Cisco GSR12/60 - 12012 Router -AnyLAN, SONET/SDH Installation And Configuration Manual page 220

Troubleshooting the Power Subsystem
The AC-input and DC-input power supplies are monitored by the MBus module and the RP
for internal temperature conditions and for overvoltage and overcurrent conditions.
Continue by checking the following to help isolate the problem with the power subsystem:
•
Are the power supply input OK LEDs on?
— If yes, the power source is good, and the power supplies are functional.
— If no, but the blower modules are operating and the alphanumeric LED displays on
— If no and there is not other obvious activity, first suspect that the power supply
— If the power supply power switch is set correctly and the input OK LED remains
5-8 Cisco 12012 Gigabit Switch Router Installation and Configuration Guide
the RP and line cards are on, suspect a faulty power supply LED. The MBus
modules driving the alphanumeric displays are powered by +5 VDC directly from
the power supply, and the blower modules use –48 VDC; therefore, if both the RP
and the blower modules are operating, all internal DC voltages are within tolerance.
Use the show environment command to check the voltages on each card.
power switch is not fully in the ON (|) position. Rotate the power supply power
switch clockwise and ensure that it is set completely in the ON (|) position.
off, suspect the AC (or DC) source or the power cable. Turn the power supply power
switch OFF (STANDBY on an AC-input power supply), and check the source AC
(or DC) circuit breaker. Verify that the breaker is on and has not tripped. Verify that
the source AC (or DC) circuit breaker has the proper current rating. Each power
supply in the Cisco 12012 should be attached to a separate power source. In the case
of systems powered by source AC, there might be an uninterruptable power supply
(UPS) for each AC-input power supply in the system. Check that the UPS is
functioning correctly.
Check the power cable or power cord from the power source to the Cisco 12012.
Verify that it is in good shape and is not damaged. If the insulation appears cracked
or broken, or the plugs appear loose, do not use the cable. Immediately replace it
with a new cord or cable.