LECTURE 2 PREVENTIVE MAINTENANCE
Preventive
Maintenance
• Preventive
maintenance (PM) refers to performing a series of maintenance tasks to prevent
system problems.
• It
is done as a precautionary measure to avoid any problem in future.
• PC
(Personal Computer) preventive maintenance includes proactive maintenance of PC
components such as, mouse, keyboard, drives, and monitor to ensure smooth
functioning of a PC.
• You
should perform these maintenance activities to avoid sudden breakdown.
Preventive
maintenance provides the following benefits:
• Saves
Money: Handling the problem areas in a PC before actually facing a problem,
substancially reduces the possibility of a sudden breakdown and the associated
expenditure.
• Saves
Time: Troubleshooting the components and their repair procedures take more time
as compared to preventive maintenance procedures. Performing preventive
maintenance procedures, reduces the possibility of system failures and data
loss
• Improves
Performance: With the passage of time, some components of a PC such as mouse
and keyboard degrade in performance. Preventive maintenance helps in improving
the performance and life of these components
• Safeguards
Data: Preventive maintenance procedures can be used to protect hardware devices
such as hard disk drives and as a result, to safe guard the software(s) and the
user data stored on these drives
Guidelines:
You will need a clean, well-lit space in which to work and
some basic hand tools.
Gather the tools you may need
and bring them to your work area. The following tools are required:
• Phillips
head screwdriver
• Grounding
strap
• Razor
knife or scissors
• Rag
or lint-free paper towels
• Non-oil-based
cleaning solution (no wax)
• Can
of compressed air
Safety Guidelines:
Use the following safety guidelines to help protect your
computer from potential damage and to help ensure your own personal safety.
1. Read
product instruction guide before you begin.
2. Handle
components and cards with care. Do not touch the components or contacts on a
card. Hold a card by its edges or by its metal mounting bracket. Hold a
component such as a processor by its edges, not by its pins.
3. Turn
off the computer as instructed in the product information guide.
4. Disconnect
all the cables at the back of the computer first and then unplug it from the
source.
Telling the
Difference Between Computer Hardware and Software Problems Hardware
problems usually occur quickly
Hardware Problem
- Happens quickly and unexpectedly.
-Computer turns off in a few minutes or so.
-Keyboard num lock, Caps lock, and/or scroll lock doesn't
work.
- Mouse laser doesn't work even when plugged in and on
Windows.
-There is no noise when starting up your computer.
- Your computer's ports don't work (such as your HDMI, LAN,
and USB ports ).
- You have trouble accessing your computer's folders and you
have a loud hard drive.
- Your computer's screen is all jumbled up (video
card ). - Your internet is slow (usually from too much traffic ).
SYSTEM CASE
In most old computers like IBM compatible computers, this
task is accomplished by removing few screws at the back of the computer and
then sliding the cover to open up.
With the evolution of technology in PCs, hardware
manufacturers have begun to design systems that are easier to maintain. Many of
today's PCs can be completely disassembled without using a single tool.
Opening the case of a latest computer step by step.
1.
Follow the instructions in caution and
guidelines.
2.
Lay the computer on its side with the cover
release latch on the top as shown in the figure.
3.
Move the cover release latch toward the top of
the computer.
4.
Raise the cover, and turn it toward the front of
the computer. Removing the Memory
1.
Follow the instructions in caution and
guidelines.
2.
Open the cover.
3.
Lay the computer on its side so that the system
board is on the bottom of the inside of the computer.
4.
Press out the securing clip at each end of the
memory module connector.
5.
Grasp the module and pull it up.
6.
Close the computer cover
Installing a PC Card
Follow the instructions in caution and guidelines.
1.
Open the cover.
2.
Lay the computer on its side so that the system
board is on the bottom of the inside of the computer.
3.
Press the lever on the card retention arm and
raise the retention arm.
4.
If you are installing a new card, remove the
filler bracket to create a card-slot opening.
5.
Place the card in the connector and press down
firmly. Ensure that the card is fully seated in the slot.
6.
Press the retention arm into place, securing the
card in the computer.
