How Do You Troubleshoot A Circuit Board Capacitor?
While capacitors may last decades on a circuit board, they’re subject to age, manufacturing defects and damage from voltage spikes. Sometimes a bad capacitor will give visual clues you can spot with a careful look. If it appears to be good, you must still test it both in and out of the circuit. A defective or damaged capacitor will reveal itself when you check it with an oscilloscope or multimeter. Examine the capacitors on the circuit board. Normally, they should have a smooth, symmetric shape. If you notice cracking, bulging or dark streaks on the capacitor, or if you’ve seen smoke coming from it, replace it. Examine the circuit schematic to find the power supply paths. Connect the oscilloscope to the circuit board’s DC power by first connecting the grounding clip to power supply ground, then hooking the probe onto a point that has positive or negative DC power. Set the oscilloscope to DC coupling. If the oscilloscope shows excessive AC ripple or reads a below-normal DC voltage, an e
