The chassis has the following boards installed.
PCIe Risers: Each riser supports two PCIe cards that are customer-replaceable. There are two risers per system, each attached to the rear of the motherboard.
Motherboard: The motherboard is a FRU and includes CPU modules, slots for 18 DIMMs, memory control subsystems, and the service processor (SP) subsystem. The SP subsystem controls the host power and monitors host system events (power and environmental). The SP controller draws power from the host 3.3V standby supply rail, which is available whenever the system is receiving AC input power, even when the system is turned off.
Power Distribution Board: The power distribution board is a FRU and distributes main 12V power from the power supplies to the rest of the storage controller. It is directly connected to the connector break out board and to the motherboard through a bus bar and ribbon cable. It also supports a top cover interlock kill switch. The power supplies connect directly to the power distribution board.
Connector Break Out Board: The connector break out board is FRU and serves as the interconnect between the power distribution board and the fan power boards, storage drive backplane, and I/O board. It also contains the top-cover interlock "kill" switch.
Fan Power Boards: The two fan power boards are FRUs and carry power to the system fan modules. In addition, they contain fan module status LEDs and transfer I2C data for the fan modules.
Storage Drive Backplane: The storage drive backplane is a FRU and includes the connectors for the storage drives, as well as the interconnect for the I/O board, power and locator buttons, and system/component status LEDs. The system has a 12-disk backplane. Each drive has an LED indicator for Power/Activity, Fault, and Locate.