Abstract:
An automated electronics circuit test cassette assembly is provided for mating with a test platform. The platform comprises a platform common signal interface and a vacuum manifold having a combined registration and vacuum port coupler. The cassette assembly includes a cassette common signal interface providing electrical communication with the platform common signal interface and an alignment bushing providing combined registration and vacuum communication with the vacuum port coupler. A pattern of test probes mimic a test pattern on a printed circuit assembly (PCA), extending upwards from a probe support substrate and optionally downward from a clamshell probe substrate. The PCA is supported by a PCA support substrate floating above the test probe support substrate. The clamshell test substrate provides a vacuum seal above the PCA support substrate. Testing is completed by applying a vacuum, which draws the probes against the PCA, and applying testing signals through electrical connections created therebetween.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This Non-Provisional Utility application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/414,763, filed on Nov. 17, 2010, which is incorporated herein in its entirety. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to an automated electronics circuit test device, and more particularly, an automated electronics circuit test device utilizing an interchangeable cassette assembly that removably engages with a test platform. 
     BACKGROUND OF THE INVENTION 
     The invention pertains to an automated electronics circuit test cassette assembly for removably mating with a test platform. 
     Automated test equipment (ATE) is commonly used in the electronics assembly process. The ATE includes a large test assembly that is placed upon a test stand. The large test fixture is dedicated to a specific test equipment manufacturer. The test fixture is heavy, bulky, and expensive to fabricate. The test frame and primary components are designed and sold by the specific test equipment manufacturer. This dictates that the assembly process utilize a test platform from the associated test equipment manufacturer or invest in a second test fixture. 
     The test fixtures are generally 30-36 inches across, 5-9 inches tall, and 18-26 inches deep. The text fixtures can weight between 30 and 65 pounds. The size and weight of the test fixtures makes it difficult for one person to transport and install into the test equipment. Additionally, the size and weight of the test fixtures makes it difficult to store, as they require a large storage area and are normally not stored above a reasonable lifting height. 
     The test fixture frame, vacuum plumbing, and basic support wiring is offered in an assembly from the specific test equipment manufacturer. This subassembly is expensive. 
     Accordingly, there remains a need in the art for a device that provides an apparatus and respective method, which reduces the storage requirements, overall fixture costs, the overall fixture weight, and the like to aid in the usability, storage, set-up and breakdown of the test equipment. 
     SUMMARY OF THE INVENTION 
     The present invention overcomes the deficiencies of the known art and the problems that remain unsolved by providing an apparatus and a respective method for testing electronic assemblies, the test platform utilising a removable cassette to reduce costs, weight, materials, and storage requirements. 
     In accordance with one embodiment of the present invention, the invention consists of an automated electronics circuit test cassette assembly for mating with a test platform, the cassette assembly comprising: 
     a test probe support substrate; 
     a plurality of test probes is arranged in a predetermined test pattern to mate with and test a target electronics assembly, the test probes being assembled to the test probe support substrate; 
     a common interface test probe set is provided in signal communication with the plurality of test probes for mating with and providing signal communication to a plurality of common interface test probe contacts of the test platform; 
     at least two cassette alignment bushings attached to the test probe support substrate, the cassette alignment bushings comprising a registration receptacle extending inward from a mating edge thereof, and a vacuum port passing therethrough, the cassette alignment bushings being positioned to align and mate with a registration and vacuum supply coupler extending from a vacuum supply manifold of the test platform providing a vacuum passage between the vacuum supply manifold and an upper surface of the test probe support substrate; 
     a printed circuit assembly test support member having a series of test probe apertures, the test probe apertures having a pattern mimicking the predetermined pin test pattern; and 
     a vacuum seal provided between the test probe support substrate and the printed circuit assembly test support member. 
     In one aspect, the automated electronics circuit test cassette assembly further comprises a clamshell test head assembly, the clamshell test assembly comprising: 
     a clamshell test substrate; and 
     a vacuum seal provided about a periphery of a mating surface of the clamshell test substrate. 
     Yet another aspect, the clamshell test assembly further comprises a registration interface, the registration interface providing alignment between the clamshell test assembly and the test probe support substrate. 
     While another aspect, the registration interface is a hinged assembly. 
     With yet another aspect, the registration interface is a plurality of registration pins that mate with a plurality of registration receptacle, respectively. 
     In another aspect, the clamshell test support substrate is assembled to a clamshell test frame. 
     With another aspect, the clamshell test support substrate is assembled to a clamshell test frame using a plurality of vertically biased sliding members, the vertically biased sliding members providing a vertical motion to the clamshell test support substrate. 
