HP 330 Service Information Manual page 80

Power Supply
Introduction
Both conlputers and expanders use this power supply. The power supply provides all power to
the assenlblies installed in the unit. It is a non-adjustable switching supply that is an exchange
assembly.
Power Supply Characteristics
Power supply characteristics are
• Operates on 120 or 240 VAC, 50-60 Hz.
• Outputs these voltages:
• +5 Vdc
• +12 Vdc
• -12 Vdc
• Power-Up RESET signal sent to processor board to initialize CPU.
Maximum power consumed by the computer or expander is 250 watts. For the computer, power
consumption by the power supply and assemblies in the system slots is included in the 250
watts. The remaining 147 watts is available for assemblies in the units system or DIO slots. In
the expander, most of the power is available for system boards or DIO cards.
The following table shows the power available to all combined motherboard, DIO, and system
slots for Model 330/350 computers and HP 98568A Opt. 132 and HP 98570A expanders.
Voltage Power Available Current Available
+5 Vdc
95 Watts 19 Amps
+12 Vdc
40 Watts
3.3 Amps
-12 Vdc 12 Watts 1 Amp
CAUTION
When boards are installed in the unit, they use power and the amount
left over is less than shown in the table above.
Before installing boards or cards in the unit, ensure the total maximum
power consumed by all cards and boards for each voltage in the unit
does not exceed the power available at that voltage. If the board or
card to be installed require more power than is available, damage to
the accessory or computer/expander may result. Refer to the Service
Handbook, Chapter 3.
Figure 3-9 is a block diagram of the power supply used in the computer and expander.
64 Functional Description