On page 99 of the schematic you can see the CMOS battery output labeled as RTC_AUX_S5. I did a text search for that and it took me to page 27 which shows VBACKUP. There are two partial circuits there. One appears to be for the CMOS battery backup and the other one, 3D3V_AUX_KBC, appears to be the backup power supplied when the unit is turned on. Both of these circuits point to EC GPIO72. Regarding the RTC_AUX_S5 diagram, there's an orange ellipse around the specifications for a resistor. It says 10mW 0R0402-PAD-2-GP. Might that be a fusible link? Also, I see the words "stuff" and "un-stuff" appearing frequently in the schematic. Are those synonyms for install and remove?
Thanks for your reply.