7.
Connect any cable that should be attached to the
card. (Sometimes some cards will have cables which need to be connected to the
motherboard.)
8.
See the documentation for the card, for information
about the card's cable connections.
9.
Close the cover.
10.
Connect all the cables and start the computer.
11.
Install the necessary drivers.
Storage Devices
• Connect
serial ATA hard drives and serial CD/DVD drives to the system board connectors
labeled SATA-0, SATA-1, SATA-2, or SATA-3. Connect IDE CD/DVD drives to the
connector labeled PRI IDE.
• When
you connect two IDE devices to a single IDE interface cable and configure them
for the cable select setting, the device attached to the last connector on the interface
cable is primary or the boot device (drive 0), and the device attached to the
middle connector on the interface cable is the secondary device (drive 1).
• When
you install a drive, you connect two cables - a DC power cable and a data cable
- to the back of the drive and to the mother board.
• Some
drives may also have an audio connector; one end of the audio cable will attach
to the drive connector and the other will attach to the mother board.
Removing the Hard
Disk
Follow the instructions in caution and guidelines.
1.
Open the cover.
2.
Lay the computer on its side so that the system
board is on the bottom of the inside of the computer.
3.
Press in on the top shroud tabs and tilt the
shroud back.
4.
Lift the shroud away from the hard drive.
5.
Disconnect the power and hard-drive cables from
the drive and from the motherboard.
6.
Press in on the tabs on each side of the drive
and slide the drive out of the cage.
7.
Close the cover.
Installing Hard Disk
1.
Follow the instructions in caution and
guidelines.
2.
Open the cover.
3.
Lay the computer on its side so that the system
board is on the bottom of the inside of the computer.
4.
Press in on the top shroud tabs and tilt the
shroud back.
5.
Lift the shroud away from the hard drive.
6.
If the hard drive does not have the bracket
rails attached, remove the rails from the old drive by removing the two screws
that secure each rail to the drive. Attach the bracket rails to the new drive
by aligning the screw holes on the drive with the screw holes on the bracket
rails and then inserting and tightening all the four screws.
7.
Install the hard drive into the computer by
gently sliding the drive into place until the tabs securely click into
position.
8.
Connect a power cable to the drive.
9.
Check all connectors to be certain that they are
properly cabled and firmly seated.
10.
Insert the bottom tabs of the shroud into the
holes on the drive cage and rotate the shroud up.
11.
Press in on the top tabs and lock them in to
place.
12.
Gently press on the shroud to ensure that it is
secure.
13.
Close the cover.
Removing the
Motherboard
Follow the instructions in caution and guidelines.
1.
Open the cover.
2.
Remove any of the components that restrict
access to the motherboard.
3.
Disconnect all cables from the motherboard.
4.
Remove the motherboard screw.
5.
Pull up on the two tabs, slide the motherboard
assembly toward the front of the computer, and then lift the assembly up and
away.
Replacing the
Motherboard
Transfer components from the existing motherboard to the
replacement motherboard:
1.
Remove the memory modules and install them on
the replacement motherboard.
2.
Remove the heat-sink assembly and processor from
the existing system board and transfer them to the replacement motherboard.
3.
Adjust the replacement motherboard by aligning
the notches on the bottom of the motherboard with the tabs on the computer.
4.
Slide the motherboard assembly toward the back
of the computer until the assembly clicks into position.
5.
Replace any components and cables that you had
removed from the motherboard.
6.
Reconnect all cables to their connectors at the
back of the computer.
7.
Close the computer cover.
Removing the Power
Supply
1.
Follow the instructions in caution and
guidelines.
2.
Open the cover.
3.
Remove the cards and the card fan.
4.
Disconnect the power supply cables and the card
fan cable.
5.
Remove the card fan guide:
1.
Pull up on the fan-guide release button.
2.
Slide the card fan guide to the right.
3.
Lift the card fan guide out of the four securing
slots in the computer.
6.
While pressing the power-supply release button,
slide the power supply toward the back of the computer.
7.
Lift the power supply away from the computer.
8.
