by eturo
In this article, you will learn about PC
computer cases and the various types that are available. You will learn about
the different parts of a computer case and the purpose of each, and you will
learn what type of motherboard is compatible with the type of computer case.
Next, you will learn about power
supplies and computer cases and the role of power supply in a PC, you will
learn how to remove and replace a power supply, as well as how to select a
replacement model if your power supply should fail. You will also learn about
the different kinds of power connections that come with a power supply.
Finally, you will learn why it is
important to keep the inside of your computer case cool.
A.
CASE FORM and
FUNCTION
Computer Case
¾
is
made up of metal (or sometimes plastic), it’s the box that houses all the
components and devices that make up a computer
External Size
One of the first issues to consider
when selecting a case is the external dimensions. The case you choose depends
on several interrelated factors:
o
Do
you plan to upgrade the system at a later date?
o
Who
will be using the system?
o
What
will be the final location on the system (for example, on top or beneath a
desk)?
Different
Types of Computer Cases
1. Full-Tower
Cases
¾
it
is likely to be the largest PC case (except for the massive server-style cases)
¾
at
least 2 feet tall that provides a maximum amount of interior space for a
variety of drives and expansion cards
¾
should
have at least four externally accessible drive bays for CD-ROM, CD-RW, and DVD-ROM
drives as well as two external floppy disk drive bays
¾ most full-tower cases have internal
space for at least three, and sometimes as many as five hard drives
2.
Mid-Tower Cases
¾
it
is very common because of the flexible design
¾
it
is usually stands about 20 inches high and has an average of three external
drive bays and one external floppy drive bay
¾
has
fewer internal drive bays, but it can sometimes hold a pair of hard drives
3. Mini-Tower
Cases
¾
usually
smaller and a little wider that a mid-tower case
¾
provide
the least amount of interior cooling so they are not the best choice
¾
have
only two external drive bays and one internal bay
4. Desktop
Cases
¾
it
lies flat on its larger side means that they are designed to sit on a desk with
a monitor resting on top of it
¾
usually
does not provide much capacity for expansion
5. Server
Cases
¾
usually
quite large with plenty of bays and expansion slots
¾
rather
than favoring in rectangular design like tower case, they tend to be in square
6.
Rack-Mount Cases
¾ used
exclusively by businesses that need a space-efficient way to organize large
numbers of servers
¾
they
are sized by unit (a single unit is 1.75 inches high)
¾
described
according to the number of units (U’s – multiple of 1.75 inches) high they are
§
example:
a 3U case is 5.25 inches high (3 x 1.7 inches)
¾
Note:
Even though rack-mount cases have different heights, they are always 19 inches
wide to fit into standard equipment racks.
Drive Bays
¾
these
are special areas to hold storage drives found in all cases
Two types of drive bays:
§
external
bays – have openings that enable to be accessed from outside the case
¾
used
to hold components like floppy disk drives and CD-ROM drives
§
internal
bays – used to hold internal components like hard drives
¾
comes
with two widths: 3 ½ inches and 5 ¼ inches
Ø
3
½ - Inch Bays
o
normally
used for a floppy drive and for hard drives
Ø
5
¼ - Inch Bays
o
back
to the days when computers used only 5 ¼ - inch floppy disk drives
o
this
bays remain because it is used for optical media like CD-ROMs and DVD-ROMs
drives
¾
rails (drive rails) – is used to mount new devices in
drive bays
Back Plates
¾
a
metal plate punched at the back of a case with a specific set of holes designed
to allow various external connectors on the motherboard to punch through the
back of the case
Nice to Know!
One way of
determining whether a computer case will accept the type of motherboard you
plan to use is by looking at the back plate to see if the holes match your
motherboard’s external connectors.
Screws and Stand-offs
Types of screws:
§
fine-threaded
screws – are used almost exclusively for mounting CD media drives
§
coarse-threaded
screws – used to mount all other devices which usually come in large and small
size
•
larger
mounting screws have a hexagonal head with notches for a Phillips-head
screwdriver
•
smaller
mounting screws usually have either hexagonal or rounded heads
§
stand-off
screws – are designed to be attached to the inside walls of the case and fit
through holes in the motherboard
Case Form Factors
¾
the
type of case you buy depends on the type of motherboard you want to use
¾
when
building a computer, you should first choose the motherboard and then a case of
the corresponding form factor to go along with it
Four Main Form Factors for Cases and
Motherboards:
§
AT
¾
this
form factor used in older computers
¾
not
many cases are built for AT motherboards anymore because they are now obsolete
§
ATX
¾
these
are the most common form factor found in modern PCs
¾
it
can fit into any tower case, as well as into desktop and some larger rack-mount
cases and even in server cases
§
microATX
¾
these
case form factors are available ranging from mid-tower and mini-tower cases to
desktop cases
¾
designed
specifically to accommodate businesses use as a file server
¾
mid-tower
and mini-tower cases can accept both ATX and microATX
§
FlexATX
¾
the
smallest ATX form factor
¾
FlexATX
motherboard form factor was created specifically for 1U rack-mount cases
