A printed circuit board (PCB) is made by etching the copper layer on the board. There are different methods of doing this, but the most common one is based on using ultraviolet light and chemicals. If this etching process is not done correctly, shorts between adjacent traces may develop. Sometimes the shorts are due to incorrect layout. Finding a short on a PCB can become quite challenging if the board is complicated and has very thin traces.
Instructions
1 Thoroughly check the PCB traces under the microscope or magnifying glass. See if you can find any traces that look shorted. Mark suspicious places on the board with the marker. Try avoiding traces while placing marks. You can place marks on nearby components or on ground or supply planes.
2 If a circuit diagram is available, find the traces you marked as suspicious on the diagram. Observe if the traces should be separate or connected. In some cases traces are deliberately connected. Go through all suspicious traces and eliminate the ones that are connected in the circuit diagram. If a circuit diagram is not available, skip this step.
3 Insert the red multimeter lead plug into the "V" socket of the multimeter and the black lead plug into the "COM" socket.
4 Set the multimeter knob to the continuity test position. This position generally has a sign with several small parallel lines.
5 Turn the multimeter on. Test the multimeter continuity tester by touching its two leads together. This should produce a beep. If it does not, you have not set the knob to the continuity tester position, or the tester battery may need to be replaced.
6 Touch the first of the suspicious traces with the two leads of the multimeter. It does not matter which lead is connected to which trace. You will have to press firmly to establish electrical connection between the multimeter leads and the traces. If a beep sounds, there is a short. Repeat this process for all suspicious traces.
