Safety and Power

Module 03

Sno Isle Skills Center

Personal Safety

— Your primary responsibility as a technician is to ensure _____________________ safety for yourself and others

— Before working on a computer

◦ Clear _____________________

◦ Get _____________________-static mat/bag

◦ Remove power _____________________from wall/device

◦ Remove _____________________battery

◦ Ensure you are _____________________*

Personal Safety

— Power

◦ The power from the wall is _____________________current

◦ It cycles at _____________________mhz with _____________________volts

◦ That is enough to _____________________you

◦ Even when the _____________________is unplugged, it retains power in capacitors

– Their job is to absorb and store power, and deliver current

– Can retain enough _____________________and _____________________to kill you, even hours after the device is unplugged*

Power Supply Safety

— A power supply is an FRU, or _____________________ _____________________Unit

— It is NOT an SU, _____________________Unit.

— Why?

◦ Because the _____________________contain enough voltage and current to kill a person*

Other High Voltage Components

— CRT (_____________________Ray _____________________Monitor)

— Laser _____________________

— Anything with large _____________________, which are necessary to deliver a consistent flow of _____________________to the device.

◦ Small capacitors, such as on a motherboard, are _____________________*

Grounding

— Use a grounding-_____________________

◦ _____________________

◦ _____________________strap

— _____________________

— Attach _____________________from strap to an _____________________surface on the computer

— NEVER ground yourself to a high _____________________device

◦ _____________________are the path of least resistance

◦ In the event of a surge, the current will go through your _____________________.

◦ This could kill you.*

Proper Grounding

Hot Stuff

— The CPU and RAM get really _____________________, so allow them to cool so that you don’t get burned.

— CPUs get hot enough to _____________________water.

— _____________________may as well.*

Other Safety Considerations

— Clean area so you nor others can _____________________over components

— Watch _____________________. It should not run across the _____________________.

— Lift _____________________devices carefully, with your knees, not your back.

Fire Safety

— Any time you work with _____________________or heat, there is the potential for _____________________.

— All work areas should have a Class C fire extinguisher in an easily accessible location.*

To Use a Fire Extinguisher

— P_____________________—the pin or plastic

— A_____________________—At the BASE of the fire

— S_____________________—the trigger

— S_____________________—from side to side until fire is out

— Do not just leave, watch it does not _____________________.

— Only fight SMALL fires with an _____________________. Large fires…get the _____________________outta there!

Extinguisher Classes

— A—_____________________only, good for wood, paper fires with no chemicals.

— B—_____________________extinguishers for flammable _____________________and _____________________sources (plugged in).

— C—Dry _____________________coat the fire with a dry chemical to smother it. _____________________the oxygen from the fuel and stops the chemical reaction from the fire.

— Use a Class _____________________ or _____________________.

MSDS

— Material Safety Data Sheet

◦ How to handle _____________________

◦ How to _____________________

◦ How to deal with _____________________

◦ _____________________at which the chemical will combust

◦ And MUCH more

— MSDS for every single _____________________ (except water) that is used in your job.41

MSDS Must be kept ON SITE

Lasers

— _____________________can cause blindness, so take care

◦ Laser _____________________

◦ Laser _____________________

◦ Laser _____________________

◦ _____________________drives (although how your eye would get in there is beyond _____________________)

◦ _____________________optic cable

— Use proper equipment for testing. Do not “_____________________” test anything with lasers.

Introduction to Basic Electricity

— Electricity starts with the _____________________.

◦ Every atom contains one or more _____________________

◦ Every electron has a negative charge

◦ Electrons _____________________around the nucleus of the atom

◦ The _____________________has a _____________________charge

— Most items (wood, plastic, etc.) have electrons _____________________bound to them. They don’t give off a charge. These would be electrical insulators.

— Some items have free _____________________that can detach and _____________________around. These are called electrical _____________________.

— In order for electrons to move, the must have some form of conductor.*

The Lowly Atom

Introduction, cont

— The flow of electrons is from a negatively charged location (terminal) to a positively charged location (terminal).

— Energy causes electrons to move from one atom to another.

— This is known as electron current flow.*

Circuit

— What makes electrons move through a circuit?

— _____________________are attracted to a _____________________charge and repelled by a negative charge.

— If there is a difference between the _____________________and negative points, this is called _____________________or _____________________force.

— Electrons always move in the direction of the _____________________, away from the _____________________.

— This force is measured in _____________________.*

What does my PSU do?

— Convert _____________________to DC

— Converts _____________________to meet the needs of the variety of components in the system.

