Identifying and troubleshooting typical problems related to electronic circuits

Date of publication: 30-08-2024 Update date: 10-04-2026 🕒 6 min read

From simple household appliances to sophisticated communication systems, electronic equipment plays a key role in the world of today. However, even the most advanced circuits and devices are not free from problems or failures. Therefore, users should be able to diagnose and troubleshoot common issues occurring in electronic circuits and systems.

This text serves as a practical guide assisting in identifying and troubleshooting problems that can be encountered while operating electronic equipment.

Symptoms of problems occurring in electronic circuits
Failures related to power supply
Failures resulting from faulty connections
Failures resulting from electronic component damage
Using meters to test electronic components
Replacing faulty components
Testing systems following repairs

Successful problem identification is a key to success

Identifying problems occurring in electronic circuits and devices is the first step in the process of failure diagnosing and repair. Potential failures may manifest themselves in various ways and are often quite difficult to pinpoint. However, if the basic principles of the repair process are followed, even the most mysterious failures will be detected. The key thing is to understand the potential source of a problem. There are certain characteristic factors suggesting that something is wrong.

One of the classic circuit failure symptoms is smoke or a burning smell. These are some of the obvious and worrying signs that should not be ignored. In such cases, the power supply must be instantly cut off to avoid more serious damage.

Moreover, clearly visible physical damage can often be encountered in electronic circuits. Bent or broken components, in particular electrolytic capacitors with bulging cases or integrated circuits damaged by an explosion, definitely mean that there is an ongoing problem that needs to be dealt with. Visible physical damage makes problem identification relatively simple. However, it is not always in plain sight, so it is important to check everything really carefully.

Frequently, the equipment works correctly at first glance, but there is a problem with one of its functionalities. If the device response differs from the expected one, it operates erratically, crashes or displays error messages, the problem may lie in the software or a specific circuitry component. In such cases, a thorough understanding of the circuit operation is necessary to correctly diagnose its faulty section.

Any worrying symptom can help identify an issue or at least narrow down the investigation area. Following the preliminary diagnosis, we can proceed to more advanced testing and repair methods, so that circuits and electronic devices can be restored to full working order.

Turn on and off – power supply inspection

Checking the power supply is one of the first steps in the process of electronic equipment diagnosis and repair. Many failures stem from issues related to energy supply, so your first step should involve checking whether there is an issue with power supply. There are certain key symptoms signalling problems related to power supply in electronic equipment and circuits, and it is worth knowing how to spot them.

If toggling the on/off switch does not bring about any effect, check whether it is connected to a supply source in a sound operating condition. A short-circuit or blown fuse in a power supply module is relatively easy to repair.

However, lack of power supply stability can also be a problem. If a device frequently shuts down, reboots or behaves erratically, it may mean that there is a problem with voltage at the output of the power supply module or built-in power supply chip. It can be caused by poor contact in the connectors, inadequate power supply source quality or voltage adjustment-related issues. It is also worth checking the condition of the power supply module or battery used.

Temperature is another vital aspect. Device overtemperature may result from excessive load or a malfunction in the cooling system. In the long run, excessive temperatures lead to gradual component deterioration, so this is a symptom that should not be underestimated.

Problems related to power supply are commonly encountered by each electronic engineer. They occur quite frequently, so in such cases the power supply module should be tested thoroughly. In the course of such tests, the input and output voltage should be checked in detail.

Connection-related problems

Connections between components and modules are extremely important in electronic equipment and circuitry. Incorrectly made connections can cause a multitude of problems, and detecting them is rather troublesome. Note, however, a few characteristic features and situations indicating problems related to both wired connections and the connections between components placed directly on the PCB.

“Cold solder joints” are an example of a common problem in this area. This term describes a situation in which solder joints connecting PCB electronic components are faulty, even though they seem to be correct at first glance. “Cold solder joints” may result in circuit discontinuity and thus faulty device operation. Therefore, a visual inspection must be performed. For this, a magnifying glass and a good light source are indispensable.

Burnt PCB traces are another problem that is commonly encountered by electronic engineers. This kind of failure often results from overload or errors in the PCB manufacturing process. If burn marks are clearly visible on the board, they should be examined carefully, and their impact on the entire circuit must be assessed. In some cases, repairing a burnt PCB trace can be quite problematic or, in the case of multilayer laminates, downright impossible. Each burnt surface area should be cleaned thoroughly, as the burning process generates carbon compounds being a natural conductor, so leaving them may lead to further short-circuits and other circuit component damage.

