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    Troubleshooting the M40e Power System When 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:
      • On an AC power supply, the green LED labeled OUTPUT OK is blinking slowly.
      • On a DC power supply, the green LED labeled CB ON is not lit and the yellow LED labeled CB OFF is lit, or the blue LED labeled OUTPUT OK is blinking or is not 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, read the message on the craft interface LCD. The display reports the number of alarm conditions and the source of each alarm, as described in M40e Craft Interface LCD Description. For a list of messages, see M40e Chassis and Interface Alarm Messages . Issue the following CLI command for more information about the cause of an alarm condition:

        user@host> show chassis alarms

        Note: The messages in the craft interface LCD and the output from CLI show commands refer to the power supply on the right as PEM 0 and the power supply on the left as PEM 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 an AC-powered router, the switch for each power supply is on the power supply faceplate. On a DC-powered router, the switches are on the circuit breaker box.
    2. Replace the faulty power supply with a spare. For instructions, see Replacing an M40e AC Power Supply and Replacing an M40e 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.
    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 or cable. For instructions, see Disconnecting and Connecting AC Power from the M40e Router or Disconnecting and Connecting DC Power on the M40e 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.

    Published: 2010-10-28