Lenovo ThinkCentre M70c Hardware Maintenance Manual page 75

Your computer has a special type of memory that maintains the date, time, and settings for built-in features,
such as parallel connector assignments (configurations). A coin-cell battery keeps this information active
when you turn off the computer.
The coin-cell battery normally requires no charging or maintenance throughout its life; however, no coin-cell
battery lasts forever. If the coin-cell battery fails, the date and time information is lost. An error message is
displayed when you turn on the computer.
Replacement procedure
1. Remove the computer cover. See "Computer cover" on page 56.
2. Remove the front bezel. See "Front bezel" on page 57.
3. Remove the optical drive. See "Optical drive" on page 60.
4. Remove the hard disk drive. See "Hard disk drive" on page 62.
5. Remove the coin-cell battery.
6. Install the coin-cell battery.
7. Reinstall all the removed parts. Then, reconnect the power cord and all disconnected cables to the
computer.
8. Reset the system date and time in the UEFI BIOS menu.
.
Chapter 6 Hardware removal and installation
69