Slide the power supply cables out of the
computer.
Removing the Processor Air Flow Shroud Follow the instructions in
caution and guidelines.
1.
Open the cover.
2.
Lay the computer on its side so that the system
board is on the bottom of the inside of the computer.
3.
Press down and back on the indentations at the
top corners of the shroud. The top anchor tabs disengage from the anchor slots.
4.
Disconnect the cooling fan power cable from the
FANREAR connector on the motherboard.
5.
Disconnect the CPU fan from the FANCPU connector
on the motherboard.
Hardware-related
problems occur due to:
• Dust
Heat
• Magnetism
• Water
or corrosive agents Irregular
power supply
Software-related
problems occur due to:
• Viruses
• Spywares
• Fragmentation
of data
Preventive
Maintenance Products
Preventive maintenance products can be used to keep the
computer components free from dust, water and also control power supply. These
products are:
• Liquid cleaning compounds
Liquid cleaning compounds include soapy water and different
forms of alcohol such as isopropyl and denatured alcohol. These are used to
remove dirt from the outer surface of the PC components such as monitor, outer
case of the system unit, and keyboard. A sponge dampened with soapy water or
mild detergent can be used to clean these components.
While using the liquid cleaning compounds to clean the PC
components, follow the instructions provided by the manufacturer regarding
their usage.
Cleaning fluids can contain ingredients that cause
corrosion. It is recommended to be cautious when using sprays or liquids around
computers.
Note: Liquid cleaning
chemicals should not be used to clean internal circuit boards.
Vacuum cleaners
Dust particles enter the system unit through its air ducts
and obstruct them. Obstructed air ducts affect the air circulation. This
results in heating up of system unit.
•
Dust particles inside the system unit are also
responsible for wear and tear of components and conduction of charge.
Therefore, the components of the system unit are prone to high risk of damage. To prevent this problem, you
can use vacuum cleaners to remove dust particles from inside the system unit.
When you blow the dust off using vacuum cleaners, make sure you are not just
blowing it back into the computer.
•
Small, portable vacuum cleaners are also
available in the market. They are economical and easy to manage.
Note
•
To Avoid Excessive Heat: Install an adequate fan
in the power supply
•
To Avoid Magnetism: Keep anything magnetic such
as phones that ring instead of beep, speakers, monitors, magnetic screwdrivers,
and magnets away from computers and floppy disks. To Avoid Water or corrosive
agents: Be cautious when using any sprays or liquids around computers
UPS and surge
suppressors
Irregular power supply and
voltage fluctuation due to overvoltage or undervoltage in power supply is
harmful for PC component Overvoltage
generates:
•
Spikes: A spike occurs when a short burst of
electricity exceeds 100 percent of the normal voltage for microseconds
•
Surges: A surge occurs when power exceeds 110
percent of the normal voltage for more than a few seconds.
Undervoltage
generates:
•
Brownouts:
A brownout or sag is a partial loss of power. It occurs when the voltage drops
below
110 volts for a few seconds due
to sudden increase in the usage. Brownouts can cause frozen keyboards and
unexpected system crashes. This could result in corrupt disks and data loss.
Brownouts also reduce the life and efficiency of a computer.
• Blackouts: A blackout is a total loss
of power. Blackouts occur due to blown fuses, transformers, and downed power
lines. A blackout does not lead to hardware damage. Instead, it leads to data
and memory loss
To guard the computer against damages caused
by irregular power supply and voltage fluctuation, the following devices can be
used:
Uninterruptible Power
Supply (UPS): A UPS controls the power supply to the computer. It also
provides power backup in case of a power failure. Components of a UPS include:
•
An inverter: To convert DC supply to AC
•
A battery: To provide backup in case of power
failure
•
Battery charger or Rectifier: To charge the
battery
There are two types of UPS:
1.
Standby: Provides power backup during a blackout
2.
Online: Provides protection against surges, spikes, and
brownouts by conditioning the power sent to the computer.
Suppressors: A suppressor provides voltage within the specified
range. It does not provide power backup in case of a power failure. It protects
the computer from surges and spikes.
