Products

	What is the difference between an X PROBE and a standard probe?
	The main difference between, for example, a X75-PRP2509S and a 100-PRP2509S is that the probe tube on the X75 Series is 1.110 [28.19] long versus 1.000 [25.4] long for the 100-PRP probe. The added length of the X75 Series is required to form the interconnect housing on the bottom of the probe tube. All other aspects of the probe are the same. The X Series probes when used with standard sockets will sit up approximately .085 [2.16] higher than a standard series probe in the same socket. This can be useful in special applications where it's desirable to have the probe sit up higher in a standard socket.

	What is the main advantage of using QA's X PROBE over conventional probe and sockets?
	The X PROBE allows larger more robust probes to be mounted on closer centers. By eliminating the socket from the system, a .100 [2.54] center probe can be mounted on .075 [1.90] centers (X75 Series) and a .075 [1.90] center probe can be mounted on .050 [1.27] centers (X50 Series).

	Can standard test probes and sockets be mixed mounted with the X PROBE Series?
	Yes, with special design considerations standard test probes can be mixed mounted with the X PROBE Series. A standard socket would mount in the Probe plate and clearance holes would have to be drilled in the Beef and Back plates. In a vacuum fixture a method would have to be designed to maintain the integrity of the vacuum. The best approach is to cut out areas in the plates where the sockets are to be mounted and design inserts to accommodate them.

	Can the X PROBE be used on existing test platforms?
	Yes, the X PROBE is compatible with Agilent, Genrad, Teradyne, and others. Fixture designs have to be able to accommodate the additional plates. In general, the height of the fixture is increased and in the case of Agilent compatible fixtures, wider rails (up to 1" depending on the set height) are required to maintain the depth of the wiring area to accommodate the Personality pins and Alignment plate.

	What type of plate materials can we use for the fixture?
	Although not recommended for the Back Plate, acrylics, polycarbonates, and PVC's may be used for the Probe and Optional Spacer Plates. Standard epoxy fiberglass laminates such as G10/FR4 and similar materials are recommended for the Back Plate due to the retention requirements of the Termination pins. The mounting hole sizes listed in the Suggested Fixture Layout drawings are designed for epoxy fiberglass laminates.

	Can the X PROBE be used with both pneumatic and vacuum fixtures?
	Yes, the X PROBE design does not limit the type of fixture that they can be used on.

	What is the Terminal (Termination) made of and how long will it last?
	The terminal is a hardened (38 HRC minimum) Beryllium Copper with a plating of hard gold over electroless nickel. This is the same material that we use for our BeCu plungers. The terminal must not only provide a good electrical path from the probe to the wire termination but also be able to withstand forces during installation, wire wrapping, and many probe insertions and extractions. The Terminal is designed to perform for the life of the fixture under typical test conditions.

	Is the Beef Plate shown on the "Suggested Fixture Layout" drawings necessary?
	No, the Beef Plate is an intermediate support plate that when fixed to the Back Plate adds additional strength. On small to medium sized fixtures this can be replaced with fixture standoffs or flanges. Note that the Beef Plate does help with the alignment of the probe to the Terminal during probe installation.

	How much weight will be added to a fixture designed around the X PROBE?
	Approximately 20 lbs for an average sized fixture. An X PROBE fixture requires a Top Plate (Support Plate), Probe Plate, optional Beef Plate, and Back Plate while the conventional fixture has a Top Plate and Probe Plate (Socket Mounting Plate).

	How are the Terminals replaced?
	If a terminal gets broken during fixture assembly, the terminal can be driven out with our ET-X50 and X75 extraction tools. In order to replace a terminal in a completely assembled fixture, the Top Plate, probes, Probe Plate, and Beef Plate will have to be removed and then our ET tools can be used to drive the terminal out through the Back Plate. If there is enough room around the top of the terminal, pliers or similar tools can be used to pull the Terminal out from the top. On smaller fixtures where headless probes are used, the plates can be removed without first removing the probes. Chamfers on the back sides of the plates will help to align the probes when reinstalling the plates.

	How many times can a probe be reinstalled on a Terminal?
	A probe can be reinstalled on a terminal a minimum of 5 times. After this, the probe retention is reduced to the point where the probe is loose on the interconnect pin. The probe retention indents on the probe are the mechanical features that hold the probe to the terminals interconnect pin. The probe is designed to be the "wear point" in the system, by replacing the probe, you've restored the retention force.

	How many times can a new probe be installed on a Terminal?
	One hundred separate new probes were subsequently installed and then removed from a single terminal. The retention force of the probe(s) to terminal was consistent and the Interconnect pin showed only light plating wear (viewed at 20X). The terminal is designed to last the life of the fixture under normal operating conditions. If damaged, however, the pin can be replaced.

