Converting a PCB to schematic

[OKors]

I need to build a schematic diagram from nothing but a 2 layer PCB.
I've already got the comonents removed from the board and their values recorded. Is there a clever way to do this? Like would Ultiboard allow me to take a scan of the PCB and 'trace' the traces in software, untimately generating a schematic in the end?

[Chen_T]

Hi there,

You can do Backannotation to Multisim.

Here are some links mightbe helpful.

Completing the Design with NI Multisim and NI Ultiboard: Annotation Fundamentals

http://www.ni.com/white-paper/7321/en/#toc7

How to Back Annotate from NI Ultiboard to NI Multisim

http://www.ni.com/white-paper/5394/en/

Regards,

[Tien_P]

Hi Okors,

What you want to do is not possible, you have to build the schematic in Multisim. Back annotation only works if you have an existing schematic and there are things that you do in the PCB that cannot be back annotate, for example adding a new part. 

[Buechsenschuetz]

I think you are thinking of a program which recognizes tracks scanned from a pcb board and will convert them to connections in a schematic.

Maybe this is possible, but Ultiboard will not do it. The tracks used by a modern layout program have a lot of attributes and it will be hard to recognize them from a scanned pcb.

Anyhow, I have done this kind of re-engineering several times. If you have an idea of the function of the circuit in question it will not be too difficult to figure out where connections between part pins should be. For example, most TTL ICs and also most op amp ICs have their supply pins at the same location. So you can easily put up the supply net. Also, many ICs are used in standard configurations and in many cases it is not too hard to guess where parts and connections on the pcb board belong to.