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Cisco ASR 903 Router Hardware Installation Guide
OL-25178-05
Chapter3 Installing the Cisco ASR 903 Router
Installing the Power Supply
Step1 Follow the steps to remove the power supply unit if installed in the chassis. See Removing and Replacing
the DC Power Supply, page3-26.
Step2 Locate the T-shaped terminal block plug on the DC power supply unit. See Figure 1-3.
Step3 Use a wire-stripping tool to strip the ends of each of the two wires coming from the DC-input power
source to 0.27 inch (6.6 mm) ± 0.02 inch (0.5 mm) and the wire for grounding. Do not strip more than
0.29 inch (7.4 mm) of insulation from the wire. Stripping more than the recommended amount of wire
can leave behind exposed wire from the terminal block after installation.
Step4 Prepare the cables by attaching the lugs to the cables.
Step5 Identify the ground, positive, and negative feed positions for the terminal block connection. The
recommended wiring sequence is
Negative (-) lead wire (top)
Ground lead wire (left)
Positive (+) lead wire (right)
Step6 Insert the lugged end of the cables to the connector and secure the cables using the captive screws.
Note The recommended torque for securing the captive screws is 0.7 N-m.
Step7 Ensure that the terminal block plug is fully seated in the terminal block header on the DC power supply
panel. See Installing the DC Power Supply, page3-21 for installing the power supply unit into the
chassis.

Activating the DC Power Supply

Perform the following procedure to activate the DC power supply:
Step1 Remove the tape from the circuit-breaker switch handle, and restore power by moving the circuit-breaker
switch handle to the On (|) position.
Step2 Verify power supply operation by checking if the power supply front panel LEDs are in the following
states:
INPUT OK LED is green
OUTPUT FAIL LED is green
If the LEDs indicate a power problem, see Chapter5, “Troubleshooting.”
If you are installing a redundant DC power supply, ensure that each power supply is connected to a
separate power source in order to prevent power loss in the event of a power failure.
If you are installing a redundant DC power supply, repeat these steps for the second power source.
Removing and Replacing the DC Power Supply
This section provides information about removing and replacing the DC power supply in the
CiscoASR903Router.