Replacing Redundant AC Power Supplies in an EX4500 Ethernet Switch Without Disrupting Service This field replacement guide provides instructions for replacing the two AC power supplies in an EX4500 Ethernet switch (Figure 1) with redundant AC power while the switch is operating. The power supplies in an EX4500 switch are field-replaceable units (FRUs) and are designed to be hot-swapped while the switch is operating in a network. You can service (remove and replace) the power supply in the top slot and the power supply in the bottom slot, one at a time, without disrupting service. NOTE: Each power supply must be connected to a dedicated AC power source outlet. This guide supplements the installation instructions in the Complete Hardware Guide for EX4500 Ethernet Switches, available on the documentation CD shipped with your switch. Figure 1: EX4500 Ethernet Switch, Front View g020845 Contents Installation Prerequisites...2 Replacing Redundant Power Supplies...3 Replacing the Power Supply in the Top Slot...3 Replacing the Power Supply in the Bottom Slot...6 1
Installation Prerequisites Before replacing the power supplies, ensure the following: Matching power supplies. Make sure you have the correct replacement power supplies for your EX4500 switch model. The color of the ejector lever on each power supply must match the color of the labels visible through the fan tray vents (see Figure 2). Orange for INTAKE. The back-to-front model has an orange ejector lever on the power supplies and an orange INTAKE label visible through the fan tray vents. Green for EXHAUST. The front-to-back model has a green ejector lever on the power supplies and a green EXHAUST label visible through the fan tray vents. CAUTION: Operating the switch with an incorrect power supply might cause the chassis to overheat. Figure 2: EX4500 Switch, Rear View Ejector lever ESD damage prevention. Ensure that you understand how to prevent electrostatic discharge (ESD) damage and have two antistatic bags or mats and an ESD grounding strap available. For details, see Prevention of Electrostatic Discharge Damage in the Complete Hardware Guide for EX4500 Ethernet Switches. If a grounding strap is not available, take these equivalent precautions: Before removing a component. Touch the exposed, bare metal of the switch to ground yourself before handling the component. Before installing a component. Hold the component in its antistatic bag in one hand and touch the exposed, bare metal of the switch with the other hand. If you do not install a replacement power supply immediately after removing the old one. Have a cover panel available to protect the empty power supply slot. 2 Installation Prerequisites
Replacing Redundant Power Supplies To replace both power supplies in an EX4500 switch during operation, service the power supply in the top slot first, and then repeat the procedure for the power supply in the bottom slot. NOTE: Each power supply must be connected to a dedicated AC power source outlet. Replacing the Power Supply in the Top Slot To replace the power supply in the top slot of the switch: 1. Ensure that the EX4500 switch you are working on is operating normally, with both power supplies turned on, by verifying that the LED on each power supply (Figure 3) is lit steadily green. Figure 3: Verify Green Power Supply LEDs for Normal Operation AC power supply LEDs g020809 2. Attach the ESD grounding strap to your bare wrist, and connect the strap to the ESD point on the lower right front of the chassis or touch the exposed, bare metal of the switch to ground yourself before handling a component. 3. To remove AC power from the old power supply: a. Identify the AC power source outlet that is powering the old power supply. b. If the AC power source outlet has an on/off switch, set it to the OFF (0) position. c. Gently pull the male end of the power cord for the old power supply out of the AC power source outlet. 4. To remove the power supply cord from the old power supply (see Figure 4 on page 4): a. On the power supply, turn the adjustment nut of the power cord retainer clockwise until you can see the power cord. b. Pull the power cord out of the slot in the adjustment nut. Replacing Redundant Power Supplies 3
