Cisco GSR12/60 - 12012 Router -AnyLAN, SONET/SDH Installation And Configuration Manual page 271

Perform the following steps to verify that the DC-input power supply powers up correctly.
Step 1 Turn the power supply power switch to ON (|).
Note Turning the power supply switch to ON (|) engages a latch that secures
the power supply in the power supply bay.
Verify that the Cisco 12012 powers up correctly. Visually check that the
Step 2
DC-input power supply input OK LED goes on and stays on.
Visually check that the power supply output fail LED flashes on and off for five
Step 3
seconds, then goes off.
•
If the output fail LED remains on, suspect a power supply failure or an
adverse environmental condition (the power supply has detected an
overvoltage or overtemperature condition and has shut down).
•
If two power supplies are installed, and the output fail LED goes on only on
one power supply, assume that the power supply or DC source (for that power
supply) is faulty.
•
If the output fail LED goes on, on two power supplies that are connected to
separate DC sources, assume that an overvoltage or overtemperature
condition is causing the power supplies to fail.
If the power supply fails to operate properly after several attempts to power it up, contact a
service representative for assistance.
Removing and Replacing a DC-Input Power Supply
Maintaining the Cisco 12012 7-31