Question : Problem: CMOS checksum error

Ok here goes...
  Have a Biostar 8500TAC- A ver3 board with AMI BIOS.

   At first would only boot if I jumpered the "clear cmos" pins.

    Flashed the bios sucsessfully to: ver 77.22, date 7-15-95.
    I now can boot without jumper.

                     Problem is:
                     CMOS won't save settings after shutdown.

                     Settings can be changed and remain in effect until powered off.
                     Then on boot receive "CMOS checksum error, F1 to enter setup" . Or CMOS checksum Bad.

                     I get this anytime system is powered off, even when no settings are changed.

                     I should add that date & time remain correct.

                     I don't see any type of battery that I recognize, or external battery connector.
                     Board works fine otherwise and detects & installs hardware under win95.

                     Board has (3) Flash ROM Type Voltage select settings:
                     1. +5V type  Flash memory used
                     2. +12V type Flash memory used
                     3. Eprom used.

                     Have tried all 3 with no change.

                     What to do?
                     Thanks,
                     Pat
                                                                           

Answer : Problem: CMOS checksum error

some boards don't work with a "battery"
but with a cystal time chip , wich is soldered on the main board..
usualy these can be replaced , but it involves soldering on the board ,wich isn't easy..
if the mainboard is in warranty , probably not , return it ..
if not ... i would just live with it...