PCB Board Repair: How To Rectify Circuit Board Issues

In this article, we will look at how to handle PCB board repair and explain the causes of PCB failure.

Like other electronic components, circuit boards can fail due to manufacturer-related, aging, or user-related issues.

But it is possible to repair the circuits if you have the technical know-how.

Read on to learn more!

Why You Need To Know How To Repair Circuit Boards

The primary reason is to save on costs. Replacing a circuit board can be costly.

And it will take time to get a new one delivered. So doing PCB repairs will save money & time and reduce the downtime of waiting for another board.

Also, circuit boards are not one-off products.

Like a regular circuit with wires and breadboards, you can repair damages and get the product working again.

And besides, the repair process gives a better understanding of circuit boards, building experience and confidence in the electronics industry.

Lastly, there is the satisfaction of detecting and solving an electronics issue, including circuit board repairs.

Why Do Printed Circuit Boards Fail?

PCBs can fail due to the following reasons.

Physical Damage

Physical damage is the primary cause of PCB failure.

And it can be due to the soldered electronic components or external electronic devices.

These factors can exert physical pressure on the board, such as when you drop the PCB or hit it with another object.

Forcefully bending, flexing, or stretching the board can also apply enough pressure to cause physical damage.

A broken PCB

Lastly, physical damage can occur after wrongfully disassembling and assembling the board from the device.

The only way physical damage repairs are not viable is if the board breaks and shatters.

Otherwise, you can remanufacture the PCB by melting the broken sections to re-attach them.

Also, you’ll have to reball copper traces and resolder/replace loose or damaged components.

Repairing physical damages can be highly technical, depending on the extent of the damage.

So you must be an expert to handle some of the repairs.

Component Failure/Faulty Components

Component failure is also typical in boards, but the good thing about it is it does not affect the board’s physical integrity.

Parts like resistors, capacitors, microprocessors, and diodes can fail due to aging, overheating, or shorting.

Also, these individual components might be loose or separated from the board. Such issues are relatively easy to fix.

You only have to replace or resolder the parts.

However, the circuit tracks might be the culprits if they become nonconductive due to voltage sags, overheating, or aging.

Repairing this issue requires more technical expertise.

A short-circuited electronic component on a PCB

But overall, you’ll need tools like voltage testers (multimeters) to test the conductivity of the board and its components.

You can easily spot damaged or shorted components because they will have a burned, broken, or cracked shell.

Also, you can quickly notice a detached part.

But with faulty traces, you need the test tools.

Trace Damage

The copper or silver conductive materials in circuit boards can experience damage due to these reasons.

• Power surges
• Wear (aging)
• Overheating
• Shorting
• Metal dust contamination
• Lightning strikes

 

Burned PCB traces

Since traces are the “wires” in the circuit, power will not get to the components if there is trace damage.

And in most cases, you can notice these damages, especially if the track is relatively thick.

The shiny metals make it easy to find damage (discoloration or breaking).

But if the trace is thin, you might have to do voltage tests or use a multimeter to check for continuity.

Repairs involve board rebelling or resoldering using the appropriate material when you identify the damage.

Poor Design

Some unscrupulous engineers and designers can cut corners during design or manufacturing, leading to poor board designs that don’t meet the required standards.

So the fault could be erroneous or intentional to cut costs.

Such a PCB might fail after a few days or months in use.

And even if you repair it, the board will continue malfunctioning.

So the solution is to get a new board because repairs will be costly, temporary, and a waste of money.

And when getting a new PCB, look for a different designer or manufacturer who adheres to the required quality standards.

Power Failure

Power failures usually occur due to component or trace damage.

It could be a conductive track failure that has cut the power supply to some components or a circuit section.

Or a component failure that has cut the electric signal flow.

 

A circuit board after water damage

The issue requires a voltage meter to identify and diagnose the electrical problems.

And the repair process might require component replacement, resoldering, or rebelling.

What Does PCB Repair and Remanufacturing Consist of?

As stated earlier, the board repair process depends on the extent and type of damage.

But with all repairs, you must adhere to ICO and IPC standards, ensuring the product reconstruction follows the required protocols.

For instance, here’s what you need for the following repairs.

Component and Conductor Repair

You will need soldering/desoldering skills, Ball-Grid-Array rework skills, and a steady hand to operate the soldering gun.

The ideal person should have lots of experience with a soldering iron to ensure the following.

• Components seat properly
• Solder spreads on the pads evenly
• Proper wetting to form sturdy joints

 

A technician using a soldering iron

Copper/Silver Trace Repair

This repair process also requires soldering-gun or heat-gun experience to replace, remove, or coat the trace material.

