Juniper Networks M160 manual Troubleshooting Packet Forwarding Engine Components

Troubleshooting Hardware Components

turns off the power supplies. The following conditions automatically cause the fans and impellers to run at full speed and also trigger the indicated alarm:

A fan or impeller fails (red alarm).

One of the impellers is removed (yellow alarm).

The router temperature exceeds the “temperature warm” threshold (yellow alarm).

The temperature of the router exceeds the maximum (“temperature hot”) threshold (red alarm and automatic shutdown of the power supplies).

For more information about impeller-related alarms, see “Chassis and

Interface Alarm Messages” on page 209.

To troubleshoot the fans and impellers, follow these guidelines:

If the red alarm LED on the craft interface lights, check the LCD on the craft interface for the source of the problem. The display reports the number of alarm conditions and the source of each alarm, as described in “LCD Alarm Mode” on page 30. For a list of messages, see “Chassis and Interface Alarm Messages” on page 209.

Issue the following CLI command for more information about the source of an alarm condition:

user@host> show chassis alarms

If the blue OUTPUT OK LED on an enhanced power supply (or the amber

NO AIRFLOW LED on an original power supply) is blinking, the airflow passing by the power supply might be insufficient. Place your hand near the exhaust vents at the rear of the chassis to determine whether the impellers are expelling air.

If both power supplies have failed, the system temperature might have exceeded the threshold, causing the system to shut down. See “All LEDs on Both Supplies Are Off” on page 215.

If the LCD on the craft interface reports failure of only one impeller and the other impellers are functioning normally, the impeller is probably faulty and needs to be replaced. For replacement instructions, see “Replacing Hardware Components” on page 139. For instructions about returning a faulty component to Juniper Networks, see “Contacting Customer Support and Returning Hardware” on page 255.

Troubleshooting Packet Forwarding Engine Components

The following sections describe how to troubleshoot FPCs and PICs:

Troubleshooting FPCs on page 214

Troubleshooting PICs on page 215

Troubleshooting Packet Forwarding Engine Components 213