Acer Aspire 5000 RTC/CMOS battery?

I have one of these laptops, and on power up it sometimes tells me at the boot screen that the prior boot was unsuccessful, and the default settings will be used. When I go into the CMOS, it does not retain the date, time, etc. I have had the laptop apart to replace the power jack, but did not see a CMOS battery anywhere on the motherboard. Has anyone had this problem before, or does anyone know the location and type of CMOS battery this model uses?