Don Wilkins said:
The system clock does not keep accurate time.
Does this mean it is time for a battery replacement on the MB? If so
am I asking for trouble if I remove the battery & it would be nice to
have the new battery present for immediate replacement. Model # for
battery would be even nicer?
Words of wisdom will be appreciated.
TIA
The P3V4X is an ATX motherboard. What this means, is when you shut down
at the end of the day, the board gets +5VSB power from the power supply
(unless you also flip the switch on the back of the computer case to
stop the power completely). If you find that the computer doesn't keep
good time while it is running from +5VSB, then the cause of the time
keeping problem might be elsewhere.
If you've done a clear CMOS operation on the motherboard, and neglected
to unplug the computer when doing it, sometimes the diodes that join
the CMOS battery to the +5VSB provided power get damaged. What this
does, is leaves the +5VSB disconnected from the Southbridge, so the
time keeping is always running from the CMOS battery. This could run the
CMOS battery down, which could cause time keeping trouble, or could
cause you to lose the BIOS settings if the computer is left unplugged
for a while.
The batteries on modern computers all tend to be the same -
CR2032 3V Lithium (Coin cell) available at Radio Shack, as noted in
the picture of the motherboard in the manual.
When new, they will give you 3 volts or slightly more. When run down,
some Southbridge chips can operate until the battery gets down to
about 2V or so.
To replace the battery, start by recording the BIOS settings on a
piece of paper. What you need to record is anything that you changed
from the default settings. There is supposed to be a small utility
for recording the settings (CMOS.exe?) which you might research in
Google, but I like the paper method.
Shut down and unplug the computer. Make sure that you make
contact with the metal of the computer case, to discharge any static
electricity. Handle the new battery with paper towel or something
similar, so no salt from you fingers is left on the battery - over
time this can mess up the contact to the battery in extreme cases.
The battery should be a force fit, so you pop out the old one and
pop in the new one. Take note of which end is (+) and put the
battery in with the same orientation.
There are reports here, that if you do this reasonably quickly, the
computer won't even lose any settings.
After the operation is complete, you can test the old battery with a
meter, to see if it was really exhausted. If you leave the power
switch on the back of the computer in the ON position all the time,
then the battery is not used to power the time keeping and the CMOS
settings. The battery is the sole source of power when the switch
on the back is OFF and/or the computer is unplugged. Like a watch
battery, you should be able to get several years of operation from
the battery, even if the computer is left neglected in a corner.
HTH,
Paul
