PRINTED CIRCUIT BOARD FACILITATING DIAGNOSIS OF FAULT OF CIRCUIT ELEMENT

PURPOSE:To diagnose a fault without detaching a circuit element in case of the occurrence of the fault, by providing a separating and connecting mechanism, which intermits a signal, to a branch pattern for inputting the same signal to >=2 circuit elements. CONSTITUTION:On a printed circuit board 1, circut elements 2 and 3 are mounted, and terminals 7 and 8 of those circuit elements and a pattern 4 are connected mutually through separating and connecting mechanisms 5 and 6 provided to branch patterns 9 and 10 respectively. When a fault is detected in a signal by the pattern 4, connectors for short-circuiting of the mechanisms 5 and 6 are detached successively to separate the circuit elements from the signal of the pattern 4; when the signal of the pattern 4 does not have the fault any more, the elements are found abnormal. When the signal of the pattern 4 has the fault successively, said operation is repeated to find an abnormal element.