Best method for converting old PCB to schematic

I’ve got a old IBM power supply I’m trying to repair from the 80’s and unfortunately a schematic for the version I have does not exist so need to do some reverse engineering.

I know KiCad can not magically take a PCB and create a schematic from it, so am wondering what the best way for me to do this is? The board is single layer so not overly complicated - about 150 components. All through hole. (And no silk screen which doesn’t help!)

At first I tried printing off a reversed photo of the PCB layout and marking off all the components on the printout (And also added my own references otherwise it’s easy to loose track of where you are). Then manually creating a schematic by colouring in the tracks I’ve added to the schematic. It’s working but very slow process and becoming painful.

I can fairly easily create the PCB layout with components in KiCad and add the symbols to the schematic. Do I then just need to work through the ratsnest and manually place the wires? I think this might be a better method and less prone to errors?

Any other tricks I can use?

Is there a PCB->schematic conversion in Eagle? Don’t really want to start using Eagle but if they offer this option will try PCB->Eagle Schematic → Kicad

KiCad-nightly V6.99 has an option to load an image into the PCB editor with PCB Editor / Place / Add Image. This image can be flipped and scaled.
You can use this as a template during reverse engineering. For more, see:

Do note however, that projects saved in a nightly version, can no longer be opened in the stable KiCad version.

It would have been nice if you could create a netlist from this in the PCB editor, and then show ratsnest lines in the schematic, but this is not supported. What you can do is open both the schematic and the PCB editors, make connections in the schematic, F8 them to the PCB and combine that with real tracks drawn over the image.

Another valuable resource are the datasheets and application notes of used IC’s. Quite often the real circuit is similar to those application notes and this can help with re-creating the schematic quicker.


Thanks - this sounds like a good option. Will load up the nightly and try it out. (It’s due in 3 months anyway (If still on sched) so might as well start learning it’s new features)

You could also load the image in the schematic editor. If you get the scaling right (as in big enough) you can place the components on their respective positions, connect them and after completing remove the image and clean everything up. Since you can use colors and different line widths and types by now I imagine it beeing quite straight forward. Might be the easier way, might be not.


Thanks for the tip. I tried this out andit works really well. Found so many errors on the original schematic I tried to do by manually marking off the tracks. The image on the PCB method is about 10x faster!

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