Jumping a mobo (motherboard) is a quick way to test whether the power switch is defective on your PC. The technique can also be used if you are operating your motherboard in a test environment on a workbench without the case present. Or perhaps you have a defective power switch and have not had an opportunity to install a new one. Whatever your motivation, the process for jumping the motherboard is quite simple.
Place an anti-static strap on your wrist and connect it to a grounded piece of metal. This is to prevent the unintentional discharge of static electricity, which can cause damage to sensitive electronic components. Anti-static straps are available at most electronic stores.
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Identify the power switch connector on your mobo. The power switch connector is a two-pin momentary switch connection. It is usually located in a block of pins also including the HD LED, reset switch and power LED. Each motherboard is different but look for these common identifiers. They will be printed in very small letters. A magnifying glass may be helpful in identifying the small lettering. Look for "pwr," "pwr_btn" or a similar set of lettering. Download a copy of the motherboard manual from your motherboard vendor if you have difficulty identifying the power switch connector. If you have disconnected the power switch then the two pins where that switch cable was connected is the point where you will jump the mobo.
Ensure that the power supply is connected to the motherboard. There are several variations of an ACPI/ATX power supply. Refer to your motherboard manual for the correct procedure for connecting a power supply. Common implementations include a 20 pin, 24 pin main power connector and a 4 (2x2) pin connector to provide supplementary 12V power to the processor voltage regulator.
Plug the power supply into a wall outlet. Switch your power supply into the "on" position if your power supply is equipped with an on/off switch. The switch is located on the back of the power supply next to the power cable.
Short the two pins of the power connector using a pair of tweezers or needle-nose pliers. Remove the tweezers or needle-nose pliers as soon as the motherboard has been jumped. You should see the processor fan start spinning or hear the hard disk spin up to give you an indication that the mobo has been successfully jumped.
Things You'll Need
Magnifying glass (optional)
Tweezers or needle-nose pliers
If you install a switch on the power switch connector, ensure it is a momentary switch.
Do not hold them there for more than a brief moment. Shorting the pins for five seconds will result in a soft shutdown of the motherboard.