Sun Enterprise 6500/5500/4500 Systems Reference Manual

Power/Cooling Modules (PCMs)

The DC power to the centerplane is supplied by one or more PCMs. Each PCM also provides cooling air for two board slots. If a slot contains a board, the adjacent PCM slot must contain a PCM to supply cooling air.

Current from individual PCMs is shared on the centerplane.

With automatic system reconfiguration (ASR), a PCM can be taken offline and replaced without halting the system. There are two restrictions:

  1. The remaining power/cooling modules must provide sufficient electrical power. As a general rule, the number of boards must be less than half the number of PCMs.

  2. The PCM should be replaced quickly so that any adjacent boards will not overheat from lack of fan cooling.

Figure B-10 PCM