     Yet another aspect, the clamshell test assembly further comprises a pattern of test probes extending downward from the clamshell test support substrate, the test probes being in electrical communication with a series of extended clamshell test signal contacts. 
     Regarding another aspect, a clamshell signal adapter provides electrical communication between a series of base clamshell test signal contacts provided upon an upper surface of the test probe support substrate and the extended clamshell test signal contacts. 
     In yet another aspect, the clamshell signal adapter is fabricated having a plurality of dual sided compression test probes assembled to a signal adapter body, wherein a first end of the double ended probe forms a base interface contact and a second end of the double ended probe end forms a clamshell interface contact. 
     While another aspect, the test probe support substrate further comprises a plurality of biasing support members provided to separate the printed circuit assembly test support member from the upper surface of the test probe support substrate. 
     With yet another aspect, the test probe support substrate further comprises a plurality of vacuum draw stops provided to maintain a minimal distance between a bottom surface of the printed circuit assembly test support member and the upper surface of the test probe support substrate. 
     Yet another aspect, the automated test cassette further comprises a removal assistance tab extending from an edge thereof. 
     Regarding another aspect, the printed circuit assembly test support member further comprises a Printed Circuit assembly registration interface. 
     In yet another aspect, the printed circuit assembly registration interface comprises at least one printed circuit assembly registration pin. 
     While another aspect, the test fixture further comprises a two-stage test controlling mechanism. 
     With yet another aspect, the two-stage test controlling mechanism comprising a two-stage test platform support vertical member extending from a lower surface of the printed circuit assembly test support member and in registration with a two-stage test platform support member clearance provided through the enclosure pivotal cover of the test chassis, wherein the two-stage test platform support vertical member is of a length that supports the printed circuit assembly test support member at a first stage test level when a two-stage test platform configuration member is positioned at least partially blocking the two-stage test platform support member clearance. 
     These and other aspects, features, and advantages of the present invention will become more readily apparent from the attached drawings and the detailed description of the preferred embodiments, which follow. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The preferred embodiments of the invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the invention, in which: 
         FIG. 1  presents an isometric view of an exemplary vacuum distribution manifold assembly which is integrated into an automated test equipment chassis; 
         FIG. 2  presents an isometric exploded assembly view of an exemplary automated test cassette and primary components of the automated test equipment chassis; 
         FIG. 3  presents an isometric exploded assembly view detailing exemplary additional test support components of the automated electronics circuit test system; 
         FIG. 4  presents a top plan view of the exemplary automated test cassette; 
         FIG. 5  presents an isometric view of a test pin portion of the exemplary automated test cassette; 
         FIG. 6  presents an isometric view of the test pin portion of the exemplary automated test cassette of  FIG. 5 , introducing an upper seal member having integrated test probes; 
         FIG. 7  presents a sectional elevation view of the automated electronics circuit test system taken along a lateral section line parallel to the rear registration components, wherein the system illustrated is in an inactive state; 
         FIG. 8  presents a sectional elevation view of the automated electronics circuit test system of  FIG. 7 , wherein the system illustrated is in an active, testing state; 
         FIG. 9  presents a sectional elevation view of the automated electronics circuit test system taken along a longitudinal section perpendicular to the rear registration components, wherein the system illustrated is in an inactive state; 
         FIG. 10  presents a sectional elevation view of the automated electronics circuit test system of  FIG. 9 , wherein the system is illustrated in an active, testing state; 
         FIG. 11  presents a top view illustrating the exemplary two stage test control mechanism, wherein the mechanism is illustrated in a partial test, first stage configuration; 
         FIG. 12  presents a sectioned elevation view illustrating the exemplary two stage test control mechanism, wherein the mechanism is illustrated in a partial test, first stage configuration, the view taken along section  12 - 12  of  FIG. 11 ; 
         FIG. 13  presents a top view illustrating the exemplary two stage test control mechanism, wherein the mechanism is illustrated in a full test, second stage configuration; 
         FIG. 14  presents a sectioned elevation view illustrating the exemplary two stage test control mechanism, wherein the mechanism is illustrated in a full test, second stage configuration, the view taken along section  14 - 14  of  FIG. 13 ; and 
         FIG. 15  presents a detailed sectioned elevation view of the registration interface having a vacuum system integrated therein. 
     
    
    
     Like reference numerals refer to like parts throughout the several views of the drawings. 