Cable connections are also the source of possible problems. Damaged or incorrectly connected cables may interrupt data transmission or exert negative impact on power supply or inter-component connectivity. In such cases, check if the components are seated properly and inspect the cable for discontinuity or short-circuits.

Electronic systems are state-of-the-art designs in which firm and stable connections play a vital role. Therefore, their quality must be thoroughly inspected.

Electronic component analysis

After a general electronic device or circuit analysis is concluded, it is worth examining specific electronic components. Various components may be subject to diverse failures, which in turn results in the occurrence of various problems, often difficult to spot.

An electrolytic capacitor failure is one of the most common issues occurring in electronic equipment. Its symptoms include a bulging case or electrolyte leaks. Such faults may result in power supply instability, circuit operation interruption or the buzzing sound emitted by audio devices. Other popular components that are worth paying attention to are transistors. They may be damaged by overvoltage or overcurrent.

Symptoms of problems related to semiconductor diodes include lack of conduction or excessive, uncontrolled conduction in one direction (or both directions, which is the worst-case scenario). Defective diodes may hinder circuit operation, which is particularly important for power supply circuits and signal processing (“rectification”).

Resistors are among the most common components used in electronic engineering. Their defects result mainly from an excessive current flow. This results in the fact that a resistor is unable to dissipate all energy and burns out, which in practice almost always manifests itself as a clearly visible, physical damage. In addition, resistor overheating may result in changing their values, so their condition should be subject to frequent monitoring.

Testing circuits with inspection instruments

In order to diagnose problems related to electronic components, a thorough analysis and deployment of specialist diagnostic tools such as a multimeter or oscilloscope are required. This rings particularly true when components seem physically intact. Such tools and necessary diagnostic skills facilitate effective problem identification and rectification, which results in restoring full equipment and circuit functionality.

Testing circuits and components may seem straightforward, but it is actually quite a complex process. Here, in-depth electronic engineering expertise is required, as you need to be able to see how specific components operate and how they need to be tested to determine their condition. Moreover, diagrams detailing how components are connected are also invaluable. In addition, in many cases, a tested component must be desoldered. A component placed within a circuit can also be inspected, but note that such measurements may be subject to errors and, as a result, should not be undertaken by fledgling electronic engineers.

When analysing an electronic circuit using measuring instruments, a precise and systematic approach is recommended. Results obtained must be compared with expected values or applicable documentation. A multimeter and oscilloscope facilitates precise problem identification and effective troubleshooting to restore electronic circuits to their full functionality.

Damaged component replacement

Once a failure is identified, damaged electronic circuit components must be replaced. Obviously, this requires precision and caution. Firstly, the damaged [component must be desoldered. Note here that it might necessitate removing a PCB from a device. This results from the fact that using a soldering iron or hot air station within a device may cause further damage. Additionally, the cramped space inside the enclosure may not be sufficient to run all necessary operations.

In order to remove a damaged component, an electronic engineer must have at least the basic command of soldering and be able to select a correct replacement. Such a part should be a direct substitute or have an almost identical size and parameters. If a component is significantly damaged, which hinders its identification, a diagram showing the components of the device being repaired comes in handy.

After the damaged component is replaced, its correct seating within a PCB must be checked. Moreover, the flux residues must be removed from the laminate using isopropyl alcohol.

Follow-up testing and documentation revisions

After an electronic device or circuit is repaired, it must be tested thoroughly, which is an important step of the process. It makes it possible to ensure that the problem is fully solved and the device operates as required.

After a damaged component is replaced and repairs are completed, the device must be activated to conduct tests showing that the problem has been rectified. At this stage, it must be checked if all functions operate as expected and no undesirable behaviour is detected.

If a repair has resulted in circuit modification or using components with slightly different characteristics, such changes must be reflected in the technical documentation. Moreover, the electronic circuit diagram, list of components and PCB installation documentation should be updated.

Developing documentation related to the repair process itself is also a good practice. Notes or a repair report should include information on the faults detected, corrective actions implemented, and test results obtained.

The post-repair testing and documentation updating process is crucial both for professionals and hobbyists. It makes it possible to maintain electronic system integrity, prevents possible future problems, and makes the life of electronic maintenance technicians and engineers easier.

Transfer Multisort Elektronik (TME) is one of the world’s largest global distributors of electronic components, electrotechnical parts, workshop equipment, and industrial automation. The catalog includes over 1,500,000 products from 1,300 leading manufacturers. TME’s modern logistics centers in Łódź and Rzgów (Poland), with a combined area of over 40,000 m², ship nearly 6,000 packages daily to customers in more than 150 countries.

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