Reassembling the Computer
Same Way, Only Backwards
When it comes time to put a computer back together,
it's usually just a matter of reversing the order in which you
took it apart. Again, you're going to visualize each step because
there may be an easier way. Is it easier to install the motherboard
or the power supply first? Are the RAM DIMMs (or SIMMs) easier
to access before, or after the power supply is in. If the motherboard
pops out the back on a tray, then install the CPU and the RAM
before replacing the tray. If you install the power supply first,
then you may be able to clip the power connectors on as you
install the motherboard and tray.
When putting the computer back together (or
disassembling it for that matter), there are some basic tools
that you'll find handy. Of course, you'll need your ESD protection
equipment and a phillips screwdriver (keep a flat-head screwdriver
nearby, too. A small flashlight and a magnifying glass may come
in handy, as well as needle nose pliers. A useful device for
any kind of computer work is a small srewdriver with a phillips
head on one end and a flat-head on the other (I have no idea
what the proper name is for the tool). Once again, you're not
in a race. A good carpenter measures twice, and cuts once. When
working on computers you want to double-check everything you
install or connect. Before you start, make sure you have taken
all your ESD precautions. As you continue, make a conscious
effort to remain aware of these precautions.
The Power Supply
A fairly basic installation, just lineup the
holes and screw it on. Don't plug it in yet. Remember, the cable
going to the remote switch on the front of the case carries
110 volts AC. If you took the wires off the switch, make sure
you connect them just as they were before (I hope you documented).
A wrong connection here can burn up your PC. After your power
supply is installed, do not plug it in, you may not be able
to tell if the switch is on or off and you don't want to turn
the power supply on without a load.
DIP memory modules are the hardest
to install. Luckily, it's not done much anymore. SIMMs are inserted
at about a 45 degree angle then stoand up until they clip into
place. If they don't clip in properly, maybe you have them in
backwards. They'll usually have a key cut into one side. DIMMs
are keyed on the edge connector side, they can only be inserted
one way. Once they are lined up, push them down until the locking
tabs on the side come up. You may have to support the motherboard
from underneath if it looks as though its going to flex too
much. COAST modules are also keyed on the bottom and insert
much like an adapter card (Coast On A STick memory is cache
Luckily, CPU sockets aren't friction fit anymore.
If you have a PGA Central Processor (Pentium MMX or Celeron,
Cyrix or AMD), it will fit into a ZIFF (zero insertion force)
socket. Pin#1 on the chip has to be lined up with pin#1 on the
socket. This can be indicated on the socket with an arrow, a
#1 silk-screened on the board, or a flattened corner. Usually
the CPU will indicate pin#1 with a flattened corner (and, or
a dot on top, and, or an arrow on the bottom center of the chip).
Unclip and lift the handle, insert the chip, lower the handle
and clip it in. If it's a Pentium II or a Pentium III, it will
fit into a Slot 1 socket. These are rectangular in shape and
have 242 pins in two rows. They're keyed, and the cartridge
should only fit in one way. Check any documentation that came
with the motherboard or CPU, and refer to your notes.
Most PC cases will allow you to remove the metal
tray that the motherboard attaches to by removing 2 or more
screws. If you didn't do that during disassembly then you should
familiarize yourself with it now. The plastic standoffs
on the motherboard are to keep the solder-side of the board
from touching the metal case and shorting out. Usually, it's
better to install the RAM and CPU first to avoid the possibility
of flexing the board and cracking solder connections or traces.
Orient the motherboard properly and either clip in, or slide
in the standoffs until the mounting screw holes line up. Insert
the screws that hold the board in place. The screws need to
be snug, but do not twist them into the motherboard. You may
be able to connect the power to the system board as you install
the tray. A power supply with a baby-AT form factor will have
two motherboard connectors (P8 and P9). These connectors are
keyed but can be reversed. Make sure the black wires on the
two connectors are beside each other. Clip the keyed edge in
at an angle, then straighten the connector up and slide it on.
ATX power connectors slide in until the tab clicks. Once the
motherboard and tray are secured in place, you can re-install
the wires for the front of the case (refer to your documentation).
At this point, you can install the video card.
Do a final check on everything installed. Re-check all installations
and connections, attach and plug in the monitor. Turn the computer
on. Watch for lights on the front panel. How far does the BIOS
POST routine get? Are there any error messages? Is this expected?
One thing that I don't like to do is to completely
re-assemble a computer and then just turn it on. If it doesn't
work at that point, then you have to tear it all apart again
to find the problem. Once you've installed the power supply,
motherboard, CPU and RAM, install the video card, hook up the
keyboard and cables and start your computer. Of course, there's
no drives installed and some expansion cards are missing, so
you're going to get errors. But if it recognizes your video
card, counts the memory and allows access to you CMOS setup
program, then you know everything installed to that point is
working. Now, turn your computer on after installing each new
device. If you get an unexpected error, then it should be due
to the last device you installed.