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Troubleshooting the T1600 Power System

 

Problem:

Description:

The following alarms, LEDs, and other conditions indicate a problem with the power system:

  • If all power supplies have failed, the system temperature might have exceeded the threshold, causing the system to shut down.

  • The blue DC OK LED blinks when a power supply detects a fault (the power supply fails, does not have sufficient airflow, is going through a startup test, or is not properly inserted).

  • The yellow OVER TEMP LED lights when a power supply is not receiving enough airflow to maintain proper temperature.

  • The green AC OK LED is off when an AC power supply is not receiving voltage.

In Table 1, the text in the column labeled ”LCD Message” appears in the display of the craft interface. The text in the column labeled “CLI Message” appears in the output from the show chassis alarms command.

Table 1: Power System Chassis Alarms

Alarm Type

LCD Message

CLI Message

Red

PEM pem-number Over Temp

PEM pem-number Over Temperature

PEM pem-number Output Fail

PEM pem-number Output Failure

PEM pem-number Input Fail

PEM pem-number Input Failure

Yellow

PEM pem-number Removed

PEM pem-number Removed

PEM pem-number Inputs Cfg

PEM pem-number Configuration Mismatch-number of inputs

Solution

  1. Check the LEDs on each three-input 240-A DC or four-input 240-A DC power supply faceplate.
    • DC OK power supply LED is blinking—Check the red alarm LED on the craft interface.

    • DC OK power supply LED is off and no red alarm condition exists—Check that the circuit breakers are switched to the ON position (|).

    • DC OK LED on one or both of the power supplies is not lit—Check the power supply fans to see if they are operating.

    • OVER TEMP LED on one of the power supplies lights—Check the fans and air filters to be sure they are functioning and providing sufficient airflow through the chassis.

  2. Check the LEDs on each six-input DC power supply faceplate.
    • The DC OK LED on one or both of the power supplies is not lit—Check that the power switch is on.

    • The OVER TEMP LED on one of the power supplies is lit—Check the fan trays and air filters to be sure they are functioning and providing sufficient airflow through the chassis.

    • An INPUT PRESENT LED on a DC power supply is not lit—Check that the input is receiving source DC power.

  3. Check the LEDs on each three-phase delta or wye power supply faceplate.
    • AC OK power supply LED is off—Check that the power supply is receiving voltage.

    • DC OK power supply LED is blinking—Check the red alarm LED on the craft interface.

    • DC OK LED on one or both of the power supplies is not lit—Check the power supply fans to see if they are operating.

    • OVER TEMP LED on one of the power supplies lights—Check the fans and air filters to be sure they are functioning and providing sufficient airflow through the chassis.

  4. Check the display on the craft interface to determine the source of a yellow or red alarm (see Table 1). Junos OS constantly updates the screen with status information for each component. Note

    On the display and in the CLI, the power supplies are referred to as PEM0 and PEM0, from top to bottom.

    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 that case, the remaining power supply assumes the load, and you can still view the system status through the CLI or display.

  5. Verify that the source circuit breaker has the proper current rating. Note

    All inputs on a DC power supply in slot PEM0 must be powered by dedicated power feeds derived from feed A, and all inputs on a DC power supply in slot PEM 1 must be powered by dedicated power feeds derived from feed B. This configuration provides the commonly deployed A/B feed redundancy for the system.

    Note

    The AC power cord on an AC power supply in slot PEM0 must be powered by a dedicated power feed derived from feed A, and The AC power cord on an AC power supply in slot PEM 1 must be powered by dedicated power feeds derived from feed B. This configuration provides the commonly deployed A/B feed redundancy for the system.

  6. Verify that the DC power cables or AC power cord from the power source to the router are not damaged. If the insulation is cracked or broken, immediately replace the DC power cable or AC power cord.
  7. Connect the power supply to a different power source with a new DC power cable or AC power cord. If the power supply DC OK LED still does not light, the power supply is the source of the problem. Replace the power supply with a spare.

    DC OK LED on the installed spare does not light—the replaced power supply might be faulty. To return it for replacement, see Contacting Customer Support.

  8. If you cannot determine the cause of the problem or need additional assistance, see Contacting Customer Support.