c. Unplug the power cord from the AC appliance inlet on the power supply. Save the cord. d. Remove the power cord retainer clip by pushing it to one side, squeezing both sides of the clip, and pulling it completely out of the power supply. Save the clip. Figure 4: AC Power Cord Adjustment Nut and Retainer Clip Retainer clip Adjustment nut 5. To remove the old power supply from the switch: g020942 a. Unseat the power supply by pressing the orange or green ejector lever next to the AC appliance inlet. b. Grasp the power supply handle and pull firmly, keeping one hand under the power supply to support it as you slide it out of the chassis. CAUTION: Do not leave the power supply slot empty for a long time while the switch is operational. Either replace the power supply promptly or install a cover panel over the empty slot. c. Place the old power supply in an antistatic bag or on an antistatic mat. 6. To install the replacement power supply in the switch: a. If you have not already done so, attach the ESD grounding strap to your bare wrist, and connect the strap to the ESD point on the lower right front of the chassis or hold the component in its antistatic bag in one hand and touch the exposed, bare metal of the switch with the other hand. b. Taking care not to touch power supply pins, leads, or solder connections, remove the replacement power supply from its antistatic bag. c. Using both hands, place the replacement power supply in the empty power supply slot in the switch and slide it in (Figure 5) until you hear a distinct click sound, indicating that the power supply is fully seated in the chassis. Figure 5: Sliding a Replacement Power Supply into the Switch ST 1 0 g020832 4 Replacing Redundant Power Supplies
7. To connect AC power to the replacement power supply (see Figure 6): a. Ensure that you have the power cord retainer clip and the power cord from the old power supply you removed in Steps 4c and 4d on page 4. b. Squeeze the sides of the retainer clip, and insert the L-shaped ends into the holes in the bracket on either side of the appliance inlet on the replacement power supply. c. Insert the female end of the power cord into the AC appliance inlet on the replacement power supply. d. Push the retainer clip toward the cord until the cord slides into the slot on the adjustment nut. e. Turn the adjustment nut clockwise until it is tight against the base of the coupler and the slot in the nut is turned 90º from the top of the switch. f. If the AC power source outlet you are using has an on/off switch, ensure that it is set to the OFF (0) position. g. Gently insert the male end of the power cord plug into the AC power source outlet, and set the on/off switch on the outlet (if any) to the ON ( ) position. Figure 6: Connecting the Replacement Power Supply Cord Retainer clip Tighten adjustment nut. Adjustment nut g020943 8. To ensure that the replacement power supply is operating normally and both power supplies are providing redundant power to the switch, verify that both power supply LEDs (Figure 7) are lit steadily green. Figure 7: Verify Green Power Supply LEDs for Normal Operation AC power supply LEDs g020809 9. To replace the power supply in the bottom slot, go on to Replacing the Power Supply in the Bottom Slot on page 6. Replacing Redundant Power Supplies 5
Replacing the Power Supply in the Bottom Slot To replace the power supply in the bottom slot of the switch: 1. If you have not already done so, ensure that the EX4500 switch you are working on is operating normally, with both power supplies turned on, by verifying that the LED on each power supply (Figure 8) is lit steadily green. Figure 8: Verify Green Power Supply LEDs for Normal Operation AC power supply LEDs g020809 2. If you have not already done so, attach the ESD grounding strap to your bare wrist, and connect the strap to the ESD point on the lower right front of the chassis or touch the exposed, bare metal of the switch to ground yourself before handling a component. 3. Remove power from the old power supply in the bottom slot (see Step 3 on page 3). 4. Remove the bottom old power supply from the switch (see Step 5 on page 4). CAUTION: Do not leave the power supply slot empty for a long time while the switch is operational. Either replace the power supply promptly or install a cover panel over the empty slot. 5. Install the bottom replacement power supply (see Step 6 on page 4). 6. Connect power to the bottom replacement power supply (see Step 7 on page 5). 7. To ensure that the replacement power supply is operating normally and both power supplies are providing redundant power to the switch, verify that both power supply LEDs (Figure 8) are lit steadily green. Copyright 2011, Juniper Networks, Inc. and its suppliers. All rights reserved. 6 Replacing Redundant Power Supplies