Cisco XR 12404 Installation Manual page 102

Identifying Startup Problems
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Cisco XR 12404 Router Installation Guide
4-4
All internal DC voltages are within tolerance.
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If the AC power source or any of the internal DC voltages exceed
allowable tolerances, the OUTPUT OK LED shuts off, or will shut off
shortly after you turn on the power. Because both the RP (which uses
+2.5, +3.3 and +5 VDC), and the fan tray assembly (which uses –48
VDC) are required for operation, a problem with any of the internal DC
lines can prevent the system from starting up or continuing operation.
For example, if there is a problem with the –48 VDC line that supplies
the fan tray, the system powers up, but will also recognize that the fans
are not operating. The system will initiate a fan failure shutdown
sequence, display the appropriate warning messages, and then shut down
after two minutes.
If there is a problem with any of the other DC lines, the RP will not be
able to initialize the system software, so the system might attempt to start
up and fail during the boot sequence.
The fan tray immediately begins operating.
The alphanumeric LED displays on the RP indicate the following:
– The left display indicates which RP software component is running.
The right display indicates the phase of the boot process that is currently
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occurring.
Chapter 4 Troubleshooting the Installation
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