30D forgetting the date!

My 30D is asking me to set the date every time I turn it on... is there a battery somewhere I need to change?

Thanks

There's a button-cell (2016?) used as backup, that's probably flat. Dunno about the 30D, but on a 300D or 40D the button-cell can be found in the battery compartment of you camera, opposite side from the door-hinge.

Just had a check and it's in the same place on the 30D as well... thanks!

thanks for the info