Troubleshooting The Mx480 Cooling System; Troubleshooting The Mx480 Dpcs - Juniper MX480 Hardware Manual

Troubleshooting the MX480 Cooling System

Problem
Description: The fans in the fan tray are not functioning normally.
Solution
Follow these guidelines to troubleshoot the fans:
Check the fan LEDs and alarm LEDs on the craft interface.
If the red alarm LED on the craft interface lights, use the CLI to get information about the source of an
alarm condition: user@host> show chassis alarms.
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).
SEE ALSO
Alarm LEDs and Alarm Cutoff/Lamp Test Button on the MX480 Craft Interface | 37
Replacing the MX480 Fan Tray | 294
Maintaining the MX480 Air Filter | 289
Maintaining the MX480 Fan Tray | 291

Troubleshooting the MX480 DPCs

Problem
Description: The DPCs are not functioning normally.
Solution
438