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Every national spacecraft charging related design guideline or design standard includes prohibitions against floating, or ungrounded, connector pins. The rationale is obvious. A floating connector pin represents ungrounded metal with a propensity to accumulate charge from the space plasma environment and, upon breakdown, effectively couple the discharge energy directly into sensitive system electronics by virtue of adjacent pins and cables. Satellite designers may recognize that, seemingly as common as the rationale is obvious, there are instances in violation of this clear guideline and impassioned arguments for permissions to do so. This paper represents a comprehensive effort to quantitatively, theoretically, analytically, and empirically assess the risk associated with ungrounded connector pins in the selected (geostationary earth orbit and medium earth orbit) orbits.

For decades, we were taught that connector pin gap must be kept to a minimum to reduce reflection and hence improve device performance and measurement accuracy. Yet, measurement inconsistencies were observed between calibration methods, such as sliding load, TRL and offset short, especially at frequencies above 18 GHz. Measurement repeatability was another frustrating experience for practitioners of high precision measurements, such as TRL calibration. The root cause of these measurement inconsistencies wasn't identified until recently. The "connector and gap effect" was discovered and finally these measurement inconsistencies can be explained with an appropriate model. This paper will review the observed measurement issues, present the theoretical base of the connector effect and show how measurement accuracy can be improved.

In this paper, we propose a design method that the crosstalk of probe connector pins satisfy the limitation of -30 dB. The parameters(inductance and capacitance) were extracted in the grid-structured probe connector pin system, and it is shown that the new parameters are easily calculated with increasing ground pin numbers using the previously calculated parameters. In addition, the crosstalk reduction algorithm by employing more grounds around the signal pin has been suggested, and it is confirmed that the suggested method is quite effective especially for the reduction of inductive couplings. Finally, we suggested the correlation between the pitch and the length of the pins to satisfy the crosstalk limitation of -30 dB with the given number of ground pins, which will be quite useful when design a probe connector pin system.

A land-grid array connector, electrically connecting an array of plated contact pads on a ceramic substrate chip carrier to plated contact pads on a printed circuit board (PCB), failed in a year after assembly due to time-delayed fracture of multiple C-shaped spring connectors. The land-grid-array connectors analyzed had arrays of connectors consisting of gold on nickel plated Be-Cu C-shaped springs in compression that made electrical connections between the pads on the ceramic substrates and the PCBs. Metallography, fractography and surface analyses revealed the root cause of the C-spring connector fracture to be plating solutions trapped in deep grain boundary grooves etched into the C-spring connectors during the pre-plating cleaning operation. The stress necessary for the stress corrosion cracking mechanism was provided by the C-spring connectors, in the land-grid array, being compressed between the ceramic substrate and the printed circuit board.

Radiology plays a crucial role in initial assessment and follow-up of cardiac conduction devices (CCDs). At least 1 million patients in the United States have permanent CCDs, which comprise pacemakers and implantable cardioverter-defibrillators. Chest radiography is unique because it is the only imaging modality that allows evaluation of the physical integrity of CCD leads. As a result, a basic knowledge of the normal and abnormal radiographic appearances of these devices and their various components is important. Radiologists should have a working knowledge of CCD anatomy as well as appropriate positioning and appearance of CCD leads and generators. Acute complications of CCD implantation include dysrhythmia, pneumothorax, perforation of the heart muscle or a vein, heart valve damage, lead damage, inadequate seating of the terminal connector pin, and presence of an air pocket. Chronic complications include twiddler syndrome, lead fracture, damage to the lead insulation, and lead displacement. Radiologists play an important role in management of patients with CCDs by providing vital information about the device, starting immediately after implantation and continuing throughout its duration in the patient. To fulfill this role, radiologists must have a firm understanding of CCDs and their evolving technology.

This appendix contains sections titled: Simulated ESD Generator Direct ESD on Accessible Connector Pin Magnetic Field, Induction Coupling Into a PCB Loop Indirect ESD (Vertical Coupling Plate) Effects on a PCB Trace Few Remarks on Simplifying Assumptions used in These Spice Simulations Few General Conclusions from Spice Modeling with 8-KV ESD

PCB traces in backplane are typically routed as striplines, which create near end crosstalk, but theoretically, no far end crosstalk. However, in practice, both near end and far end crosstalk introduced by via antipads and layer misalignment in the connector pin field due to manufacturing process variations can be significant. This paper presents an analysis for the first time of the PCB trace crosstalk in the connector pin field of high speed backplanes. Crosstalk from the adjacent differential pairs on the same layer and in particular, from neighboring layers is first modeled and simulated with the consideration of PCB design tolerances and routing constraints in the connector pin field. The model is then correlated with a 10ps edge TDR measurement. Finally, the simulated and measured results are provided to demonstrate the significance of the crosstalk due to connector pin field traces.