     DETAILED DESCRIPTION 
     Detailed embodiments of the present invention are disclosed herein. It will be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale, and some features may be exaggerated or minimized to show details of particular embodiments, features, or elements. Specific structural and functional details, dimensions, or shapes disclosed herein are not limiting but serve as a basis for the claims and for teaching a person of ordinary skill in the art the described and claimed features of embodiments of the present invention. The following detailed description is merely exemplary in nature and is not intended to limit the described embodiments or the application and uses of the described embodiments. As used herein, the word “exemplary” or “illustrative” means “serving as an example, instance, or illustration.” Any implementation described herein as “exemplary” or “illustrative” is not necessarily to be construed as preferred or advantageous over other implementations. All of the implementations described below are exemplary implementations provided to enable persons skilled in the art to make or use the embodiments of the disclosure and are not intended to limit the scope of the disclosure, which is defined by the claims. 
     For purposes of description herein, the terms “upper”, “lower”, “left”, “rear”, “right”, “front”, “vertical”, “horizontal”, and derivatives thereof shall relate to the invention as oriented in  FIG. 1 . Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. It is also to be understood that the specific devices and processes illustrated in the attached drawings, and described in the following specification, are simply exemplary embodiments of the inventive concepts defined in the appended claims. Hence, specific dimensions and other physical characteristics relating to the embodiments disclosed herein are not to be considered as limiting, unless the claims expressly state otherwise. 
     The present invention is directed towards an improvement in equipment used for testing a printed circuit assembly  400  ( FIGS. 9 and 10 ). The printed circuit assembly  400  is fabricated assembling a plurality of electronic components  404  onto a printed circuit board  402 . The present invention utilizes an automated test cassette  200  in conjunction with an automated test equipment platform  100 , which provides the end user with a device having several advantages over the existing technology as shown throughout the figures. The use of a removably insertable automated test cassette  200  reduces the cost of the test fixture, reduces the weight of the entire test fixture, and reduces the storage size of the test fixture. 
     The automated test equipment platform  100  integrates functional utility supply elements into an automated test equipment chassis  102 , wherein the functional utility supply elements include a vacuum distribution manifold assembly  130  and a common interface test probe contact base interface assembly  160  disposed within a platform enclosure interior  106 . The vacuum distribution manifold assembly  130  provides a vacuum conduit from a vacuum source (such as a vacuum motor) and the common interface test probe contact base interface assembly  160  provides an electrical power and signal interface from an electrical test control circuit. The vacuum distribution manifold assembly  130  is defined having two sections, a vacuum source manifold assembly  140  and a vacuum supply manifold assembly  150 , as detailed in  FIG. 1 . The vacuum source manifold assembly  140  controls and distributes a source vacuum flow, wherein the source vacuum flow is introduced through at least one vacuum source interface  148  and controlled by a vacuum control solenoid  146 . The vacuum flow continues through a vacuum source conduit  144  and into a vacuum transfer member  142 , where the vacuum flow transitions from the vacuum source manifold assembly  140  to the vacuum supply manifold assembly  150 . A vacuum supply manifold  152  provides fluid communication of the vacuum flow between the vacuum transfer member  142  and at least one registration and vacuum supply coupler  154 . It is understood that a plurality of registration and vacuum supply couplers  154  are desired, as illustrated in the exemplary embodiment illustrated in  FIG. 1  and throughout the figures. A cassette alignment bushing  170  removably engages with the registration and vacuum supply coupler  154 . The additional functions provided by the cassette alignment bushing  170  will be detailed further in this disclosure. 
     Additional elements integrated into the automated test equipment platform  100  include an access panel  103 , a pair of chassis mounting rails  112 , and a lid prop member  110 . The access panel  103  provides access to the platform enclosure interior  106  from a respective side of the automated test equipment enclosure  102 . The access panel  103  can include a user interface for controlling the pneumatics, the electrical testing, and the like. The user interface can be switches, a touch screen, and the like. A pair of chassis mounting rails  112  are assembled to the automated test equipment enclosure  102  providing a means for transporting and mounting the automated test equipment enclosure  102  as needed. The platform cassette receiving chassis member  104  is hingeably attached to the automated test equipment enclosure  102 . A lid prop member  110  can be integrated into the automated test equipment enclosure  102  to maintain the platform cassette receiving chassis member  104  in a raised position. The lid prop member  110  can be any form factor, where the preferred embodiment is a rotating support arm. 
