Replacing Offline T640 Hardware Components

1. Power Off the T640 Router
2. Replacing the Standard CBs with T-CBs in the T640 Router
3. Replacing the Standard SIBs in the T640 Router
4. Replacing the Routing Engines in the T640 Router

Power Off the T640 Router

Note: The CBs and T-CBs are hot-removable and hot-insertable if the router contains redundant host subsystems. SIBs and T640-SIBs are hot-removable and hot-insertable. However, we recommend that you power off the T640 router before you replace the CBs and SIBs.

1. Issue the request system halt both-routing-engines operational mode command from the console or other management device connected to the T640 router. The command shuts down the Routing Engines cleanly, so their state information is preserved.
   user@host> request system halt both-routing-engines

   Wait until a message appears on the console confirming that the operating system has halted. For more information about the command, see the Junos OS System Basics and Services Command Reference .

2. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
3. Switch the circuit breakers on each power supply faceplate to the off position (O).

Replacing the Standard CBs with T-CBs in the T640 Router

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. Set the switches on each T-CB (see Figure 1):
   • Set the chassis ID switch to a value from 0 through 3. You must use the same chassis ID on each T-CB.

     Note: If the routing matrix contains only one T640 router, we recommend that you assign a chassis ID of 0 to the router.

   • Set the M/S switch on the T-CB faceplate to M.
3. Replace each CB with a T-CB. Use the standard replacement procedure described in the T640 Core Router Hardware Guide .

Figure 1: T-CB

Replacing the Standard SIBs in the T640 Router

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. Replace each SIB with a T640-SIB. Use the standard replacement procedure described in the T640 Core Router Hardware Guide .

   Note: Ensure that the ejector handle tabs are properly mated inside their corresponding chassis slots before you tighten the captive screws on the ejector handles. You might have to close and open the handles a few times before the tabs catch the slots.

Replacing the Routing Engines in the T640 Router

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. Follow the standard replacement procedure described in the T640 Core Router Hardware Guide .