Juniper EX9253 Hardware Manual page 171

Problem
Description
The power system is not functioning normally.
Cause
Solution
• Check the LEDs on each power supply faceplate. If a power supply is installed correctly and is
functioning normally, the status LED lights steadily.
• Issue the CLI show chassis environment pem command to check the status of the power supplies. As
shown in the sample output, the value Online in the rows labeled State must indicate that each of the
power supplies is functioning normally.
user@switch> show chassis environment pem
If a power supply is not functioning normally, perform the following steps to diagnose and correct the
problem:
• If a major alarm condition occurs, issue the show chassis alarms command to determine the source of
the problem.
• If all power supplies have failed, the system temperature might have exceeded the threshold, causing
the system to shut down.
NOTE: If the system temperature exceeds the threshold, Junos OS shuts down all power
supplies so that no status is displayed.
Junos OS also can shut down one of the power supplies for other reasons. In this case, the
remaining power supplies provide power to the switch, and you can still view the system
status through the CLI or display.
• Check that the DC circuit breaker or AC input switch is in the on position and that the power supply
is receiving power.
• Verify that the source circuit breaker has the proper current rating. Each power supply must be
connected to a separate source circuit breaker.
162