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No Fault Found
No fault found (NFF), no trouble found (NTF) or no defect found (NDF) are terms used in the field of maintenance, where a unit is removed from service following a complaint of a perceived fault by operators or an alarm from its BIT (built-in test) equipment. The unit is then checked, but no anomaly is detected by the maintainer. Consequently, the unit is returned to service with no repair performed. If there is an underlying fault that has not been detected the unit may be returned for repair several times with no fault identified. Alternative descriptors include: * No fault found (NFF) * Cannot duplicate (CND) * Fault not found (FNF) * No trouble found (NTF) * No defect found (NDF) * Hidden failures * False failures The NFF problem As the figure shows once a fault has been reported, investigated, and no fault found any future problems caused by the fault cause additional work which is a waste of maintainer time. Different causes have been suggested for this issue. * Some can ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Condition-based Maintenance
The technical meaning of maintenance involves functional checks, servicing, repairing or replacing of necessary devices, equipment, machinery, building infrastructure, and supporting utilities in industrial, business, and residential installations. Over time, this has come to include multiple wordings that describe various cost-effective practices to keep equipment operational; these activities occur either before or after a failure. Definitions Maintenance functions can defined as maintenance, repair and overhaul (MRO), and MRO is also used for maintenance, repair and operations. Over time, the terminology of maintenance and MRO has begun to become standardized. The United States Department of Defense uses the following definitions:Federal Standard 1037C and from MIL-STD-188 and from the Department of Defense Dictionary of Military and Associated Terms * Any activity—such as tests, measurements, replacements, adjustments, and repairs—intended to retain or restore a func ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Built-in Self-test
A built-in self-test (BIST) or built-in test (BIT) is a mechanism that permits a machine to test itself. Engineers design BISTs to meet requirements such as: *high reliability *lower repair cycle times or constraints such as: *limited technician accessibility *cost of testing during manufacture The main purpose of BIST is to reduce the complexity, and thereby decrease the cost and reduce reliance upon external (pattern-programmed) test equipment. BIST reduces cost in two ways: # reduces test-cycle duration # reduces the complexity of the test/probe setup, by reducing the number of I/O signals that must be driven/examined under tester control. Both lead to a reduction in hourly charges for automated test equipment (ATE) service. Applications BIST is commonly placed in weapons, avionics, medical devices, automotive electronics, complex machinery of all types, unattended machinery of all types, and integrated circuits. Automotive Automotive tests itself to enhance safety ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United States Department Of Defense
The United States Department of Defense (DoD, USDOD or DOD) is an executive branch department of the federal government charged with coordinating and supervising all agencies and functions of the government directly related to national security and the United States Armed Forces. The DoD is the largest employer in the world, with over 1.34 million active-duty service members (soldiers, marines, sailors, airmen, and guardians) as of June 2022. The DoD also maintains over 778,000 National Guard and reservists, and over 747,000 civilians bringing the total to over 2.87 million employees. Headquartered at the Pentagon in Arlington, Virginia, just outside Washington, D.C., the DoD's stated mission is to provide "the military forces needed to deter war and ensure our nation's security". The Department of Defense is headed by the secretary of defense, a cabinet-level head who reports directly to the president of the United States. Beneath the Department of Defense are th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Troubleshooting
Troubleshooting is a form of problem solving, often applied to repair failed products or processes on a machine or a system. It is a logical, systematic search for the source of a problem in order to solve it, and make the product or process operational again. Troubleshooting is needed to identify the symptoms. Determining the most likely cause is a process of elimination—eliminating potential causes of a problem. Finally, troubleshooting requires confirmation that the solution restores the product or process to its working state. In general, troubleshooting is the identification or diagnosis of "trouble" in the management flow of a system caused by a failure of some kind. The problem is initially described as symptoms of malfunction, and troubleshooting is the process of determining and remedying the causes of these symptoms. A system can be described in terms of its expected, desired or intended behavior (usually, for artificial systems, its purpose). Events or inputs t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unintended Consequences
In the social sciences, unintended consequences (sometimes unanticipated consequences or unforeseen consequences) are outcomes of a purposeful action that are not intended or foreseen. The term was popularised in the twentieth century by American sociologist Robert K. Merton and expanded by economist Thomas Sowell and psychologist Stuart Vyse.Robert K. Merton, Versatile Sociologist and Father of the Focus Group, Dies at 92 Michael T. Kaufman, '''' Unintended consequences can be grouped into three types: * ''Unexpected benefit'': ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
