create schematic from circuit board images?

Automation would be nice, but I do it by hand, with the aid of a computah to do the photo manipulation, drawings, and to connect the dots. Something like this: The difficult parts (for me) are identifying the components and photographing the PCB inside the original box, where the tangle of wires and mechanical parts usually get in the way. I've never tried to reverse engineer something as complex as the above example PCB. Even with simple PCB's, I always wiring errors and component errors.

Plenty of articles and videos on other ways to do it: I should probably read/view a few of these to see what I've been doing wrong:

Incidentally, if you have more than one of the PCB that you're trying to reverse engineer, I've found it better sacrifice one PCB to the electronics gods by removing all the parts and photographically reproducing the PCB. Once the holes are located and cleared with a solder sucker, it's easy to photo graphically locate the holes (light from behind the PCB). Then, using a continuity checker (buzzer or light), just connect the dots (holes) and you have a schematic. The hard part is to NOT rip out the plated through holes when removing the components. Chop off the component, leaving the leads. Heat the leads with an SMD hot air desoldering station, and pull out what's left of the lead with a pliers or tweezers. Then, clear the holes by heating the PCB, and either blowing solder slag all over your workbench, to sucking the solder out of the hole with a desoldering pump. Solder braid will tear up the pads and traces and should be avoided.

Good luck.

--
Jeff Liebermann     jeffl@cruzio.com 
150 Felker St #D    http://www.LearnByDestroying.com 
Santa Cruz CA 95060 http://802.11junk.com 
Skype: JeffLiebermann     AE6KS    831-336-2558

Target 3001

has a facility that can help.

You start with an image of the board, Then add components to another layer and connect the components. The schematic then comes out as "rats nest" that you have to sort out.

It would appear that KiCAD is also a possibility for RE:

(I have Target 3001 as well)

John :-#)#

Thanks, downloaded and tried it out today, but ran into a couple of hitches. I was trying to use the instructions shown at the above link:

1) I refer to step 4, import packages. It says to place it on the layout, which I did, but does not indicate how to release it there so it stays put. How is this done? Tried double clicking, etc but to no avail. 2) I was trying to place a 555 timer. It was only about half the size of the image underneath. Which can I reduce/ enlarge and how?

That's it for now. If remedied, I can then try proceeding forward to the next steps. I am using a simple, single sided board with less than

30 components, which are mostly resistors, capacitors and diodes.

Thanks in advance!

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Alright, have to press the ESC key. Got it.

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One other thing I'm running across. Not all components on the circuit board can be readily identified. There is a flyback, for example, that doesn't show up anywhere in data as well as what looks like a small torodial transformer would with input and output turns. How can I go about adding these unknowns?

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This evening, I identified values for almost all of the components in preparation for placement tomorrow.

I solved the issue of scaling differences between the board and the components. I just had to reverse the length and width specs.

There are still two components I have been unable to locate, what I believe is a line filter (a bifilar toroid with bifilar input and output) and a 9 pin flyback. Nothing comes up in cross reference online

nor on the database Target 3001 offers, so would welcome any suggestions

as to what to do here.

Otherwise, I think I'm ready to proceed.

That can be a problem. You probably have to do it manually but then figure out how to work it into the drawing in the software.

Another thing is two sided boards have been around for a longtime, I have no idea how you put that together but you can bet you have to depopulate the board to get a picture of it.

It might be a good idea to try it on a board that you know, well the schematic of. You can get used to what kind of errors and other shit you can run into.

If you got more than a two sided board, like four layers which are in many things now, such a program will not do much good. The outer foil patterns could be nothing but a power plane and a ground plane. The real works is hidden underneath.