— Cleans up the _____________________ (to some extent).

— Problems with the PSU can show up in a variety of ways.

— Most work either in the US or Europe

◦ _____________________US

◦ _____________________Europe

Power Supply Troubleshooting Guidelines

— A failing power supply may display a variety of symptoms.

— Power supplies typically convert about _____________________watts, enough for all of the typical components found in a computer.

— You can calculate the total wattage required for all your computer devices and compare the total to the rated _____________________of the power supply.*

Remember!!

— A power supply should typically run at about _____________________% of its rated capacity or less.

— Since the power supply contains the _____________________that cools the _____________________with the flow-through of air, be sure to keep the vents on the power supply clear. Otherwise, the computer can _____________________.

— Since a _____________________power supply can destroy a system board, never replace a system board without first _____________________that the power supply is functioning properly.*

Upgrading the Power Supply

— If the power supply can no longer supply enough power or watts for the system to operate normally, it should be _____________________.

Review

— What are some symptoms of power supply problems?

— How many watts does a typical power supply convert?

— What can be a worst case scenario with a bad PSU?

— How do you figure what wattage rating your power supply should have?

— Power supplies should run at _____________________ of capacity for safety.

Surge Protection and Battery Backup

— The following are three categories of backup power and conditioning devices:

◦ surge _____________________

◦ _____________________conditioners

◦ _____________________power supplies (UPSs).

— These devices install between the _____________________current and the computer to filter the AC input and provide backup power when the AC v fails.*

Surge Suppressor

— A surge _____________________or surge protector provides power outlets that are protected from an over-voltage of AC power.

— Not always _____________________because a fuse that is used to protect the devices plugged into it may be blown, but everything apparently continued to function properly.

— For this reason, it is best to replace surge protectors every _____________________months.*

Buying a Surge Protector

— When purchasing a surge suppressor, it will have a _____________________rating that indicates the maximum voltage allowed through a surge protector to the devices.

— The _____________________the let-through measurement, the better the surge protection.

— The degree of protection of a surge suppressor is measured in _____________________.*

Line Conditioner

— In the event of “dirty power” a line _____________________can clean up the signal.

— Often used in _____________________equipment to produce static-free sound.

— Can also be used in the home/business.*

Uninterruptible Power Supply

— The best kind of power protection is an _____________________power supply (UPS).

— It provides excellent _____________________protection as well as backup power in the event that the AC current fails.

— A UPS is rated by the amount of _____________________it provides and the length of time it can provide power during a blackout.

The Intelligent UPS

— Connects to the _____________________or _____________________port and can:

◦ Send a warning to users logged into a server about _____________________shutdown.

◦ Run a _____________________or batch file when power is lost.

◦ Send a second message to users if power is _____________________.

◦ Shut down a _____________________/computer correctly before batteries die.*

When Buying a UPS

— Consider:

◦ Whether it conditions the line for both _____________________and spikes.

◦ Whether it provides power during a _____________________.

◦ Whether it protects against very high _____________________

◦ Whether the VA rating for the UPS is at least 25 percent higher than your total _____________________output

◦ Whether the _____________________and service policies are satisfactory

◦ Whether the length of time the _____________________backup will last fits your needs*

Review

— What are three things you can purchase to protect your computer from spikes, browns, and other electrical problems?

— What does a surge protector do?

— What is the purpose of a line conditioner?

— How does a UPS work?

— What are two types of UPSs?

— What can a smart UPS do?

ESD and EMI

— ESD (_____________________discharge)—a brief flow of electricity caused by two objects with different voltage potentials coming into contact with each other.

— ESD can cause _____________________damage to computer components.

— Before you work on a computer, it is very important that you are _____________________.*

Just a Little Shock, Right?

— The human body carries an electrical charge of 200-300 volts.

— A “shock” can send 10,000+ volts of power into a _____________________.

— This is enough to _____________________electrical equipment.

— The more painful the shock, the more volts.*

Exceptions

— When working on power _____________________or _____________________.

— Capacitors in these devices _____________________a high charge even when they are turned off.*

EMI

— _____________________interference is a magnetic field produced as a side effect from the flow of electricity.

— EMI can cause corrupted data in _____________________lines that are not properly shielded.

— _____________________is temporary and does not cause _____________________damage to computer equipment.*

Shorts and Grounding

— Short–when _____________________flows un-controlled from hot line to neutral line or from hot line to ground.

— The _____________________line helps contain the energy to avoid fire.

