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Troubleshooting Cisco 1800 Series Routers (Modular)
OL-5883-01
Problem Solving
Problem Solving
The key to problem solving 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 router aid you in determining router performance and operation. The LEDs are
described in the “Reading LEDs” section on page 4.
When solving problems, consider the following router subsystems:
• Power and cooling systems—External power source, power cable, router power supply, circuit
breaker, and router fan. Also check for inadequate ventilation or air circulation.
• Interface cards—LEDs on the interface cards 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:
Normal Indications
With the power switch on, the normal indications are:
• SYS PWR LED on green and continuous
• Fan operating
Fault Indications
Check the following symptoms to locate or eliminate faults in the power and cooling systems:
• With the power switch on, is the SYS PWR LED on?
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If the LED is green and continuous, the router is receiving power and is functional.
–
If the LED is off, check the power source and power cable.
• With the power switch on and the SYS PWR LED on and green, does the fan operate?
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If no, check the fan.
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If yes, the power system is functioning.
• With the power switch on and the SYS PWR LED off, does the fan operate?
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If yes, the router is receiving power. The fan is connected directly to the DC outputs of the power
supply.
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If no, check the power source and power cable.
• Does the router shut down after being on a short time?
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Check for an environmentally induced shutdown. See the next section, “Environmental
Reporting Features.”
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Check the environmental site requirements in the “General Site Requirements” section on
page 3 of the “Preinstallation Requirements and Planning for Cisco 1800 Series Routers
(Modular)” document.