Abstract:
An improved probe includes a conductive tubular housing or body containing a coil spring and a conductive plunger movable in the housing and having a contact tip outwardly extending from one end of the housing. The plunger and tip are urged to a normally outward position by the bias force of the spring. The opposite end of the housing has an opening for mating with a conductive pin of a connector. The connector is retained in a mounting plate of an associated fixture and has terminal ends of desired configuration. The terminal end may include a wire-wrap pin, a crimp type terminal or wire jack for attachment to a wire, or the terminal may include a spring loaded pin for engagement with an associated electrical contact. An air tight seal may be provided between the probe and the connector and the connector may be mounted in a mounting such that when vacuum is applied to an associated test fixture, air cannot be drawn through the fixture or through the body of the probe.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application is a continuation-in-part of U.S. application Ser. No. 09/759,980 entitled Test Probe and Connector, filed Jan. 12, 2001, the disclosure of which is incorporated by reference herein. 

   STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
   N/A 
   BACKGROUND OF THE INVENTION 
   The present invention relates to probes that are used in printed circuit board test fixtures and more particularly, to a socketless, leaktight replaceable probe for use in a test fixture. 
   It is known to provide testing fixtures for printed circuits boards (PCBs) and the like, for testing the integrity of the electrical connectivity of the circuit boards. A conventional embodiment of a testing apparatus is shown in  FIG. 1 , and includes a fixed, stationary substantially horizontal probe plate  10  and an overlying vertically spaced movable top plate  12 . Top plate  12  is linked to probe plate  10  by means of a peripheral elastomeric spacer  14  which allows top plate  12  to vertically move towards probe plate  10  upon a vacuum being created inside the sealed enclosure formed by probe plate  10 , spacer  14 , top plate  12 , and an overlying pressure plate (not shown) sealingly engaging the upper face of top plate  12 . The downward movement of top plate  12  is accomplished by elastomeric spacer  14  partly collapsing under the movable top plate  12  being sucked downwards by the vacuum. 
   Top plate  12  holds on its upper surface a printed circuit board  18  which is securely anchored thereto by the above-mentioned pressure plate upon the vacuum being created. Circuit board  18  is spaced from top plate  12  by means of rigid spacers  20 ,  22  and is aligned, relative to probe plate  10 , by means of a number of alignment rods  16  which are fixedly attached to probe plate  10  and which upwardly extend through and loosely engage respective vertically registering channels  23  provided in top plate  12  to engage alignment holes provided in circuit board  18 . 
   A number of tapered channels  24  extend transversely through top plate  12 , with a test probe  26  being located under and vertically registering with each channel  24 . Each test probe  26  is fixedly attached to probe plate  10  in a manner described hereinafter, and vertically extends above and below probe plate  10 . Top plate channels  24  further vertically register with electrical contact points  28  to be tested on printed circuit board  18  upon engagement with the probe tip of the test probe  26 . Thus, upon top plate  12  moving downward, the probe tip of the test probe  26  abuts the selected contact point  28  to be tested on the printed circuit board  18 . Through the instrumentality of known software, electric current is transmitted sequentially through selected probes to test the integrity of the electrical connectivity of the printed circuit board  18 . 
   The probes  26  of known construction are removably inserted in a sleeve (socket)  30  fixedly anchored to the probe plate  10 . Sleeve  30  in turn is connected to a computer-controlled circuit which allows electrical current to be selectively transmitted therethrough. Probe  26  includes a tube in which a plunger is vertically movable under the bias of a spring, between a lower and an upper limit position. The plunger, the tube and the sleeve are all electrically connected to each other, for allowing the electric current to be transmitted to the printed circuit board. The movable plunger is continuously biased upwardly, and is downwardly forced against the bias of the spring when the printed circuit board downwardly moves against the upper tips of the probes when the vacuum is created inside the sealed enclosure. The purpose of providing a probe which is distinct from its holding sleeve is that the probe has a limited life span, and will thus have to be changed after a certain number of uses because of wear. 
