Power SuppliesPower Supplies

Power SuppliesPower Supplies

Takes electricity from the wall socket and transforms it into electricity to run the motherboard and other internal components

EXAM TIP Some questions on the CompTIA A+ certification exams could refer to a power supply as a PSU, for power supply unit. A power supply also falls into the category of field replaceable unit (FRU), which refers to the typical parts a tech should carry, such as RAM and a floppy disk drive.

Understanding Understanding ElectricityElectricity The pressure of the electrons in the wire is called

voltage and is measured in units called volts (V) The amount of electrons moving past a certain

point on a wire is called the current or amperage, which is measured in units called amperes (amps or A)

The amount of amps and volts needed by a particular device to function is expressed as how much wattage (watts or W) that device needs

The correlation between the three is : V × A = W

Common Electrical Common Electrical ComponentsComponents

Circuit BreakerCircuit Breaker

Circuit breakers and ground wires provide the basic protection from accidental overflow

A circuit breaker is a heat-sensitive electrical switch rated at a certain amperage

If you push too much amperage through the circuit breaker, the wiring inside will detect the increase in heat and automatically open, stopping the flow of electricity before the wiring overheats and breaks

You reset the circuit breaker to reestablish the circuit and electricity will flow once more through the wires

A ground wire provides a path of least resistance for electrons to flow back to ground in case of an accidental overflow

EXAM TIP An electrical outlet must have a ground wire to be suitable for PC use!

Hot, Neutral, and Hot, Neutral, and Ground (Ground (continuedcontinued) )

Hot, Neutral, and Hot, Neutral, and Ground (Ground (continuedcontinued))

MultimeterMultimeter

A multimeter—often also referred to as a volt-ohm meter (VOM) or digital multimeter (DMM)—– Enables you to measure a number of different

aspects of electrical current– Provides at least four major measurements: AC

voltage, DC voltage, continuity, and resistance A multimeter consists of two probes:

– An analog or digital meter, and a dial to set the type of test you want to perform

UPSUPS

UPS - uninterruptible power supply (UPS) – Protects your computer (and, more

importantly, your data) in the event of a power sag or power outage

– A UPS essentially contains a big battery that will provide AC power to your computer, regardless of the power coming from the AC outlet

Uninterruptible Power Uninterruptible Power SuppliesSupplies

BenefitsBenefits– Condition line for brownouts and spikesCondition line for brownouts and spikes– Provide backup power during a blackoutProvide backup power during a blackout– Protect against very high potentially Protect against very high potentially

damaging spikesdamaging spikes ConsiderationsConsiderations

– CostCost– UPS ratingUPS rating– Degree of line conditioningDegree of line conditioning– Warranty and service policiesWarranty and service policies

Power SuppliesPower Supplies

The power supply unit (PSU) takes over, converting high-voltage AC into several DC voltages (notably, 5.0, 12.0, and 3.3 volts) usable by the delicate interior components

PC uses the 12.0-volt current to power motors on devices such as hard drives and CD-ROM drives, and it uses the 5.0-volt and 3.3-volt current for support of onboard electronics

Power SuppliesPower Supplies

Power to the Motherboard Use a 20- or 24-pin P1 power

connector. Some motherboards may require special 4-, 6-, or 8-pin connectors to supply extra power

Power to Peripherals: Molex Molex Connectors

– The most common type of power connection for devices

– Need 5-volts or 12-volts of power is the Molex connector

– The Molex connector has notches, called chamfers, that guide its installation

Power to Peripherals: Mini Connectors Mini Connectors

– A second type of connector, called a mini connector

– Supplies 5 and 12 volts to peripherals, although only floppy disk drives in modern systems use this connector

Power to Peripherals: SATA Power Connectors SATA Power Connectors

– Serial ATA (SATA) hard drives need a special 15-pin SATA power connector

– The larger pin count supports the SATA hot-swappable feature, and 3.3 V, 5.0 V, and 12.0 V devices. SATA power connectors are L shaped, making it almost impossible to insert one incorrectly into a SATA drive

– No other device on your computer uses the SATA power connector

Power to Peripherals: Splitter & Adapters Not enough connectors to power

all of the devices inside your PC– Purchase splitters to create more

connections

Power to Peripherals: Auxiliary Connector Motherboard power connector

– Commonly called an AUX connector– To supply increased 3.3- and 5.0-volt

current to the motherboard

Power Supply Form Factors All use standard ATX connectors, but

differ in size and shape from standard ATX power supplies– TFX12V A small power form factor

optimized for low-profile ATX systems– SFX12V A small power form factor

optimized for systems using FlexATX motherboards

– CFX12V An L-shaped power supply optimized for Micro BTX systems

– LFX12V A small power form factor optimized for low-profile BTX systems

Protecting Your Computer Protecting Your Computer System: General System: General PrecautionsPrecautions Make notes so you can backtrackMake notes so you can backtrack

Remove packing materials from work areaRemove packing materials from work area

Keep components away from hair and Keep components away from hair and clothingclothing

Keep screws and spacers in an orderly Keep screws and spacers in an orderly placeplace

