The system battery maintains system configuration, date, and time information in a special section of memory when you turn off the system. The operating life of the
battery ranges from 2 to 5 years, depending on how you use the system (for example, if you keep the system on most of the time, the battery gets little use and thus
lasts longer). You may need to replace the battery if an incorrect time or date is displayed during the boot routine along with the following or similar message:
Time-of-day not set -- please run SETUP program
Strike the F1 key to continue, F2 to run the setup utility
or
System CMOS checksum bad -- Run SETUP
Strike the F1 key to continue, F2 to run the setup utility
or
Invalid configuration information -- please run SETUP program
Strike the F1 key to continue, F2 to run the setup utility
To determine if the battery needs replacing:
1. Reenter the time and date through the System Setup program.
2. Turn off and disconnect the system from the electrical outlet for a few hours.
3. Reconnect and turn the system on again.
4. Enter the System Setup program.
If the date and time are not correct in the System Setup program, replace the battery.
You can operate the system without a battery; however, the system configuration information maintained by the battery in NVRAM is erased each time you shut down
the system. Therefore, you must reenter the system configuration information and reset the options each time the system boots until you replace the battery.
The battery is a 3.0-volt (V), coin-cell battery. To remove the battery, perform the following steps.
NOTE: Some software may cause the system time to speed up or slow down. If the system seems to operate normally except for the time kept in the System
Setup program, the problem may be caused by software rather than by a defective battery.
NOTE: If the system is turned off for long periods of time (for weeks or months), the NVRAM may lose its system configuration information. This situation is
not caused by a defective battery.
WARNING: Before you perform this procedure, you must turn off the system and disconnect it from its power source. For more information, see
"Safety First— For You and Your System" in "Troubleshooting Your System."
WARNING: There is a danger of a new battery exploding if it is incorrectly installed. Replace the battery only with the same or equivalent type
recommended by the manufacturer. Discard used batteries according to the manufacturer's instructions.