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Maintaining the EX9251 Power System

 

Powering Off an EX9251 Switch

Before you power off an EX9251 switch:

  • Ensure that you have taken the necessary precautions to prevent electrostatic discharge (ESD) damage. See Prevention of Electrostatic Discharge Damage.

  • Ensure that you have the following parts and tools available to power off an EX9251 switch:

    • An ESD wrist strap

    • An external management device such as a PC

    • The appropriate cable to connect the external management device to the console port labeled CON on the switch

Note

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

To power off the switch:

  1. Connect a management device to the console (see Connect a Device to a Management Console Using an RJ-45 Connector).
  2. On the external management device connected to the switch, issue the request vmhost power-off command.
    user@host> request vmhost power-off
    Power-off the vmhost ? [yes,no] (no) yes

    The switch shuts down and the console displays the message Power down.

To power on the switch again, press the button labeled OFFLINE on the front panel of the switch for one second.

You can take the switch offline by pressing the button labeled OFFLINE on the front panel of the switch for three seconds. If the switch is offline, you can bring it online by pressing the button labeled OFFLINE for one second.

You can reset the switch by pressing the button labeled RESET on the front panel of the switch. You must not use any sharp object to press the RESET button. You can use any blunt object of 1.5 mm diameter to operate the RESET button.

Removing an AC Power Supply from an EX9251 Switch

The AC power supply in an EX9251 switch is a hot-removable and hot-insertable field-replaceable unit (FRU). You can remove and replace it while the switch is running without turning off power to the switch or disrupting switching functions. You remove AC power supplies from the rear of the chassis.

Caution

Before you remove a power supply, ensure that you have power supplies sufficient to power the switch that remains in the chassis (see Power Requirements for EX9251 Switch Components).

Caution

Do not leave the power supply slot empty for a long time while the switch is operational. Either replace the power supply unit promptly or install a cover panel over the empty slot.

Note

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

Before you remove an AC power supply from the switch:

Ensure that you have the following parts and tools available:

  • An ESD wrist strap

  • A replacement power supply or a cover panel for the power supply slot

To remove an AC power supply from an EX9251 switch (see Figure 1):

  1. Switch off the dedicated customer-site circuit breaker for the power supply, and remove the power cord from the AC power source. Follow the instructions for your site.
  2. Verify that the input status LED on the power supply is not lit.
  3. Wrap and fasten one end of the ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
  4. Remove the power cord from the AC appliance inlet on the AC power supply faceplate.
  5. Press the release latch on the side of the AC power supply to disconnect the power supply from the chassis.
  6. Pull the power supply straight out of the chassis.
  7. Either replace the power supply promptly or install a cover panel over the empty slot.
    Figure 1: Removing an AC Power Supply from an EX9251 Switch
    Removing an AC Power
Supply from an EX9251 Switch

Installing an AC Power Supply in an EX9251 Switch

The AC power supply in an EX9251 switch is a hot-insertable and hot-removable field-replaceable unit (FRU). You can remove and replace it while the switch is running without turning off power to the switch or disrupting switching functions. You can install up to two AC power supplies in an EX9251 switch. The power supplies install in the slots on the rear panel of the chassis.

Caution

EX9251 switches use either AC or DC power supplies. Do not mix AC and DC power supplies in a switch.

Before you install an AC power supply in the switch:

Ensure that you have the following parts and tools available:

  • An ESD wrist strap

  • Phillips (+) screwdriver, number 2 (not provided)

Note

Each AC power supply must be connected to a dedicated AC power source outlet.

To install an AC power supply in an EX9251 switch (see Figure 2):

  1. Wrap and fasten one end of the ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
  2. If the power supply slot has a cover panel on it, unscrew the screw on the side of the cover panel in the counterclockwise direction using the screwdriver, and remove the cover panel. Save the cover panel for later use.
  3. Taking care not to touch power supply components, pins, leads, or solder connections, remove the power supply from its bag.
  4. Using both hands, hold and slide the AC power supply straight into the chassis until the power supply is fully seated in the power supply slot. The power supply faceplate must align with the power supply faceplate or the cover panel installed in the adjacent power supply slot.
    Figure 2: Installing an AC Power Supply in an EX9251 Switch
    Installing an AC
Power Supply in an EX9251 Switch
Note

If you have a Juniper J-Care service contract, register any addition, change, or upgrade of hardware components at https://www.juniper.net/customers/support/tools/updateinstallbase/ . Failure to do so can result in significant delays if you need replacement parts. This note does not apply if you replace existing components with the same type of component.

To connect power to an AC power supply, see Connecting AC Power to an EX9251 Switch and Powering on the Switch.

