Silicon Graphics 1450, Maintenance Manual

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14 007-4276-001
1: Detailed Chassis Description
DC power is sourced through 20-pin and 24-pin power cables to the baseboard. Remote
sensing signals are provided through one 14-pin auxiliary power cable to the baseboard.
The AC power status of each power supply module is indicated by an LED. The LED is
located on the power supply module. Table 1-4 shows the AC power LED status.
There are also three standby channels and each has an LED called a standby LED. These
LEDs are located on the right side of the power subsystem bay and each indicates the
status of that standby channel.
Individual power supply modules are hot-swappable. In other words, you can remove
and install a power supply module without shutting down the server. After a power
supply module has been removed from the system, airflow patterns are disrupted within
the system. To maintain correct airflow patterns within the chassis and to ensure that all
components remain within specification under all system environmental conditions,
power supply module hot-swap operations should not exceed two minutes in duration.
System Cooling
The SGI 1450 server uses up to six fans mounted in a fan board assembly in the middle
of the chassis between the E-Bay and peripheral bays. The six fans are noted by “A” in
Figure 1-7.
Table 1-4 AC Power LED State Status
LED State Status
Solid green AC power is applied to the power subsystem and standby voltage is available.
Off The LED is off when one of the following conditions occur:
The power supply modules are disabled by the DC enable signal.
The power supply module is disabled by another switch.
The power supply module has been overstressed.
The power supply module has failed and replacement of the unit is necessary.