Disk fragmentation.
In some operating systems, data files over a certain size
are scattered among various clusters. Accessing these files is time consuming
because all clusters are searched to put the files together.
Because the data is spread
across the drive, fragmentation occurs. Bad clusters, on which you cannot
perform read/write operations, also need to be recognized and marked so that
applications do not use them.
All these problems can be prevented by using software
utilities that safeguard the data stored on your computer. These utilities are:
1.
Disk Defragmenter
2.
ScanDisk
3.
CHKDSK
Disk Defragmenter
You can use the Disk Defragmenter utility to join the
separated blocks by moving the data to contiguous blocks and thereby increasing
the system performance.
The Disk Defragmenter utility is available with Windows 95,
98, 2000 and XP. To run the Disk Defragmenter, select
Start -> Programs -> Accessories -> System Tools
-> Disk Defragmenter.
Select the drive to defragment
using Select Drive dialog box and click OK to complete the process.
ScanDisk
You can use the ScanDisk utility to examine disks to mark
out physical and logical errors on them. You can try to recover any valuable
data that is present in the bad sectors.
The Scandisk utility is available
with Windows 95, 98, and NT. To run the ScanDisk utility, select Start ->
Programs -> Accessories -> System Tools -> ScanDisk.
Follow the steps given in the
ScanDisk dialog box to complete the process.
CHKDSK
You can use the CHKDSK utility
to check for disk errors. It is available in DOS, Windows 2000 and XP.
Keyboard
Keyboard also accumulates
dirt. This affects the working of the keyboard and causes the keys to stick
with the dust particles on being pressed. The dust particles can also cause
short-circuit, which results in incorrect characters being displayed on the
screen. Liquids such as tea or coffee spilled on the keyboard can also cause a
short-circuit. To avoid this, cover the keyboard when not in use.
To clean the keyboard, follow these steps:
1.
Switch off the computer.
2.
Disconnect the keyboard from the computer.
3.
Remove the key tops from the keyboard.
4.
Blow the dust using a vacuum cleaner.
5.
Clean the key tops with a cotton swab dipped in
denatured alcohol.
6.
Dry the key tops with a lint-free cloth.
7.
Put the key tops back in place
8.
Connect the keyboard to the computer
Drives
CD-ROM/CD-writer/DVD Drive: To clean the
CD-ROM/CD-writer/DVD drive, you need a CD lens cleaner, which is similar to a
CD but has a tiny brush on track zero.
The steps are as follows:
1 .Insert the CD lens cleaner in the CD-Rom drive.
2 .Access the drive. When the
CD lens cleaner rotates, the brush cleans the CD lens.
Hard Disk Drive:
The hard disk is a sealed unit and therefore it needs less
maintenance. As a preventive measure, you must check the following issues:
Heat: A new hard
disk generates lot of heat while running. To control the heat, ensure that the
interior case has sufficient cooling and ventilation. Avoid placing the hard
disk between other hot components and prevent it from excessive dust.
Vibration: A new
hard disk vibrates more when it runs at high speed. If a hard disk begins to
vibrate more over time than it did before, it indicates some problem.
Shock: Many
people prefer carrying hard disk drives from one place to another, though it is
not recommended by the manufacturer. Hard disks are prone to permanent damages
when moved out of a PC while the disks inside are still spinning
Acclimation: To prevent the problem of adaptation, allow the cold components to rise to room temperature
before using the hard disk.
Diagnosing Computer
Start Up Problems - "Non-system disk" or similar error?
Some of the most common reasons for these errors include:
• There
is no operating system on your computer
• Your
computer has been infected by a virus
• A
blank bootable CD/DVD is in your computer's optical drive
• It
has recently overheated and the hard drive is protecting itself from
overheating again
• The
boot manager isn't looking at the hard drive when the BIOS is loading
• Your
hard drive is having boot sector or similar issues
• Your
computer is having internal electrical problems with the motherboard
• Your
hard drive cables have become unplugged
Monitor
Monitors are of two types, Cathode Ray Tube (CRT) and flat
panel Liquid Crystal Device (LCD). Monitors gather dust quickly due to static
charge generation. Therefore, the outer case and screen require regular
cleaning.