     The common interface test probe contact base interface assembly  160  provides a first portion of an electrical power and signal communication interface between the automated test equipment platform  100  and the automated test cassette  200 . Details of the common interface test probe contact base interface assembly  160  are presented in  FIG. 2  with the common interface test probe contact base interface assembly  160  shown assembled into the automated test equipment chassis  102  in  FIG. 3 . In the exemplary embodiment, the common interface test probe contact base interface assembly  160  is assembled to and located by the registration and vacuum supply coupler  154  via a respective number of substrate assembly apertures  164 . It is understood that the common interface test probe contact base interface assembly  160  can be assembled to any location within the automated test equipment chassis  102 , wherein the common interface test probe contact base interface assembly  160  maintains a registration for properly engaging with a common interface test probe contact conveyance substrate  220  of the automated test cassette  200  as illustrated in  FIGS. 7 through 10 . A series of common interface test probe contacts  166  are disposed upon a contact surface of the common interface test probe contact base interface assembly  160  for electrical engagement with a respective common interface test probe set  222 . The common interface test probe contacts  166  can be contact points on a printed circuit board, test probe heads, and the like. Each of the common interface test probe contacts  166  are in signal communication with a test control circuit using either a printed circuit board, wires, a combination thereof, and the like. 
     The automated test cassette  200  utilizes a test probe support substrate  210  as a primary support member. The test probe support substrate  210  is of a size and shape to adapt to an opening in the platform cassette receiving chassis member  104  of the automated test equipment platform  100 . A plurality of registration pins  216  can extend downward from the test probe support substrate  210 , with the exemplary embodiment positioning each registration pin  216  adjacent to a respective corner. A test probe support substrate surface  212  is provided as an upper surface or testing surface of the test probe support substrate  210 . In the exemplary embodiment, the test probe support substrate surface  212  is fabricated of a ⅜″ thick piece of glass reinforced phenalic. 
     A test probe support substrate  210  is configured for testing a specific printed circuit assembly by drilling a pattern of a series of apertures for receiving an automated test probe layout  213  as illustrated in  FIGS. 4 through 6 . The pattern mimics a test pattern of PCB bottom side test points  410  applied to a lower surface of the printed circuit assembly. The test probes  213  can be selected from a variety of form factors, spring rates, compression distance, and the like. The specific form factor of each test probe  213  is determined for each individual test location. The test probes  213  are forcibly inserted into each respective drilled hole. Each test probe can include a feature to ensure the test probe  213  is positioned having a consistent height. At least one vacuum transfer aperture  214  is provided through the test probe support substrate surface  212  providing a means for passing the vacuum flow through the test probe support substrate surface  212 . A vacuum seal  260  is adhered proximate a perimeter of the test probe support substrate  210 . The vacuum seal  260  provides a vacuum gasket between the test probe support substrate  210  and a printed circuit assembly test support member  250 . 
     Additional elements are assembled to the test probe support substrate  210  as best illustrated in  FIG. 6 . A series of return spring members in any form factor, such as a spring loaded support member  290  and/or a spring support member  292 , are assembled to the test probe support substrate surface  212 . 
     A common interface test probe contact conveyance substrate  220  is assembled to the test probe support substrate  210 , the common interface test probe contact conveyance substrate  220  being located in registration with the common interface test probe contact base interface assembly  160 . The common interface test probe contact conveyance substrate  220  can be rigidly attached to the test probe support substrate  210  using a plurality of common interface substrate mounts  224 . A series of common interface test probe set  222  are assembled to the common interface test probe contact conveyance substrate  220  as illustrated in  FIGS. 7 through 10 . The common interface test probe set  222  is arranged in a pattern emulating the pattern of the common interface test probe contacts  166 . Each probe of the common interface test probe set  222  provides electrical communication with the respective common interface test probe contact  166 . Each test probe  213  is in signal communication with a respective common interface test probe set  222  a printed circuit board, wires, a combination thereof, and the like. The preferred embodiment utilises a wire wrapping process. The exemplary spring loaded support member  290  is a biased sliding pin. The exemplary spring support member  292  is a coiled spring. As illustrated, the moveable element of the probes  213  extend upward from the test probe support substrate surface  212  and are biased allowing the probe section to retract at least to the test probe support substrate surface  212 . A plurality of vacuum draw stops  294  is assembled to the test probe support substrate surface  212  to support and maintain the printed circuit assembly test support member  250  at a consistent distance when the vacuum force is applied to the test fixture. The vacuum draw stops  294  can be fabricated of any vertically rigid material, such as a small phenalic disc. At least two clamshell pin registration receptacles  280  are assembled to the test probe support substrate  210  for alignment of the printed circuit assembly test support member  250  and a clamshell test head assembly  300 . A removal assistance tab  218  can be attached to at least one edge of the test probe support substrate  210  for aiding the user in removal of the automated test cassette  200  from the automated test equipment platform  100 . The removal assistance tab  218  provides the user with a member which the user can grip and apply a lifting force to separate the automated test cassette  200  from the automated test equipment platform  100 . 
