Flex PCB Damage and Repair

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Oakley Mae

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Flex PCB damage is common in electronics; when it happens, you should be ready for repairs.

But when the damage is beyond repair, you have no other option than to replace the whole PCB. 

We know that PCB damage is due to many reasons, including environmental causes, corrosive design flaws, physical stress, and manufacturing errors.

Since PCB are important and delicate products, repairing them efficiently should be your top priority.

And if you can’t do this, you better spend money on a professional technician. 

Luckily, we have put together some PCB damage and repair guides to help you keep it in good shape. Let’s get rolling. 

Table of Contents

The Common Flex PCB Damages

The first step to solving a problem is understanding its cause, which applies even to PCBs. So, what are the main flex PCB damages? 

Physical Damage

The most common cause of circuit board faults is physical damage to the internal and external components.

And it is mainly caused by anything resulting from physical shock and pressure.

For example, if you drop your PCB or hit it with another stronger device, there is a high chance it’ll damage. 

And as long as the device didn’t completely damage, you can still restore it to full functionality through remanufacturing.

This involves either disassembling or reassembling the circuits or melting down the damaged parts.

However, only professional technicians should do the repairs. 

Component Failure

Circuit board components are not designed to last forever.

If you’re certain, there was no physical damage to your PCB, but it is not working, there is a high chance some components are experiencing failure.

By circuit board components, we mean anything you connect to the board, including resistors, diodes, and capacitors. 

Components often fail because of overheating, voltage sags, and aging. You need to do a thorough circuit board test to identify the component with failure. 

Trace Damage

Traces involve the circuit board’s conductive lines of copper or silver materials. Therefore, these lines are responsible for transmitting power and signals.

You can monitor some trace problems with your naked eye but not always. 

Generally, a problematic trace affects components, the whole component, and conductivity.

Moreover, trace damage results mainly from normal wear, overheating, and power surges.

Furthermore, they might originate from metallic dust contamination, lightning strikes, and shorts. 

Poor Design

As much as we would like to believe that all design engineers and manufacturers are competent in creating high-quality PCB, this is not always the case.

Sometimes, manufacturers or engineers take shortcuts while designing PCBs for unknown reasons. 

For example, they might opt for low-quality materials and components to cut costs.

As a result, the PCB will develop problems sooner or later. 

Power Failure

There is no major difference between power and component failure.

However, power failure storms from the fact that all or some parts of the board experience a power failure.

For example, exposing your board to a higher voltage will likely overheat and explode. 

Moreover, the circuit traces might have problems, thus causing a short.

Whatever the case, you can use a multimeter to troubleshoot the problem. 

Flex PCB Repair Process

A short circuit on a printed circuit board

(A short circuit on a printed circuit board)

Many people find flex repair challenging.

However, everything changes with the right skills and tools.

In this section, we highlight steps to follow while repairing a flex PCB: 

Identify The Problem

How can you repair or solve a problem that you don’t know?

Therefore, your first step should be to diagnose and identify the problem affecting the board. 

In some cases, the damage could require you to replace components completely.

You should buy a similar component in such a case. 

Choose A Setting

Since flex PCB has many small components, you must exercise extra caution.

Therefore, start by getting the relevant tools and platforms.

We recommend tapping the board on a spacious table.

Alternatively, consider holding it with clippers. 

Remove Defective Components

You’ll need a hot air gun to remove defective components from your PCB.

A hot air gun works by being held a few inches from the target component. And after the component gets loose, remove it with tweezers. 

Solder New Components

Finally, place copper braids on the circuit board pad where you removed defective components.

Next, use your soldering iron tip to apply heat to the pad.

The copper braids assist in absorbing extra solder on the pads. 

After you finish this process, use alcohol swaps to clean the pads.

Always avoid using wet clothes as they might release moisture onto the board.

As a result, the board might experience another short circuit, or the moisture might be an ingredient for corrosion.  

Flex PCB Repair Safety Practices

A repairman with safety glasses

(A repairman with safety glasses)

Safety precaution is important while handling PCBs to protect the circuit board and your health. We’ll highlight some important things to worry about below.

Unplug or discharge electronics: To prevent electrocution or short circuits, unplug the defective component.

And if possible, discharge it completely.

Moreover, in the case of supplementary batteries, discharge them. 

Use safety glasses: This is a safety precaution to protect yourself.

Safety glasses will prevent solder and leads from flying into your eyes during soldering.

Therefore, you don’t have to worry about the safety of your eyes.

Avoid static discharge: You can prevent electrostatic discharge by not combining several PCBs.

Furthermore, you must keep the PCB at rest and not move it against other devices. 

Wash your hands to avoid PCB contamination: Contaminating the circuit board translates into solderability problems.

Also, it could cause corrosion or dendritic growth.

Therefore, wash your hands using electronic safe hand lotions.

The Best Desoldering Methods

Desoldering station tools

(Desoldering station tools)

You use a soldering iron, flux, and solder when soldering components.

However, removing this solder in case of damage might be a challenging task.

Fortunately, we highlight some of the desoldering methods for you below: 

Solder wick: This method uses copper braids that absorb the solder.

It would be best if you coated the solder wick with flux to ensure the melted solder is easily drawn.

Therefore, this method can extract solder from hidden sections without causing thermal stress. 

Solder suckers: As the name suggests, the method employs a vacuum to suck up solder from the board.

But first, you should melt the solder using a heat gun or soldering iron.

However, the method works with exposed solder. 

Desoldering stations: The method involves a soldering iron with a hole at the center. Therefore, the hole will draw up all the solder upon melting. 

Hot air solder stations: moreover, we have this option that blows hot air over the board, thus melting the solder.

You can then remove the solder in ways you see fit.

Tips To Guarantee Efficient and High-Quality Desoldering

A female engineer working on a circuit board

(A female engineer working on a circuit board)

Follow these tips for efficient and high-quality desoldering: 

  • First, the soldering iron tip should always be clean and tinned for excellent heat conduction
  • Secondly, avoid exposing the PCB and components to high temperatures for a long time to avoid damage
  • Thirdly, always match the wick width and solder joint or contact pad
  • Fourthly, to guarantee more accuracy, match the soldering iron tip to the braid width
  • Furthermore, the cleaning process should match the type of flux
  • Finally, use a high-quality flux remover to prevent corrosion issues

FAQs

Are there problems with fixing the Flex PCB yourself?

There is no problem whatsoever as long as you’re qualified to do so.

Fixing a PCB is a technical process that requires a professional technician or engineer.

Surprisingly, any slight mistake during the repair could damage the PCB even further.

That’s why we recommend spending money and hiring a professional is better. 

What do you need to repair a PCB?

The most important thing is knowledge especially relating to the PCB components.

Also, you’ll need the tools to troubleshoot the PCB, with testing probes and a multimeter being enough.

However, some situations might call for an oscilloscope, an LCR meter, a logic analyzer, and a power source.

Finally, you’ll need some extra components to make replacements just in case those on the board are faulty. 

Final Remarks

Nothing lasts forever, and no matter how perfect your PCB is, it’ll likely experience damage at some point.

Some common damage it experiences includes physical damage, component failure, trace damage, poor design, and power failure.

Therefore, when this happens, you must be ready to do repairs.

And even when you can’t do it yourself, hiring a professional engineer or technician is still possible. 

If you opt for a DIY repair, follow the process and tips above.

However, remember to abide by the PCB repair safety practices.