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Troubleshooting the MX2000 Router Power System

 

Problem

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

  • If all AC or DC power supply modules (PSMs) have failed, the system temperature might have exceeded the threshold, causing the system to shut down. See Step 9 for instructions on how to restart a high-capacity AC or DC PSM after a shut down due to an over-temperature situation.

  • The yellow PWR OK LED blinks when an AC or a DC PSM is out of the power limit or is in an overcurrent condition.

  • The red FAULT LED lights when the PSM is not receiving enough airflow to maintain the proper temperature.

  • The red FAULT LED lights when the AC or DC output voltages are not within range.

  • The yellow INP0 LED blinks when the AC or DC voltage is present, but out of limits. This LED blinks continuously for approximately a few seconds on and a few seconds off.

  • The yellow INP1 LED blinks when the AC or DC voltage is present, but out of limits. This LED blinks continuously for approximately a few seconds on and a few seconds off.

  • The red -48V LED lights when the wrong polarity of DC input voltage is connected on the DC PDM.

Solution

To troubleshoot the MX2000 router power system:

  1. Check the LEDs on all AC or DC PSM faceplates.
    • PWR OK PSM LED is blinking—Check the fans and air filters to be sure that they are functioning and providing sufficient airflow through the chassis.

    • PWR OK PSM LED is off and no red alarm condition exists—Check that the circuit breakers are switched to the ON position. Check that the AC or DC power switch is in the on (|) position.

    • PWR OK LED on PSMs is not lit—Check that the PSMs are inserted and are operating.

    • If an AC PSM or a DC PSM is correctly installed and functioning normally, the PWR OK, INP0, and INP1 LEDs light steadily, and the FAULT LED is not lit.

  2. Check the LEDs on each DC power distribution module (PDM) faceplate.
    • –48V or 240 V China PDM LED is off—Check that the PDM is receiving voltage.

    • –48V or 240 V China PDM LED is lit red—Check that the PDM is connected to correct input voltage and polarity.

      Note

      This does not apply to the 240 V China DC PDM.

    • Check that the DC PDM switch is set to 60 A or 80 A depending on the current feed coming from the DC source circuit breaker.

    • –48V or 240 V China LED on a DC PDM is not lit—Check that the input is receiving source DC power.

    • If a DC PDM is correctly installed and functioning normally, the –48V source input LEDs light green steadily.

  3. Check the LEDs on each AC PDM faceplate. There is one LED for each input feed. See Mapping Input Power from AC Power Distribution Modules to AC Power Supply Modules on MX2000 Routers.
    • On the three-phase delta AC PDM, the left arrow () green LED is lit steadily, indicating that the left input feed is receiving voltage.

    • On the three-phase delta AC PDM, the right arrow () green LED is lit steadily, indicating that the right input feed is receiving voltage.

    • On the three-phase wye AC PDM, the left arrow () green LED is lit steadily, indicating that the left input feed is receiving voltage.

    • On the three-phase wye AC PDM, the right arrow () green LED is lit steadily, indicating that the right input feed is receiving voltage.

    • On the single-phase AC PDM, the green LED for each feed is lit steadily, indicating the input feed is receiving voltage.

  4. Verify that the source circuit breaker has the proper current rating. Each PDM must be connected to a separate source circuit breaker. Check that the AC or DC circuit breaker is in the on (ON) position.
  5. Verify that the DC power cable or the AC power cord from the power source to the router is not damaged. If the insulation is cracked or broken, immediately replace the DC power cable or AC power cord.
  6. Connect the PDM to a different power source with new power cables. If the PSM PWR OK LED still does not light, the PSM is the source of the problem. Replace the PSM with a spare.

    If the PWR OK LED on the installed spare does not light, the replaced PSM might be faulty. To return it for replacement, see Contacting Customer Support.

  7. Check the status of a PSM, issuing the following CLI command. The value Online in the rows labeled State indicates that each of the PSMs is functioning normally.Note

    For the MX2010, the PSMs are referred to as PSM0 through PSM8.

