Replacing a T640 Standard Control Board or T-CB

The router can have up to two control boards. You can use this procedure for either standard control boards or 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 standard control board or T-CB, perform the following procedures:

1. Removing a T640 Standard Control Board or T-CB
2. Installing a T640 Standard Control Board or T-CB

Removing a T640 Standard Control Board or T-CB

Caution: Before you replace a control board, 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 T640 Host Subsystem Offline.

Caution: If the control board to be replaced is associated with the Routing Engine currently functioning as the master Routing Engine, switch it to the backup before removing the control board. See Taking the T640 Host Subsystem Offline.

To remove a standard control board or T-CB (see Figure 1 and Figure 2):

1. Take the host subsystem offline. See Taking the T640 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. For T-CBs in a T640 router connected to a TX matrix router, 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 control board faceplate.
6. Flip the ejector handles outward to unseat the control board.
7. Grasp the ejector handles, and slide the control board about halfway out of the chassis.
8. Place one hand underneath the control board to support it, and slide it completely out of the chassis.
9. Place the control board on the antistatic mat.
10. If you are not replacing the control board now, install a blank panel over the empty slot.

Figure 1: Removing a Standard Control Board

Figure 2: Removing a T-CB

Installing a T640 Standard Control Board or T-CB

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 control board with the guides inside the chassis.
3. Slide the control board into the chassis, carefully ensuring that it is correctly aligned.
4. Grasp both ejector handles, and press them inward to seat the control board.
5. Tighten the captive screws on the ejector handles, using a Phillips (+) screwdriver, number 2.

   Note: If power is applied to the Routing Engine and its corresponding control board is functioning normally, the control board comes online automatically.

6. For a T-CB in a T640 router connected to a TX matrix router, reconnect the cable previously plugged into the CIP port.

7. Verify that the control board is functioning normally:

   • Check the LEDs on the control board faceplate. The green OK LED should light steadily a few minutes after the control board is installed. If the FAIL LED is lit steadily, remove and install the control board again. If the FAIL LED still lights steadily, the control board is not functioning properly. Contact your customer support representative.
   • Use the CLI command show chassis environment cb to check the status of the control board.

Figure 3: Installing a Standard Control Board

Figure 4: Installing a T-CB