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How to replace a Swich Control Board on EX9200

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Article ID: KB34227 KB Last Updated: 24 Mar 2021Version: 2.0
Summary:

When replacing a SCB (​Switch Control Board) on EX9200s, its corresponding RE (routing engine) will also be disconnected from the switch.  While Backup RE modules are hot-insertable and hot-removable (meaning you can remove and replace it without powering off or disrupting the function of the switch), primary RE modules are only hot-pluggable, indicating there is no need to power-off the switch, but functions are interrupted until the component is reinserted. 

This article provides the steps to replace a defective SCB without impacting services on dual RE scenarios.

show chassis hardware 
​Hardware inventory:
​Item             Version  Part number  Serial number     Description
​Chassis                                JN122000RFC      EX9204
​Midplane         REV 07   750-050276   ACRB2221          EX9204-BP
​FPM Board        REV 01   760-049619   CABL4002          Front Panel Display
​PEM 0            Rev 10   740-029970   QCS1000U04Z       PS 1.4-2.52kW; 90-264V AC in
​PEM 1            Rev 10   740-029970   QCS1000U037       PS 1.4-2.52kW; 90-264V AC in
PEM 2            Rev 10   740-029970   QCS2000U08Z       PS 1.4-2.52kW; 90-264V AC in
PEM 3            Rev 10   740-029970   QCS1000U08A       PS 1.4-2.52kW; 90-264V AC in
Routing Engine 0 REV 03   740-049603   9000000336        RE-S-EX9200-1800X4
​Routing Engine 1 REV 03   740-049603   9000000456        RE-S-EX9200-1800X4
CB 0             REV 05   750-049608   CABR2000          EX9200-SCBE
CB 1             REV 07   750-049608   CACJ2001          EX9200-SCBE
Solution:

First step

  1. Determine whether the host subsystem is the primary or backup using one of these methods:

    • Look at the MASTER LED on the RE module faceplate. If the MASTER LED is lit steady green, the corresponding host subsystem is functioning as the primary.

    • Issue the 'show chassis routing-engine' CLI command. The output of this command will show whether the host subsystem is functioning as the primary or backup.

      user@host> show chassis routing-engine | match "Slot|state"
      ​Slot 0:
      Current state Master
      ​Slot 1:
      ​Current state Backup
  2. If the host subsystem of the CB to be replaced is functioning as the primary, switch it to backup mode using the 'request chassis routing-engine master switch' command.

    user@host> show chassis routing-engine | match "Slot|state"
    ​Slot 0:
    ​Current state Backup
    ​Slot 1:
    Current state Master

Second step

  1. After making sure the CB in question is not the primary, get to the CLI operational mode of the backup RE and run the command, 'request system halt'. This command shuts down the Routing Engine gracefully, so its state information is preserved. 

    user@host> request system halt                                                                                                 
    warning: This command will not halt the other routing-engine.                                                                               
    If planning to switch off power, use the both-routing-engines option.                                                                       
    Halt the system ? [yes,no] (no) yes 

    ​Halting re0..


    user@host> show chassis routing-engine | match "Slot|state"
    Slot 0:
    Current state                  Present
    Slot 1:
    Current state                  Master
  2. Wait until a message appears on the console confirming that the operating system has halted. The SCB might continue forwarding traffic for approximately 5 minutes after the 'request system halt' command has been issued.

Note: Taking the host subsystem offline includes both the Routing Engine and CB. If there is only one host subsystem, taking the host subsystem offline shuts down the router.

Third step

After host subsystem is offline:

  1. Place an electrostatic bag or antistatic mat on a flat, stable surface.

  2. Attach an ESD grounding strap to your bare wrist and connect the strap to one of the ESD points on the chassis.

  3. Rotate the ejector handles simultaneously counterclockwise to unseat the Switch Control Board.

  4. Grasp the ejector handles, and slide the Switch Control Board about halfway out of the chassis.

  5. Place one hand underneath the Switch Control Board to support it, and slide it completely out of the chassis.

  6. Place the Switch Control Board on the antistatic mat.

  7. If you are not replacing the Switch Control Board now, install a blank panel over the empty slot.

Fourth step

  1. Attach an ESD grounding strap to your bare wrist and connect the strap to one of the ESD points on the chassis.

  2. Carefully align the sides of the Switch Control Board with the guides inside the chassis.

  3. Slide the Switch Control Board into the chassis until you feel resistance, carefully ensuring that it is correctly aligned.

  4. Grasp both ejector handles, and rotate them simultaneously clockwise until the Switch Control Board is fully seated.

  5. Place the ejector handles in the proper position, horizontally and toward the center of the board.

  6. Check the LEDs on the Switch Control Board faceplate to verify that it is functioning normally.

    • The green OK/FAIL LED should light steadily a few minutes after the Switch Control Board is installed.

    • If the OK/FAIL LED is red, remove and install the Switch Control Board again. If the OK/FAIL LED still lights steadily, the Switch Control Board is not functioning properly. Contact your customer support representative.

  7. Check the status of the Switch Control Board using 'show chassis environment cb'

    show chassis environment cb
    
    CB 0 status:
    State Online Standby
    Temperature 41 degrees C / 105 degrees F
    Power 1
    1.0 V 1005 mV
    1.2 V 1202 mV
    1.5 V 1511 mV
    1.8 V 1804 mV
    2.5 V 2507 mV
    3.3 V 3312 mV
    5.0 V 5027 mV
    5.0 V RE 5008 mV
    12.0 V 12026 mV
    12.0 V RE 0 mV
    Power 2
    4.6 V bias MidPlane 4846 mV
    11.3 V bias PEM 11292 mV
    11.3 V bias FPD 11234 mV
    11.3 V bias POE 0 11330 mV
    11.3 V bias POE 1 11292 mV
    Bus Revision 96
    FPGA Revision 0
    PMBus Expected Measured Measured Calculated
    device voltage voltage current power
    XF ASIC A 1031 mV 1033 mV 17000 mA 17561 mW
    XF ASIC B 1031 mV 1031 mV 17000 mA 17527 mW
    CB 1 status:
    State Online Master
    Temperature 45 degrees C / 113 degrees F
    Power 1
    1.0 V 1005 mV
    1.2 V 1198 mV
    1.5 V 1504 mV
    1.8 V 1807 mV
    2.5 V 2513 mV
    3.3 V 3300 mV
    5.0 V 5014 mV
    5.0 V RE 4962 mV
    12.0 V 12123 mV
    12.0 V RE 12065 mV
    Power 2
    4.6 V bias MidPlane 4840 mV
    11.3 V bias PEM 11311 mV
    11.3 V bias FPD 11330 mV
    11.3 V bias POE 0 11292 mV
    11.3 V bias POE 1 11292 mV
    Bus Revision 96
    FPGA Revision 16
    PMBus Expected Measured Measured Calculated
    device voltage voltage current power
    XF ASIC A 1033 mV 1033 mV 17500 mA 18077 mW
    XF ASIC B 1034 mV 1033 mV 18000 mA 18594 mW

Optional step:

  1. If required, switch the primary role again by running request chassis routing-engine master switch 
Modification History:
2021-03-23: Updated the article terminology to align with Juniper's Inclusion & Diversity initiatives
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