How To Recognize And Repair Computer Power Supply Problems
Otis Cooper

The Computer Power Supply convert's your regular household current into
low DC voltage used by the computer. When this component
fails, there is simply no activity going on with your
computer. Remember to do the easy troubleshooting first. Inspect
the Power Supply for any damage. Double-Check all connections.

Learning how to check your power supply and how to replace it
when needed can be a life saver if you're a computer buff or in
business with the trusted PC. Don't take for granted the simple
pleasure of turning on your PC and everything works just fine.

We turned on one of our computers recently and in about one
hour, it just re-booted itself. And it continued doing so about
10 times a day until we found out the power supply was the
culprit. Things to look for when your power supply is going bad
or just dies on you are the following.

NO POWER TO THE COMPUTER

Here you must first check the wall outlet for power by
connecting another device such as a radio or lamp to be sure
power is present .If the computer is connected through a surge
protector, check it as well.

If the wall out has power, check the power cable going to the PC
to see if AC voltage is making its way to the system unit. Do
this with the use of a multimeter.

If there is power ,you will have to open the PC and check for
power from the power supply to the motherboard.

When using a multimeter to check voltage, be sure you have a
good ground for the black lead of the multimeter.

RE-BOOTING PROBLEMS

One main problem you may face with an ailing Power Supply is
that it may re-boot the computer without any warning. All
information is lost and it seems as though this happens at the
worst possible time.

Booting errors when the computer first start's up is another
indicator of this component going on the blink.

POWER DISTRIBUTION PROBLEMS

When the power supply begins to fail, you may receive power at
one device and not another. For example, the Hard Drive may
receive power but the CD ROM Drive has nothing at all.

Another headache with would cause re-booting is the
intermittent power going to the drives or the motherboard
itself. Follow the steps below to check your power supply should
you experience some of the above problems.

CHECKING THE POWER SUPPLY

If the wall outlet, and the power cord are good, make sure the
connection at the motherboard is secure. Then you may have to
face the fact that the power supply itself is bad. If you have a
Multimeter you can test the power supply output before
purchasing a new one. Simply follow these steps.

Turn off the PC, but do not unplug it, open the system unit. Set
the multimeter to read DC volts in the next range higher than
12 volts. Locate a power connector similar to the hard drive, or
cd rom drive connector that is unused and turn on the PC.

You can also unplug a drive connector and use it as well. Turn
on the PC and insert the BLACK probe into the power connector
on one of the BLACK wires. Touch the RED probe to the YELLOW
wire on the power connector.

The multimeter reading should be +12 volts Now touch the RED
probe to the RED wire and the reading should be +5 volts. If no
readings or different readings occurred, you'll have to replace
the power supply. If the readings were correct, you should check
the P8 or P9 connectors at the motherboard. These connectors
may also be named P4 and P5.To check these connectors, perform
the following...

Insert the BLACK probe into P8 at one of the BLACK wires.
Insert the RED probe into the P8 connector at the RED wire. The
reading on the multimeter should be +5 volts

Check the power going to the Motherboard connections by
inserting the RED probe into P8 at the YELLOW wire and you
should get +12 volts. Leave the BLACK wire touching the black
wire at the P8 connector. Check the BLUE wire and the reading
should be a -12 volts.

Now move the BLACK probe to the BLACK wire on the P9
connector. Test the WHITE wire by inserting the RED probe and
the reading should be -5 volts. Check the RED wires on the P9
connector and you should get +5 volts on each red wire. You
won't get exactly 5 or 12 volts but the readings will be very
close, such as 5.02 volts.

If the Power Supply is a couple of volts off, in either
direction, such as when the RED wire should be reading -5 volts
but it reads -8 volts, or if there are no readings, replace the
power supply.

DO NOT remove the power supply from the system unit case when
performing these tests. DO NOT perform these tests if you do not
feel comfortable. Be sure to remove any and all electrical static
build-up from your clothes and body BEFORE touching any parts
inside the system unit. And NEVER open the power supply case for
any reason, since high voltage may be present.

About The Author: Otis F. Cooper is solely dedicated to
boosting the knowledge and confidence of every computer user.
Use his informative articles and videos to understand all about
the PC. Read more in depth articles for pc training and repair
at http://www.repairarticles.com


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