When a domestic electronic comes in need of repairs and servicing but its circuit diagram is unavailable or the PCB has been taken out of circulation, there might be a grueling task ahead as far as the repairs are concerned. The only way to re-create the PCB electronic circuit diagram in such cases is to reverse engineer the PCB electronic.
PCB reverse engineering is the process of replicating the functionalities and specifications of a PCB electronic by dissecting and analyzing the PCB electronic with or without the use of the manufacturing documents. It’s a tedious task, as it requires you to progress from a point where you have very limited information about a product to a point where you can roll out the production of the said electronic board.
With PCB reverse engineering, you can re-position and replace obsolete components, enhance various functionalities, and analyze and reinforce security in a PCB electronic.
Tool Required for Reverse Engineering
For simple boards, i.e., single or double layer boards, you can disassemble, analyze and reassemble the PCB electronic by using a pencil and a paper to draw the board on a squared paper, designating symbols to each of the components. Here, you can avoid tampering with components if you change track crossing places.
For more complex boards, you’ll need to use both hardware and software to reverse engineer it. The most widely used PCB reverse engineering software includes Photoshop, Adobe Fireworks, AutoTrace, pstoedit, Dia, Gimp, and Inkscape.
How PCB Reverse Engineering Works
PCB reverse engineering usually revolves around the following steps:
Step #1: Prep Pictures of the PCB on Your Image Editing Software
The first thing you need to do is to take the most detailed pictures of both sides of the PCB. You can also scan the PCB by placing the bottom side of the board on the scanner. Note that many scanners are unable to capture the top layer due to the obstructing height of the components.
Next, import the picture to an open window of your favorite editing program. In this guide, we’re using Adobe Fireworks.
After importing the files, organize the image in separated layers. Crop all sides of the board from all pictures using the Polygon Lasso tool. Place the picture in the proper positions by using the Rotation CW/CCW and Flip Horizontal/ Vertical options. Use the zoom/magnifier to ensure that all the sides of the images are properly aligned with each other.
It’s crucial for all the images to be properly aligned. Reduce the top layer’s opacity to around 50% – 75% to make it more transparent.
Step #2: Blend the Images
There are numerous ways you can blend images, so you have a range of options here for you to choose the one that works best for you, depending on your board color, illumination, and other optical factors.
- Screen Blend: To use screen blend, drag the bottom side up towards the component side. Set the bar in the Brightness/Contrast filter to -50 to dim the copper layer. Next, highlight the copper layer and then choose blend mode on the Screen/Interpolationor Average (set to 80).
- Luminosity Blend: Drag the bottom side up towards the component side, and then use the Levels filters to increase the contrast of the copper layer. Next, highlight the copper layer and chose blend mode in Luminosity and set to 50.
Brush and Threshold the Picture
Drag the bottom side upwards toward the component side. Highlight the copper area and then draw a network of lines that connect the solder pads and holes using Brush (or the path/line tool for straight lines). Choose colors that do not match those of the solder mask.
Afterward, extract only the solid color using the Levels filter or Threshold filter. And then move the left pin across to the right. Next, adjust the Hue/saturation filter and then select your preferred track color, rotating the Hue.
Next, highlight the copper layer and then choose the blend mode in Additive, and then adjust the track’s intensity by setting the opacity to around 70.
The final step is to record the values, and then replicate the values on a CAD software.
As seen above, PCB engineering is a tedious task that requires not only deft technical knowledge but also a lot of strength of character. However, the dedication and the consistent efforts will pay off in the end when you’re able to transition from being poorly informed about a PCB electronic to mastering the entire PCB electronic.
And with our team of seasoned experts and state-of-the-art equipment, we can straighten out the learning curve of PCB reverse-engineering for you. Reach out to us whenever you’re ready.