     A vertical support member  240  extends downward from the test probe support substrate  210  proximate a front edge to provide a supporting edge that is planar to the common interface test probe contact conveyance substrate  220 . The vertical support member  240  can be assembled to the test probe support substrate  210  using mechanical fasteners (as illustrated), adhesives, and the like, or any combination thereof. The vertical support member  240  is preferably fabricated of the same material of the test probe support substrate  210 . 
     A series of base clamshell test signal contacts  230  can be integrated into the test probe support substrate  210  providing signal communication with a clamshell test member. Each of the base clamshell test signal contacts  230  is in signal communication with a respective common interface test probe set  222  a printed circuit board, wires, a combination thereof, and the like. The base clamshell test signal contacts  230  can be contact points on a printed circuit board, test probe heads, and the like. At least two clamshell interface registration apertures  232 , or similar features, are provided for ensuring registration between a plurality of base interface contacts  274  of a clamshell signal adapter  270  and the base clamshell test signal contacts  230 . Details of the function of the interface will be detailed later in this disclosure. 
     A printed circuit assembly test support member  250  is fabricated of a test support substrate  252 ; where details of the printed circuit assembly test support member  250  are best illustrated in  FIG. 5 . At least two printed circuit assembly registration pins  254  are assembled to the test support substrate  252 , extending upward from an upper surface thereof. The printed circuit assembly registration pins  254  provide an alignment mechanism for receiving and aligning the printed circuit assembled to the printed circuit assembly test support member  250 . At least two registration apertures  256  are cut through the test support substrate  252  providing a registration mechanism for aligning the printed circuit assembly test support member  250  with the automated test cassette  200 . The registration apertures  256  are located in registration with and sized to slideably engage with the clamshell pin registration receptacle  280 . A series of test probe apertures  253  are provided replicating the pattern of the automated test probe layout  213 , each aperture being sized having a diameter slightly larger than the diameter of the respective test probe  213  providing sufficient clearance to allow the test probe  213  to slideably pass therethrough. Optional component clearances  258  can be strategically located to create clearances for components, leads, and other protrusions, which extend from a contact side of the printed circuit assembly. An optional clamshell interface aperture  257  can be cut through the test support substrate  252  allowing the clamshell signal adapter  270  to pass therethrough. The clamshell interface aperture  257  is included only for applications that utilise the clamshell signal adapter  270  as illustrated in  FIG. 3 . 
     A clamshell test head assembly  300  provides a seal for the vacuum system. Details of the clamshell test head assembly  300  are illustrated in  FIG. 6 . At least two clamshell registration pins  380  are assembled to an element of the clamshell test head assembly  300 , such as a clamshell test support substrate  310 , where the clamshell registration pin  380  are positioned in registration with each respective clamshell pin registration receptacle  280 . The clamshell test support substrate  310  is assembled to the clamshell test frame  302  using a plurality of biasing members, such as a clamshell substrate biasing members  312 . The clamshell test support substrate  310  is retained in an upward position by the clamshell substrate biasing members  312 . A vacuum seal  360  is adhesively assembled to a rigid peripheral chamber  362 , wherein the rigid peripheral chamber  362  is provided about a circumference of the clamshell test support substrate  310 , as illustrated in  FIGS. 7 through 10 . The vacuum seal  360  provides a vacuum seal between the clamshell test support substrate  310  and the test support substrate  252 . The rigid peripheral chamber  362  is fabricated of a rigid material and maintains a repeatable minimum distance between the clamshell test support substrate  310  and the test support substrate  252 . This ensure against damaging the printed circuit assembly  400 , any electronic components  404 , test probes  313 , contact-less test probe  314 , pressure applicators  320  and the like. The vacuum force draws the clamshell test support substrate  310  downward against the upward biasing force generated by the clamshell substrate biasing members  312 . 
     The clamshell test support substrate  310  is configured for testing a specific printed circuit assembly by drilling a pattern of a series of apertures for receiving a clamshell test probes  313  as illustrated in  FIG. 6 . The pattern mimics a test pattern applied to an upper surface of the printed circuit assembly. The test probes  313  can be selected from a variety of form factors, spring rates, compression distance, and the like. The specific form factor of each test probe  313  is determined for each individual test location. The test probes  313  are forcibly inserted into each respective drilled hole. Electrical communication between the clamshell test probes  313  and the automated test equipment platform  100  is provided by integrating a pattern of extended clamshell test signal contacts  330  into the clamshell test support substrate  310  and providing electrical signal communication between the clamshell test probes  313  and the extended clamshell test signal contacts  330 . Each of the clamshell test probes  313  is in signal communication with a respective extended clamshell test signal contact  330  using a printed circuit board, wires, a combination thereof, and the like. 