   Three important problems exist with the above-described conventional circuit board testing apparatus: 
   a) The first problem is that the stationary sleeves holding the probes prevent the use of more sturdy probes for any given probe spacing. In fact, the contact points of the probes on the printed circuit boards are closely adjacent to one another, and thus the probes need to be positioned in a closely adjacent fashion. This is becoming more and more important as the miniaturization of the printed circuit boards evolves. Thus, if the contact points of the probes on a printed circuit board are very close to one another, probes of a smaller diameter need to be used to allow the probes to be positioned closer to each other. Since the sleeves carrying the probes have a larger diameter than the probes themselves, circuit board contact points which are closer to one another require sleeves of smaller diameter, and consequently probes of even smaller diameter. Probes having a very small diameter are less sturdy and more prone to accidental breakage. 
   b) The second problem is that the vertical alignment of the probe tips with their respective registering circuit board contact points is in practice not always achieved. Indeed, when inserting the probes inside their respective sleeves, a certain vertical angular offset may occur. The top plate channels are tapered to promote self-alignment of the probes therein; however, the probe tips may still be slightly misaligned when they protrude beyond their respective channels in the space between the top plate and the printed circuit board. The consequence of this misalignment is that the probe tips may be allowed to contact the printed circuit board in a slightly offset fashion relative to their intended respective contact points, which may result in electric current not being transmitted to the circuit board. Thus, the testing software could falsely indicate a connection error. 
   c) The third problem also relates to a possible misalignment between the probe tips and their corresponding intended circuit board contact points, due to the fact that the alignment rods, which are used to position the circuit board, are fixed to the probe plate. Indeed, it is possible that a misalignment of the top plate relative to the probe plate may result in the top plate through-channels being laterally offset relative to their corresponding underlying probes, since the circuit board position is determined by the alignment rods which are integrally attached to the probe plate, while the position of the through-channels depends on the position of the top plate. If the through-channels are laterally offset relative to their corresponding probes, then certain probes may be laterally deflected by the edges of their corresponding through-channels when the top plate is lowered, which may result in the tips of these deflected probes abutting against the circuit board aside from their intended position. Again, the testing software would then detect a connection error on the printed circuit board where there is none. 
   Reference is here also made to U.S. Pat. No. 4,885,533 assigned to the assignee of the present application which discloses a probe which, in use, is firmly engaged in an electrically conductive socket mounted tightly in a dielectric plate of a PCB testing fixture. 
   BRIEF SUMMARY OF THE INVENTION 
   In accordance with the present invention an improved probe and connector are disclosed that are adapted for use in a printed circuit board test fixture. The probe includes a conductive tubular housing or body and a conductive plunger that is contained and movable within the housing. The plunger includes a contact tip that extends out one end of the housing. The plunger and tip are urged to a normally outward position by a bias force created by a coil spring disposed within the housing. At the opposing end of the probe from the contact tip, the probe end defines a bore that is suitable sized to receive a cooperative pin located at one end of a connector. 
   The connector includes a tubular body that may be mounted in a through-hole within a fixture plate. The connector may be fixedly retained within the fixture plate via an annular barb or a plurality of annular beads located on the tubular body. In a preferred embodiment, the connector includes the connector pin at one end and a terminal of a desired configuration at the opposing end. The terminal may include a wire-wrap pin, a crimp type terminal or wire jack for attachment to a wire, or a spring loaded plunger for wireless conductive engagement with an electrical contact such as is located on a printed circuit board. The connector pin receiving end of the probe may contain one or more detents for retaining in the end to retain the probe on the connector once the connector pin is disposed in assembled relation with the probe bore. 
   Additionally, the connector includes a tapered portion between the connector pin and the connector body. The tapered portion increases in diameter from the connector pin to the connector body so that an air tight seal is created between the probe and the connector upon seating of the pin receiving end of the probe over the connector pin. 
