In today’s electronic devices, PCB printed circuit boards play a core role, just like neural networks in electronic systems, connecting and supporting various electronic components. However, with the increase of usage time or the influence of external environment, PCB may experience various malfunctions, which can affect the normal operation of the equipment. Today, the editor of Huihe Circuit will provide you with a detailed introduction to the basic steps and common search methods for troubleshooting PCB circuit boards, helping you efficiently locate and solve these problems.
1. Preparation before malfunction
Before starting troubleshooting, ensure that appropriate safety measures are taken, such as wearing anti-static wristbands, to avoid damage to sensitive components caused by static electricity. At the same time, prepare necessary tools such as a multimeter, oscilloscope, magnifying glass, thermal imager, etc., which are crucial for accurately diagnosing faults.
2. Visual inspection
Step 1: Appearance inspection
Firstly, perform a visual inspection to check for any obvious physical damage on the surface of the PCB, such as cracks, burnt marks, component detachment, or loose solder joints.
Step 2: Cleaning and inspection
Gently clean the surface of the PCB with alcohol and a soft brush to remove dust and corrosion. Sometimes, accumulation of impurities may also cause short circuits or poor contact.
3. Electrical testing
Step 3: Resistance detection
Measure the resistance values of critical paths and components using a multimeter, and compare them with the standard values. Abnormal high or low resistance may indicate an open or short circuit.
Step 4: Voltage and current measurement
In the energized state, measure the voltage and current of key nodes, compare them with expected values, and abnormal values indicate power supply issues or abnormal loads.
Step 5: Signal Integrity Analysis
Use an oscilloscope to check the waveform of key signal lines and observe for issues such as noise, distortion, or delay.
4. Functional isolation method
Step 6: Segmented isolation
After determining the approximate area of the fault, the “segmentation method” can be used to gradually reduce the range, that is, to disconnect or replace some circuits to isolate the source of the fault.
5. Thermal imaging detection
Step 7: Hotspot Analysis
Using a thermal imager to detect the temperature distribution of a PCB in its working state, high temperature areas may indicate overloaded components or poor heat dissipation.
6. Replacement method
Step 8: Component Replacement
For suspected faulty components, it is possible to try replacing them with known good components of the same model to see if the problem is solved. This is a direct and effective verification method.
7. Software and diagnostic tools
Step 9: Software Diagnosis
For embedded systems, using a debugger or specific software tools to check for firmware errors or runtime logs can help identify logical or programming issues.