Removing a DC Power Supply

The DC power supplies are located at the bottom rear of the chassis, as shown in Figure 2. Each DC power supply weighs approximately 12 lb (5.5 kg).

Caution: Do not leave a power supply slot empty for more than a short time while the router is operational. The power supply must remain in the chassis for proper airflow.

To remove a DC power supply, follow this procedure (see Figure 67, Figure 68, and Figure 69):

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. Verify that the router is attached to a proper earth ground. For more information about ESD, see Preventing Electrostatic Discharge Damage.
2. Press the power switch for the power supply (located on the power supply faceplate) to the OFF (O) position.

   Note: If you are power cycling the power supply rather than shutting it off for a time, wait at least 60 seconds after turning it off before turning it back on. If you need to power it off again, wait for at least 60 seconds after powering it on.

3. Shut off the power flowing to the power supply from the external power source, so that the voltage across the leads of the power cables is 0 V. Ensure that there is no chance that the cable leads might become active during the procedure.
4. Using a Phillips screwdriver, loosen and remove the screws securing the protective shield over the terminal studs on the power supply faceplate. Remove the cover.
5. Using a 7/16-in. nut driver or wrench, loosen the outer nut on each power supply terminal stud. Remove the outer nut and locking washer from each stud and slide the power cable lugs off the studs.

   Caution: Do not substitute a metric nut driver or wrench. A tool that does not fit the nuts exactly can damage them.

6. Loosen the thumbscrew at each end of the power supply faceplate, using a Phillips screwdriver if necessary. Unscrew both thumbscrews simultaneously and at about the same rate (unscrewing the two screws alternately or at very different rates can cause the power supply to become lodged in the slot, making it difficult to turn the screws).
7. Pull the ejector handle away from the faceplate.
8. Grasp the handle on the power supply faceplate and pull firmly to slide the unit about halfway out of the chassis.
9. Place one hand under the power supply to support it, then slide it completely out of the chassis.

Figure 67: Press the Power Switch to the Off Position on a DC Power Supply

Figure 68: Disconnecting Power Cables from a DC Power Supply

Figure 69: Removing a DC Power Supply