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Cisco UCS C24 Server Installation and Service Guide
OL-26647-01
Chapter 2 Installing the Server
Service Headers and Jumpers
Using the Clear CMOS Header CN14
See Figure 2-5 for the location of this header. You can jumper this header to clear the server’s CMOS
settings in the case of a system hang. For example, if the server hangs because of incorrect settings and
does not boot, use this jumper to invalidate the settings and reboot with defaults.
Caution Clearing the CMOS removes any customized settings and might result in data loss. Make a note of any
necessary customized settings in the BIOS before you use this clear CMOS procedure.
Step 1 Power off the server as described in Shutting Down and Powering Off the Server, page 3-6.
Step 2 Disconnect all power cords from the power supplies.
Step 3 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.
Step 4 Remove the top cover as described in Removing and Replacing the Server Top Cover, page 3-7.
Step 5 Move the shorting jumper to pins 2 and 3 of the CN14 header (see Figure 2-5).
Step 6 Reinstall the top cover and reconnect AC power cords to the server. The server powers up to standby
power mode, indicated when the Power LED on the front panel is amber.
Step 7 Return the server to main power mode by pressing the Power button on the front panel. The server is in
main power mode when the Power LED is green.
Note You must allow the entire server, not just the service processor, to reboot to main power mode
to complete the reset. This is because the state of the jumper cannot be determined without the
host CPU running.
Step 8 Press the Power button to shut down the server to standby power mode, and then remove AC power cords
from the server to remove all power.
Step 9 Remove the top cover from the server.
Step 10 Move the shorting jumper from header pins 2 and 3, back to its default position on pins 1 and 2.
Note If you do not move the jumper, the CMOS settings are reset to the default every time that you
power-cycle the server.
Step 11 Replace the top cover, replace the server in the rack, replace power cords and any other cables, then
power on the server by pressing the Power button.