The correct way to clean the monitor depends on the type of
monitor:
CRTs: Use a cloth
dampened with water or a mild window cleaning solution to wipe the glass screen
and clean the monitor case. Alternatively, you can use moistened paper towels
to clean them. Do not spray any liquid directly on the screen. Never open the
monitor case which contains electric voltage that can cause a shock.
LCDs: Use a soft, dry cotton cloth or a small amount of isopropyl
alcohol with dampened cloth to remove finger prints and smudges from an LCD
screen. To avoid any damage, do not use paper towels, sharp objects, and strong
cleaners such as ammonia to clean an LCD screen.
Note
Gas Plasma: Another
popular monitor type is Gas Plasma. Gas Plasma display is a type of flat
display screen, called a flat-panel display. It is used in some portable
computers. Images on gas plasma displays generally appear as orange objects on
a black background. Although gas plasma displays produce very sharp monochrome
images, they require much more power than the more common LCD displays.
Static Charge is generated between materials through friction,
pressure, or separation of two materials. One material out of the two materials
is generally non-conductive.
Printer
• A
printer accumulates dust particles while printing.
• Bits
of paper also gather inside the printer.
• The
dust particles and bits of paper produce electrical charge that is harmful for
the components of the printer. The dust particles are also responsible for
mechanical wear and tear of the components of the printer.
• To
avoid this, insert papers with clean edges and stack them evenly in the printer
tray.
• Remove
bits of paper that are stuck in the printer using tweezers.
• If
you open the printer for repair, clean it using a vacuum cleaner.
Mechanizing
Preventive Maintenance
Automating Preventive
Maintenance
As you have seen in the previous sections, preventive
maintenance also includes activities related to software maintenance. The
advantage of software-related preventive maintenance activities is that they
need not be performed manually. You can automate them. There are system tools
that automatically run programs at a specific time. However, you need to set up
the system to perform various software checks and maintenance activities.
Operating systems are capable of mechanizing these activities or third-party
utilities can be used to perform these activities. These maintenance activities
result in increasing the performance and safeguarding the data of the computer.
The following software-related activities can be mechanized:
• Error
checking in file system and hard disks
• Virus
scanning in files and hard disks Defragmenting
hard disk volumes
Need for Creating PM
Schedule
• For
preventive maintenance measures to be effective you need to plan them in
advance But you tend to forget the exact time of carrying out PC preventive
maintenance activities. Therefore, it is important to create a preventive
maintenance schedule and use it for reference.
• PM
schedule is a chart that shows various maintenance activities and their
frequency.
• You
can modify the schedule as and when required.
• After
setting up a schedule, you can translate it to actual dates, which will help
you remember date and time to perform various preventive maintenance activities
Implementing Safety Measures and Procedures ESD Precautions and
Procedures
Danger Posed by ESD
Always perform PC preventive maintenance activities with a
lot of care. Otherwise, it can cause harm to you as well as the PC. Always be
very careful with Electro-Static Discharge (ESD).
• ESD
is most prevalent in dry, low humidity environments.
• It
occurs when two objects of dissimilar charge come in contact with each other
such as your body and a computer component.
• To
equalize the electrostatic charge, the two objects exchange electrons. The
object with the higher charge, your body, passes voltage to the object of lower
charge, the electronic component.
• ESD
of 10 volts can damage computer components such as Complimentary Metallic Oxide
Semiconductor (CMOS) chips because these chips contain a thin metal oxide layer
that is hypersensitive to ESD.
• Dirt
and dryness contribute to ESD. Dirt holds the charge, and dryness in the
atmosphere increases the ability of dirt to hold this charge.
ESD Protection
Devices
ESD is a natural phenomenon so
it cannot be eliminated. But, you can use various ESD protection devices such
as antistatic wrist strap, antistatic bags, ESD static mats, and antistatic
sprays to prevent damage to PC components.
