Abstract: A computerized apparatus for performing functional and incircuit tests on complex printed circuit boards is disclosed. A printed circuit board under test is held in a vertical fixture and electrically coupled with the power circuit of a primary test unit. A limited bed of nails unit is interfaced with the vertical fixture holding the printed circuit board under test and the multiple spring contact probes of the limited bed of nails unit are maintained by spring pressure with predetermined terminals on the rear solder side of the printed circuit board under test. The limited bed of nails unit includes an etched printed circuit panel whose circuitry is connected with the spring probes of the unit through soldering.

Abstract: A precision rectangular fixture frame includes top, bottom and grooved side members. A middle bar of the frame parallel to the top and bottom members has a pair of recesses aligned with opposing recesses in the top member whereby a single vertical bar having a pair of spaced notches can be interlocked with the top member and middle bar of the frame in two positions of use parallel to the side members. The vertical bar is grooved in its opposite sides whereby in each position of use of the vertical bar one of a pair of contact gage and alignment bars can be supported at plural elevations on the fixture frame during servicing of successive ranks of contacts in two distinct areas of an upper tier of contacts in a receiver. A third contact gage and alignment bar is employed without the vertical bar and is engaged with grooves of the frame side members at plural elevations during servicing of successive ranks of contacts across a lower tier of contacts in the receiver.