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Replacing an M320 Control Board

  1. Removing an M320 Control Board

  2. Installing an M320 Control Board

Removing an M320 Control Board

The router can have one or two CBs. They are located in the upper rear of the chassis in the slots marked CB0 and CB1. Each weighs approximately 3.4 lb (1.5 kg).

To remove a CB, (see Figure 1):

  1. Take the host subsystem offline. Caution

    Before you replace a CB, you must take the host subsytem offline:

    • Before taking the host subystem offline, switch the Routing Engine to be the backup if the CB to be replaced is associated with the Routing Engine currently functioning as the master Routing engine.

    • 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.

    See Taking the M320 Host Subsystem Offline.

  2. Place an electrostatic bag or antistatic mat on a flat, stable surface.
  3. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
  4. If applicable, disconnect the cables plugged into the ports labeled EXTERNAL CLOCK INPUTS.
  5. Loosen the captive screws (using a Phillips (+) screwdriver, number 2) on the ejector handles on both sides of the CB faceplate.
  6. Flip the ejector handles outward to unseat the CB.
  7. Grasp the ejector handles, and slide the CB about halfway out of the chassis.
  8. Place one hand underneath the CB to support it, and slide it completely out of the chassis.
  9. Place the CB on the antistatic mat.
  10. If you are not replacing the CB now, install a blank panel over the empty slot.
Figure 1: Removing a CB
Removing a CB

Installing an M320 Control Board

To install a CB (see Figure 2):

  1. Attach an electrostatic discharge (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 CB with the guides inside the chassis.
  3. Slide the CB into the chassis, carefully ensuring that it is correctly aligned.
  4. Grasp both ejector handles, and press them inward to seat the CB.
  5. Tighten the captive screws on the ejector handles, using a Phillips (+) screwdriver, number 2.
  6. If applicable, reconnect the cable previously plugged into the port or ports.
  7. If power is applied to the Routing Engine and its corresponding CB is functioning normally, the CB comes online automatically. To verify that the CB is functioning normally, check the LEDs on its faceplate. The green OK LED should light steadily a few minutes after the CB is installed. If the FAIL LED is lit steadily, remove and install the CB again. If the FAIL LED still lights steadily, the CB is not functioning properly. Contact your customer support representative.

    To check the status of the CB, use the CLI command:

    user@host> show chassis environment cb
Figure 2: Installing a CB
Installing a CB