Every now and then a call comes into the CAD cave that goes something like this: “I’ve got a broken flex circuit and I need to buy a replacement, but I don’t have any drawings and I have no idea who made it.” Time for reverse engineering!

I love working on these projects – each is a mystery to be solved. As Hercule Poirot would say they exercise “the little grey cells”. In this article, I’ll share the eight steps I use for reverse engineering a flex circuit.

I use AutoCAD, Electronics Packaging Designer (EPD), Photoshop, a flatbed scanner, an ohm meter, a good magnifier, and two calipers – a digital one that measures in both inches and millimeters, the other a dial caliper that measures in inches.