Over the past few years card connectors have progressed significantly from the 0.100" pitch gold tabs of the first PC's. New developments in card technology are driving higher connector pin count and denser, more unique connector packaging. Since more and more circuits must go from card to card, the card edge connectors have migrated to surface mount and are now straddling the card in order to achieve this higher number of required interconnections. A straddle mount connector system is evaluated in an electronic card assembly test facility for both material and process impacts. Emphasis is placed on the connector and associated process materials used. The contact integrity after successful solder attach has been evaluated. While in-depth details of the attach and subsequent repair process have been reported previously, the critical process parameters will be highlighted in this paper.

A rate responsive dual chamber pacemaker system (Medtronic Inc.) was implanted without complications. At 6-week postimplantation a routine pacemaker check showed a spontaneous switch from programmed bipolar pace-sense to unipolar pace-sense on the atrial and ventricular leads. Pacing and sensing thresholds were not significantly changed from implantation. The atrial and ventricular lead impedances increased from 680 and 720 ohms at implantation to 1,290 and 2,400 ohms, respectively. The device was reprogrammed to bipolar pace-sense and the continuous lead telemetry trend option was programmed On. Evaluation of the system 1 month later revealed a decrease in atrial and ventricular lead impedances, 680 and 2,100 ohms, without a change in pace-sense polarity. One month later, the lead polarity had again switched from programmed bipolar to unipolar pace-sense. The lead trend data revealed stable atrial impedances with sporadic increases in the ventricular lead impedance to values > 3,000 ohms. The pacemaker lead system was invasively investigated and visible gross corrosion of the ventricular lead distal connector pin was discovered.

Transcatheter closure of the left atrial appendage with the Amplatzer™ cardiac plug device and double antiplatelet treatment for 3 mo has become an alternative treatment for patients with atrial fibrillation at high embolism risk and contraindications for chronic oral anticoagulation. The inadequate implantation of the left atrial appendage closure device and the discontinuation of double antiplatelet therapy are well-known as factors related to device thrombosis. Nevertheless, device thrombosis after adequate implantation requiring surgical treatment or restarting chronic oral anticoagulation has been reported and can reach 15% of patients. The connector pin thrombosis of the Amplatzer™ cardiac plug, despite a good adherence to antiplatelet treatment, has been recently described as a potential mechanism for device thrombosis. Our clinical case reports the management of this condition for the first time, showing that the early detection of thrombotic complications by transesophageal echocardiography permits solving this serious complication with medical treatment only.

The General Purpose Work Station (GPWS) is a laboratory multiuse facility, as demonstrated during the Spacelab Life Sciences 1 (SLS-1) flight. The unit provided particulate containment under varying conditions, served as an effective work space for manipulating live animals, e.g., rats, served as a containment facility for fixatives, and was proposed for use to conduct in-flight maintenance during connector pin repair. The cabinet has a front door large enough to allow installation of a full-size microscope in-flight and is outfitted with a side window to allow delivery of items into the cabinet without exposure to the spacelab atmosphere. Additional support subsystems include inside cabinet mounting, surgical glove fine manipulations capability, and ac or dc power supply for experiment equipment, as will be demonstrated during Spacelab J. The GPWS, integrated and maintained in a double flight-rack, interfaces to spacelab systems including water cooling, avionics and cabin air, and power. Verification has been completed for multiple spacelab scenarios including SLS-2, SL-J, and SLS-3.

Before accepting percussive arc welding as a production process for making electrical interconnections, it was necessary to determine the effects of the main variables (materials, equipment, and operators) which are certain to be encountered in production. This report deals with a study made to develop the required information. The variables selected for study were materials (wire lots and connector pin lots), operators, and welding machines, each variable at two levels. Two different wire types were investigated. Statistically designed experiments were performed to determine the effects of these variables upon flexing strength, tensile strength, and electrical resistance. In general, significant effects were found for wire lots, operators, and welding machines (usually as interactions.) Although these effects are significant, the magnitude of the change does not appear to be excessive in terms of mean values. These results show that the process is controllable and that initial process standards can be calculated from the data presented.

The disclosure is directed to process and apparatus for the removal, site preparation, and replacement of any single connector pin contained within a sizeable array of closely spaced very small connector pins on an electronic packaging structure (substrate or module) without causing deleterious metallurgical effects either to the remaining pins or the ceramic substrate.