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The CMOS memory
The BIOS uses the CMOS memory to store all the settings that have been made through the
BIOS Setup pages.
Battery
The CMOS memory remembers all settings, even when the system is switched off, by use
of a 3V Lithium battery. If this battery runs low CMOS is unable to keep its settings and
you will need to replace the battery. The BIOS will give you an error message when it
detects a low battery voltage. The error message ‘CMOS checksum error’ may also point to
a low battery problem.
Restoring default settings
You can load default values into the CMOS memory by selecting ‘Load Optimized
Defaults’ in the BIOS Setup. If you need to force the CMOS settings to default without
entering the BIOS Setup page you can use the JP6 jumper. For the location of the jumper
and the battery, refer to the following picture:
Battery
JP 4
Normally JP4 will be in the 2-3 position, this will connect the battery to the southbridge of
the chipset which contains the CMOS memory. If JP4 is temporarily set to 1-2 this will
interrupt the battery electricity flow, and the CMOS memory will be erased, this will
however only work if the power supply is not switched on. Now at the next reboot the
BIOS will automatically load the CMOS default values.