Antistatic Wrist
Strap: Or ESD strap is made of an insulated material with a wire attached
to it. Attach one end of the ESD strap to an earth ground that is the ground
pin on an extension cord and wrap the other end around your wrist. The strap
consists of a resistor that provides protection if the wire touches a charged
object
Antistatic Bags: Are
designed to collect static charges on the outside of the bags rather than on
the electronic components. These bags keep the dust and stray charges away from
the computer components when they are being shipped or stored
ESD Static Mats: Is
also made of an insulated material and has two wires with alligator clips, one
at the end of each wire. Spread the mat on a flat surface near the ground.
Attach one clip to the ground and the other to the computer. This ensures that
the charge is transferred from the computer to the ground.
Antistatic Sprays:
Are used on carpets to reduce ESD. Thus, they prevent the damage to the
computer components.
Apart from using these ESD protection devices, you can take
the following precautions to prevent damage posed by ESD to computer
components:
•
Do not plug in or remove devices when the power
is on
•
Store PC cards, chips, and other PC components
in appropriate anti-static containers such as envelopes and bags.
•
Have a reliable ground point so that you can
connect your body to it with a wrist strap.
•
Keep the carpets dust-free.
•
Wear shoes with rubber soles to get rid of
static charge.
•
Do not wear clothes made of synthetic material
because it is a conductor of charge.
•
Do not wear jewelry because metals are
conductors of electricity.
Maintain the relative humidity at around 50 percent.
Any power-on or
system startup failures or lockups
•
Spontaneous rebooting or intermittent lockups
during normal operation
•
Intermittent parity check or other memory-type
errors
•
Hard disk and fan simultaneously failing to spin
(no +12 V)
•
Overheating due to fan failure
•
Small brownouts that cause the system to reset
•
Electric shocks felt on the system case or
connectors Slight static
discharges that disrupt system operation
Erratic recognition of bus-powered USB peripherals
Situations that could
Present a Danger or Hazard
If you do not use ESD protection devices as per the
guidelines, you can harm yourself by getting a shock. Consider the following
situations:
•
An ESD strap is specially designed to drain
electric charges away and provide safety to you. For this purpose, it uses
1-megaohm resistor to drain the charge away. If, instead of using this safety
device, you wrap a simple wire around your wrist, you can get electrocuted.
•
An ESD strap can provide safety against low
voltage. If you wear an antistatic wrist strap when there is a possibility to
encounter a high-voltage capacitor, the strap could channel that voltage
through your body. Such situation could be working on the inside of a monitor
or power supply.
•
Antistatic bags are not designed to drain the
charges away. Do not use them in place of antistatic mats to transfer static
charge from the computer to the ground
PC Components posing
potential hazard and safety procedures related to them are as follows:
If you do not use ESD protection devices as per the
guidelines, you can harm yourself by getting a shock. Consider the following
situations:
Lasers: Lasers
are high-intensity light rays that can cause severe damage to human eyes,
including blindness. Therefore, never look directly into a laser beam of the
laser printer. If the radiation of the laser beam comes in direct contact with
skin, it can cause severe burns or even death, depending on the intensity. So,
avoid direct contact with laser beams. The laser beams used in printers and
CD-ROM drives are of significantly low intensity but as laser printers generate
excessive heat, be careful when handling the inside of the printer. To avoid
the damage to parts of a laser printer, such as the EP cartridge, do not touch
them. Do not put any object into the feeding system when the printer is
running. High-voltage equipment: High-voltage
equipment is extremely hazardous. Carelessness while working with them can lead
to shock, severe burns, or electrocution. The potential damage due to
mishandling of the equipment is written on the warning or caution label that is
stick to the equipment. As a safety measure, read the documentation provided by
the manufacturer before you start working with high-voltage equipment. Ensure
that you are properly grounded to get rid of static charge and to prevent the
equipment from any damage.
Power supply: The
power outlet provides alternating current (AC) and the Power Supply Unit (PSU)
converts it into direct current (DC) to be used by your computer. During
conversion, a significant amount of heat is generated, which can cause burns if
you come in direct contact with it. If you try to open the PSU, which contains
capacitors that store electric charge, there is a risk of shock or
electrocution.
