Replacing a T640 Two-Input 160-A DC Power Supply

1. Removing a T640 Two-Input 160-A DC Power Supply
2. Installing a T640 Two-Input DC Power Supply

Removing a T640 Two-Input 160-A DC Power Supply

Caution: Do not leave a power supply slot empty for more than 30 minutes while the router is operational. For proper airflow, the power supply must remain in the chassis, or a blank panel must be used in an empty slot.

The router has either one nonredundant power supply or two redundant, load-sharing power supplies. Each redundant power supply is hot-insertable and hot-removable. When a redundant power supply is powered down or removed, the other power supply automatically assumes the entire electrical load for the router. If you have only one power supply, you must power off the system before removing the power supply.

1. Make sure that the voltage across the DC power source cable leads is 0 V and that there is no chance that the cables might become active during the removal process.
2. For a nonredundant power supply, power off the system. For redundant power supplies, verify that the other power supply is functional.
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. Switch the circuit breakers on the power supply faceplate to the off position (O).

   Note: After powering off a power supply, you must wait at least 60 seconds before turning it back on.

5. Remove the clear plastic cover protecting the terminal studs on the faceplate.
6. Using a 7/16-in. (11 mm) nut driver, remove the nuts and washers from the terminal studs (see Figure 1).

   Figure 1: Disconnecting Power Cables from a Two-Input 160-A DC Power Supply

   

   Caution: You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity. There is no standard color coding for DC power cables. The color coding used by the external DC power source at your site determines the color coding for the leads on the power cables that attach to the terminal studs on each power supply.

7. Remove the cable lugs from the terminal studs.
8. Loosen the captive screws on the cable restraints on the right edge of the power supply faceplate.
9. Carefully move the power cables out of the way.
10. Loosen the captive screws on the lower corners of the power supply faceplate completely. Twist the ejector handles on the upper corners of the faceplate counterclockwise to unseat the power supply.
11. Twist the ejector handles on the upper corners of the faceplate counterclockwise to unseat the power supply.
12. Grasp the handle on the power supply faceplate, and pull firmly to start removing the power supply. Slide it halfway out of the chassis (see Figure 2).

    Caution: Each two-input 160-A power supply weighs approximately 23 lb (10.5 kg). Be prepared to support the full weight of the power supply as you remove it from the router.

13. Place one hand underneath the power supply to support it, and slide it completely out of the chassis.

    Warning: Do not touch the power connectors on the rear of the power supply (see Figure 3). They can contain dangerous voltages.

Figure 2: Removing a Two-Input 160-A Power Supply

Figure 3: Rear of the Power Supply Showing Midplane Connectors

Installing a T640 Two-Input DC Power Supply

To install a power supply (see Figure 4):

1. Make sure that the voltage across the DC power source cable leads is 0 V and that there is no chance that the cables might become active during installation.

   Caution: You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity. There is no standard color coding for DC power cables. The color coding used by the external DC power source at your site determines the color coding for the leads on the power cables that attach to the terminal studs on each power supply.

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 the power supply faceplate to the off position (O).
4. Using both hands, slide the power supply into the chassis until you feel resistance.
5. Twist the ejector handles at the upper corners of the power supply faceplate clockwise until they stop.
6. Tighten the captive screws at the lower corners of the power supply faceplate to secure the power supply in the chassis.
7. Remove the clear plastic cover protecting the terminal studs on the faceplate.
8. Remove the nut and washer from each power terminal stud. If no washers and nuts are already installed, they should be in the accessory box.
9. Secure the cable lug on the DC power cable to the terminal stud, first with a washer, then with a nut (see Figure 5). Use a 7/16-in. (11 mm) nut driver or wrench to tighten the nut (see Figure 4). Apply between 23 lb-in. (2.6 Nm) and 25 lb-in. (2.8 Nm) of torque to each nut:
   1. Secure each positive (+) DC source power cable lug to a RTN (return) terminal.
   2. Secure each negative (–) DC source power cable lug to a –48V (input) terminal.

   Note: All inputs on the two-input 160-A DC power supply in slot PEM0 must be powered by dedicated power feeds derived from feed A, and all inputs on the two-input 160-A DC power supply in slot PEM1 must be powered by dedicated power feeds derived from feed B. This configuration provides the commonly deployed A/B feed redundancy for the system.

   Note: INPUT 0 and INPUT 1 on the three-input 240-A DC power supply in slot PEM0 must be powered by dedicated power feeds derived from feed A, and INPUT 0 and INPUT 1 on the three-input 240-A DC power supply in slot PEM1 must be powered by dedicated power feeds derived from feed B. This configuration provides the commonly deployed A/B feed redundancy for the system.

   Caution: You must ensure that power connections maintain the proper polarity. The power source cables might be labeled (+) and (–) to indicate their polarity. There is no standard color coding for DC power cables. The color coding used by the external DC power source at your site determines the color coding for the leads on the power cables that attach to the terminal studs on each power supply.

10. Loosen the captive screws on the cable restraints on the right edge of the power supply faceplate.
11. Route the positive and negative DC power cables through the top and bottom of each cable restraint.
12. Tighten the cable restraint captive screws to hold the power cables in place.
13. Verify that the power cabling is correct, that the cables are not touching or blocking access to router components, and that they do not drape where people could trip on them.
14. Replace the clear plastic cover over the terminal studs on the faceplate.
15. Switch the circuit breakers on the power supply to the on position (|).

    Note: If you have only one power supply, or if the router is completely powered off when you power on the power supply, the Routing Engine boots as the power supply completes its startup sequence.

16. Check the LEDs on the power supply faceplate. If the power supply is correctly installed and is functioning properly, the DC OK LED lights steadily, and the CB ON LED blinks momentarily, then lights steadily.

    Note: After a power supply is powered on, it can take up to 60 seconds for status indicators—such as the output status LEDs on the power supply, the command output displays, and messages on the LCD on the craft interface—to indicate that the power supply is functioning normally. Ignore error indicators that appear during the first 60 seconds.

    Note: After powering on a power supply, wait at least 60 seconds before turning it off. If you have only one power supply, power off the system before turning off the power supply.

Figure 4: Installing a Replacement Two-Input 160-A DC Power Supply

Figure 5: Connecting Power Cables to a Two-Input 160-A DC Power Supply