Dell PowerEdge 1750 - Manual (Page 24)

Inside the System
In Figure 4 -3 , the system covers are open and the bezel is removed to provide an interior view of the system.
Figure 4-3. Inside the System
The system board can accommodate one or two microprocessors. The PCI riser board assembly accommodates up to two PCI expansion cards. Up to four
memory modules may be installed on the system board.
The hard-drive bays provide space for up to three 1-inch SCSI hard drives. SCSI hard drives are connected to a SCSI controller on the system board through
the SCSI backplane board.
The peripheral bays provide space for an optional 3.5-inch diskette drive and a CD drive.
The power distribution board (PDB) provides hot-plug logic and power distribution for the system. Two hot-pluggable, redundant power supplies provide
power to the system board and internal peripherals.
During an installation or troubleshooting procedure, you may be required to change a jumper. For information about the system board jumpers, see " Jumpers
and Connectors ."
Expansion Cards
Up to two half-length, PCI-X expansion cards can be installed in the system, one on each side of the riser board assembly. See Figure 4 -4 . The riser board
assembly consists of two riser boards permanently attached to each other with plastic standoffs. It plugs into twin riser connectors on the system board and
is considered an extension of the system board. See
Figure 5 -3 .
The PCI slot locations are marked on the system board as PCI 1 and PCI 2. The PCI 1 connector on the riser board assembly is higher than the PCI 2
connector, because the PCI 1 card installs above the optional ROMB card.
Two different PCI card configurations are available:
l Two PCI-X, 64-bit, 133-MHz, 3.3-V expansion cards
l One PCI-X, 64-bit, 133-MHz, 3.3-V expansion card in PCI 2, and one PCI, 64-bit, 33-MHz, 5-V expansion card in PCI 1.
Figure 4-4. Riser-Board Expansion-Card Connectors
NOTICE: If you purchased a system with redundant power supplies, you must connect both power cables to the system; otherwise, the fans operate
at the maximum RPM, which increases the fan noise. To ensure redundancy, connect the power cables to two different electrical power sources.