Juniper Networks MX480 - Manual (Page 176)

Troubleshooting the MX480 Cooling System
Problem 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).
Related
Documentation
Alarm LEDs and Alarm Cutoff/Lamp Test Button on the MX480 Craft Interface on
page 37 •
• Replacing the MX480 Fan Tray on page 168
• Maintaining the MX480 Air Filter on page 124
• Maintaining the MX480 Fan Tray on page 124
Troubleshooting the MX480 DPCs
Problem The DPCs are not functioning normally.
Solution • Monitor the green LED labeled OK above the DPC on the craft interface as soon as a
DPC is seated in an operating router.
The Routing Engine downloads the DPC software to it under two conditions: the DPC
is present when the Routing Engine boots Junos OS, and the DPC is installed and
requested online through the CLI or push button on the front panel. The DPC then runs
diagnostics, during which the
OK LED blinks. When the DPC is online and functioning
normally, the OK LED lights green steadily.
• Make sure the DPC is properly seated in the midplane. Check that each ejector handle
has been turned clockwise and is tight.
Copyright © 2013, Juniper Networks, Inc. 152
MX480 3D Universal Edge Router Hardware Guide