The design and modeling of the tester reduces the failure rate and the number of boards with defects. Moreover, it allows to make the cycle time of each card constant and to test more cards in a reduced time. To do this, we began by presenting the problem and proposing solutions to reduce the number of cards with defects in the production process on the SMD line. Then, and after a study of the system, we chose the hardware to ensure its proper functioning which helps us to automate the tester.