    For the MX2020, the PSMs are referred to as PSM0 through PSM8 (bottom) and PSM9 through PSM17 (top).

    Here is an example of the AC PSM input status for an MX2020:

    user@host> show chassis environment psm

    Here is an example of the DC PSM (-48) input status for an MX2020:

    user@host> show chassis environment psm

    Here is an example of the DC PSM (240 V China) input status for an MX2020:

    user@host> show chassis environment psm
    Note

    If two input sources are grounded at the positive terminal (i.e. -240 V DC source) and if both positive input wiring are connected to the PDM, the PSM reports both inputs to be active and reports the higher of the two -240V DC input source. This is the case even if one negative input source is switched off through a breaker.

    Note

    For midpoint impedance grounded source, the CLI display of the input voltage is inaccurate for the input source with lower input voltage. For example, if one source is +/-120V, and the other source is +/-125V, the CLI input voltage display is 250 V for one input, and is 245 V (should be 240 V) for the other.

  8. If a red alarm condition occurs, issue the show chassis alarms command to determine the source of the problem.
  9. If all PSMs have failed, the system temperature might have exceeded the threshold, causing the system to shut down.Note

    If the system temperature exceeds the threshold, the Junos OS shuts down all power supplies so that no status is displayed.

    The 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 router, and you can still view the system status through the CLI or display.

To restart a high-capacity AC power supply after a shut down due to an over-temperature situation:

  1. Move the power switch on the power supply to the off (o) position.
  2. Turn off power to where the AC line goes into the power distribution module (PDM) area.
  3. Wait for the power supply LEDs to fade out and for the fans inside the power supply to shutdown. This can take up to 10 seconds.Caution

    Do not attempt to power-on the power supply if the LED is still lit and the fan is still running. If you do, the router will not reboot.

  4. Turn on power to where the AC line goes into the power distribution module (PDM) area.
  5. Move the power switch on the power supply to the on (|) position.
  6. Verify that the LEDs on the power supply faceplate are properly lit.
  7. Issue the CLI show chassis environment pem command and verify the State is ONLINE and the Temperature is OK.

To restart a high-capacity DC power supply after a shut down due to an over-temperature situation:

  1. Switch off the circuit breaker(s) on the DC distribution panel to remove power to the chassis and power supplies.
  2. Switch on the circuit breaker(s) on the distribution panel to power up the chassis and power supplies.Note

    The power switch on the power supplies is not part of the outer or inner DC circuits and therefore does not need to be switched off when restarting the chassis.

    If output power is not load-balancing correctly in the same zone on an MX2000 router with a high-capacity AC or DC power supply module, connect two feeds and change the DIP switch to 1 to boost the voltage on the power supply module.

Each High Capacity AC or DC power supply accepts two AC or DC feeds in two unique AC or DC receptacles. It is possible to operate with one feed, but there is a reduction in the power supply output. The DIP switch must be set according to the number of AC or DC feeds that are present for the power supply. Refer to Figure 1

Figure 1: Setting the MX2000 Router DIP Switch
Setting the MX2000 Router DIP Switch
  • Position – 0 indicates that only one AC or DC feed is provided.

  • Position – 1 indicates that two AC or DC feeds are provided.

To check the DIP switch position:

  1. Issue the show chassis power command and check to see how many feeds are connected. The following example shows there are two AC input feeds connected for PEM 0 and one AC input feed connected for PEM 1. This indicates that the DIP switch for PEM 0 is in position 1 and the DIP switch for PEM 1 is in position 0. These are the proper settings.
    # run show chassis power
  2. Issue the show chassis alarms command to see if there are any active alarms on the DIP switch:
    > show chassis alarms
  3. If the show chassis alarms output shows an alarm on Dipswitch, issue the show chassis power command to check the DIP switch position.
    # run show chassis power

    In this example, the DIP switch is in the wrong position since there is one AC feed expected but two AC feeds are connected. Change the DIP switch to position 1. This should clear the alarm.

    Note

    Changing the DIP switch position does not impact traffic. However, it is always recommended to do so in a maintenance window.

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