Assembled board testing Faults

This economical test exposes die climatically unstable points of electronic components. Due to the nature of the test, the entire board is evaluated. This test accelerates the mechanisms of electrochemical migration. Consequently, faults that previously would appear after months or even years can be detected during the development process. To identify potential weak points, the assembly is operated in standby mode and immersed in deionized water. Testing while the assembly is in full operation is even more effective. The sensitivity of the circuit to moisture exposure is assessed on the basis of flie recorded test current, combined with a subsequent examination of the assembly. Through weak point analysis, a Yes/No decision can be determined concerning the expected service life, of the assembly. 

The bad-connection test with heaters in lEC Publication 695-2-3 (1984) refers to a fault condition in a terminal or terminations which may give rise to the production of abnormal heat. The test is intended to simulate such an overheated connection, taking into account the design of the connection and the current supplied under normal conditions of use. The test is only to be applied to screw connections. The specimen (a complete unit, its sub-assembly or component) and the test conditions (the arrangement of the material either in its normal environment or underlaid with a pinewood board covered by tissue paper) are again identical to the former standards. 

The raw materials, which comprise electronic components and printed circuit boards, are cleaned. Various metal and plastic parts are plated, moulded, trimmed and printed. Workers then assemble the parts and components using screws or clips, by soldering or with the use of adhesives. The assembled product is usually a functional unit. This is tested and any fault rectified. The functional units are assembled into the final... 

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