Look for blackened components or melted or broken parts of the printed circuit traces, the little metal lines that connect components together on both sides of the board. Components can burn out and when they do they can smoke. Also look for swollen or discolored components.

Place your meter probe on the circuit directly after the first resistor. Set your volt meter to the "resistance" setting. Power the board and make a note of the reading. The meter will signal a zero reading if the resistor has shorted or is not connected.

The causes can vary, however some common ones are environmental factors like exposure to heat, dust and moisture, accidental impact AKA drops and falls and power overloads/surges can be causes of circuit board failure. However, the most damaging cause of premature circuit board failure is electrostatic discharge (ESD) at the assembly stage.