Ensure that you switch off the main power when you are not
using your computer. Allow the PSU to cool before you start working on it
A bad power supply can be the
root of many PC problems. Experience can help a tech diagnose problems caused
by a faulty power supply that would normally be overlooked by a novice. This
article outlines how to diagnose a faulty supply by testing its voltage
outputs, as well as how to replace the defective unit.
The symptoms
Just about any intermittent problem can be caused by a
faulty power supply. I normally look there first when the symptoms are a little
weird.
Common power-related symptoms include:
•
Any power-on or system startup failures or
lockups
•
Spontaneous rebooting or intermittent lockups
during normal operation
•
Intermittent parity check or other memory-type
errors
•
HDD and fan simultaneously failing to spin (no
+12V)
•
Overheating due to fan failure
•
Small brownouts that cause the system to restart
Electric
shocks that are felt when the case is touched
There are also some clues that should lead you to suspect a
faulty power supply. These include:
•
A system that is completely dead (nothing
happens when the system is turned on)
•
Smoke
•
Circuit breakers popping when the PC is turned
on
Measure the output
voltages
One of the simplest tests you
can perform on a power supply is to measure the output voltages. This will show
whether the supply is operating correctly and if the supplied voltage is within
the proper tolerance range. Note that you must check the output voltages while
the supply is under a load, which means that it will be installed and running
in the PC.
Caution: Power
supplies can be dangerous
I do not recommend that any inexperienced person open the cover
of a power supply. Even when unplugged,
a supply should be considered dangerous. Capacitors can maintain a line
voltage charge for a considerable period of time. Shorting one by mistake feels
just like being electrocuted by 120 volts from a receptacle. If you are unsure or uncomfortable with
working around high voltage,don’t!
Potential Hazards and
Safety Procedures
CRT monitors: A
CRT monitor is high-voltage equipment. It contains capacitors that store static
charge for a long time even when the CRT is disconnected from the mains.
This static charge can be fatal.
•
As a safety measure, call a certified monitor
technician, who can discharge the monitor before examining, to repair the CRT.
•
Handle the monitor very carefully, as it is
vacuum-sealed. If the glass breaks, it might implode violently.
• Keep
your monitor switched off when not in use, even if your computer has energy
saving settings enabled. Tip
To discharge a monitor, you
need a flat screwdriver with a well-insulated handle and a piece of metal wire.
Tie one end of the wire to the metal part of the screwdriver and the other end
to the frame of the monitor. Touch the metal end of the screwdriver under the
anode boot of the monitor. A flash and a loud popping sound indicate that the
monitor has been discharged. Remove the residual charge by repeating this
procedure.
Protecting the
Environment
Environment Friendly Disposal Procedures
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Every computer component has a life span after
which it needs to be replaced. Once you replace a component, you need to know
how to dispose of it. You cannot dump all of these components in landfills,
because some components, such as CRTs, batteries, wiring, and toner cartridges,
contain harmful chemicals. Monitors contain several carcinogens and phosphors,
as well as mercury and lead. Printers contain plastics and chemicals such as
toners and inks. The computer itself contains several lubricants and chemicals
as well as lead.
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These chemicals can seep into the water table
and contaminate our drinking water, resulting in adverse effects on the central
nervous system of human beings, animals, and plant tissues. These chemicals
also have adverse effects on the environment.
• To
protect the environment from these hazardous substances, you need to dispose
them of by following the procedures that are environment friendly such as
recycling the component or substance. Note
Carcinogens are harmful substances that can cause cancer.
Environment Friendly Disposal Procedures
Batteries:
Batteries contain several chemicals, such as nickel and lead that are harmful
to the environment. These chemicals do not degrade safely, so you must not
throw them. Instead, you should recycle batteries.
CRTs: A CRT
contains phosphors on the inside of the screen that can harm the environment if
placed in a landfill. The size of the CRT also takes up a lot of space in a
landfill. You must dispose of a monitor at your local hazardous-waste recycling
center.
