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Chapter 4: Motherboard Connections
4.4 Jumpers
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. Refer
to 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
Connector Pins with a Jumper
installed on Pins 1 and 2
Top View
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. Re-install the motherboard battery.
6. Replace the cover, reconnect the power cord(s), and power on the system.
Note 1
: Clearing CMOS will also clear all passwords.
Note 2
: Do not use the PW_ON connector to clear CMOS.
