Troubleshooting a circuit board is a challenging task. The first thing to do when checking out a faulty board is to look it over. You may see a broken wire or missing parts. Next, look at the circuits schematic and get an understanding of how it works and what signals youd expect to see. Power up the circuit and probe it with an oscilloscope. The oscilloscope will reveal whats working in the circuit and whats not.
Instructions
1 Look for visual clues on the circuit board. Overloaded parts may show obvious burn marks. A glass fuse will turn dark if its blown. Examine the trace side of the board for burn marks, errant solder blobs, and broken traces.
2 Study the schematic and understand the kinds of signals you expect to see from your circuit board. Determine what voltages, frequencies, and waveforms are produced at each point in the board.
3 Turn your oscilloscope on. Connect the ground clip of its probe to a grounding point on the circuit board.
4 Set the oscilloscope to the sweep speed that will best handle the frequencies coming from your circuit. Adjust the voltage range of your scopes input channel to match what your schematic indicates. Set the channels coupling to DC and zero the horizontal trace.
5 Turn your circuit on. Touch the oscilloscope probe tip to the various points you determined in step 1. Work forward in the circuit, from the power supply through any signal generation and amplification points. When you look at the power, observe that the voltage offsets you see on the scope are what the schematic specifies. If any part of the circuit is erratic or dead, the oscilloscope will reveal it quickly.
