Troubleshooting the M10i Power System When the LED on One Power Supply Is Off

Problem

The LED on one power supply is off, but the LED on the other supplies indicate that they are functioning properly.

Solution

Perform the following diagnostic procedure:

1. Check the red alarm LED on the HCM:
   • 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 Table 1.

     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 M10i AC Power Supply and Replacing an M10i DC Power Supply. If the LED lights correctly on the spare, the original power supply is faulty. Return it to Juniper Networks for replacement, as described in Returning a Hardware Component to Juniper Networks, Inc..
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 cable (on a DC-powered router). For instructions, see Removing an M10I AC Power Cord and Disconnecting Power Cables to a DC-Powered M10i Router (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 Contacting Customer Support.