Chapter 2: Installation CMOS Clear JBT1 is used to clear CMOS and will also clear any passwords. Instead of pins, this jumper consists of contact pads to prevent accidentally clearing the contents of CMOS. To clear CMOS, 1) First power down the system and unplug the power cord(s). 2) With the power disconnected, short the CMOS pads with a metal object such as a small screwdriver for at least four seconds. 3) Remove the screwdriver (or shorting device). 4) Reconnect the power cord(s) and power on the system. Notes: Do not use the PW_ON connector to clear CMOS. The onboard battery does not need to be removed when clearing CMOS, however you must short JBT1 for at least four seconds.
JBT1 contact pads I 2 C to PCI Enable/Disable The JI 2 C1/2 pair of jumpers allows you to connect the System Management Bus to any one of the PCI expansion slots. The default setting is closed (on) for both jumpers to enable the connec- tion. Both connectors must be set the same (JI 2 C1 is for data and JI 2 C2 is for the clock). See the table on right for pin defi nitions. Audio Enable/Disable Jumper JPAC is used to enable or disable the audio. Onboard audio is provided by AC97 audio CODEC for high quality 6-channel (5.1) sound. The default setting is on pins 1-2 to enable the audio. See the table on right for pin defi nitions.
2-17 I2C to PCI Enable/Disable Jumper Settings (JI2C1/2) Jumper Setting Defi nition Closed Enabled Open Disabled Audio Enable/Disable Jumper Settings (JPAC) Both Jumpers Defi nition Pins 1-2 Enabled Pins 2-3 Disabled