Asus P2B-N User Manual page 35

III. INSTALLATION
19. CPU Fan Connector (3-pin CHASIS_FAN, 3-pin CPU_FAN)
These connectors support cooling fans of 500mA (6 Watts) or less. Orientate the
fans so that the heat sink fins allow airflow to go across the onboard heat sink(s)
instead of the expansion slots. Depending on the fan manufacturer, the wiring
and plug may be different. The red wire should be positive, while the black
should be ground. Connect the fan's plug to the board taking into consideration
the polarity of the this connector. NOTE: The "Rotation" signal is to be used
only by a specially designed fan with rotation signal.
WARNING! The CPU and/or motherboard will overheat if there is no airflow
across the CPU and onboard heatsinks. Damage may occur to the motherboard
and/or the CPU fan if these pins are incorrectly used. These are not jumpers,
do not place jumper caps over these pins.
P2B-N 12-Volt Cooling Fan Power
CPU Fan Power
Rotation
+12 Volt
Ground
Rotation
+12 Volt
Ground
Chassis Fan Power
ASUS P2B-N User's Manual 35