Replacing a T320 DC Power Supply

The router has two redundant, load-sharing DC power supplies. Each power supply is hot-insertable and hot-removable. When one power supply is powered down or removed, the other power supply automatically assumes the entire electrical load for the router.

1. Removing a T320 DC Power Supply
2. Installing a T320 DC Power Supply

Removing a T320 DC Power Supply

The power supplies are located at the rear of the chassis below the SIBs. Each power supply weighs approximately 12 lb (5.4 kg).

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.

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

To remove a 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.

   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. For more information about ESD, see Preventing Electrostatic Discharge Damage to a T320 Router.
3. Switch the circuit breaker on the power supply faceplate to the off position (O).
4. Remove the clear plastic cover protecting the terminal studs on the faceplate.
5. Remove the nuts and washers from the terminal studs (see Figure 1). (Use a 7/16–in. nut driver or pliers.)

   Figure 1: Disconnecting Power Cables from the DC Power Supply

   
6. Remove the cable lugs from the terminal studs.
7. Loosen the captive screws on the cable restraint on the right edge of the power supply faceplate.
8. Carefully move the power cables out of the way.
9. 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.
10. Twist the ejector handles on the upper corners of the faceplate counterclockwise to unseat the power supply.
11. 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).

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

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

    Caution: Each power supply weighs approximately 12 lb (5.4 kg). Be prepared to support the full weight of the power supply as you remove it from the router.

Figure 2: Removing a T320 Power Supply

Figure 3: Rear of the Power Supply Showing Midplane Connectors

Installing a T320 DC Power Supply

Caution: Each power supply must be connected to a dedicated DC power source.

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. For more information about ESD, see Preventing Electrostatic Discharge Damage to a T320 Router.
3. Switch the circuit breaker 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 nuts and washers from the terminal studs.
9. Attach the lugs on the DC source power cables to the terminal studs.
   1. Attach the positive (+) DC source power cable lugs to the RETURN (return) terminals.
   2. Attach the negative (–) DC source power cable lugs to the –48V (input) terminals.

   Secure the cable lugs to the terminal studs, first with the washers, then with the nuts. Apply between 23 lb-in. (2.6 Nm) and 25 lb-in. (2.8 Nm) of torque to each nut.

10. Verify that the power cables are not touching or in the way of any other components.
11. Loosen the captive screws on the cable restraint on the right edge of the power supply faceplate.
12. Route the positive and negative DC power cables through the top and bottom of each cable restraint.
13. Tighten the cable restraint captive screws to hold the power cables in place.
14. Verify that the ground and power cabling are correct, that they are not touching or blocking access to router components, and that they do not drape where people could trip on them.
15. Replace the clear plastic cover over the terminal studs on the faceplate.
16. Switch on the external circuit breakers to provide voltage to the DC power source cable leads.
17. Switch the circuit breaker on the power supply to the on position (|) and observe 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 powering off a power supply, wait at least 60 seconds before turning it back on. After powering on a power supply, wait at least 60 seconds before turning it off. If the system is completely powered off when you power on the power supply, the Routing Engine boots as the power supply completes its startup sequence. If the Routing Engine finishes booting and you need to power off the system again, see Powering Off the T320 Router. 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 display output, 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.

Figure 4: Installing a Replacement T320 Power Supply