Technical information

Troubleshooting Cisco 3900 Series, 2900 Series, and 1900 Series ISRs
Problem Solving
3
Cisco 2900 and 3900 Series Hardware Installation
– If yes, the router is receiving power. The fan is connected directly to the DC outputs of the power
supply.
– If no, check the power source and power cable.
• Does the router shut down after being on a short time?
– Check for an environmentally induced shutdown.
– Check the environmental site requirements in “General Site Requirements” (Cisco 3900/2900,
Cisco 1900).
• Router partially boots
– Check for a power supply failure by inspecting the SYS LED on the front panel of the router. If
the SYS LED is blinking or continuously green, the power supply is functional.
– If the SYS LED is not on, refer to “Obtaining Documentation and Submitting a Service
Request” for warranty information, or contact customer service.
Environmental Reporting Features
If the router is operating at an abnormally high temperature, consider the following causes:
• Fan failure
• Air conditioner failure in the room
• Air blockage to cooling vents. See the “Airflow Diagrams and Chassis Ventilation” (Cisco
3900/2900, Cisco 1900).
Take steps to correct the problem. Refer to “Preparing for the Installation” (Cisco 3900 and 2900 Series
Routers) and “Preinstallation Requirements and Planning” (Cisco 1900 Series Routers).
Troubleshooting Cables, Connections, and Interface Cards
Network problems can be caused by cables, cable connections, or interface cards, or by external devices
such as a modem, transceiver, hub, wall jack, WAN interface, or terminal. Check for the following
symptoms to help isolate the problem.
• Card is not recognized by the router.
– Make sure that the card is firmly seated in its slot.
– Check the LEDs on the card. Each card has its own set of LEDs. For information on these LEDs,
refer to Cisco.com online support for the individual card.
– Make sure that you have a version of Cisco IOS software that supports the card. Check the
Cisco.com online support document for software requirements for the interface card.
• Card is recognized, but interface ports do not initialize.
– Make sure that the card is firmly seated in its slot.
– Check external cable connections.
– Make sure that you have a version of Cisco IOS software and feature license that supports the
card. Check the software requirements for the affected card, which can be found in the
configuration note for the card.
• Router does not boot properly, or constantly or intermittently reboots.
– Make sure that the card is firmly seated in its slot.