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Removing an MX80 DC Power Supply

Before you remove a power supply, be aware of the following:

Note: The minimum number of power supplies must be present in the router at all times.

Warning: Before performing DC power procedures, ensure that power is removed from the DC circuit. To ensure that all power is off, locate the circuit breaker on the panel board that services the DC circuit, switch the circuit breaker to the off position, and tape the switch handle of the circuit breaker in the off position.

Caution: To maintain proper cooling and prevent thermal shutdown of the operating power supply unit, each power supply slot must contain either a power supply or a blank panel. If you remove a power supply, you must install a replacement power supply or a blank panel shortly after the removal.

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

To remove a DC power supply (see Figure 1):

1. Switch off the dedicated customer site circuit breaker for the power supply being removed. Follow your site's procedures for ESD.
2. 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.
3. Verify that the status LED on the power supply is not lit.
4. Attach an electrostatic discharge (ESD) grounding strap to your bare wrist, and connect the strap to one of the ESD points on the chassis.
5. Move the DC circuit breaker on the DC power supply faceplate to the off (O) position.
6. Remove the clear plastic cover protecting the terminal studs on the faceplate (see Figure 2).
7. Remove the screw from each of the terminals. (Use a number 2 Phillips screwdriver.)
8. Remove the cable lugs from the terminals.
9. Carefully move the power cables out of the way.
10. Press the latch located on the left side of the power supply, to release it from the chassis.
11. Pull the power supply straight out of the chassis.

Installing an MX80 DC Power Supply

Warning: Before performing DC power procedures, ensure that power is removed from the DC circuit. To ensure that all power is off, locate the circuit breaker on the panel board that services the DC circuit, switch the circuit breaker to the off position, and tape the switch handle of the circuit breaker in the off position.

To install a DC power supply (see Figure 3):

1. Ensure that the voltage across the DC power source cable leads is 0 V and that there is no chance that the cable leads might become active during installation.
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 DC circuit breaker on the DC power supply faceplate to the off (O) position.
4. Using both hands, slide the power supply straight into the chassis until the power supply is fully seated in the chassis slot. The power supply faceplate should be flush with any adjacent power supply faceplate or blank installed in the power supply slot.
5. Remove the clear plastic cover protecting the terminal on the faceplate.
6. Remove the screws from the terminals.
7. Secure each power cable lug to the terminal with the screw (see Figure 4). Apply between 5 lb-in. (0.6 Nm) and 6 lb-in. (0.7 Nm) of torque to screw. Do not overtighten the nut. (Use a number 2 Phillips screwdriver.)
   1. Secure the positive (+) DC source power cable lug to the RTN (return) terminal.
   2. Secure the negative (–) DC source power cable lug to the –48V (input) terminal.

   Caution: Ensure that each power cable lug seats flush against the surface of the terminal block as you are tightening the screws. Ensure that each screw is properly threaded into the terminal. Applying installation torque to the screw when improperly threaded may result in damage to the terminal.

   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.

   Note: For information about connecting to DC power sources, see MX80 Router DC Power Specifications.

8. Replace the clear plastic cover over the terminals on the faceplate.
9. 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.
10. On each of the DC power supplies, switch the DC circuit breaker to the center position before moving it to the on ( | ) position.

    Note: The circuit breaker may bounce back to the off (O) position if you move the breaker too quickly.

    Note: If more than one power supply is being installed, turn on all power supplies at the same time.