Table 3–7 (Cont.) Power System Functional Summary
FRU
Functional Summary
DC5 H7179-AA
DC to dc converter which pr5 Vdc to the CPU, MMB,
SIMMs, I/O ATM, interface and console extender modules, as
well as +5 Vdc to the I/O ATM in5 Vdc to +3.3 Vdc
converter for the SOC.
Provides EMI filtering on the 48 V bus, and fusing to prevent
the power system from crashing due to a short circuit on a
converter input. Supports the crowbar SCR on a 5 V overvoltage
or undervoltage fault.
DC3 H7178-AA
DC to dc converter which pr3 Vdc to the CPU, I/O ATM,
interface and console extender modules. Pr12 Vdc to the
console extender 12 V to -12 V converter for the CPU
and I/O ATM modules, and the +21 V converter for the CPU and
I/O ATM clock logic.
Provides EMI filtering on the 48 V bus, and fusing to prevent
the power system from crashing due to a short circuit on a
converter input. Supports the crowbar SCR on a 3 V or 12 V
undervoltage or overvoltage fault. Provides system temperature
sensing through the thermal emulator.
The emulator provides system temperature information to the
PSC for system cooling fan speed control and for power off in the
event of an overtemperature condition.
CAMP module
Control and Miscellaneous Power module. Provides
miscellaneous custom power control circuits.
Console extender
module
Provides local and remote console terminal ports, modem port,
and zone control panel interface.
Fan current sense
board (FCSB)
Monitors the fan current and rotation, and generates a
rotation signal to the CAMP module. The CAMP module in
turn generates a tachometer signal to the PSC for fan speed
monitoring and control.
Zone A and B power
controllers
Provide ac utility power to the peripheral devices. Power
controllers are located in the expansion cabinet.
Power I2C bus
Provides serial communication between the PSC, console
extender, and I/O ATM modules. The PSC uses the bus to
write power status information.
The I/O ATM uses the bus to control the zone control panel
LEDs through the console extender module. It also writes the
Ethernet hardware addresses.
System Maintenance 3–11