Cisco Systems 3700 Series manual Solving Problems, Troubleshooting the Power and Cooling Systems

Appendix A Troubleshooting

Solving Problems

Solving Problems

The key to solving problems is to isolate the problem to a specific subsystem by comparing what the router is doing to what it should be doing.

The LEDs on the front and rear panel of the router enable you to determine router performance and operation. LEDs are described in the following sections:

•Reading Front-Panel LEDs, page A-4

•Reading Rear Panel LEDs, page A-6

When solving problems, consider the following router subsystems:

•Power and cooling systems—External power source, power cable, router power supply and circuit breaker, and router blower and fan. Also consider inadequate ventilation or air circulation.

•Modules—LEDs on the modules help identify a failure.

•Cables—External cables that connect the router to the network.

Troubleshooting the Power and Cooling Systems

Both the system LED and the fans can help you troubleshoot a power problem. Check the following items to help isolate the problem:

•With the power switch on, does the system LED stay on or blink?

–If the LED is green, the router is receiving power and is functional.

–If the LED is amber, the router is receiving power but is not functional.

–If the LED is off, check the power source and power cable.

•With the power switch on and the system LED on, do the fans operate?

–If no, check the fans.

•With the power switch on and the system LED off, do the fans operate?

–If yes, the router is receiving power. The fans are 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 for a short time?

–Check for an environmentally induced shutdown. See the next section, “Environmental Reporting Features.”

–Check the environmental site requirements in the “General Site Requirements” section on page 2-3.

–Check for a power supply failure by inspecting the system and power supply LEDs on the front panel. If they are green, the power supplies are functional.

Cisco 3700 Series Routers Hardware Installation Guide

A-2 OL-2180-08