M160 Internet Router Hardware Guide
A blown fuse can cause a component to fail even though it is correctly
installed and the power supplies are functioning. Check for a blown
fuse in the following circumstances:
The LED that indicates normal operation for the component fails to light.
The appropriate CLI
show chassis environment
command indicates that the
component is installed but is not receiving power.
For instructions for replacing a blown fuse, see “Replacing a Fuse” on page 204.
Juniper Networks Technical Assistance Center
If you need assistance during troubleshooting, you can contact the Juniper
Networks Technical Assistance Center (JTAC) by e-mail or telephone.
See “Requesting Support” on page xxiii.
Troubleshooting the Cooling System
The router’s cooling system comprises separate front and rear subsystems:
The front subsystem includes the fan tray located behind the cable
management system and the impeller located behind the craft interface. They
cool the FPCs, PICs, and midplane. See Figure 1.
The rear subsystem include upper and lower impellers in the rear of the
chassis. They cool the SFMs, host module, PCGs, and power supplies. See
Figure 2.
The cooling system draws in room air through the air intake vent located at
the front of the chassis below the cable management system. After entering
the chassis, the air stream separates into separate flows for the front and rear
subsystems, and the MCS monitors the temperature of each flow independently.
For a graphic depiction of the airflow, see Figure 20.
For the cooling system to function properly, the clearance around the chassis
must be sufficient for unobstructed airflow. See Clearance Requirements
for Airflow and Hardware Maintenance on page 62.
During normal operation, the impellers and fans in the fan tray function at less than
full speed. The MCS constantly monitors the temperatures detected by sensors on
the midplane and router components, adjusting the speed of the fans and impellers
as necessary. If the router temperature exceeds the acceptable maximum, the MCS
212
Troubleshooting the Cooling System
Summary of Contents for Internet Router M160
Page 12: ...M160 Internet Router Hardware Guide xii Table of Contents ...
Page 16: ...M160 Internet Router Hardware Guide xvi List of Figures ...
Page 18: ...M160 Internet Router Hardware Guide xviii List of Tables ...
Page 24: ...M160 Internet Router Hardware Guide xxiv Requesting Support ...
Page 26: ...2 Product Overview ...
Page 30: ...M160 Internet Router Hardware Guide 6 Safety Requirements Warnings and Guidelines ...
Page 66: ...M160 Internet Router Hardware Guide 42 Cable Management System ...
Page 80: ...M160 Internet Router Hardware Guide 56 Routing Engine Architecture ...
Page 82: ...58 Initial Installation ...
Page 104: ...M160 Internet Router Hardware Guide 80 Unpacking the Router ...
Page 148: ...M160 Internet Router Hardware Guide 124 Configuring the JUNOS Internet Software ...
Page 150: ...126 Hardware Maintenance Replacement and Troubleshooting Procedures ...
Page 242: ...M160 Internet Router Hardware Guide 218 Troubleshooting the Power System ...
Page 244: ...220 Appendixes ...
Page 292: ...M160 Internet Router Hardware Guide 268 Packing Components for Shipment ...
Page 301: ...Part 5 Index Index 277 ...
Page 302: ...278 Index ...