The RTC battery provides power to keep the current date, time and other setup information in memory (CMOS memory) while the computer is turned off. Charging time and data preservation period of the RTC battery depend on the specific PC model. Note that not all PC's support charging dedicated RTC batteries (depending on the type of dedicated RTC battery). For details, please refer to the user's manual.

     Dedicated RTC battery mounted on a mainboard

When the power is turned on, the system performs the power-on self-test (POST). The POST tests each IC on the system board and initializes it. If one of the following error messages is displayed on the screen, press a key or button specified by the message. If you press the key or button, the SETUP screen will appear. Set the correct date and time.

In case such an error message appears repeatedly at power-on, replace the battery pack or RTC battery (in case your PC is equipped with a dedicated RTC battery).

   Error messages associated to a defective battery pack or RTC battery

• (a)**** Date and Time reset to default ****
  Press [F2] key to set Date and Time.
  
• (b)**** Date and Time reset to default ****
  Press Windows button to set the Date/Time in OS.
  
• (c)**** Date and Time reset to default ****
  Press ENTER to set Date and Time.

Please check Resolution section below for further information about charging or replacing the battery pack or RTC battery.

To resolve above described error messages, depending on your PC, charge either the main battery or RTC battery. In case your PC is equipped with a dedicated RTC battery, which support charging (please refer to the user's manual), let the PC powered on for several hours to charge it.

Should the error message still be shown, contact   dynabook Service to either replace the battery pack or RTC battery.

To resolve above described error messages, depending on your PC, charge either the main battery or RTC battery. In case your PC is equipped with a dedicated RTC battery, which support charging (please refer to the user's manual), let the PC powered on for several hours to charge it.

   Charging the RTC Battery

In case your PC is equipped with a dedicated RTC battery, which support charging, let the PC powered on for several hours to charge it.

The RTC battery will only be charged under following conditions *:

1. Unit is attached to AC power
2. Main battery is fully charged
3. Let the PC powered on for several hours to charge it
   
      Sample text contained in a user manual
   

For further details, please refer to the user manual for your PC, which can be downloaded via https://emea.dynabook.com/support/manuals/.

Should the error message still be shown, contact   dynabook Service to either replace the battery pack or RTC battery.

* Depending on the specific PC model. For details, please refer to the user manual of your PC.