   Other features, aspects and advantages of the presently disclosed probe and connector will be apparent from the Detailed Description of the Invention that follows. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING 
     The invention will be more fully understood by reference to the following Detailed Description of the Invention in conjunction with the drawings, of which: 
       FIG. 1  is a schematic side elevation showing a prior art circuit board testing fixture; 
       FIG. 2  is a schematic elevation showing a circuit board testing fixture according to the present invention; 
       FIG. 3  is a cross-sectional side elevation of a sleeveless testing probe according to the present invention; 
       FIG. 4  is an under view of the probe of  FIG. 3 ; 
       FIG. 5  is an elevation of one embodiment of connector for connecting and supporting the probe of  FIG. 3 ; 
       FIG. 6  is a sectional elevation of an alternative embodiment to the connector of  FIG. 5 ; 
       FIG. 7  is an illustrative arrangement showing various probe and connector implementations; 
       FIG. 8  is a partial side view of the probe plunger of  FIG. 3  illustrating alternative embodiments of probe tips that may be employed; 
       FIG. 9  is a schematic side elevation illustrating one embodiment of a connector for use with the test probe depicted in  FIG. 3 ; 
       FIG. 10  is a schematic side elevation illustrating another embodiment of a connector for use with the test probe depicted in  FIG. 3 ; 
       FIG. 11  is an elevation view of a further embodiment of the connector having a wire jack; 
       FIG. 12  is a cross-sectional view of the connector of  FIG. 11  at the wire jack receptacle end; 
       FIG. 13  is an elevation view of another embodiment of the connector having a wire jack; and 
       FIG. 14  is a cross sectional view of the embodiment of  FIG. 13  at the wire jack receptacle end. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 2  depicts a circuit board testing fixture  40  with a probe and one embodiment of probe connector in accordance with the present invention. A testing fixture  40  includes a movable dielectric top plate  42  provided with a number of bores  44  which transversely extend through the top plate  42 . These will be detailed hereinafter. Testing fixture  40  further comprises a dielectric intermediate alignment plate  46  which is spaced from top plate  42  by a peripheral elastomeric spacer  48  of known construction. A dielectric lower probe plate  52  is located spaced under intermediate plate  46  by a rigid peripheral wall  54 . A printed circuit board  58  to be tested is installed so as to rest on the top surface of top plate  42  and is properly positioned relative to top plate  42  by means of alignment rods  60 ,  62  which protrude from and are fixed to top plate  42  and which engage holes (not shown) in printed circuit board  58 . As known in the art, a pressure plate  64  is positioned spacedly over printed circuit board  58 , plate  64  being supported by a rigid peripheral wall  66  provided with an underlying peripheral elastomeric pad  70 . Downwardly projecting fingers  74 ,  76  are integrally carried by an intermediate portion of pressure plate  64 . 
   A number of testing probes  78  (only one testing probe being shown in  FIG. 2 ) are provided on testing fixture  40 . Referring to  FIGS. 3 and 4 , each testing probe  78  comprises a gold clad electrically conductive hollow tube  80  which is engaged by a vertically slidable gold-plated electrically conductive plunger  82  continuously upwardly biased by a coil spring  84 . Plunger  82  has a gold-plated probe tip  85  and is provided at its intermediate portion with an annular shoulder  86  which abuts a complementary upper annular seat  88 , adjacent the upper end of tube  80 , to prevent plunger  82  from moving beyond an upper limit position under the bias of spring  84 . Between the seat  88  and the open end  89  of the tube  80 , through which the plunger  82  extends to the tip  85 , is a reduced diameter elongate retaining and sliding bearing region  90  produced by swaging or rolling the tube  80  radially inwardly against a reduced diameter outer portion  91  of the plunger  82  connecting the annular shoulder  86  with the tip  85 . This bearing region  90  has a close clearance with the outer portion  91  to provide excellent tolerance to side loading forces and smooth long life reciprocal axial movement of the plunger  82  against the bias of the spring  84  with no edges or corners to contact, scrape and wear the plunger  82 . Additionally, the swaging or rolling of the tube  80  against the outer portion  91  of the plunger  82  produces the desired clearance between the bearing region  90  and the outer portion  91  as a result of material spring back (hysteresis) following the swaging or rolling operation. 
   Tube  80  also has a lower annular spring seat  92  against which rests the lower end of spring  84 . Plunger  82  preferably has an inclined lower surface  93  which is engaged by the upper end of spring  84 , to simultaneously bias plunger  82  upwardly and radially against tube  80  to ensure a reliable electrical connection between plunger  82  and tube  80 . The lower end of tube  80  comprises an axial bore  94  for sealed resilient connection between tube  80  and a connector  96  (see  FIG. 5 ) providing good electric transmissibility and probe support. 
     FIG. 2  show that probe  78  is carried by a connector  96  fixedly anchored in probe plate  52 , and more particularly that connector  96  engages bore  94 , as will be detailed hereinafter. Moreover, probe  78 , and more particularly tube  80 , extends through intermediate plate  46  in a registering guiding channel  81  provided therein. 
   A sealed enclosure is formed between lower probe plate  52  and pressure plate  64 , with channels  81  and  44  providing for fluid communication the areas between plates  52 ,  46 ,  42  and  64 . A vacuum port (not shown) is provided in probe plate  52 , to allow a vacuum to be created in the sealed enclosure. 
   In use, a vacuum is created in the sealed enclosure, wherein the elastomeric peripheral spacer  48  will gradually collapse to allow top plate  42  to downwardly move towards intermediate plate  46  for the probe tips  85  to come into contact with selected registering contact points on printed circuit board  58 ; and wherein the peripheral elastomeric pad  70  will also collapse to allow pressure plate  64  to move towards top plate  42  whereby the fingers  74 ,  76  of pressure plate  64  will abut against and firmly support printed circuit board  58  against the upward bias of the numerous probe plungers  82 . 