If the monitor is damaged and is not in working order, you
can contact companies that buy monitors for spare parts or melt them for scrap
metal.
Ink and Toner
Cartridges: Ink and toner cartridges should be disposed off at recycling
centers. You can also sell them to companies that refill and reuse them.
However, re-use is not always advisable since it may harm the device or lower
the print quality.
Chemical Solvents and Cans: The most common cleaning chemicals used
for computers are alcohol and water, neither of which is particularly hazardous
to the environment. You can dispose them easily. As consumers, you can promote
the proper disposal of computer equipment:
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Check with the manufacturer if they take back
outdated equipment or parts.
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Reuse the parts that are in working condition.
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Check out businesses that can melt down the
components for the lead or gold plating
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Contact the Environmental Protection Agency
(EPA) to get a list of local or regional waste disposal sites that will accept
used computer equipment.
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Check with local nonprofit or education
organizations interested in using the equipment.
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Material Safety Data Sheet (MSDS)
Each type of equipment that
has a potential environmental risk associated with it has a MSDS. It provides
information on hazardous chemicals present in various materials. The topics
include composition of ingredients, handling and storage methods, lethal dose
information, and toxicology and ecology. The aim of MSDS is to inform people
about the adverse effects of various chemicals and how to properly handle these
chemicals.
General Hardware
Troubleshooting Tips
Regardless of the problem there are a few steps that must be
taken whenever troubleshooting a hardware problem. Here are some quick steps:
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Power
Cords - Make sure that all of the power cords are firmly in place on all of
the devices that could possibly be causing or attributing to the symptoms you
are experiencing. Then trace the cords back to the wall and make sure that the
other end of the cord is attached to a power outlet.
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Outlet
Power - if the outlet in question is not receiving power then you should
not expect devices connected to the computer to receive power. You can test
this simply by looking at the device and seeing if any LEDs (Light Emitting
Diodes) are lit. Try plugging in a device that you know works into the outlet.
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Power
Button - Some devices have two power switches on them, and both must be in
the "on" position in order for the device to work.
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Communication
Connections - Make sure that these cables are firmly connected at each end,
and to the correct port/interface.
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Device
Configuration - There may be jumpers
or switches on the hardware that need to be configured. If they accidentally
got moved or switched the device would fail to work properly. Make sure that
the software configurations are compatible with what you are trying to
accomplish. Follow Instructions - Computers are not evasive when they report
errors. Many times there are suggestions on how to fix a problem accompanied
with an error message. Simply follow the steps the message suggests.
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Windows
Recognition - If you go into the Control Panel, open the System dialog,
click on the Hardware tab, and then open the Device Manager, you will see a
tree-like structure of all of the hardware that is attached to your computer.
Look under the appropriate category and click on the item/items that you are
having problems with then click on properties. The dialog that opens will
inform you if the operating system is having any know troubles with the device.
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Update
Drivers - If possible, connect to the internet and go to the manufacture's
web site to download the latest drivers for your hardware. Often conflicts can
arise when you install new hardware and software; although these are
unanticipated, once found the developer will fix the problem and post updated
drivers.
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Refresh
Device Manager/Reinstall Device - Open the device manager again and delete
the devices that are not working properly. You will probably be prompted to
restart your computer, if not restart it manually.
Windows Shutdown
Problems
If your computer does not shut down try these tips:
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Try pressing CTRL-ALT-DEL and see if the
computer responds.
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You can usually tell if your computer won't
shutdown for good if you press the "Num Lock" key and the light on
the keyboard shows up.
• Manually
shut off the computer by cutting power to the computer or holding the power
button for longer than 9 seconds (shorter for some computer systems). Computers
usually don't shut down because:
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A program on Windows won't allow itself to be
turned off, is stalled, or is waiting for another program to turn off before it
can shut down, etc.
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A virus is present on your computer.
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A person on the internet or a network
administrator is preventing your computer from shutting down.
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A piece of computer hardware has not finished
its task and needs to do so before shutting down
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You have faulty computer hardware
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There are older or poorly written software
programs on your computer.