	How do we wire wrap on the X50 PROBE Series and can more than one wire be wrapped to the post?
	The X50 termination is designed around a .500 [12.70] long .016 [0.41] square post. The length of the post allows up to four 30 AWG wires to be wrapped to it. Due to its size, a regular style wrap and the installation of shrink tubing on every other post is recommended. Please request our 050 Wire Wrap applications note where a more detailed explanation is given.

	How is the distance from the Probe Plate to the tip of the probe adjusted for the various heights of components on my PCB?
	The height of the probe is controlled by the set height of the terminal. Our IT-X50 set .XXX and X75 set .XXX installation tools can be used to set the terminal between .000 and .140 [3.56] off the surface of the Back Plate. Note that the set height of conventional fixtures is calculated from the Probe Plate where as the set height of an X PROBE fixture is from the Back Plate (see Suggested Fixture Layout drawings).

	Can the Probe Plate holes be relieved on the bottom side in order to help maintain hole accuracy when drilling?
	Yes, the purpose of the .500" thick Probe Plate that is shown on our Suggested Fixture Layout drawings is to support the probe and guide it to the intended target. The backside or bottom of this plate can be drilled oversized to reduce the top-hole depth. A .250" engagement is sufficient.

	How are additional probes and Terminals added to a completed fixture?
	Because the X PROBE system relies on accurately drilled and aligned holes, the recommended approach is to remove all of the probes and plates. The new hole locations must be accurately registered from the original reference points so that the probe and terminal will align during assembly.

	Will pointing accuracy be affected when switching from standard probes and sockets to the X PROBE Series?
	Pointing accuracy is defined as the maximum radial deviation of a probe tip from the true centerline of a probe's mounting hole. The total probe-to-target accuracy is dependent upon the "Fixture Offset", the "Scatter Pattern Offset", and the "Scatter Pattern Diameter". When compared to standard probes and sockets, the X PROBE's pointing accuracy is increased because the "Scatter Pattern Offset" is reduced through the elimination of the socket. For a more in depth description of pointing accuracy see the applications note on Pointing accuracy in QA's Technical Reference Book.

	For two identical test fixtures, one built with standard probes and the other with X PROBES, how do their costs compare?
	When building fixtures where large numbers (1,500 +) of .050 [1.27] center contact points are involved, a cost savings can be realized when using the X50 probes over conventional .050 [1.27] center probes and sockets. If your fixtures consist mainly of .100 [2.54] and .075 [1.91] contacts with only a small number of .050 [1.27] contacts, a conventional fixture will be less expensive.

	What are the temperature limits for this probe Series?
	Both the X50 and X75 Probe Series have the same temperature limits as standard probes with a maximum temperature limit of 250°F [120°C] for probes assembled with springs made from music wire. The X75 Series low (-L) force spring is made from stainless steel. This spring has a temperature rating of 400°F [204°C] due to the material properties of the stainless steel. The low temperature limit is 40°F [5°C], the same as our standard probes. When operating at temperatures below 40°F [5°C] add a -N to the part number, this denotes No Probe Lubrication.

	How do I relate X Probe set heights to standard socket set heights?
	X Probe set heights depend on the set height of the Termination and the stack-up height of the Probe and Beef plates versus the distance from the top of the Probe plate to the top of the socket as measured with standard test probes and sockets. X Probe, by decreasing the thickness of the Probe and Beef plates and increasing the Termination set height; the distance from the tip of the probe to the top of the Probe plate is increased.

	When installing the Terminations into G10/FR4 we notice that little shavings of metal form around the base of the Termination, what causes this?
	The hole diameter in the Back Plate is too small and the Retention Bead(s) is being sheared off during installation. This is a bad situation. These shavings will create shorts between adjacent terminations. Worst yet, these shavings will float and be moved by the vacuum so that the shorts may occur at random making troubleshooting difficult. Making sure that the hole diameter is within the recommended hole sizes for the Termination being installed can prevent this. Do not assume that drilling G10/FR4 or equal with a .038* carbide circuit board drill will result in a .038* diameter hole. Quite often, the drills diameter starts out .0003* undersized and the end hole diameter can be as much as .001* undersized. Spot-check hole diameters with the proper Pin Gauge (PG) while drilling to ensure that the hole diameter stays within tolerance.

	Should the Optional Spacer (Beef) Plate be drilled larger than the recommended min hole size?
	In large fixtures where the alignment of holes between the three plates is difficult to maintain, it is recommended that the holes in the Spacer Plate be enlarged to accommodate any misalignment, as the size of these holes is not crucial to the X PROBE assembly. The holes in the Spacer Plate act as a guide for the X PROBE Interconnect Receptacle onto the Interconnect Pin. If a relieved hole is desired on the Spacer Plate it is recommended that the oversized hole be on the top surface versus the bottom as this additionally guides the probe.