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4.4 Jumpers
Explanation of Jumpers
To modify the operation of the motherboard, jumpers are used to choose between optional
settings. Jumpers create shorts between two pins to change the function associated with it. Pin
1 is identified with a square solder pad on the printed circuit board. Refer to the motherboard
layout diagram in Section 1.5 for jumper locations.
Note: On a two-pin jumper, "Closed" means the jumper is on both pins and "Open" indicates
the jumper is either on only one pin or has been completely removed.
CMOS Clear
JBT1 is used to clear CMOS, which also clears 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. Remove the cover of the chassis to access the motherboard.
3. Remove the onboard battery from the motherboard.
4. Short the CMOS pads with a metal object such as a small screwdriver for at least four
seconds.
5. Remove the screwdriver (or shorting device).
6. Replace the cover, reconnect the power cord(s) and power on the system.
Notes: Clearing CMOS also clears all passwords. Do not use the PW_ON connector to clear
CMOS.
Chapter 4: Motherboard Connections
3
2
1
Connector
Pins
Jumper
3
2
1
Setting
JBT1 contact pads
45
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