Chapter 11 (software)

Powered off

The first rule when working inside a computer is always to make sure that it’s ()?

True

True or False?:

Many times, it is actually preferred to leave the computer plugged in BUT POWERED OFF because it grounds the equipment and can help prevent electrostatic discharge.

True

True or False?:

You don’t have to power off the computer when working with hot-swappable parts because they are designed to be unplugged and plugged back in when the computer is on.

Field replaceable unit (FRU)

Because a power supply is considered to be a (), it is safer and probably cheaper to buy a new one than to try and fix it. Also, it is not recommended to replace a power supply due to the danger of it.

Monitor

Other than the power supply, the most dangerous component to try to repair is a computer (), specifically, older-style cathode-ray tube (CRT).

True

True or False?:

It is recommended not to try and repair power supplies or monitors.

High-voltage probe

If you have to open a monitor, you must first discharge the high-voltage charge on it by using a ().

High-voltage probe

A tool that has a very large needle, a gauge that indicates voltes, and a wire with an alligator clip.

False

True or False?:

You should use an ESD strap when discharging a monitor.

Inverter

A liquid crystal display (LCD) monitor requires an (), which provides the high-voltage, high-frequency energy needed to power the backlight.

Higher

The lower the humidity, the (higher or lower?) the amount of electrostatic discharge (ESD) that can be produced.

Electrostatic discharge (ESD)

One of the biggest concerns for components is ().

CPU chips and memory chips are particularly sensitive to this.

ESD antistatic strap

To use an (), you attach one end to an earth ground or the computer case and wrap the other end around your wrist. This grounds your body and keeps it at zero charge.

True

True or False?:

In order for an antistatic wrist strap to work properly, the computer must be plugged in but turned off. When the computer is plugged in, it is grounded through the power cord.

ESD mats

Sold as mouse/keyboard pads to prevent ESD charges from interfering with the operation of the computer.

Antistatic bags

Used when servicing electronic components because they protect sensitive electronic devices from stray static discharges. By design, the static charges collect on the outside of these silver or pink (), rather than on the electronic components.

No

Do antistatic bags drain the charges away?

Humidity

Another preventive measure that you can take to minimize electrostatic discharge is to maintain the relative () at around 50 percent.

Electromagnetic inference (EMI)

An unwanted disturbance caused by electromagnetic radiation generated by another source.

2.4

802.11b/g/n/ax use the () GHz range for transmissions. Bluetooth devices happen to use the same frequency.

Cordless phones

Can operate at a variety of frequencies, of which the more common are 900 MHz, 1.9 GHz, 2.4 GHz, and 5.8 GHz.

True

True or False?:

Copper wires are susceptible to electromagnetic interference (EMI).

False

True or False?:

Fiber-optic cables, which use light to transmit data, are susceptible to electromagnetic interference (EMI).

Ground

A safe path for electrical current to flow away in the event that a device or cable is faulty.

Low

Are most PC circuits (low or high?) voltage/current.

High

Power supplies, CRT monitors, LCD display inverter card, and laser printers are (low or high?) voltage/current.

Fire extinguishers

Electrical fire safety:

Use CO2 () with a black label, because dry powder ones can damage electronic equipment.

True

True or False?:

In the event of electrical fires, you should cut the power supply.

Electrostatic discharge (ESD)

A situation that occurs when electrons rush from one statically charged body to another with an unequal charge, following the path of least resistance. Occurs with high voltage and low current.

True

True or False?:

People feel electrostatic discharge at 2,500V, but equipment can be damaged by as little as 100V.

Self-grounding

The act of touching a grounded object before touching electronic equipment.

False

True or False?:

Self-grounding is more effective than using an electrostatic discharge wrist/leg strap.

Highest

During cool, dry conditions when humidity is low, the risk of electrostatic discharge is (lowest or highest?)

High

When humidity is (high or low?), the static electricity can dissipate through the moisture present in the air.

Power supplies

Which computer component presents the most danger from electrical shock?

Occupational Safety and Health Act/Administration

States that every working American has the right to a safe and healthy work environment.

Electricity and water

What are the two forms of environmental accidents related to computers?

Material safety data sheets

Provide specific procedures on how to clean up chemical spills.

Brownout

A temporary power reduction that is used by electrical power companies to deal with high power demands.

Digital Rights Management (DRM)

A way to control access to copyrighted content that is presented in digital format.

Personally Identifiable Information (PII)

Any information that can be used by itself or in combination with additional information as a way to identify, contact, or find a single person, or to identify a particular individual by using the various pieces of information together to determine the person’s identity.

Payment Card Industry Data Security Standard (PCI DSS)

A set of shared rules developed by the world’s major credit card companies and administered by the PCI Council.

Acceptable Use Policy (AUP)

A policy that includes the practices and guidelines that should be followed by employees when using and accessing company resources and computer equipment.

Incident report

A record of any instance where a person is injured or computer equipment is damaged due to environmental issues. Also, a record of accidents involving hazardous materials, such as chemical spills, that could have an impact on the environment itself.

Sag

Occurs when the line voltage dips below the nominal operating voltage within ½ second to 3 seconds of a power cycle. Normally the voltage should stay consistent at 90 percent of the voltage specification.

Brownout

Occurs when the line voltage dips below the nominal operating voltage for more than 3 seconds of a power cycle. Commonly caused by large upstream draws on electrical demand.

Spike

Occurs when the line voltage increases over the nominal operating voltage that lasts only 1 to 2 nanoseconds.

Surge

Occurs when the line voltage increases over the nominal operating voltage that lasts over 3 nanoseconds.

Surge protectors

Have a fuse inside them that is designed to blow if it receives too much current and not to transfer the current to the devices plugged into it.

Computer vacuum

Which tool is being described (Computer vacuum, mild soap and water, demineralized water, Denatured isopropyl alcohol, monitor wipes, lint-free cloth, or compressed air)?:

Used for sucking up dust and small particles.