How to reverse engineer a PCB

PCB reverse engineering is a PCB copy or PCB clone engineering technique which aim at replicating existing electronic products and circuit boards. The following are the five steps for PCB reverse engineering:

1、 Record component information on PCB:

When obtaining a PCB board, record in detail the models, parameters, and positions of all components on paper, especially the direction of diodes and transistors, as well as the direction of IC notches. It is best to take two photos of the positions of the components with a camera.

2、 Disassembly and cleaning all components from PCB:

Disassemble all components and remove solder from the PAD holes. Then,use alcohol to clean component surface. Place the board into the scanner and set a higher scanning resolution to obtain a clear PCB image. Next, gently polish the top and bottom layers with sandpaper until the copper film becomes shiny. Scan the board again and scan the two layers into the computer in color. Ensure that the PCB is placed flat in the scanner to obtain usable images.

3、PCB Image processing:

In the image processing software, adjust the contrast and brightness to ensure that the area with copper film and the area without copper film form a clear contrast. Then convert the image to black and white mode and check if the lines are clear. If the image is not clear, continue adjusting. If the image is clear, save it as two files in black and white BMP format. If any issues are found, use image processing software to make corrections.

4、 Generate PCB file:

Convert the two BMP format files to PROTEL format files separately. Import all layers in PROTEL and compare whether their PAD and VIA positions accurately overlap. If it is not accurate, repeat the third step until it can accurately overlap. Convert the BMP of the all layers PCB file and draw the lines on the SILK layer (i.e. yellow layer), and place the device according to the drawing in the second step. After completion, delete the SILK layer and repeat this process until all layers are drawn.

5、 Merge and verify:

Import all layer on Protel software， Merge into a complete PCB file. Use a laser printer to print the TOP layer and BOTTOM layer,and othe layer on transparent film in a 1:1 ratio. Compare the film with the original PCB to ensure there are no errors. If everything is correct, then the PCB copying process is successfully completed.

PCB copying is a complex task, through which technical information of electronic products can be extracted for replication and cloning. But careful operation is required to ensure accuracy and legality.