PCB reverse engineering
, also known as PCB cloning
or PCB copy, is using reverse engineering technology onto the PCB which was designed and manufactured by others, it is to use PCB related software to copy someone else’s circuit board and then manufacture the circuit board by yourself. This is the tradditional explanation for the PCB reverse engineering. with the pcb reverse engineering technology development, the impact and scope of this industry continues to expand rapidly, and the definition of pcb reverse engineering also extend from the narrow sense that: pcb reverse engineering only refers to extraction of PCB file from electronic circuit board and then restore it for the purpose of PCB cloning or copy; To the wide sense that pcb reverse engineering not only include PCB file extraction, circuit board cloning/copy and other related technical aspect, but also modify PCB file, the shape of the mold for electronic products, extraction of 3-dimensional model data on a variet of electronic products, compile the components list assembled on the PCB circuit board as well as individual data sheets on each component where available, decrypt microcontroller on the circuit board, crack encrypted IC on the PCB, moreover, inverse assemble the firmware of PCB circuit board and etc, a whole set of PCB reverse engineering technology.
Step 1: Clean the Surface of PCB
There is a 4 layer PCB need to being reversed engineering, all the components assembled on the surface have already been removed by hand-held soldering iron and air pressure gun, during this stage operator must be aware of components especially for those components with fine lead and high unit price delicate IC, after that, pcb board surface must be cleaned by washer water Washer which main ingredients are chlorinated solvents, buffer, corrosion inhibitor, antioxidant, surface active agent composition. Features of washer water is Low toxicity, no risk of explosion, the maximum allowable concentration in air 100PPM.
Step 2: Scan PCB Each Layer
1 Scan TOP layer circuit board, save the scanning picture and name as TOP.jpg, the DPI value can be set according to the density of PCB, hereby we choose 400DPI as reference;
2 Scan Bottom layer and name it as BOTTOM.jpg;
3 Use sand paper to abrade the TOP layer copper and expose the 2nd layer copper circuit pattern, scan the circuit pattern after clean it out and name it as MID1.jpg;
4 Use sand paper to abrade the 2nd layer copper and expose the 3nd layer copper circuit pattern, scan the circuit pattern after clean it out and name it as MID2.jpg;
Step 3: Software Processing
5 Instruct leveladjustmen for each picture we have ever scanned through POTOSHOP (rotate pictures to ensure all of them are level which will make the circuit pattern looks better, moreover multilayer PCB with over 1 picture can make it easy for alignment); Hereby we suggest to turn the BOTTOM layer picture into Mirror Horizontally, simutaneously you should adjust TOP layer picture which will make it has the same orientation as well as fixing holes on each corners. Finally save each layer file as the format of .BMP, such as TOP.bmp, BOTTOM.bmp, MID1.bmp, MID2.bmp, please noted not to cut out the pictures exactly but leave some space around each of them;
6 Open PCB Reverse Engineering software, click on “file” from MAIN MENU, and then click “OPEN BMP”, select the TOP.bmp file and open it, set up DPI value and then choose the layer feature as TOP layer, start to place components, through-hole and arrange circuit line, after you have arranged everything on the TOP layer, save file as temporary and name as TOP-1.dpb ( save the files periodically under different name such as TOP-2, TOP-3, TOP-4 prevent files lost from unexpected power cut-off or computer breakdown );
7 Click on “file” from MAIN MENU, and then click “OPEN BMP”, select the BOTTOM.bmp file, at the same time open temporary file TOP-1.dpb, and you will find that TOP layer picture which has been finished already can’t align to BOTTOM layer background picture, so you have to use cursor “UP”, ”DOWN”, ”LEFT”, ”RIGHT” to move its location, now you can choose some reference points to align the layers and after you have finished alignment you can start to place components, through-hole and arrange circuit line on BOTTOM layer, what if circuit line on the TOP layer block your eyesight on BOTTOM layer? It is easy, just from the main menu "Options" select "layer color settings”, cancel the selection of TOP layer as well as silkscreen, after you have arranged everything on the BOTTOM layer, save file as temporary and name as BOTTOM-1.dpb, or as BOTTOM-1.pcb;
8 Repeat the process from point 5 to point 7 you have just been through then can output completed PCB file of 4 layer circuit board.