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Chapter 4: Motherboard Connections
4.4 Jumper Settings
How Jumpers Work
To modify the operation of the motherboard, jumpers can
be used to choose between optional settings. Jumpers
create shorts between two pins to change the function of the
connector. Pin 1 is identified with a square solder pad on the
printed circuit board. See the diagram below for an example
of jumping pins 1 and 2. Refer to the motherboard layout page
for jumper locations.
Note:
On two-pin jumpers, "Closed" means the jumper is on
and "Open" means the jumper is off the pins.
Connector
Pins
Jumper
Setting
3 2 1
3 2 1
CMOS Clear
JBT1 is used to clear CMOS, which 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.
Remove the cover of the chassis to access the motherboard and remove the battery
from the motherboard.
3.
Short the CMOS pads with a metal object such as a small screwdriver for at least four
seconds.
4. Remove the screwdriver (or shorting device).
5. Replace the cover, reconnect the power cord(s), and power on the system.
Note:
Clearing CMOS will also clear all passwords.