|
A computer needs a certain
amount of information to operate; for example, the date
and time, the amount of memory installed, the number of
drives and their configuration, and so on. In the early
days of computers, either the user typed in this
information each time the computer started, or it was set
using DIP switches and jumpers. Today, computers store
this information in a CMOS chip that uses a small battery
to retain the information when the computer is shut off.
CMOS (complementary metal
oxide semiconductor) is type of chip that consumes very
little power; therefore, while the computer is turned off,
the battery discharges very slowly. But the battery will
totally discharge if you leave your computer turned off
for a year or so. Even if you turn your computer on every
day, the battery is designed to last only a couple of
years. Occasionally a battery will fail prematurely.
Today's plug-and-play
computers can detect most of the necessary settings, but
if your CMOS battery is dead, your computer will not be
able to retain the date and time. The computer will also
lose any custom settings, for example, the boot sequence.
If you set a password in CMOS, you may be locked out of
the computer. If the CMOS battery does fail, you might
receive the message "System Configuration Lost"
when you start the computer. It would be wise to record
all the CMOS settings as a precaution.
To record the CMOS
settings, watch for an on-screen prompt when you first
start your computer. The prompt tells you to press a key,
usually the Del or F2, to enter CMOS. To enter the CMOS
configuration utility, you have to press the indicated key
while the message is on the screen. After the CMOS
configuration screen appears, follow the instructions
provided to page through all the screens and record all
the settings.
If your computer loses its
time setting overnight, the CMOS battery may not be
holding a charge. The CMOS battery is located inside the
case on the motherboard. Changing the battery is usually a
job for a computer technician. In fact, a layman might not
even be able to find the battery.
If you want to locate the
CMOS battery in your computer, be aware that a static
discharge from your hands can damage components inside the
case. After taking proper precautions, open the case and
look on the motherboard for a battery. If you have a
diagram of your motherboard, locate the battery on the
diagram first.
Different motherboards use
different types of batteries. The battery may be shaped
like a barrel or a coin. Some motherboards use a component
that resembles a chip which contains the CMOS and the
battery (made by DALLAS or Benchmarq). Batteries come in
different voltages, so make sure you get an exact
replacement.
Sometimes the battery is
mounted in a holder. Sometimes it is soldered to the
motherboard. De-soldering and re-soldering a battery is
usually a job for a computer technician. An inexperienced
solderer can cause a lot of damage. If you want to try to
do it yourself, first practice on an obsolete circuit
board. You may change your mind.
If the CMOS battery has
failed because it's too old, this might be an opportunity
to upgrade your motherboard. When upgrading a motherboard,
the most important considerations are to make sure the new
motherboard is the correct form factor for your case, and
that the new motherboard has the correct bus connector
slots for your expansion boards.
Copyright(C) Bucaro TecHelp
Permission is granted for
the below article to forward, reprint, distribute, use for
ezine, newsletter, website, offer as free bonus or part of
a product for sale as long as no changes are made and the
byline, copyright, and the resource box below is included.
|
