Apparatus for detecting the presence of contamination films and foreign material on the conducting fingers of a circuit board. The apparatus includes a guide block assembly (11) designed to receive and momentarily hold a circuit board (100) and a spring biased hold down bar (25) for securely holding...http://www.google.se/patents/US4225819?utm_source=gb-gplus-sharePatent US4225819 - Circuit board contact contamination probe
