In the testing of printed circuit boards, a flying probe test system may be used for testing low to mid volume production, prototypes, and boards that present accessibility problems. Flying probe testing uses electro-mechanically controlled probes to access components on printed circuit assemblies (PCAs). The probes are moved around the board under test using an automatically operated two-axis system, and one or more test probes contact components of the board or test points on the printed circuit board.
Flying probe testing is commonly used for test of analog components, analog signature analysis, and short/open circuits. They can be classified as in-circuit test (ICT) systems or as Manufacturing Defects Analyzers (MDAs). They provide an alternative to the bed-of-nails technique for contacting the components on printed circuit boards. The precision movement can probe points on integrated circuit packages without expensive fixturing or programming required.
The main advantage of flying probe testing is the substantial cost of a bed-of-nails fixture, costing on the order of US $20,000, is not required. The bed-of-nails fixture may require changes if the printed circuit board layout is changed. However, since the tester makes measurements serially, instead of making many measurements at once, the test cycle may become much longer than for a bed-of-nails fixture. A test cycle that may take 30 seconds on such a system, may take an hour with flying probes. Test coverage may not be as comprehensive as a bed of nails tester, because fewer points are tested at one time.