Removing a DC Power Supply from an EX9251 Switch

The DC power supply in an EX9251 switch is a hot-removable and hot-insertable field-replaceable unit (FRU). You can remove and replace it while the switch is running without turning off power to the switch or disrupting switching functions. You remove DC power supplies from the rear of the chassis.

Caution

Before you remove a power supply, ensure that you have power supplies sufficient to power the switch that remains in the chassis. See Power Requirements for EX9251 Switch Components.

Caution

Do not leave the power supply slot empty for a long time while the switch is operational. Either replace the power supply unit promptly or install a cover panel over the empty slot.

Before you remove a DC power supply from the switch:

Ensure that you have the following parts and tools available:

  • An ESD wrist strap

  • A socket screwdriver

  • A replacement power supply or cover panel for the power supply slot

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.

Note

After powering off a power supply, wait for at least five seconds before turning it back on.

To remove a DC power supply from an EX9251 switch (see Figure 4):

  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 input status LED on the power supply is not lit.
  4. Wrap and fasten one end of the ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
  5. Move the DC circuit breaker on the DC power supply faceplate to the off position.
  6. Remove the clear plastic cover protecting the terminal studs on the faceplate.
  7. Using a socket screwdriver, remove the screws from the DC power terminals.
  8. Remove the cable lugs from the terminal studs.
  9. Carefully move the power cables out of the way (see Figure 3).
    Figure 3: Removing DC Power Cables
    Removing DC Power
Cables
  10. Press the latch located on the DC power supply, to release it from the chassis.
  11. Pull the power supply straight out of the chassis.
  12. Either replace a power supply promptly or install a cover panel over the empty slot.
Figure 4: Removing a DC Power Supply from an EX9251 Switch
Removing
a DC Power Supply from an EX9251 Switch

Installing a DC Power Supply in an EX9251 Switch

The DC power supply in an EX9251 switch is a hot-removable and hot-insertable field-replaceable unit (FRU). You can remove and replace it while the switch is running without turning off power to the switch or disrupting switching functions. You can install up to two DC power supplies in an EX9251 switch. All DC power supplies install in the slots on the rear panel of the chassis.

Caution

EX9251 switches use either AC or DC power supplies. Do not mix AC and DC power supplies in a switch.

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.

Before you install a DC power supply in the switch:

  • Ensure you understand how to prevent electrostatic discharge (ESD) damage. See Prevention of Electrostatic Discharge Damage.

  • 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.

Ensure that you have the following parts and tools available:

  • An ESD wrist strap

  • Phillips (+) screwdriver, number 1 and 2

To install a DC power supply in an EX9251 switch (see Figure 5):

  1. Wrap and fasten one end of the ESD wrist strap around your bare wrist, and connect the other end of the strap to the ESD point on the switch.
  2. If the power supply slot has a cover panel on it, unscrew the screw on the side of the cover panel in the counterclockwise direction using the screwdriver, and remove the cover panel. Save the cover panel for later use.
  3. Taking care not to touch power supply components, pins, leads, or solder connections, remove the power supply from its bag.
  4. Move the DC circuit breaker on the power supply faceplate to the off position.
  5. Using both hands, hold and slide the DC power supply straight into the chassis until the power supply is fully seated in the power supply slot. The power supply faceplate must align with the power supply faceplate or the cover panel installed in the adjacent power supply slot.
Figure 5: Installing a DC Power Supply in an EX9251 Switch
Installing a DC
Power Supply in an EX9251 Switch
Note

If you have a Juniper J-Care service contract, register any addition, change, or upgrade of hardware components at https://www.juniper.net/customers/support/tools/updateinstallbase/ . Failure to do so can result in significant delays if you need replacement parts. This note does not apply if you replace existing components with the same type of component.

To connect power to a DC power supply, see Connecting DC Power to an EX9251 Switch and Powering on the Switch.

Maintaining Power Supplies in EX9251 Switches

Purpose

For optimum switch performance, verify the condition of the installed power supplies.

Action

On a regular basis:

  • Check the status of the power supplies by issuing the show chassis environment pem command. The output for EX9251 switches is similar to the following:

    user@switch> show chassis environment pem
  • Make sure that the power and grounding cables are arranged so that they do not obstruct access to other switch components.

  • Routinely check the status LEDs on the power supply faceplates and the front panel in EX9251 switches to determine whether the power supplies are functioning normally.

  • Check the alarm LEDs on the front panel in EX9251 switches. Power supply failure or removal triggers an alarm that causes one or both of the LEDs to light. You can display the associated error messages by issuing the following command:

    user@switch> show chassis alarms
  • Periodically inspect the site to ensure that the grounding and power cables connected to the switch are securely in place and that there is no moisture accumulating near the switch.