   The guiding channels  81  provided in intermediate plate  46  will correctly vertically align probes  78  so that they register with the contact points on circuit board  58  which they are intended to contact. Moreover, the top plate throughbores  44  also promote proper self-alignment of probes  78  relative to the corresponding circuit board contact points. Indeed, the top plate bores  44  each have a lower portion  44   a  of increased diameter, which allows the corresponding probe tip  85  to engage the bore  44  even if the probe tip is slightly misaligned; a tapered intermediate neck portion  44   b , which allows the probe tip orientation to be corrected if it is slightly misaligned; and an elongate upper portion  44   c  which extends up to the printed circuit board  58  and which has a diameter to guide the corresponding probe tip  85  to the circuit board contact point. 
   Additionally, the fact that circuit board  58  rests directly on top plate  42  and is positioned thereon by means of the alignment rods  60 ,  62  which are fixedly attached to the top plate  42 , ensures that the contact points of circuit board  58  which are intended to come into contact with respective probe tips  85 , will be properly aligned relative to the top plate bores  44 . Thus, in view of these improvements over prior art devices, misalignment of the probe tips  85  relative to their corresponding intended circuit board contact points is very unlikely, if not almost completely obviated. 
   Also, according to the invention, the testing probe  78  is not installed in a socket or sleeve, as with prior art devices. Indeed, probe  78  engages a connector  96  directly, through the instrumentality of its axial bore  94 . The intermediate plate guiding channel  81  allows vertical alignment of the probe to be achieved even though no elongate supporting socket or sleeve is present. 
   The axial bore  94  is an elongate cylindrical bore defined by a cylindrical tubular extension  98  of the tube  80  opposite the elongate bearing  90 . The tubular extension  98  extends from an annular shoulder forming the spring seat  92  and is coaxial with the longitudinal axis  99  of the tube  80 , spring  84  and plunger  82 . The tubular extension  98  defines a circular connector pin receiving opening  100  which is itself defined by a smooth circular inner edge  101 . 
   The tubular extension  98 , as with the bearing region  90 , is integral with the remainder of the tube  80  and may be formed by rolling or swaging. 
   At least one detent  102  is pressed or stamped inwardly into the wall of the extension  98  intermediate the length of the extension  98  between the shoulder for the spring seat  92  and the opening  100 . Preferably there are three such detents  102  evenly spaced about the circumference of the extension and in a plane normal to the axis  99 . The detents  102  do not perforate the tubular extension  98 . 
   Alternatively, the one or more detents can be provided in a separate tube, rather than the extension of the main tube. 
   Referring now to  FIG. 5 , a first embodiment of connector  96  is described. The connector  96  is gold plated, electrically conductive and includes a connector pin  103  terminating in an annular curved tip, to facilitate entry into probe bore  94  ( FIG. 3 ) through opening  100  and a parallel portion  104  to closely fit within the probe bore  94  and to engage the detent(s)  102  to resiliently and firmly, but removably, support and retain the probe  78  on the connector  96  in good electrical contact therewith. 
   The inner end of pin  103  remote from the curved tip terminates with an annular taper  105  sized to sealingly engage the smooth circular edge  101  of the probe extension opening  100  when the connector pin  103  is fully engaged in the bore  94 . 
   The connector pin  103  is connected to a wire-wrap pin  109  by way of a plate connector portion  106  sized to extend through plate  52  ( FIG. 2 ) and to be fixedly mounted in a circular opening extending through the plate  52 . The fixed mounting is, as shown, by an interference fit aided by an annular plate engaging ridge  107 . Alternative fixed mountings could be provided by splines on the portion  106 , the use of adhesives, molding-in, etc., as would be well known to those skilled in this technology. 
   A positive stop flange  108  is designed to control the degree of insertion of the connector  96  into the plate  52 . 
   Typically, by way of example, for a probe having an O.D. of 0.054 inch, the bore  94  has an I.D. of 0.0265 inch and the pin  103  has a parallel portion  104  with an O.D. of 0.025±0.0003 inch, a taper  105  increasing from the parallel portion  104  to a maximum O.D. of 0.028±0.001 inch with an included angle of 15±2 degrees. Probes of these dimensions with sleeve mounting would require probe spacing in a fixture of 0.100 inch, whereas with the present invention a center spacing for the probes without sleeves may be reduced to 0.075 inch. Similarly, center to center reductions apply also to probes of other sizes. 
