A computer's motherboard is a Printed Circuit Board or PCB where all the data is processed. Its main component is the Central Processing Unit (CPU) where all instructions are processed and executed. The CPU contains the brain of the computer, that is the microprocessor. A motherboard also contains different types of controllers, memory units, timers and data bus drivers. A short circuit on a motherboard can severely affect its performance or fail it completely. Finding an electrical short on a motherboard is a tedious process but can be accomplished with the help of a multimeter.
Visually inspect the motherboard under a magnifying glass to locate potential short circuit points. Specially look at the copper traces and the terminals of electronic chips. A short can not only be due to a broken trace or terminal but also some foreign conducting piece, such as a piece of broken wire, that has got stuck between two terminals. Do not rush during this process, as a typical motherboard has numerous components and very thin copper traces. Scan the whole board slowly and mark every potential short-circuit location with a marker.
Turn the multimeter on and set it at the continuity test mode. This can generally be done by turning its knob to the point marked with two or three curved lines. Make sure that its leads are inserted in the sockets marked as "COM" and "V". The colour of the leads is not important for this testing.
Place the motherboard on a flat and dry surface. Go to the first potential short-circuit location you marked earlier and test its continuity. This can be done by simply touching the two terminals with the tips of the multimeter leads. If there is a short circuit, the multimeter will beep. Test all the marked locations using this method. If you could not find any short but still suspect one, carry on this procedure on all terminals of the electronic components on the board as well as on all the copper traces.
Do not power the motherboard during this test since it can damage one or more electronic components on the board.
Tips and warnings
- Do not power the motherboard during this test since it can damage one or more electronic components on the board.