American Megatrends MegaPlex II, System Manual

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Chapter 1 Hardware Installation 27
Step 6 Connect Power Supply,
Continued
+12 Volt Requirements The Megaplex motherboard and CPU fans only use one amp at +12
volts. But the AT power supply specifications require that a +12 volt line must
be available for peripheral devices, hard disk drives, and adapter cards. The
+12V load depends on the +12 volt requirements of the drives and adapter cards
installed in the computer. We recommend 20 amps at +12 volts.
-12V and -5V Requirements Standard output is enough.
Cooling Requirements Each CPU dissipates 50 watts of power. To maintain a junction
temperature of less than 158
°
F (75
°
C), adequate cooling must be provided.
AMI provides custom-made heatsinks for the Pentium II Xeon CPU. The CPU
requires cooling by convection. At a maximum ambient temperature of 35
°
C,
airflow of 250 LFM is required above each CPU heatsink.
Note: If you plan to use different heatsinks, you must provide adequate airflow
over the heatsinks to maintain a safe operating temperature.