LCD
Good colour representation
More expensive to produce than TN
Vertical alignment LCD
compromise between TN and IPS
OLED display
True black representation, computer will turn off
Made from plastic
Display can be curved
Contrast ratio
Contrast between true black and true white
Higher contrast ratio, the better
What is brightness measured in
Lumens/m2
DVI - digital visual interface
Video adapter desigmed to replace VGA port
Can support digital only or digital and analog (DVI - D /I)
HDMI - high definition multimedia interface
High specification digital connector for audio-video equipment
Version 1.4 supports 4k
Version 2.1 supports 10k at 120hz
Display configuration issues
For no display
Verify connection power to monitor make sure its not in standby mode
Verify connection between video card and monitor
Use OSD controls to verify display input
Try use monitor with another PC
Display configuration issues
For dim images
Adjust brightness and contrast controls and check for power save mode
Display configuration issues
For
Image quality issues
Check video cable and connector
Adjust resolution refresh rate and image controls
Display configuration issues
For oversized images
Increase resolution
Verify no zoom
Display configuration issues
For colour quality issues
Calibrate to scanners and printers
Check connectors and cabling
Most likely cause of a flickering display
On an LCD it could indicate problem with the backlight
Verify connectors are secure and cabling problems
Audio subsystem
Made up of a sound card and 1/more I/O devices
Basis of a soundcard
• digital signal processor chip which contains digital to analog converter
DACs convert digital signals generated by CPU to analog electrical signal
Audio jack
Blue - audio in
Pink- mic in
Green- audio out
Black- audio out
Orange- subwoofer
5.1 dolby digital
3 front speakers, 2 rear and subwoofer
7.1 dolby digital plus
3 front speakers, 2 side, 2 read and subwoofer
Sound recording equipment
Higher sampling rates and resolutions provide more accurate sound
Distortion (noise)
Noise levels are measured using total harmonic disruption and signal to noise ratio
THD measured as % SNR is decibels.
Lower numbers= better performance
What size and colour connector would you look for to plug a basic microphone into PC
Pink connector
CPU definition
Main chip on system board
Performs software instructions
CPU
Operating system technologies
Hardware drivers are specific to the OS version (32/64-bit)
32-bit (x86) 64-bit (x64)
32-bit OS can’t run 64-bit apps but 64-bit OS can run 32-bit apps
Apps in a 64-bit Windows
OS
32-bit apps: \program files (x86)
64-bit apps: \Program Files
Processor cores: A CPU can have multiple cores
A CPU with
2 cores- a dual-core processor
4 cores- a quad-core
6 cores- hexa-core
Eight cores- octa -core
System bus between CPU and memory consists of
Data bus determines how much data can be transferred per clock cycle
Address bus determines how many memory locations the PC can access
Address bus for 32-bit CPUs is 32 or 36 bits wide
Address bus for 64-bit CPUs is usually 48 bits wide
How wide is the data bus on modern PCs
64 bits wide
How much address space can 32-bit bus access
4 GB
How much address space can be accessed by 36-bit bus
64 GB of address space
How much address space can a 64-bit bus access
256 TB address space
Cache
Small block of high-speed memory that enhances performance by preloading instructions and data from system RAM that the CPU uses regularly
Multithreading
allows multiple threads to run through the CPU at the same time
SMP
Symmetric multiprocessing: 2 or more physical CPUs share an OS
Normally used with servers
Clock speed
Key performance indicator
3.5G-4.2Ghz, 4.8-5GHz
Some run slower but better performance- more cache
Core clock speed
Speed at which the CPU runs internal processes and accesses L1,2,3 cache
3.5GHz -4.2GHz or 4.8-5GHz
What is front side bus
Speed of the interface between CPU and system memory
What is throttling
Technology that allows CPU to adjust speed to improve performance
CPUs can implement power management oil enter low power states which helps conserve energy and heat production
Too hot can lead to damage
What’s VM
Virtualisation support - run other OS within a single hardware platform
can be enabled in the UEFI setting VT or AMD-V
CPU form factor
CPU packaging and how it connects to the motherboard
LGA
Land grid array
Intel technology where pins are located on the socket
PGA
Pin grid array in which pins are on the CPU
AMD CPU - PGA socket types only
ZIF
Zero insertion force
Like a lever allowing for little damage to the pins on processor chip
Cooling mechanisms
Heat sink- metal that conducts heat
Thermal paste- draws heat from CPU and connects heat sink to CPU
CPU heat sink _ fan= cooler
Cooling mechanism for laptop
Heat pipe- tube containing water or ethanol coolant
Heat spreader- similar to heat pipe but its a flat container
Why can cache improve performance
Routines are stored in fast cache RAM, can be accessed more quickly
What limits upgrade potential for system processsor
The type of CPU society and chipset provided on the motherboard
How can CPU performance be improved
Overclocking
What must you check when inserting a PGA CPU chip
That pin 1 is aligned properly in the socket
