Get an exemplary circuit board and scan it as a backup before removing the components. Remove the higher part first, and then perform a second scan to record the image. Do the cleaning work before scanning to ensure that the IC model and the PCB characters are visible on the picture after scanning.
Use a hot air gun to heat the component to be removed. The removal order is first the resistor, then the capacitor, and finally the IC. Before disassembling, It should prepare a form with recorded items such as tag, package, model, and value. After removing all the components, use a bridge to measure its value. After the measurement is completed, enter the data into the computer for archiving.
Remove the remaining tin dross on the PCB surface of the removed component. Pay attention to the electric iron temperature should not be too high not to burn the ink.
After scanning the surface image, it is determined as the top and bottom layers, respectively. First, package the components (including small screen printing, pad diameter, positioning holes, etc.). After all, parts are completed, place them in corresponding positions, and adjust them to match the original board.
Sand the surface with sandpaper to expose bright copper.
If it is a multi-layer board, take an 8-layer board as an example:
After one or eight layers have been copied, then one and eight copper layers are ground off. Two and seven layers are copied, then three and six layers, and finally, four or five layers are sufficient. During the operation, make sure that the base map’s size is correct and then adjust the PCB components’ position one by one so that they coincide entirely with the base map.
Using image processing software, combined with PCB drawing software and physical circuit connection, can make 100% accurate judgment.
In the traditional clone PCB method in the interview, if the non-destructive method is adopted, the circuit board is scanned by CT to obtain a projected image. Then a three-dimensional image is obtained using image reconstruction technology. Then It can get the pictures of each layer by correcting and layering.