     The clamshell signal adapter  270  provides an electrical interface between the automated test cassette  200  and the clamshell test head assembly  300 . Details of the clamshell signal adapter  270  are best illustrated in FIGS.  3  and  7 - 10 . The clamshell signal adapter  270  is fabricated having a series of double ended probes assembled to a signal adapter body  272 . A first double ended probe end forms a base interface contact  274  and a second double ended probe end forms a clamshell interface contact  276 . At least two adapter registration pins  278  are integrated to aid in registration of the clamshell signal adapter  270  with the automated test cassette  200 . The adapter registration pin  278  can include a drilled cavity on an upper end thereof for receiving a registration pin (not shown) that can be integrated with the clamshell test support substrate  310  as desired. The pattern of extended clamshell test signal contacts  330  mimics the pattern of base clamshell test signal contacts  230 . The pattern of extended clamshell test signal contacts  330  provides electrical communication between the clamshell test probes  313  and clamshell interface contacts  276  of the clamshell signal adapter  270 . The clamshell signal adapter  270  is inserted between the test probe support substrate  210  of the automated test cassette  200  and the clamshell test support substrate  310  of the clamshell test head assembly  300 , creating electrical communication between the base clamshell test signal contacts  230  and the extended clamshell test signal contacts  330 . 
     The following describes the assembly and interface between the primary components and the functionality of the system. The automated test cassette  200  is assembled to the automated test equipment platform  100  by inserting the test probe support substrate  210  into a cavity provided within the platform cassette receiving chassis member  104 . The cassette edge support and retention member  244  is inserted either below an edge of the platform cassette receiving chassis member  104  or into a receiving slot provided within the platform cassette receiving chassis member  104 . The automated test cassette  200  is secured into location by sliding a cassette locking member  242  through a respective aperture provided through the vertical support member  240 , as illustrated in  FIGS. 9 and 10 . The cassette alignment bushing  170  engages with the registration and vacuum supply coupler  154  providing both mechanical registration and vacuum communication therebetween. Details of the interface between the registration and vacuum supply coupler  154  and the cassette alignment bushing  170  are illustrated in the section view shown in  FIG. 15 . The registration and vacuum supply coupler  154  extends upward from the vacuum supply manifold assembly  150 . In the exemplary embodiment, the common interface test probe contact base interface substrate  162  is assembled to the interface between the vacuum supply manifold assembly  150  and the registration and vacuum supply coupler  154 , such as by a vacuum supply assembly interface  156 . A vacuum port  158  is provided along a central longitudinal axis of the registration and vacuum supply coupler  154 , providing a vacuum passage in communication between the removal assistance tab  218  of the vacuum supply manifold assembly  150  and a vacuum port  178  provided along a central longitudinal axis through the cassette alignment bushing  170 . An engaging end of the registration and vacuum supply coupler  154  is shaped to direct and align the cassette alignment bushing  170  into proper position by engaging with a registration receptacle  174  within an engaging end of the cassette alignment bushing  170 . The registration receptacle  174  is shaped to mechanically align to and fluidly seal with the registration and vacuum supply coupler  154 . An upper region of the cassette alignment bushing  170  is mechanically secured to the test probe support substrate  210  such as by an alignment bushing assembly interface  176 . The common interface test probe contact conveyance substrate  220  can optionally engage with a lower region of the cassette alignment bushing  170 , increasing the rigidity of the overall assembly of the automated test cassette  200 . 
     When the automated test cassette  200  is installed within the automated test equipment platform  100 , the common interface test probe set  222  engage with the common interface test probe contacts  166  providing an electrical interface between the test probes  213  and the test controller. A series of common interface substrate mount  224  are integrated between the test probe support substrate  210  and common interface test probe contact conveyance substrate  220  providing stability and rigidity to the common interface test probe contact conveyance substrate  220 . The automated test probe layout  213  provides electrical contact and communication with test points located in a bottom side of the printed circuit assembly  400 . The printed circuit assembly test support member  250  is placed upon an upper surface of the automated test cassette  200 , engaging the registration apertures  256  with each respective clamshell pin registration receptacle  280  as a means for aligning the printed circuit assembly test support member  250  with the automated test cassette  200 . The alignment includes proper registration between the test probe apertures  253  and the automated test probe layout  213 . It is understood that any form factor known by those skilled in the art can be utilized as a means for aligning the printed circuit assembly test support member  250  and the automated test cassette  200 . The vacuum seal  260  provides a fluid seal between the test probe support substrate surface  212  and a lower surface of the printed circuit assembly test support member  250 . The vacuum seal  260  is fabricated of a collapsible or pliant material such as foam, soft rubber, shaped plastic, and the like. 