Otherwise, risk damaging the pins when the ZIF lever is lowered
Difference between a heat sink and heat pipe
A heat sink uses solid metal fins to dissipate heat
A heat pipe contains fluid that evaporates in the area over the CPU
Firmware definition
Software stored in nonvolatile memory chips
Firmware definition
Software stored in nonvolatile memory chips
System firmware definition
Provides low-level code that allows computer components to be initialised and load the main OS software
UEFI
Newer standard of firmware to interface with PC. Improvement over BIOS
Boot option test answer
Hold down shift when clicking restart
BIOS secure boot
Helps a computer resist attack and infection from malware
What widely supported boot method is missing from the following list? HDD,FDD,optical, USB
PXE
Name 3 keys commonly used to run a PC’s BIOS/UEFI system setup program
Esc, Del, F1,F2, F10
What advantages does UEFI have over BIOS
UEFI supports 64-bit CPU operation and better hardware support at boot
UEFI allows for full GUI
Startup security options (OS authentication)
DC - direct current
What voltages can it produce in a computer
Charge flows in one direction at constant voltage
Can produce 3,3V, 5V and 12V
What’s PSU
Power supply unit - takes in AC and converts it to DC
PSU modular power supplies and benefits
Power supply units with detachable cables
Benefits
Less overheating, only power cables that your PC need
Better organisation
What is OCP
Overcurrent protection- power supply rail safety feature that cuts the circuit if the power exceeds a safe limit
What is voltage regulator and the main connector P1
Deliveries voltage required by the cpu or will separate the voltage for more than one CPU
P1 connector is 24 pin - main power plug that supplied power to the motherboard
What is Molex connector
Old power connector used to supply power to PATA drives, optical drives and SCSI drives
PSU adapter types
PCIe connectors- 6-pin
P4-CPU and 9-pin for graphic connectors
Power needs calculation
List the devices that need to have power served by the PSU
Motherboard
CPU
RAM
Hard drives
CD drives
Expansion cards
Power needs calculation (2)
Determine power requirements for each device
Add up the power requirements for total
Add up a buffer of 50% for future power needs
What is the significance of a PSU’s power output when you are designing a custom build PC
Determines the number of drives expansion cards and peripherals the PC can support
What setting should you check before installing a PSU
Vol selector needs to be adjusted to correct voltage
Power supply with a 8-pin connector on it. What is it used for
Supplied power to a PCIe graphics card
Basic hardware problems step 1
Question the user and back up date if needed
Basic hardware problem step 2
Establish a theory
Examine the system and take a guess of problem source
Basic hardware problem step 3
Test your theory
Basic hardware problem step 4
Plan steps to fix problem (e.g when the client is away)
Fix problem
Basic hardware problem step 5
Verify and present
Verify if problem is solved with the client
If problems could have been prevented take preventative action
Basic hardware problem step 6
Document findings, actions , outcomes
What can you use to test power
Use a multimeter
What is a power supply tester
A type of meter designed specifically to test PSUs
What does the power supply tester include ports for
Includes ports for:
20/24-pin P1
Molex
SATA
8-pin connectors
6-pin connectors
4-pin connectors
what is a POST
Power on self test
Hardware checking routine built into the PC firmware
The test monitors the state of memory chips, the processor, system clock, display and firmware itself
POST not running
If power is available but computer doesn’t start, screen remains black and there are no beeps, POST is likely not happening
If possible try another monitor
Check faulty cables, wrong CPU motherboard issues
OS boot troubleshooting and log entries
When boot device is located code from the boot sector is loaded into memory
Code from boot sector takes over from the system’s firmware
Motherboard component problems
Inspect for physical damage
Pins are not bent
Dirty contacts on connectors
Chips and boards are properly seated
Scorch marks and distended capacitors
Mother board component problems 2
Determine if intermittent problems have a pattern
Very power supply provides stable voltage
Check for overheating issues ensure that
CPU fan is working
Heat sink is properly fitted
Processor is at the correct speed
What cause might you suspect if a PC experiences intermittent lockups
Thermal or power problems
Loose connections or faulty memory
What measurement would you expect from a multimeter if a fuse is good
0 ohms
Network types
LANS, WANS, MANs
Types of networks and network connections
PAN ( personal area network) personal devices- phone
LAN- group of computers connected by cabling and one or more network switches that are all installed at a single location
WLAN (wireless local area network) uses radios for data transfer
MAN - covers a large campus/city
WAN- covers a large area and made up of small networks
SAN (storage area network)- network that provides network access to storage devices
SOHO definition
A network with clients, using single internet appliance as access point such as Ethernet switch, internet router
