| 摘要 |
PURPOSE: To quickly and accurately discriminate a faulty device out of a plurality of electric devices connected to a certain node of a board being tested by performing passive voltage measurement when individual devices drive the node and analyzing the measured voltage values. CONSTITUTION: When in-circuit tests are performed on a device, a diagnostic system 10 for bus failure is triggered against a certain failure condition and an increment is generated in the measured voltage value of a specific insulated device 13. After the in-circuit tests are completed on all devices, all triggered measured voltage values are converted so that the values can be compared with each other and analyzed for discriminating the devices at each node. For the in-circuit tests of each device 13, a test pin 40 which is brought into contact with a node 38 to which the lead of each device 13 is connected is used. In addition, another pin 40 which is brought into contact with the node at the input of another device which controls the input of the device 13 to be tested is also used. A test vector which is supplied to the input of a digital device is detected and compared with an expected answer.
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