Sun Enterprise 6500/5500/4500 Systems Reference Manual

Power/Cooling Module (PCM)

The power/cooling module (PCM) provides power for two boards. The PCM also supplies cooling air to the board slots, so in normal operation each board must be next to a working PCM.

Figure 7-5 PCM

Graphic

The PCM incorporates an AC inrush limit circuit and two precharge inputs (3.3V and 5V) that enable it to be hot-pluggable into a live centerplane.

Within a system all PCMs operate in a parallel redundant mode, sharing 2.0V, 3.3V, and 5V output currents. The shared 5V output also includes the 5V output of a peripheral power supply.

Requirements for Redundant Power

If a DC supply in a PCM fails, the system boards will continue to be powered and cooled by the other power supplies if sufficient redundancy (an additional power supply) is present.

For example, if an Enterprise system needs a minimum of three power supplies and four are present, then the system has redundancy. However, fully configured Enterprise systems represent a different situation and are always hot-pluggable. That is, an Enterprise 5500 or 4500 system with seven or eight boards and four PCMs is hot-pluggable. (The peripheral power supply acts as the "extra" power supply.) Similarly, an Enterprise 6500 system with fifteen or sixteen boards and eight power supplies is also hot-pluggable. (Seven PCMs are sufficient to power sixteen active boards; the eighth PCM is "extra." However, the eighth PCM is required for cooling purposes.) See Table 7-3.


Note -

The presence of an additional (extra) PCM in the system provides redundancy and allows hot-plug of PCMs.


Table 7-3 Minimum and Redundant Working Power Supplies Required to Power Active Boards

 

Enterprise 5500/4500 Systems 

Enterprise 6500 System 

Number of Boards 

Minimum Working Power Supplies 

Redundant Working Power Supplies (Hot-pluggable) 

Minimum Working Power Supplies 

Redundant Working Power Supplies (Hot-pluggable) 

1-2 

3-4 

5-6 

7-8 

3 + peripheral supply*

4 + peripheral supply 

*Note: System needs a fourth PCM for cooling purposes  

9-10 

 

 

11-12 

 

 

13-14 

 

 

15-16 

 

 

7* 

  *Note: System needs an eighth PCM for cooling purposes

Failed power supplies must be replaced as soon as practical. Operating an Enterprise system without a redundant power supply will result in an outage at the next PCM failure.

Cooling Requirements


Note -

In the Enterprise system, all boards must be adjacent to a PCM. The fans in the PCM cool the boards. The minimum configuration is one PCM for every two adjacent boards.


The power supplies incorporate redundant bulk fan electrical power so that the fans continue to operate in a failed power supply with the redundant fan power from the peripheral power supply.

Troubleshooting a PCM

A green LED is lit on the power supply when it is operational. When a PCM fails, a yellow LED is lit on the power supply.

You will see a message similar to the following example on your system console when a PCM fails:


WARNING: Core Power Supply 2 Failing
WARNING: Redundant power lost

See Chapter 10, Flow Diagrams for Troubleshooting for more information.

Replacing a PCM


Caution - Caution -

Do not replace a PCM while the system is in the low power mode. Remove and replace the PCM only in a running system. Replacing a PCM during low power mode will cause the system to power up immediately and result in a severe overload condition for that PCM (the other PCMs will remain in the low power mode). (The system is in the low power mode if the front panel and board LEDs are all off while the yellow LEDs are lit on the power supplies.)



Caution - Caution -

Replace the PCM within several minutes or risk overheating the board(s) cooled by the fans in that power supply.


Remember the following rules for hot-plug replacement of a PCM:

Figure 7-6 PCM -- Front and Rear Installation

Graphic

  1. Use the printdiag (1M) command to determine if precharge current is present.

  2. Use a Phillips #1 screwdriver to turn each quarter-turn access slot on the power supply to the unlocked position (Figure 7-7).

    Figure 7-7 Quarter-Turn Access Slots

    Graphic

  3. Pull the end of the extraction lever outward to release the power supply from the centerplane.

  4. Pull out the power supply.

    You will see a message similar to the following example on your system console:


    NOTICE: Core Power Supply 2 Removed

  5. Insert the replacement power supply halfway into the guide slots, then:

    1. Verify that power supply is oriented so that the extraction lever is toward the outside edge of the system (Figure 7-6).

    2. Verify that the arrows in the quarter-turn access slots are turned to the unlocked position.

    3. Open the extraction lever to the unlocked position.

      The power supply will not seat fully unless the extraction lever is in the unlocked position.


      Caution - Caution -

      DO NOT FORCE the power supply into a slot; this can cause damage to the power supply and system.


    The power supply should insert and seat smoothly. If it binds, remove it, and inspect the slot for obstructions. Take care to avoid damaging the springfingers at the bottom of the power supply.

  6. Slide the power supply to the centerplane, then use the extraction lever to seat the power supply.

    Swing the lever inward to the locked position. Do not press on the front panel of the power supply to seat it; doing so will damage the connector pins.

  7. Use a Phillips #1 screwdriver to turn each quarter-turn access slot to the locked position (Figure 7-7).

  8. Check to be sure the green LED is lit.

    If the green LED is not lit, the power supply is not seated properly. Repeat Step 2 to Step 8. If the green LED is still not lit, see Chapter 10, Flow Diagrams for Troubleshooting for more information.

    When the power supply is correctly installed, you will see a message similar to the following example on your system console:


    NOTICE: Core Power Supply 2 Installed
    NOTICE: Core Power Supply 2 OK
    NOTICE: Redundant power available