• Supported Platforms
• T320 Routers

• Related Topics
• Preventing Electrostatic Discharge Damage to an M Series, MX Series, or T Series Router
• T320 T-CB Description
• T320 T Series Control Boards (T-CBs) Components and LEDs
• Maintaining the T320 T-CBs

Replacing a T320 T-CB

The router can have up to two T-CBs. They are located in the upper rear of the chassis in the slots marked CB0 and CB1. Each weighs approximately 5 lb (2.3 kg).

To replace a T-CB, perform the following procedures:

1. Removing a T320 T-CB
2. Installing a T320 T-CB

Removing a T320 T-CB

Caution: Before you replace a T-CB, you must take the host subsystem offline. If there is only one host subsystem, taking the host subsystem offline shuts down the router. See Taking the T320 Host Subsystem Offline.

Caution: If the T-CB to be replaced is associated with the Routing Engine currently functioning as the master Routing engine, switch it to the backup before removing the T-CB. See Taking the T320 Host Subsystem Offline.

To remove a T-CB (see Figure 1):

1. Take the host subsystem offline. See Taking the T320 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. For more information about ESD, see Preventing Electrostatic Discharge Damage to an M Series, MX Series, or T Series Router.
4. If the router connected to a TX matrix platform, disconnect the cable plugged into the port labeled CIP.
5. Loosen the captive screws (using a Phillips (+) screwdriver, number 2) on the ejector handles on both sides of the T-CB faceplate.
6. Flip the ejector handles outward to unseat the T-CB.
7. Grasp the ejector handles and slide the T-CB about halfway out of the chassis.
8. Place one hand underneath the T-CB to support it and slide it completely out of the chassis.
9. Place the T-CB on the antistatic mat.
10. If you are not replacing the T-CB now, install a blank panel over the empty slot.

Installing a T320 T-CB

To install a T-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 T-CB with the guides inside the chassis.
3. Slide the T-CB into the chassis, carefully ensuring that it is correctly aligned.
4. Grasp both ejector handles, and press them inward to seat the T-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 CIP port.
7. If power is applied to the Routing Engine and its corresponding T-CB is functioning normally, the T-CB comes online automatically. To verify that the T-CB is functioning normally, check the LEDs on its faceplate. The green OK LED should light steadily a few minutes after the T-CB is installed. If the FAIL LED is lit steadily, remove and install the T-CB again. If the FAIL LED still lights steadily, the T-CB is not functioning properly. Contact your customer support representative.

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

   
   

   user@host> show chassis environment cb