Troubleshooting the MX80 Fan Tray
Problem
The fans in the fan tray are not functioning normally.
Solution
Follow these guidelines to troubleshoot the fans:
- Check the alarm LEDs on the front panel.
- Issue the show chassis fan command to get status
information about the fans.
user@host> show chassis fanItem Status RPM Measurement Fan 1 OK 4560 Spinning at intermediate-speed Fan 2 OK 4560 Spinning at intermediate-speed Fan 3 OK 4560 Spinning at intermediate-speed Fan 4 OK 4560 Spinning at intermediate-speed Fan 5 OK 4560 Spinning at intermediate-speed - If the red alarm LED on the front panel lights, issue
the show chassis alarms command to get information about
the source of an alarm condition.
If the CLI output lists only one fan failure, and the other fans are functioning normally, the fan is most likely faulty and you must replace the fan tray.
- Place your hand near the exhaust vents at the side of the chassis to determine whether the fans are pushing air out of the chassis.
- If a fan tray is removed, a yellow alarm and a red alarm occur.
The following conditions automatically cause the fans to run at full speed and also trigger the indicated alarm:
- A fan fails (red 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).
user@host> show chassis temperature-thresholdsFan speed Yellow alarm Red alarm Item Normal High Normal Bad fan Normal Bad fan Chassis default 48 54 65 55 75 65 Routing Engine 55 60 75 65 85 70
