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What are the methods for rapid detection of PCB circuit board faults?
2023-12-15
Today, I will tell you what are the fault detection methods of PCB circuit board? PCB circuit board fault detection method. There are many reasons for PCB circuit board failure, only by accurately finding the problem point, can the fault be quickly solved, and then STG Electronic will introduce you to the PCB circuit board fault detection method.
1. Determine the location of the fault
Once signs of a problem appear, the next step is to track and locate until the defect is identified. Different ways to determine the location of a fault include a visual inspection, as well as a physical inspection using test equipment. Testing technology relies on high-end test equipment or the use of basic tools such as multimeters, thermal imaging cameras, magnifiers, and oscilloscopes.
2. Testing equipment
Typical equipment includes automated flight detection instruments, as well as automated optical inspection (AOI) machines. AOI uses high-resolution cameras to inspect a wide range of defects, including short-circuited, open-circuited, missing, incorrect, or misaligned components.
3. Visual and physical inspection
Visual inspection identifies defects such as overlapping marks, short circuits in solder joints, signs of board overheating, and burned components. When some problems are difficult to identify with the naked eye, the magnifying glass can help identify some short circuits, solder bridges, open circuits, cracks in solder joints and circuit board traces, component offsets, etc.
4. Specially detect components
When low resistance is detected between component pins, the best thing to do is to remove the component from the PCB circuit and perform a specialized inspection. If the resistance is still low, then this component is the culprit, otherwise further investigation is required.
5. Power on the circuit board for testing
Visual inspection is only applicable to the exterior inspection of the board, not to the inspection of the internal layers of the board. If there are no obvious defects on the surface, you will need to power up the board and perform more detailed testing to determine if the board is healthy.
6. Low voltage measurement
This technique involves controlling the current amount of current passing through a short circuit and finding out where the current is flowing. Since the copper traces on the circuit board also have resistance, the voltages generated through different parts of the copper traces are also different. With a voltmeter, when you measure the voltage between different parts along a short route and find that the voltage value is getting smaller and smaller, you are getting closer to a short circuit.
7. Use your finger to sense the heating area of the circuit board
Since a short circuit can cause the local temperature of the board to rise, finding areas with heat can help find the point where the short circuit is causing problems. However, it is important to use caution when using the power supply of short-circuited copper traces and to avoid burns or electric shocks.
8. Repair short/open lines
Once a short or open circuit point has been identified on the PCB, the next step is to isolate the problem. While it's easy to do this on the outer surface of the board, it's a challenge for the inner layer. Possible solutions include drilling through-holes or cutting appropriate external copper traces.
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