Don’t stack boards on top of each otherDon’t stack boards on top of each other

Protecting Your Computer Protecting Your Computer System: General System: General PrecautionsPrecautions Don’t touch chips on motherboard or Don’t touch chips on motherboard or

expansion cardsexpansion cards

Don’t touch chip with magnetized Don’t touch chip with magnetized screwdriverscrewdriver

Don’t change DIP switch settings with a Don’t change DIP switch settings with a graphite pencilgraphite pencil

Protecting Your Protecting Your Computer System: Computer System: General PrecautionsGeneral Precautions

Have classroom instructor check your Have classroom instructor check your work before putting cover on and work before putting cover on and powering uppowering up

Turn off a computer before moving itTurn off a computer before moving it

Keep disks away from magnetic fields, Keep disks away from magnetic fields, heat, and extreme coldheat, and extreme cold

Protecting Yourself Protecting Yourself Against ElectricityAgainst Electricity

Turn off power and unplug computerTurn off power and unplug computer

Always use a ground braceletAlways use a ground bracelet

Never touch inside of a computer Never touch inside of a computer while it is turned onwhile it is turned on

Never remove cover or put your Never remove cover or put your hands inside monitor or power supplyhands inside monitor or power supply

Static Electricity (or Static Electricity (or ESD)ESD) Can cause catastrophic failure or Can cause catastrophic failure or

upset failureupset failure

Protection against ESDProtection against ESD

– Ground bracelet or static strapGround bracelet or static strap

– Ground matsGround mats

– Static shielding bagsStatic shielding bags

Ground BraceletGround Bracelet

EMI EMI (Electromagnetic (Electromagnetic Interference)Interference)

Caused by magnetic field produced as Caused by magnetic field produced as side effect when electricity flowsside effect when electricity flows

Protection against EMIProtection against EMI

– Cover expansion slotsCover expansion slots

– Do not place system close to or on same Do not place system close to or on same circuit as high-powered electrical circuit as high-powered electrical equipmentequipment

– Use line conditionersUse line conditioners

Upgrading Your Power Upgrading Your Power SupplySupply Sometimes necessary when you Sometimes necessary when you

add new devicesadd new devices

Easiest way to fix a power supply Easiest way to fix a power supply you suspect is faulty is to replace you suspect is faulty is to replace itit

Introduction to Introduction to TroubleshootingTroubleshooting Isolate the problemIsolate the problem

– Problems that prevent PC from bootingProblems that prevent PC from booting

– Problems that occur after a successful Problems that occur after a successful bootboot

Learn as much as you can by asking Learn as much as you can by asking questions of user(s)questions of user(s)

PC Problem SolvingPC Problem Solving

Troubleshooting the Troubleshooting the Power System: General Power System: General GuidelinesGuidelines

Any burnt parts or odors?Any burnt parts or odors?

Everything connected and turned on? Everything connected and turned on? Loose cable connections? Computer Loose cable connections? Computer plugged in?plugged in?

All switches turned on? Wall outlet All switches turned on? Wall outlet good?good?

If fan is not running, turn off computer: If fan is not running, turn off computer: Connections to power supply secure? Connections to power supply secure? Cards securely seated?Cards securely seated?

Troubleshooting the Troubleshooting the Power System: General Power System: General GuidelinesGuidelines

Check for correct wire connections Check for correct wire connections to motherboardto motherboard

Remove nonessential expansion Remove nonessential expansion cards one at a timecards one at a time

Vacuum entire unitVacuum entire unit

Troubleshooting an Troubleshooting an ATX Power SupplyATX Power Supply

Troubleshooting the Troubleshooting the Power SystemPower System

Power supply itselfPower supply itself

Power supply fanPower supply fan

Power problems with the Power problems with the motherboardmotherboard

OverheatingOverheating

Preventing Preventing OverheatingOverheating

Preventing Preventing Overheating (Overheating (continuedcontinued))

Energy Star SystemsEnergy Star Systems(The Green Star)(The Green Star)

Satisfy energy-conserving standards of Satisfy energy-conserving standards of the US EPAthe US EPA

Generally have a standby program that Generally have a standby program that switches device to sleep mode when switches device to sleep mode when not in usenot in use

Apply to computers, monitors, printers, Apply to computers, monitors, printers, copiers, and fax machinescopiers, and fax machines

Power Management Power Management MethodsMethods Advanced Power Management (APM)Advanced Power Management (APM)

AT Attachment (ATA) for IDE drivesAT Attachment (ATA) for IDE drives

Display Power Management Display Power Management Signaling (DPMS) standards for Signaling (DPMS) standards for monitors and video cardsmonitors and video cards

Advanced Configuration and Power Advanced Configuration and Power Interface (ACPI)Interface (ACPI)

Power Management Power Management FeaturesFeatures Green timer on the motherboardGreen timer on the motherboard

Doze timeDoze time

Standby timeStandby time

Suspend timeSuspend time

Hard drive standby timeHard drive standby time

Power Management Power Management Setup ScreenSetup Screen

Energy Star MonitorsEnergy Star Monitors

Most adhere to DPMS Most adhere to DPMS specificationsspecifications

– Allow video card and monitor to go Allow video card and monitor to go into sleep mode simultaneouslyinto sleep mode simultaneously

Changing Power Changing Power OptionsOptions