Troubleshooting The Mx240 Cooling System - Juniper MX240 Hardware Manual

MX240 SCB-MX Description
MX240 Routing Engine Description | 69
MX240 Craft Interface Overview | 38
MX240 Component LEDs on the Craft Interface | 40
MX240 Alarm LEDs and Alarm Cutoff/Lamp Test Button | 39
MX240 Alarm Relay Contacts on the Craft Interface | 39
MX240 AC Power Supply Description | 47
MX240 DC Power Supply Description | 55

Troubleshooting the MX240 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
MX240 Alarm LEDs and Alarm Cutoff/Lamp Test Button | 39
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