Detecting faults on a printed circuit board

摘要

An automatic circuit board tester for testing for shorts, opens, and interconnected pins or nodes on a circuit board. The tester first classifies the nodes as being in one of three categories based upon the design of the board and the intended interconnection of the nodes. The categories of nodes are: (1) connected to ground; (2) interconnected to other nodes in the test group; or (3) isolated from all other nodes. The tester utilizes the digital signal from a driver and tests the circuit board to ensure that the physical embodiment of the circuit board accurately reflects the circuit board design. The circuit board tester has a testhead containing a plurality of test channels (212), each configured to be coupled to a node on the circuit board. The testhead utilizes a digital signal from a digital driver 302 to drive the node at a predetermined voltage and a digital receiver 304 to read the node voltage to determine if it is coupled to ground. Each test channel also includes a switch means 306 to connect the digital driver 302 and receiver 304 to the test node as well as a ground switch 308 to selectively couple the node to ground. Various combinations of switch positions and testing sequences enables the circuit board tester to test all node connections and to ensure that the physical embodiment of the circuit board accurately reflects the circuit board design.