HP Compaq nc6220 Maintenance And Service Manual page 155

7. Disconnect the RTC battery cable 1 from the system board.
8. Remove the RTC battery 2 from the clip in the top cover.
✎
The RTC battery is included in the Miscellaneous Plastics Kit,
spare part number 379812-001.
Removing the RTC Battery
9. Position the computer with the rear panel toward you.
Maintenance and Service Guide
Removal and Replacement Procedures
6–53