Everything You Need to Know About How to Test PCB

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When we invest in buying PCB and PCB assembly for our devices, we expect them to work at their best for a longer time. If, unfortunately, the Printed circuit board of the devices stops working after a short time, we feel restless. It is like damping our money in some garbage container.

You need to learn how to test PCB by going through different steps and methods to understand whether it is facing a minor problem of malfunctioning or a major problem of losing the circuit design. We feel such situations due to failure of PCB design that stops working, and hence the device's working also gets ruined.

All you need to know about how to test PCB

Everyone should know how to test PCB by understanding which components they need to inspect by following which steps and methods. The electronic device's owner must inspect the printed circuit board instead of throwing his device away. There are many components in the circuit board connected one after another and need to be inspected through a proper PCB inspection test.

What components of PCB do you need to analyze during PCB inspection?

As we are well aware of the importance of the PCB manufacturing process and the components used in it, we understand why there is a need for an inspection of PCB and how to test it. All components have significance, and every part plays its role in the development of the circuit.

Whatever component of the circuit is disturbed, you will get it to fail in achieving its manufacturing goal. While working on how to test PCB, first, we need to identify deeply which components need a primary inspection. Following are a few components that you need to inspect when you are testing PCB.

  • Capacitors
  • Diodes
  • Resistors
  • Fuses
  • Transistors etc.

These basic components need to be inspected when you observe any abnormality of your PCB or device. If any of these components is in trouble, your electronic device will not work properly.

General steps included in the inspection of PCB

As PCB has different components and may have different designs, it needs different ways to inspect the PCB. Before we go with different methods to be clear about questioning how to test PCB, we need to go through some general steps that we should follow in approximately all methods of PCB testing.

For the PCB testing, we use different devices like multimeter, soldering gun, and magnifying glass. A few things are necessary to follow before going through the process of how to test PCB. Following are some steps to follow while testing PCB.

Spot visual defects inspection

Every PCB design has inner and outer layers that you need to test if your PCB observes any problem or failure. So, before you check the inside or inner layer of PCB, you should look for visual defects. When you learn how to test PCB, you should first of all have a proper inspection of its visual components, especially the resistors, capacitors, and ICs.

 You can visualize the defects of the circuit by using a magnifying glass. You need to find out the cracks in the circuit board, burnt copper wires, or broken traces. You also need to identify the spot where you feel major problems are occurring and try to fix them.

 PCB

Check the power system of the circuit.

If you have checked the visual components, you do not find any damaged or broken parts in the circuit; you need to check the power supply system of the PCB. You will need a multimeter, a device to measure current, resistance, and capacitance.

By using a multimeter, check whether the input and output voltage is following the expected value. If you observe an unexpected value of voltage passing through the circuit, you need to make amendments by replacing the fuse.

If you replace the fuse with a new one and you still get the fuse breaks off, you need to check other circuit components that are using over-flow of the current through it. Using a multimeter, you can easily identify the problem if it is related to voltage amount.

Inspection of input and output system

The third step is to inspect the input and output system after checking the power system and visual spot inspection. If the input-output system fails or is damaged, you will find the whole circuit out of the range. As the fuses control the input-output system, you need to focus on changing the fuses.

Also, look for communication ports.

In the end, you need to check the communication ports of the PCB. When you observe communication port failure, do check the cracks of communication ports like Ethernet.

Methods to test PC designs you need to know about

If your PCB is observing any failure and you are looking for the methods how to test PCB, then you should follow any of the following methods.

Burn-in testing

Burn-in testing, no doubt, is quite much helpful in detecting any type of failure in PCB or PCB assembly, but on the other hand, along with such intense and quick results, it is quite damaging. It no doubt tries to identify the problem at the start, but later it starts damaging some parts of the PCB assembly by flowing high voltage of current.

When performing this test to identify the reason behind the failure of PCB, the current passes through different electrical components for more than 50 hours. This flow of current is not good for the copper wires and fuses of the PCB.

Flying probe testing

Flying-probe is a very common, easy, and cheap way of detecting the problems of PCB layers. It depends upon the fault you are looking for. During this method, there is no need to spend too much money to use higher power, but here, you need to use a needle probe to detect the faults of the PCB circuit. It is not only an authentic way to find out the problem but also inexpensive.

This method is suitable for checking the PCB for short circuits, capacitance, resistance, and diode issue. So, all you need to do is to use this probe by having a grip on its use and identify the problem of your PCB.

Automated optical inspection

By reading the name of this method to test PCB, we know it uses some optical lenses. Yes, it uses the lens cameras to obtain the picture of the printed circuit board. The professionals use this method for identifying or testing 2D or 3D cameras.

 It takes pictures and compares those pictures with the expected circuit board and identifies the little flaws to cope with deficiencies in the design. This method is good s you can identify the problem at the initial chain.

In-circuit testing

This is the most effective and error-free PCB test. During the PCB testing, the circuit testing method is prepared for obtaining 100% coverage, but it can obtain a maximum of 85 to 90 percent only. It is the best method of PCB testing as it is also inexpensive but most effective as it uses a fixed probe for testing PCB. The professionals use the fixed probe to match the integrity of the PCB's solder connection.

X-ray inspection

As the name indicates that the user needs to use the X-rays to identify the defects. X-rays have a high penetrating capacity. Therefore, they can scan the inner faults of PCB. If you have gone through a visual inspection and do not find any defect or damage, then you need to look deeply in the circuit to find out the problem and then look for the decisions.

By using X-rays, the designers can identify the very little things about a design, especially when the defect is found in the chip of the inner layer of the PCB designer.

Functional testing

It is the older method of PCB testing in which the professional test the PCB compatibility with design. They check whether the PCB design is workable or the working style of PCB is quite good with this design or not.

By using this method, the product managers ensure whether the PCB design will be suitable for the electronic device or not. This method is best for testing PCB before launching its products, finding out the problems, and making corrections.

Boundary scan

It is another modern technique used to test the functionality of PCB assembly. It is used to check the connections of PCBs with other electronics, especially to test ICs. In this technical, physical probe are used as cells to check the connection of input and output plugs.

Conclusion

When you are looking to know everything about how to test PCB, you should have an idea of which components need to be tested and by following which steps. You can use any of the above 7 methods for PCB testing and make things right before time.

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