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Cisco UCS C420 Server Installation and Service Guide
OL-27640-01
Chapter3 Maintaining the Server
Installing or Replacing Server Components
Replacing the Motherboard RTC Battery
Warning
There is danger of explosion if the battery is replaced incorrectly. Replace the battery only with the
same or equivalent type recommended by the manufacturer. Dispose of used batteries according to
the manufacturer’s instructions.
[Statement 1015]
The CMOS real-time clock (RTC) battery retains system settings when the server is disconnected from
power. The battery type is Panasonic CR2032 or equivalent.
To replace or install the motherboard CMOS battery, follow these steps:
Step1 Remove the RTC battery (see Figure3-19):
a. Power off the server as described in Shutting Down and Powering Off the Server, page3-8.
b. Slide the server out the front of the rack far enough so that you can remove the top cover. You might
have to detach cables from the rear panel to provide clearance.
Caution If you cannot safely view and access the component, remove the server from the rack.
c. Remove the top cover as described in Removing and Replacing the Server Top Cover, page3-9.
d. Locate the RTC battery. See Figure3-19.
e. Bend the battery retaining clip away from the battery and use a pair of needle-nose pliers to pull the
battery from the socket.
Step2 Install the RTC battery:
a. Bend the retaining clip away from the battery socket and insert the battery in the socket.
Note The flat, positive side of the battery marked “+” should face the retaining clip.
b. Push the battery into the socket until it is fully seated and the retaining clip clicks over the top of
the battery.
c. Replace the top cover.
d. Replace the server in the rack, replace cables, and then power on the server by pressing the Power
button.