Active board concurrent maintenance

Due to the shrinking time allowed for deferred repair of system hardware in an increasing number of customer environments, it became evident that concurrent maintenance was a highly desirable capability. Concurrent maintenance is a method of installing or replacing a circuit card into a functioning, powered board without disrupting any part of the active system. With the appropriate hardware and software, defective cards can be replaced without impacting system operation or availability. When the power connection between a card and board is made, large transient current surges occur in the power distribution system. This creates noise on adjacent card voltage plates and signal lines. This disturbance can be reduced by slowing down and limiting the current surge into a card during a field replacement. This paper reviews the general requirements needed to implement concurrent maintenance in a card on board package. Concurrent maintenance impacts card design, board design, and power system design. However, the key to implementing concurrent maintenance is the design of a multiple pin length connector system.<>