IBM 9117-MMB User Manual page 29

Attention: Two power supplies must be present in the expansion unit. If one power supply fails, the
expansion unit continues to operate. If you are performing this procedure concurrently (with the power
turned on), there is a time limit. From the moment the power supply is removed, the exchange of the
power supply must be completed in less than 5 minutes. If you cannot replace the power supply in less than
5 minutes, the I/O drawer automatically shuts down.
Before installing or reinstalling a power supply, inspect the signal connector pins to ensure that the pins
are not bent or damaged.
Attention: Bent pins damage the midplane receptacle. Be careful not to touch or damage the signal
connector pins.
Read the following steps, but do not perform them yet. Then decide if you are ready (and able) to
complete this repair within 5 minutes.
1. Have the replacement power supply or fan ready.
2. Remove the power supply from the expansion unit.
3. Install the fan or fans into the power supply as required for the service procedure being performed.
4. Install the power supply into the enclosure.
If your system is not managed by an HMC or an SDMC, complete the following steps to replace the
power supply in an expansion unit or system while the system power is turned on:
1. If you are replacing a power supply or power-supply fan because of a failure, remove the failing
part as described in Removing a power supply or fan from a 5802 or 5877 expansion unit with the
power turned on.
2. Perform the prerequisite tasks, as described in Before you begin.
3. Open the front rack door.
4. Attach the wrist strap.
Attention:
v Attach a wrist strap to an unpainted metal surface of your hardware to prevent electrostatic
discharge (ESD) from damaging your hardware.
v When using a wrist strap, follow all electrical safety procedures. A wrist strap is for static control.
It does not increase or decrease your risk of receiving electric shock when using or working on
electrical equipment.
v If you do not have a 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. Optional: If you must replace a failing power-supply fan, complete the following steps:
a. Align the new fan with the opening in the power-supply assembly.
b. Press the fan (A) into its connector in the assembly as shown in Figure 17 on page 18.
c. Tighten the thumbscrew (D) as shown in Figure 17 on page 18.
17
Power supplies