     FIG. 6  illustrates a second embodiment of connector  97 . In this embodiment features common with those of the first embodiment of connector will not be described again. The connector  97  is a two-part assembly for connecting an insulated wire  110  to the probe  78  by way of a gold plated electrically conducting pin  111  externally similar to pin  103  but hollow to receive the electrical conductor  112  of the wire  110  which is crimped at  113  in the hollow interior of the pin  111  to provide good electrical interconnection. A polyester (nylon) sleeve  114  is attached to the pin  111  by an annular protrusion  115  on an extension of the pin  111 . The sleeve  114  covers the junction of the pin  111  and the insulation  116  of the wire  110  and provides for the fixed engagement of the connector  97  in a circular opening in plate  52 . 
   The connector(s)  96 ,  97  are sealingly engaged with the plate  52  to provide an air tight mounting such that air and any contaminants cannot be drawn through the fixture or the body of the probe when a vacuum is applied during a testing phase. 
     FIG. 7  illustrates a variety of probe arrangements providing differing probe heights achieved by varying the length of protruding outer portions  91  of the plungers  82  and/or the axial length of the stop flange  108  of the connectors  96  (or  97 ). Additionally, this figure shows two connectors  117 , the ends  118  of which include wireless terminations for engaging a printed circuit test board. An exemplary connector that provides a wireless termination is illustrated in greater detail in FIG.  10  and is discussed below. 
   The probe  78  may be provided with a probe tip of configurations that differ from the probe tip  85  depicted in FIG.  3 . Referring to  FIG. 8 , exemplary alternative probe tips are shown. For example, a spherical probe tip  130 , a spear probe tip  132  or a chisel probe tip  134  may be provided on the end of the plunger  91  intended to contact the printed circuit board  58 . Probe tips of other configurations may also be used. 
   Referring to  FIG. 9  an alternative embodiment of a connector  140  having a wirewrap pin termination is depicted installed in the lower probe plate  52 . The connector  140  includes a connector pin  142 , a plate connector portion  144  and an annular tapered portion  146  between the connector pin  142  and the plate connector portion  144 . Additionally, the connector  140  includes a wire wrap pin  148  at the opposite end of the plate connector portion  144  from the connector pin  142 . Two annular beads  150  are provided on the plate connector portion  144 . The diameter of the annular beads  150  is specified to provide an interference fit with the respective hole in the lower probe plate  52 . Upon insertion of the connector  140  within the respective hole in the probe plate  52 , the annular beads  150  secure the connector within the probe plate  52  and maintain vertical alignment of the connector  140  within the probe plate  52 . 
   Referring to  FIG. 10  a further embodiment of a connector  160  that provides a wireless termination is depicted both with a printed circuit board  162  present beneath the connector  160  and absent beneath the connector  160 . The connector  160 , in one embodiment, is fabricated in first and second connector portions  164  and  166  respectively. The first portion  164  includes a connector pin  168  for insertion within the axial bore  94  of the testing probe  78  (FIG.  3 ). Additionally, the first portion includes a body  170  and the connector pin  168  extends from one end of the body  170 . A tapered annulus is provided between the connector pin  168  and the body  170  to provide a seal when the connector pin  168  is disposed within the axial bore  94  as discussed hereinabove. An axial bore  174  is provided in the end of the first portion  164  opposite the connector pin  168  to receive a cooperative mating pin  176  at one end of the second portion  166  of the connector  160 . The mating pin  176  extends from one end of a tube  178 . A probe  180  having a probe tip  182  is disposed within the tube  178  and is urged outward via a coiled bias spring (not shown). As shown in the connector  160  on the left in  FIG. 10 , the probe is disposed in an extended position the absence of the printed circuit board. As shown in the connector  160  on the right of  FIG. 10 , the probe tip  182  is urged into contact with the printed circuit board  162  so as to make an electrical connection with a contact point located on the printed circuit board  162 . The first connector portion  164  includes two annular beads  184  for securing the first connector portion  164  within the lower probe plate  52  and maintaining vertical alignment of the connector  160  within the probe plate  52 . 
