Troubleshooting A Dc Power Subsystem - Cisco XR 12406 Installation Manual

Chapter 4 Troubleshooting the Installation
Step 6

Troubleshooting a DC Power Subsystem

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Is the power supply DC LED on?
If yes, the power supply is functioning normally.
•
• If no, and there is no other system activity (blower module is off; line cards
are unpowered), the power supply is faulty and needs to be replaced.
If no, but the blower module is operating, it means all internal DC voltages
•
are within tolerance. Suspect a faulty DC LED.
Use the show environment command to check the voltages on each card.
–
The blower module uses –48 VDC.
In a Cisco XR 12406 router with two power supplies, the output power
Note
from the second power supply is adequate to maintain router operation.
If you are unable to resolve the problem or if you determine that either the power
supply or power cable is faulty, contact a service representative for assistance.
The DC PEMs and PDUs provide DC power to the router which is distributed to
the card circuitry.
Begin checking the power subsystem by first looking at the three LEDs on PEM.
The INPUT OK LED on an DC PEM goes on when DC power is applied; the
OUTPUT OK LED goes on when the PEM power switch is turned on.
The amber OUTPUT FAIL LED is normally off, but goes on if the PEM
•
detects a fault.
The DC PEMs are monitored by the MBus module and the RP for
•
over-or-under voltage and current conditions.
Figure 4-2 shows the location of the LEDs on the DC PEM.
Troubleshooting a DC Power Subsystem
Cisco XR 12406 Router Installation Guide
4-9