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Cisco UCS C420 Server Installation and Service Guide
OL-27640-01
Chapter3 Maintainin g the Server
Installing or Replacing Server Components
DIMM Replacement Procedure
This section includes the following topics:
•Identifying a Faulty DIMM, page3-26
•Replacing DIMMs, page 3-26

Identifying a Faulty DIMM

Each DIMM socket on the motherboard has a corresponding DIMM fault LED. See Internal Diagnostic
LEDs, page 3-7 for the locations of the LEDs and how to activate them.

Replacing DIMMs

To install a DIMM assembly, follow these steps:
Step1 Remove the DIMMs that you are replacing:
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” section on
page 3-9.
d. Remove the internal air baffle that covers the DIMM sockets.
e. Locate the faulty DIMM and remove it from the socket on the motherboard by opening the ejector
levers at both ends of the DIMM socket.
Step2 Install a new DIMM:
Note Before installing risers or DIMMs, refer to the population guidelines. See DIMM Performance
Guidelines and Population Rules, page3-21.
a. Align the new DIMM with the socket on the motherboard. Use the alignment key in the DIMM
socket to correctly orient the DIMM.
b. Push the DIMM into the connector until it is fully seated and the ejector levers on either side of the
connector lock into place.
c. Replace the internal air baffle, and then replace the top cover.
d. Replace the server in the rack, replace cables, and then power on the server by pressing the Power
button.