Physical Board Damage Repair

Since this repair process requires baseboard rebuilding, you must have experience handling substrate materials like FR4.

Also, you might have to disassemble parts of the board, so soldering skills are critical.

PCB Internals Repairs

Internal repairs are highly technical because they need electrical, mechanical, and engineering skills to fix.

If you lack this knowledge, we recommend employing PCB repair services.

What Materials Are Necessary for PCB Repairs?

Depending on the repair, you might need the following materials.

• Silver or copper for repairing/reseating the conductive surfaces
• Substrate materials (fiberglass, epoxy, FR4, metal, phenolic resin, etc.)
• Gold for surface finishing (electroplating or immersion)

How To Troubleshoot a Circuit Board

Map the PCB

PCBs have different components and sections, so the first step is to map out where everything is on the layout.

If you have the design documents, it will be easier to figure it out. You should distinguish sections like the power supply, filters, chokes, voltage dividers, etc.

A PCB is placed against its schematic for easy mapping

Do a Visual Inspection

Visually check the surface components on the board to find if there are any hot spots, cold joints, arcing, tombstoning, excessive solder on joints, cracks on the board, missing or lifted pads, or any other unusual occurrences.

Do a Comparative Analysis

If you can access a good, working version of the same board, use it to compare with this faulty circuit.

A comparative analysis is like an extension of the visual inspection step because it requires you to place the two boards side-by-side and then identify any errors, misplacements, or missing parts.

Take it up a notch by checking the input and output readings of both boards using a multimeter. They should be the same. If not, you’ll have narrowed it down to a specific section or component.

Isolate the Defective Components

If you’ve identified a faulty section or haven’t found any, you should go through each component to test its electrical performance.

You need to have the specifications of each part to determine if the multimeter reading matches the datasheet and PCB design requirements.

Alternatively, you can do a nodal analysis on each component to measure the V/I response.

Nodes, branches, and circuit elements in a circuit

Test or Replace the Chips

Integrated circuits are not that expensive nowadays, so you can test or replace them. Identify the chip’s markings and specifications first then test it using an oscilloscope or logic analyzer. Check the component’s orientation, as well, and verify that all the solder joints are in order. Remember to also evaluate the heat sink and thermal pads. You can do a direct replacement to avoid this testing hassle because it is an easier troubleshooting option.

Check the Power Supply

A faulty power supply can affect the performance of all components because they might be getting more or less juice than what they need. Use a multimeter to measure the rail voltages, which can indicate if there is a short or open circuit if the reading is zero.

Identify the Hotspot

Faulty connections or components usually create a hotspot when power flows through them. You can inject power into the board and feel the heat levels after some time or use a thermal camera to observe the circuit. The latter is better because it is less likely to cause electrical accidents.

Do a Signal Probe

If you know the waveforms and expected values of all the test points, you can use a wave-capturing device, such as an oscilloscope, to analyze the PCB for errors like low voltages.

Necessary Safety Measures When Repairing PCBs

Wear Protective Gear

Harmful compounds or metals, like hot, molten solder, can splutter when making these repairs, so you must wear protective gear to protect your eyes, hands, and nose (to avoid breathing in harmful elements).

A technician wearing protective glasses when repairing a PCB

Eliminate Electrostatic Discharge

Electrostatic discharge is common when handling electronics, and it can damage sensitive components. To eliminate static before it causes electrical faults, use anti-static wrist straps ESD-safe mats, and ground your workstation.

Discharge the Electronic Components

Capacitors and components in the power supply section can hold the charge even after you disconnect the board from its power source. These can cause harmful static or even spark you a little. The shock can be more intense if the board has an internal supplementary battery, so remember to remove this component, as well.

Operate in a Clean Environment

Your hands or the working surface can have corrosive compounds like salts and water that will damage the board, especially around the edges. So remember to clean your workstation and use electronics-safe hand sanitizer to clean your hands. You can wear gloves but some people prefer bare hands.

Then, How to Repair Circuit Boards?

After identifying the damaged area or components, follow these steps to complete the repairs.

Gather the Repair Tools and Materials

Have at least these tools.

• Hot air gun
• Soldering gun
• Copper foil
• Tweezers
• Sharp knife
• Scissors
• Sandpaper
• Adhesive copper tape
• Paper clip
• Rubbing alcohol
• Cotton swabs
• Pen

 

A soldering gun

Remove the Damaged Pad/Sections

Hot air melts the solder, so use the hot air gun to heat the damaged area.