   While the connector  160  is illustrated as being fabricated in first and second portions  164  and  166 , in an alternative embodiment, a connector that permits wireless termination may be fabricated as a component that includes a tubular body portion having a connector pin at one end that is sized for insertion within the axial bore  94  of the testing probe  78 . A probe is disposed within the tubular body and includes a probe tip that extends from the end of the body opposite the connector pin. A plurality of annular beads may be provided on the body to secure the connector within the lower probe plate  52 . In this manner, the electrical connection between the mating pin  176  and the bore  174  of the first connector portion  164  depicted in  FIG. 10  is eliminated. 
   Another embodiment of the connector is shown in  FIG. 11  which provides a wire jack termination by which a wire can be pluggably mated to the connector. The connector  200  includes a connector pin  202 , a plate connector portion  204  and an annular tapered portion  206  between the connector pin  202  and the plate connector portion  204 . Two annular beads  208  are provided on the plate connector portion as in the above embodiment, the diameter of the annular beads being such to provide an interference fit with the respective hole in the probe plate  52 . As in the connector embodiment described above, alternative fixed mountings can be provided by an annular plate engaging ridge, as in  FIG. 5 , or by splines, adhesives, molding-in, etc., as would be well known to those skilled in the technology. Upon insertion of the connector  200  within a respective hole in the probe plate, the annular beads secure the connector within the probe plate and maintain vertical alignment of the connector within the probe plate, in the same manner as described above. At the opposite end of the connector from the connector pin  202 , there is provided a wire jack receptacle  210  which can pluggably receive a terminal pin  212  attached to a wire  214 . The wire jack receptacle is formed by a blind hole drilled or otherwise provided in the end of the connector body and typically by a pair of diametrically opposite slots  216  through the wall of the wire jack end. The slots are typically formed by saw cuts. The slots provide crimpable walls of the receptacle end to provide a non-circular and typically slightly oval cross-section for interference fit of an inserted wire jack pin. The oval cross-section is illustrated in FIG.  12 . It is seen that the receptacle end is crimped along an axis which is transverse to the slots. The slots also serve to allow flow of a plating solution during nickel or other plating of the receptacle end. 
     FIG. 13  illustrates an alternative embodiment of the wire jack receptacle  310  of the connector  300 . The wire jack receptacle is formed by a blind hole drilled or otherwise provided in the end of the connector body and by at least one detent  302  pressed or stamped inwardly into the wall of the connector  308  between the end  312  of the connector and the inner end of the blind hole  314 . The detents  302  do not penetrate the wall of the connector  308 . Preferably, there are three such detents  302  evenly spaced about the circumference of the connector between the end of the connector  312  and the end of the blind hole  314 . At least one opening  304  is provided near the inner end of the blind hole  314  to facilitate the flow of a plating solution during nickel or other plating of the receptacle end.  FIG. 14  illustrates an end view of this embodiment of the wire jack receptacle. 
   These embodiments having a wire jack termination permits the pluggable insertion of connecting wires into the test probe connector, and also permits smaller spacing between probes since clearance for wire wrapping of wire wrap pins is not needed. While the connector  200  (or  300 ) is illustrated as being fabricated as a single component, in an alternative embodiment, a connector having a wire jack receptacle  210  on the end opposite the connector pin  202 , may also be fabricated as an assemblage of two or more components. 
   An advantage of the presently described probe and connector is that no sleeves or sockets are used for holding and vertically aligning the probes. Indeed, the probes are positioned on their corresponding connectors which engage detents in the probe that resiliently and releasably hold and support the probe. This prevents the probes from being accidentally released e.g. during assembly of the fixture. Moreover, the intermediate plate allows the probes to be substantially vertically aligned. The absence of the probe-carrying sockets or sleeves allow the use of probes of larger diameters, for a given required probe spacing, which will consequently be more sturdy and less likely to be accidentally damaged and which will resist wear longer than probes using sleeves or sockets. 
   Also, the alignment of the probes with their respective contact tips on the printed circuit board is enhanced by the presence of the top plate throughbores which extend from the probe tip up to the printed circuit board, thus preventing the probe tip from being laterally offset and to contact the printed circuit board elsewhere than on its intended contact point thereon. The intermediate plate throughbores, and the fact that the alignment rods are fixed to the top plate instead of the probe plate, also help improve alignment of the probes with their respective intended contact points on the printed circuit board. 
   It should be noted that the presently disclosed test probes and connectors may be fabricated of any suitable metal such as berylium copper and may be plated with gold or other suitable material to enhance conductivity and/or to reduce corrosion. 
   It will be appreciated by those of ordinary skill in the art that modifications to and variations of the above described socketless probe may be made without departing from the inventive concepts described herein. Accordingly, the invention should not be viewed as limited except as by the scope and spirit of the appended claims.