Datasheet

Solution Perform the following diagnostic procedure:
1. Check the red alarm LED on the craft interface:
• If it is lit, issue the following CLI command for information about the cause of an
alarm condition:
user@host> show chassis alarms
For a list of messages that can appear in the output, see “Hardware and Interface
Alarm Messages” on page 80.
A common cause of power supply shutdown is that the temperature of the power
supply or another router component has exceed the maximum limit.
• If the red alarm LED is not lit, check that the power switch is in the ON position on
the power supply faceplate.
2. Replace the faulty power supply with a spare. For instructions, see “Replacing an M7i
AC Power Supply” on page 111 and “Replacing a DC Power Supply” on page 116. If the
LED lights correctly on the spare, the original power supply is faulty. Return it to Juniper
Networks for replacement, as described in “Contacting Customer Support” on page 195.
3. If the spare power supply also does not work, connect the router to a different power
source. You might also try replacing the AC power cord (on an AC-powered router)
or DC power cables (on a DC-powered router). For instructions, see Replacing an AC
Power Cord and “Replacing an M7i DC Power Cable” on page 120 (you do not need to
disconnect and reconnect the grounding cable).
4. If you cannot determine the cause of the problem or need additional assistance, see
“Contacting Customer Support” on page 195.
Related
Documentation
M7i Power System Description on page 23•
• M7i Router Power Requirements on page 167
• Maintaining the M7i Power Supplies on page 76
• Powering On the M7i Router on page 63
Troubleshooting the M7i Fan Tray
Problem The fans in the fan tray are not functioning normally.
Solution The router's single fan tray provides cooling for the router, including the CFEB or CFEB-E,
PICs, power supplies, and Routing Engine.
The cooling system draws in room air through the air intake vent on the left side of the
chassis. After entering the chassis, the air stream separates into separate flows for the
front and rear components. For a graphic depiction of the airflow, see Figure 18 on page 27.
For the cooling system to function properly, the clearance around the chassis must be
sufficient for unobstructed airflow. See “M7i Router Clearance Requirements for Airflow
and Hardware Maintenance” on page 40.
Copyright © 2012, Juniper Networks, Inc.86
M7i Multiservice Edge Router Hardware Guide