     If the clamshell test head assembly  300  includes a test system, the optional clamshell signal adapter  270  is inserted through the optional clamshell interface aperture  257 , placing the adapter registration pin  278  into each respective clamshell interface registration apertures  232 , thus aligning the base interface contacts  274  with the base clamshell test signal contacts  230 . As introduced above, the clamshell signal adapter  270  is fabricated having a series of double ended probes assembled to a signal adapter body  272 . The first double ended probe end forms a base interface contact  274  and a second double ended probe end forms a clamshell interface contact  276 . Each probe end is biased outward, and retracts within the probe when pressure is applied, thus providing a compliant interface to ensure proper contract during the testing process. 
     The printed circuit assembly  400  is placed upon the test support substrate  252  for testing, oriented with the bottom side contacting the test support substrate  252 . A series of component clearances  258  are provided within the top surface of the test support substrate  252  providing a clearance for any projections, such as leads, components, and the like, extending from the bottom side of the printed circuit assembly  400 . The PCB is aligned using any known alignment elements, such as a pair of printed circuit assembly registration pins  254  as illustrated in  FIGS. 9 and 10 . The registration aligns the automated test probe layout  213  with the respective test points located on the printed circuit assembly  400 . 
     The clamshell test head assembly  300  is placed onto the test fixture, inserting the clamshell registration pin  380  into each respective clamshell pin registration receptacle  280 . Alternately, the clamshell test frame  302  can be assembled to a hinged frame member attached to the automated test equipment platform  100 , preferably using a quick disconnect interface. The clamshell registration pin  380  slideably engages with a registration passage provided through the clamshell pin registration receptacle  280 , allowing the clamshell registration pin  380  and thus the clamshell test support substrate  310  to adjust vertically when subjected to the vacuum force. A vacuum seal is provided between the clamshell test support substrate  310  and the test support substrate  252  by the vacuum seal  360 . The vacuum seal  360  is fabricated of a collapsible or pliant material such as foam, soft rubber, shaped plastic, and the like. A rigid peripheral chamber  362  provides a rigid support to limit the vertical motion of the clamshell test support substrate  310 . The clamshell test frame  302  is supported by a hinged member attached to the automated test equipment platform  100 . The clamshell test support substrate  310  is assembled to the clamshell test frame  302  using a series of clamshell substrate biasing members  312 . Each clamshell substrate biasing member  312  includes a vertical registration pin and a biasing member, such as a coil spring. The vacuum force draws the clamshell test support substrate  310  downward against an upward biasing force provided by the biasing members. 
     The test support substrate  252  is supported by the spring support member  292  and/or spring loaded support member  290  separated from the test probe support substrate surface  212 , as illustrated in  FIGS. 7 and 9 . The test support substrate  252  is drawn towards the test probe support substrate surface  212  by applying a vacuum force through the vacuum supply manifold assembly  150 , continuing through the cassette alignment bushings  170  and entering a gap provided between the test probe support substrate surface  212  and the printed circuit assembly test support member  250 . The vacuum is activated by a signal sent to the vacuum control solenoids  146 . The vacuum control solenoids  146  allow a vacuum flow to the registration and vacuum supply coupler  154 , continuing through the cassette alignment bushing  170  and exiting into the gap. The vacuum then draws the test support substrate  252  towards the test probe support substrate surface  212 , against the return force generated by the spring support member  292  and/or spring loaded support member  290 , as illustrated in  FIGS. 8 and 10 . The plurality of vacuum draw stops  294  are spatially arranged upon the surface of the test probe support substrate surface  212  to maintain a proper distance between the test support substrate  252  and the test probe support substrate surface  212  during testing the printed circuit assembly  400 . The supported distance ensures testing repeatability and the components of the test fixture are not damaged. 
