Microcomputer-based testing and repairing system using digital signature mapping

A new approach known as digital signature mapping (DSM) is proposed for testing and repairing loaded printed circuit boards (LPCBs). This method uses standard state-of-the-art measurement equipment to record the response of a well-known LPCB during its operation, on a microcomputer, and uses the recorded references to compare the board under test output response in what is known as signature testing. In such a test, no test generation is required. The method can be used to perform real-time measurement for LPCBs under test with a focus on computer numerical control (CNC) controller boards. The DSM employs an MC6809 and uses well-known test tools. Therefore, the proposed system is not very expensive. It is very useful in testing and repairing small quantities of LPCBs. In addition, the software required, which is generated from mapping the signature of test points of a good LPCB, makes it suitable for a factory that uses a variety of CNC machines