Redundant power supply replacement

The MSS high-availability configuration (MSS-H) has two power supplies, allowing one to take over in case the other fails. Either power supply is considered "hot swappable" and can be replaced while the system is in service.

The MSS-H uses two types of redundant power supply. Follow the procedure for your model. See figure MSS-H with vertically stacked power supplies or MSS-H with side-by-side power supplies.

Caution! Never remove the cover on a power supply. If a power supply is faulty, replace the entire component.

Replacing an MSS-H power supply

To replace a power supply on the MSS high-availability configuration:

1. Verify that the replacement equipment is on site and appears to be in usable condition, with no obvious shipping damage.
2. Identify and remove the faulty power supply.
3. Install a new power supply and verify operation.

Identify and remove the faulty power supply

To identify which of the two power supplies is malfunctioning and remove it:

1. Turn off the power failure alarm buzzer. Use one of the following methods:
• At the rear of the machine, press the buzzer reset button. See figure MSS high-availability configuration (back view).
  • For the vertically stacked model, this red button is located to the left side of the stacked units.
  • For the side-by-side model, this button is located below the rightmost power supply.
• At the front of the machine, remove the front bezel, and then insert a narrow tool into the BUZZER RESET switch.

Note: The P/S FAIL LED on the front of the machine remains lit until the power problem is resolved.

2. At the rear of the machine, locate the power supply that failed (its green LED should be dark).
3. Remove the faulty power supply as follows:
• For the vertically stacked model: See figure Removing or replacing a redundant power supply (vertically stacked model).
1. Press the rocker switch to turn off power to the faulty power supply.

Note: If the rocker switch is already off, turn it on to see if the power supply is working (the green LED on the unit should come on, and the P/S FAIL LED on the front of the machine should go dark). The MSS-H requires that two functional power supplies be installed with their power switches on, or it generates a power supply alarm.

2. Unplug the AC power cord from the faulty power supply.
3. Unscrew the retaining screw at the side of the faulty power supply.
4. Pull on the handle to remove the faulty power supply.
• For the side-by-side model: See figure Removing or replacing a redundant power supply (side-by-side model).
1. Give the thumbscrew beneath the handle several turns towards the unlocked position until it is fully released (see the unlock symbol on the power supply).

Caution! Do not turn off the rocker switch on the side-by-side model of power supply. A single AC power source supplies both power supplies.

2. Lift the handle.
3. Pull on the handle to remove the faulty power supply.

Install a new power supply and verify operation

To install a new power supply and verify its correct operation:

1. Slide in the replacement power supply until it is firmly seated.
2. Flatten the handle against the unit.
3. Secure the power supply in the unit and verify power:
• For the vertically stacked model: See figure Removing or replacing a redundant power supply (vertically stacked model).
1. Tighten the retaining screw.

Note: For safety reasons, tighten the retaining screw with a screwdriver until it cannot be loosened by hand.

2. Plug back in the AC power cord.
3. Turn the power switch for this unit on.

The green LED should light, indicating that the power supply is ready for service.

• For the side-by-side model: See figure Removing or replacing a redundant power supply (side-by-side model).
1. Verify that the green LED lights, indicating that the power supply is operating correctly.
2. Tighten the thumbscrew beneath the handle in the locked position (see the lock symbol on the power supply). .
4. Verify that the P/S FAIL LED on the front of the machine is dark.

Note: An alarm buzzer sounds and the P/S FAIL LED on the front of the machine lights unless two functional power supplies are installed and their power switches are on.

 

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