     The vacuum also draws the clamshell test support substrate  310  towards the test support substrate  252 . The vacuum is routed through the cassette alignment bushing  170  and continuing through the various apertures provided through printed circuit assembly test support member  250 . The vacuum draws the clamshell test support substrate  310  towards the printed circuit assembly test support member  250 . The vacuum seal  360  compresses as a result of the applied vacuum force. The rigid peripheral chamber  362  is rigid and maintains a desired distance between the clamshell test support substrate  310  and the printed circuit assembly test support member  250  when the system is placed in a fully enveloped vacuum condition. A plurality of pressure applicators  320  can be assembled to the clamshell test head assembly  300 , extending downward from a lower surface of the clamshell test support substrate  310 . The pressure applicators  320  apply a downward pressure to the printed circuit assembly  400 , ensuring proper pressure is applied between the test probes  213  and the respective bottom side test contacts of the printed circuit assembly  400 . The vacuum additionally generates a pressure applied between the test probes  313  and the respective PCB top side test points  412  ( FIGS. 9 and 10 ) of the printed circuit assembly  400 . The clamshell test head assembly  300  can additional include at least one optional contact-less test probe  314  extending downward from the lower surface of the clamshell test support substrate  310 . 
     Certain printed circuit assemblies  400  require a two-stage test process. The system is configured to be adapted to a two stage testing process with the integration of the features of a two-stage test controlling mechanism  500  illustrated in  FIGS. 11 through 14 . Generally, the first stage test verifies certain power circuits to avoid permanently damaging the printed circuit assembly  400  during testing. The second stage test validates the complete functionality of the printed circuit assembly  400 . The two-stage test controlling mechanism  500  includes a two-stage test control solenoid  502 , which extends and retracts a two-stage test platform configuration member  504  attached by a two-stage test platform support member actuating arm  506 . The two-stage test control solenoid  502  can be any operative mechanism that extends and retracts the actuator arm  506 . The two-stage test platform configuration member  504  is attached at a distal end of the two-stage test platform support member actuating arm  506 . An upper surface of the two-stage test platform configuration member  504  is in horizontal alignment with a cassette receiving member support edge  105  of the automated test equipment platform  100 . At least one two-stage test platform support vertical member  510  is provided extending downward from a lower surface of the printed circuit assembly test support member  250  and in registration with the two-stage test platform configuration member  504  when the two-stage test platform configuration member  504  is oriented in an extended state. A two-stage test platform support member clearance  512  is provided through the test probe support substrate surface  212 , wherein the two-stage test platform support member clearance  512  is sized and located to align with the two-stage test platform support vertical member  510 . The two-stage test platform support vertical member  510  can slide through the two-stage test platform support member clearance  512  when the two-stage test platform configuration member  504  is in a retracted state. The two-stage test platform support vertical member  510  is supported, raising the printed circuit assembly test support member  250 , when the two-stage test platform configuration member  504  is in an extended state. 
     The automated test probe layout  213  includes two arrangements of test probes: a first stage series of test probes comprising a plurality of extended throw test probes  226  and a second stage series of test probes comprising a plurality of short throw test probes  228 . When the two-stage test platform configuration member  504  is extended, the printed circuit assembly test support member  250  is elevated. The elevated configuration exposes the extended throw test probes  226 , while insulating the short throw test probes  228  as illustrated in  FIG. 12 . The extended throw test probes  226  subsequently provide electrical contact with the respective PCB bottom side test points  410  to support a partial, first stage test process. When the two-stage test platform configuration member  504  is retracted, the two-stage test platform support vertical member  510  continues passing through the two-stage test platform support member clearance  512 , lowering the printed circuit assembly test support member  250  against the test probe support substrate surface  212  and exposing both the extended throw test probes  226  and the short throw test probes  228  as illustrated in  FIG. 14 . Both the extended throw test probes  226  and the short throw test probes  228  subsequently provide electrical contact with the respective PCB bottom side test points  410  to support a complete, second stage test process. 
     It is understood that alternate configurations can be provided to accomplish the two stage testing process. The two-stage control mechanism can be configured in the reverse, lowering the printed circuit assembly test support member  250  when the two-stage test platform configuration member  504  is extended and supporting the printed circuit assembly test support member  250  when the two-stage test platform configuration member  504  is retracted. 
     The test process is initiated by placing the printed circuit assembly  400  onto the printed circuit assembly test support member  250  of the automated test fixture. The operator then lowers the clamshell test head assembly  300  into a test position. The electrical test commences based upon a test fixture status sensor, an operator directive, and the like. 
     The above-described embodiments are merely exemplary illustrations of implementations set forth for a clear understanding of the principles of the invention. Many variations, combinations, modifications or equivalents may be substituted for elements thereof without departing from the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all the embodiments falling within the scope of the appended claims.