All LEDs on One Supply Are Off or LED States Are not Correct

If either of the following conditions applies, perform the diagnostic procedure described following the list of conditions:

• The LEDs on one power supply are all off, but the LEDs on the other supply indicate that it is functioning properly.
• The LED states on one or both supplies indicate a problem: the green LED labeled OUTPUT OK is not lit and the amber LED labeled FAULT is lit.

Perform the following steps to diagnose and correct the problem:

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. 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 AC Power Supply and Replacing a DC Power Supply. If the LEDs light correctly on the spare, the original power supply is faulty. Return it to Juniper Networks for replacement, as described in Contacting Customer Support and Returning Hardware.
3. If the spare power supply also does not work, connect the router to a different power source. You might also try replacing the power cord (on an AC-powered router) or power cable (on a DC-powered router). For instructions, see Replacing an AC Power Cord and Disconnecting and Connecting DC Power (you do not need to disconnect and reconnect the grounding cable on a DC-powered router).
4. If you cannot determine the cause of the problem or need additional assistance, see Juniper Networks Technical Assistance Center.