— A fuse in a _____________________prevents too much current from flowing through. *

Wiring

— In most home wiring, a _____________________or _____________________wire is used for ground, white for neutral, and black for hot.

— In most PC wiring, however, _____________________is used for ground, red for hot, and green for neutral.*

Review

— What is a short?

— What is the purpose of a fuse in a circuit?

— What does a ground line do?

— How is wiring in a computer and wiring in a house different?

— What is ESD?

— Why do you need to protect from ESD.

Review again

— The human body carries _____________________of voltage.

— How many volts can a “shock” of static electricity cause?

— What is EMI?

— Is EMI dangerous?

— How can you protect data from EMI?

— When should you use a grounding strap?

— When not?

Measuring Electricity

— Use a _____________________for most electrical measurements

Measuring Electricity

— _____________________—measure the electrical difference using a voltmeter.

◦ Attach the leads to either side of a component and measure the difference between the two.

◦ The difference or drop in voltage is measured across the wire

— Amps—measure the volume of electricity flow using an ammeter

◦ place in the path of the flow with power on.*

Measuring Electricity, cont.

— _____________________—measure the resistance of a cable using an ohmmeter.

◦ The device should not be plugged in.

◦ The _____________________or multimeter sends a small charge through the wire and measures the resistance in the wire*

Voltage

— _____________________is the measure of the electrical force that drives electrons through a system.

— The difference in

"electrical pressure"

between two points is

called the voltage and

is measured in _____________________.*

Amperes (Amps)

— An _____________________system maintains the same amount of "current" throughout the whole system.

— The measurement of this electrical "current" is called _____________________or amps for short.*

The Relationship Between Voltage and Current

— To increase the amount of _____________________flow through the water system you simply increase the water pressure.

— The same holds true for electricity: to increase the amount of electrical "current" (amps), you simply increase the amount of electrical "pressure" (Volts).*

OHMS

— _____________________is the force that opposes the flow of electricity.

— An _____________________is the electrical measurement for resistance.

— A _____________________controls electricity by resisting its natural flow.

— Objects with low resistance are conductors (copper, for example)

— Objects with his resistance are _____________________ (plastic, glass)*

Relationships Among Voltage, Current, and Resistance

— An _____________________system has a direct relationship between pressure differential (voltage) and current.

— Resistance (measured in _____________________) has an inverse relationship between voltage and current

— As resistance increases, either current or _____________________decreases.

— As resistance decreases, current increases. This is known as _____________________law and states that there is an inverse relationship between resistance and current.*

Wattage

— _____________________measures the total amount of power needed to operate an electrical device.

— To determine wattage, use the following formula: _____________________x _____________________= Wattage (watts)*

Ground

— What is a ground?

— Ground _____________________means there is no difference in voltage between a circuit point and the earth.

— In other words, there is not pathway for electricity to flow. _____________________stop.

— A grounding strap allows us to not attract the _____________________if there is a short in the system.

Review

— _____________________ are a measurement of resistance.

— _____________________ is a measurement of differential.

— _____________________ is a measurement of the flow of current.

— What is wattage?

— What is the purpose of a ground?

— If you increase _____________________ you reduce amps.

— If you increase _____________________ you increase amps.

— If you decrease _____________________ you increase amps.

Review

— Define voltage

— Define amperes

— How do you measure voltage?

— Define ohms

— What is current?

— Watt (he he) is electricity?

— AC is?

— DC is?

Review 2

— What converts AC to DC and vice versa?

— Wall plugs give you __ current.

— How can you determine wattage?

— What is Ohms Law?

— What is a resistor? What are they used for?

— A power supply converts house current from _____________________volts ________________________ or _____________________volts.

PCs Electrical Components May Be Made From

— _____________________such as gold or copper wire that easily conduct electricity.

— _____________________such as glass or ceramic that resist the flow of electricity.

— _____________________such as silicon that conduct electricity.

— Transistors made of layers of _____________________material that serve as a gate or switch for an electrical signal and can amplify the flow of electricity. *

PC Electrical Components May Be Made From:

— _____________________that hold an electrical charge for a period of time are used to smooth out the uneven flow of electricity through a circuit such as those in monitors or power supplies.

— _____________________that allow electricity to flow in only one direction and may act as a rectifier.*

Environmental Concerns

— You must _____________________of things properly

◦ Cannot go in garbage

– _____________________

– Motherboards

– _____________________

– _____________________supplies

– Printer and toner _____________________

– Cleaning _____________________

— You are responsible for ensuring you know what to do with these to comply with local/state laws.