Troubleshooting printed circuit boards is an extensive process that involves several steps. It also requires a systematic approach and proper care to avoid causing additional damage. In this guide, we take you through the procedure, step by step.
How do you Troubleshoot Printed Circuit Boards?
You troubleshoot printed circuit boards by visually inspecting and testing them. The steps require various tools and materials. You must also understand the problem-detection methods to use.
The job’s complexity depends on the specific PCB design and type. Some boards, such as multilayered or miniature types, are more intricate and challenging to fix.
After troubleshooting, you must address issues correctly. That, in turn, requires you to have adequate knowledge of the repair procedures. They include replacing electronic components, pads, traces, etc.
Printed Circuit Board Common Problems
PCBs fail in different ways, depending on the cause of damage and the type of parts affected. The following are common printed circuit board issues you’re likely to come across when troubleshooting one.
- Component damage due to environmental factors, overheating, drops, impact, etc.
- Signal issues caused by broken traces, missing parts, or damaged EMI shields.
- Corrosion resulting from moisture, debris, or manufacturing flaws.
Resource: https://www.youtube.com/watch?v=R7Of8VWNR7I
Circuit Board Troubleshooting Techniques and Steps
Troubleshooting a circuit board begins with performing a visual check before proceeding to more conclusive procedures like electrical tests. Below, we take you through the process and the problems to look out for.
Materials and Tools
- Magnifying glass
- Digital multimeter
- External power supply
- Solder wire or solder paste
- Soldering equipment, such as a soldering iron
- Thermal camera or temperature probe
- Oscilloscope
- LCR meter
- Logic analyzer
- Isopropyl alcohol
- Wipes/ lint-free cloth
- Kapton tape
- PCB glue, such as epoxy
- Knife
- A flat workspace with adequate ventilation and lighting.
Clean the affected board or part with isopropyl alcohol. Wipe it dry with the lint-free cloth or use compressed air. You can now begin the troubleshooting process.
Visual Inspection
- Visually inspect the circuit board.
- Check for signs of damage, warping, breakage/cracks, or delamination.
- Look for board surface or component corrosion and burnt or discolored parts.
- Examine the solder joints and other connections for damage or looseness
- Look out for missing or misaligned parts
- You may need a magnifying piece for minor details
- Use the board’s schematic diagram to understand the circuits and components better
- You could also utilize a comparison board if you can find one
Power and Continuity checks
- Use the multimeter and LCR meter to conduct power and continuity tests.
- The multimeter detects opens, short circuits, and other defects.
- The LCR meter measures values like inductance, capacitance, etc.
Testing Individual Components
- Test individual components, such as resistors, capacitors, and inductors.
- Test integrated circuits (ICs) by connecting their pins to the logic analyzer or oscilloscope.
- Ensure the correct orientation of the ICs.
- Consider in-circuit and out-of-circuit tests.
Signal and Function Testing
- Power the PCB to conduct signal and function tests.
- Ensure the power is within safe limits.
- Trace signals from the inputs to the outputs using the oscilloscope and logic analyzer.
- Examine clock signals and logic levels for anomalies.
- Measure the voltage across transmission lines or power rail and components.
Thermal Checks
- With the board powered, identify thermal issues that could be causing it to fail.
- Use a thermal camera to check for and identify heating components or circuits.
- You may also place your hand above the board to feel the warmer areas.
Resource: https://www.youtube.com/watch?v=meulzHIq4Us
Circuit Board Repair after Testing
Repair the problems your checks and tests helped identify. It restores the board’s functionality and performance. It also extends the lifespan and reduces replacement costs. Circuit board repair involves the following practices.
Joint Re-soldering
Re-solder broken or replaced joints. Use quality solder. Ensure the solder matches the type used on the board to ensure uniformity and application suitability. Use correct soldering steps to avoid issues like voiding, bridges, etc.
Component Replacement
Remove damaged parts and replace them with new ones or better versions, depending on the reason for failure. Ensure the new component has the correct values to avoid incompatible and possible board malfunctions.
Pad and Trace Repair
Repair lifted pads and broken traces. You may use PCB glue, such as epoxy, to keep the parts on the board. You could also use wires to connect separated traces. Ensure the wire width matches that of the trace.
Fixing EMI Shields
EMI shields can break and expose sensitive parts to interference. Replace them to make the board’s operation dependable after repair. In some cases, you only need conductive ink or paint to fix the shields.
Board Cleaning and Testing
Clean the board to remove dirt and debris, including soldering materials like flux. Finally, test it to ensure it works as required. This check involves powering the board and taking various measurements.
Resource: https://www.youtube.com/watch?v=pYa1Ld7IafM
Safety and Precautions When Troubleshooting Circuit Boards
Circuit board troubleshooting procedures involve handling electrical parts and circuits. Some of these parts can expose you to accidents. You could also damage sensitive components with static electricity if you do not ground properly.
Power Disconnection
Disconnect power from the PCB before working on it. Faulty connections could expose you to electric shocks and electrocution. Remove batteries, too, and discharge capacitors.
Protective Wear
Wear glasses, gloves, and other appropriate gear, such as a nose mask. The protection is essential to avoid inhaling toxic fumes and accidents, especially if the process involves cutting or drilling.
ESD Protection
Use ESD protection measures, such as wrist bands and ESD-safe mats, to prevent electrostatic discharges from damaging delicate PCB parts. Disconnect the application device from power and discharge fully.
Proper Documentation
Record the troubleshooting process for future reference. The information to include ranges from time and day to the types of problems identified and how you addressed them.
How to Prevent Future Circuit Board Failure
Taking measures to prevent the repaired board from getting damaged again is an essential part of the troubleshooting process. Various steps can help you ensure that, especially if the problems are not design flaws.
Most circuit board failures are related to solder joints. Ensure the joints are firm and robust. Use appropriate formulations and solder types to ensure that the replaced parts are sturdy and will last long.
Overheating is a leading cause of PCB failure. Identify hotspots and improve cooling in those areas. You may change heating parts or incorporate cooling mechanisms.
Ensure the usage environment and conditions are safe for the PCB. That includes keeping it protected from the causes of damage and cleaning it regularly. Ensure the power doesn’t exceed safe levels, too.
Conclusion
Troubleshooting circuit boards involves various steps and techniques. Understanding its requirements can help you to find and fix problems successfully, extending the board’s lifespan.
Venture implements design-level and manufacturing strategies to ensure your printed circuit boards are defect-free and suitable for your application needs.
We also conduct a series of tests to identify and correct flaws. Contact us now to discuss your project with our technical team and receive a quote.
