There are two major parts to the process: data entry/learn followed by schematic drawing. Node learning and measurement is achieved by means of clips, connectors, and probes that are attached to clusters of components. SYSTEM8 Ultimate software guides the operator to place and move the clips around the reference circuit, measuring the resistance between the component pins. The short circuit threshold is set at 7 Ω. The probes provide 5 V into an open circuit and 10 mA into a short circuit on an unpowered board. Typically the system delivers 10 µA into a circuit. To minimize operator errors, the system applies an orientation check and a pin check to confirm clip contact and position. 

SYSTEM8 Ultimate software generates an efficient sequence of clip combinations and movements that will learn all possible connections, but the operator can modify or override the automatic placement of the clips if necessary. RevEnglearns without applying power to the board. It limits the measurement voltage and current. Semiconductor gates and low power technologies are not affected.

It is also possible to learn part of the circuit. Simply define those components to be included in the drawing and follow the standard procedure. You can include part or all of the remainder of the circuit later.  RevEng is very accurate: to ensure complete confidence RevEng offers ReScan and Verification procedures.

The RevEng System is available as an entry-level system with 256 measurement channels for low budget or small to medium circuits. For larger, more complex circuit needs, a high pin-count system equipped with up to 2048 channel measurement channels is also available. The advantage of more channels is reduced learning time - a function of the number of components and the number of clips available.  

RevEng is already used by a wide range of customers around the world, mainly to generate documentation for the repair of complex and costly PCBs. Most of these boards are irreplaceable: either the original manufacturers are out of business, or they refuse to supply documentation or spare parts - or would charge prohibitively for the service. Where the legacy equipment and spare parts have been discontinued, generating schematics with RevEng has allowed customers to repair and maintain existing working equipment as well as creating new PCBs based on the original design.

While many RevEng customers are either military or government companies, their projects are necessarily confidential. However, a typical case in the private sector comes from Brazil. Eletrograf ( ) specializes in the maintenance of printing presses manufactured by companies such as Heidelberg, Gutenberg, Roland, etc. They saw RevEng as a viable tool that would allow them to generate the PCB documentation required for repairing as well as reverse engineering obsolete PCBs, solving frequent breakdowns by improving the original design with the addition of more robust components or by daughter boards that would bypass a troubled section on the original PCB.  They then started offering this retrofit service as an add-on to their electronics maintenance plans, which proved a very profitable and convenient idea for Eletrograf and their customers.

Some other RevEng customers include: UK MoD, INDRA (Spain, MoD), SENA (Colombia, education), Brazilian Air Force, Turkey Armed Forces, Australia’s Defence Science and Technology Organisation (DSTO), Chilean Navy, Egyptian Navy, INSA (Ethiopia), Dornier, Deutsche Aerospace, Al Taif Technical (UAE, MoD), Telefonica (Argentina), and METRO Sao Paulo.

For additional information contact the Saelig Company of Fairport, NY (


Fig. 1.     RevEngfor REVerse ENGineering

Fig. 2.     Circuit diagram redrawn by RevEng.