Keep the nozzle about ¼ to ½ inches away from the surface and heat for 30 seconds.

After that, use the tweezers to lift the component from the copper pad or thru-hole.

If stuck, continue applying heat for 15-20 seconds until the solder melts.

But be careful not to overheat the area. However, you can still fix this issue. If heat damages the pad, remove it using a knife.

And don’t force the copper pad out because you can damage the conductive track.

We recommend sanding down the surface to remove debris or excess solder and restore the shiny look.

Clean the Track and Remove the Unwanted Solder

Cleaning the track ensures the new pad or component creates a solid connection. The process involves:

• Rubbing the alcohol-soaked cotton swab on the track
• Use the craft knife to remove the remaining damaged parts
• Marking the cut track end using a pen to know where to position the new pad/component

 

A bottle of rubbing alcohol

Place Copper Tape Over the Track

With a clean track, place the copper tape above it to help create a solid connection with the new pad or component.

Ensure the adhesive tape is slightly longer than the track, but the ends should flush with the PCB edges.

Solder the Joints

Next, solder the joints where the copper tape attaches to the existing track. And try to solder in one go.

Keep in mind copper melts quickly at the high soldering temperature.

So only start the process when you can finish soldering in one go.

Copper tape

Also, apply a small solder quantity on the pads, then use the soldering gun to heat the solder until it melts.

After that, use the gun tip to hold the copper tape in place until the solder cools and solidifies.

Solder Components

The next step is to solder the component on the copper tape. But if it is a through-hole component, you must rebuild this hole.

You can identify the hole by pressing down on the soldered area using a pen or object with a rounded edge.

Since the adhesive is still tacky, you’ll be able to find the thru-hole point.

Pierce it using a paper clip and expand the hole to be the same diameter as the component’s lead.

A thru-hole component undergoing soldering

Insert the component, flip the board, then solder the lead using the soldering gun.

Trim the Excess Copper Tape

Use the scissors or knife to cut the excess tape from the repair area.

Ensure you don’t slice the tracks or pads in this process.

What Are Common Electronic Board Repair Applications?

• Home applications: smart home, alarm, HVAC, and lawn irrigation systems
• Lab equipment: analytical equipment and measurement & testing devices
• Office applications: networking devices, phones, security equipment, and printers
• Manufacturing equipment: pumps, motors, sensors, control devices, etc.

PCB Board Repair: Can All PCBs Be Repaired?

No. Boards with poor design/build quality are not worth repairing. And it might be impossible to repair completely shattered PCBs.

In such cases, it is economically viable to get a new PCB.

PCB Repair FAQs

How Do You Repair a Broken Trace on a PCB?

The most common method is to bypass the damaged section using a wire.

Identify the damaged section and scratch about 2mm on either side to scrape the resist and expose the copper line.

Ensure you create a proper path on that section to avoid EMI issues.

Clean the area with flux, cut and peel the wire, dip the ends in flux, and then surface mount them to the exposed track.

Finish off by applying a conformal coating.

A broken PCB with electrical connections on both sides

How Do You Repair a Damaged Pad on a PCB?

The simplest and quickest repair is to use a copper tape or copper foil patch, which repairs the outer layers and requires minimal tools.

How Do You Repair Breaks in EMI or RF Shielding?

You can apply fast-drying silver-filled polymer or conductive paint, which will dry in minutes to patch the shield. But ensure to maintain or not block the whole pattern.

How Do You Repair a PCB Crack or Open Area of the Solder Resist on a PCB?

It depends on where the crack is and how bad it is. If the crack cuts across a copper trace and is too extensive, you’ll have to glue the pieces back together and then repair the broken trace(s) using the steps explained earlier.

But if it doesn't cut across copper traces, such as on the edge, glue the pieces, and you’ll be good to go.

What Is the Best Glue for PCB Repair?

The best glue for PCB repair and electronics in general is epoxy, but you can also use UV-curing acrylics.

What Wire Should I Use for Trace Repair?

You should use enameled wire, an insulated conductor, the same as what you should use to repair electromagnet or transformer coil wire cuts.

This enamel coating comes off easily when you apply heat using the solder gun, leaving the copper core exposed.

So remember to apply the conformal coating to protect the wire from oxidation and corrosion.

Summary

As you can see, the PCB repair process is highly technical. So you should not attempt it if you don’t know what you are doing.

But learning this skill is critical if you are in the electronics industry because it helps cut costs.

Also, it is one of the defining qualities that make you a qualified electronics professional.

But if you’re not in this industry, get a repair technician to do the work for you.

That’s it for now. Thank you for reading!