Cisco XR 12404 - Manual (Page 107)

4-9
Cisco XR 12404 Router Installation Guide
OL-13830-02
Chapter 4 Troubleshooting the Installation
Troubleshooting the DC Power Subsystem
• If no, but the fan assembly is operating, suspect a faulty power supply
INPUT OK LED. If the fan assembly is operating, all internal DC voltages
are within tolerance. Use the show environment command to check the
voltages on each card. The fan assembly uses –48 VDC.
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.
Troubleshooting the DC Power Subsystem
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 the
PEM. The INPUT OK LED on an DC PEM is on when DC power is applied, The
OUTPUT OK LED is on when the power switch is turned on.
• The amber OUTPUT FAIL LED is normally off, but comes 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 PEM.
todd.book Page 9 Monday, March 16, 2009 2:47 PM