Preparing the system to remove and replace a power supply

To prepare the system to remove and replace a power supply, complete the steps in this procedure.

1. Complete the prerequisite tasks. For instructions, see Before you begin.
2. Identify the part and the system that you will be working on. For instructions, see Identifying a part.
3. If applicable, open the rack door at the rear of the system.
4. Attach the electrostatic discharge (ESD) wrist strap.
   Attention:

   • Attach an electrostatic discharge (ESD) wrist strap to an unpainted metal surface of your hardware to prevent the electrostatic discharge from damaging your hardware.
   • When using an ESD wrist strap, follow all electrical safety procedures. An ESD wrist strap is used for static control. It does not increase or decrease your risk of receiving electric shock when using or working on electrical equipment.
   • If you do not have an ESD wrist strap, just prior to removing the product from ESD packaging and installing or replacing hardware, touch an unpainted metal surface of the system for a minimum of 5 seconds.
5. Locate the light-emitting diodes (LEDs) on the power supplies. Two power supplies are installed in the rear of the system. Figure 1 shows the LED locations.
   Figure 1. Location of the power supplies and LEDs

   
   The power supply has three LEDs that indicate the status of the power supply:

   • An ac power-on LED (green)
   • A dc power-on LED (green)
   • An error LED (amber)
   Table 1 provides the descriptions for the states of the power supply LEDs and helps to identify whether the power supplies are working or have a failure.

   Table 1. Description of the power supply LED states

   ac power LED (Green)	dc power LED (Green)	Error and identify LED (Amber)	Power supply status
   On (Solid)	On (Solid)	Off	The power supply is operating correctly.
   On (Solid)	Flashing	Off	The system is turned off, but the power supply is still connected to the power source.
   On (Solid)	Off	On	The power supply is not operating correctly or has failed.

6. Determine whether the repair can continue concurrently with the system power turned on. To continue the repair concurrently, the following conditions must be true:
   • If you are servicing an 8335-GCA system:
     • Power supplies must be installed in both slots.
     • If only one amber fault LED is On, the repair can be completed concurrently.
     Attention:

     • Removing and replacing the power supply is a time sensitive task when you are servicing with the system power turned on (concurrent).
     • To avoid a system shutdown, you must replace the failed power supply within five minutes after you remove the power supply from the system.
     • Ensure that you have read the complete procedure to remove and replace a power supply and that you are prepared to remove and replace the power supply within the time limit.
   • If you are servicing an 8335-GTA system, concurrent repair of the power supply is not supported; the system must be turned off. Continue with step 7 and follow the instructions for a noncurrent repair.
7. Select an action:
   • To do a concurrent repair with the system running:
     1. Continue the procedure with the system power turned on.
     2. Remove the failed power supply that is indicated by the amber fault LED. For instructions, see Removing a power supply.
        Remember: Failure to replace the power supply after removing the power supply from the system within five minutes can cause the system to automatically power off.
   • To do a non-concurrent repair with the system power turned off:
     1. Label the failed power supply that is indicated by the amber fault LED.
     2. Stop the system. For instructions, see Stopping the system.
     3. Disconnect the power source from the system by unplugging the system. For instructions, see Disconnecting the power cords.
     4. Using your label, remove the failed power supply. For instructions, see Removing a power supply.