HP 9000 Series 310 Service Information Manual page 52

Ac
,...
+5
+
'f'
-12V
POWER SUPPLY
@
fRONT PAN
LED
EL
Telt_ Point.
I
LARGE fAN
I -
"7
MOTHERBOARD
I
SMAlL fAN
I
.~
I/O BACKPLANE
Figure 3-3. Bus Expander Power Distribution
Power supply outputs are distributed through the motherboard. Test points for power measure-
ment are located on the motherboard.
Power is connected from the motherboard to the I/O backplane via a ribbon cable. In the
computer, boards in the system slots are powered directly from the motherboard.
Two fans are connected to motherboard power connections. The large fan is tied to the
+
12
and ground. The small fan is tied between +5 and -12 V dc.
Wires from the front-panel LED are connected to the
+
12 and -12 V dc voltages on the moth-
erboard.
CAUTION
When custom designed accessory cards are being developed for the
I/O card cage, their power consumption must not exceed the power
available at the backplane. Information regarding the design of custom
accessory cards is contained in the HP 9000 Series 200/300 Accessory
Development Guide, HP Part Number 09800-90011.
42 Functional Description