Gideon Analytical Laboratories received two printed circuit board (PCB) assemblies, each of which had a single multilayer ceramic capacitor (MLCC) suspected of failing. These MLCCs are Johanson Dielectrics PN 500T15W103MV4E. A PCB mechanically supports and electrically connects electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate. Components (e.g. capacitors, resistors or active devices) are generally soldered on the PCB. Advanced PCBs may contain components embedded in the substrate.
Gideon Analytical Laboratories received four Printed Circuit Boards which had either opens or intermittent behavior on some of the P1 connector pins. A Printed Circuit Board (PCB)mechanically supports and electrically connects electronic components using conductive tracks, pads and other features etched from copper sheets laminated onto a non-conductive substrate. PCBs can be single sided,double sided,or multi-layered. An open circuit is an incomplete electrical circuit in which no current flows. Gideon Analytical Laboratories was asked specifically if the soldering on the PCBs was problematic.
Gideon Analytical Laboratories received four Spectrum Control Pi filters N49927 Bus A (capacitor components FL1, FL2, FL3, and FL4). Capacitor-input filters (also known as Pi filters) are a type of electronic filter used to remove unwanted frequencies from a signal. Pi filters are primarily constructed of two capacitors and an inductor. They are used in situations where the ripple of a signal or the AC and DC currents within the signal are found to interfere with each other.
Gideon Analytical Laboratories received two 153D8496G1 printed circuit boards (PCBs)for failure analysis. A PCB mechanically supports and electrically connects electronic components using conductive tracks, pads, and other features etched from copper sheets laminated onto a non-conductive substrate. Some of the electronic components that might appear on a PCB include semiconductors like diodes or transistors, discharge devices, power sources, resistors, and capacitors. The153D8496G1 circuit card assembly has 6 capacitors, 20 resistors, and 18 semiconductors all mounted to a printed wiring board.
Gideon Analytical Laboratories received several Tusonix Pi filters that were failing in the field. Capacitor-input filters (also known as Pi filters) are a type of electronic filter used to remove unwanted frequencies from a signal. Pi filters are primarily constructed of two capacitors and an inductor and are used in situations where the ripple of a signal or the AC and DC currents within the signal are found to interfere with each other.
Gideon Analytical Labs received one failed relay with one good one for comparison. The failed relay was intermittent @ 2 KHz.
A reed relay is a switch that uses an electromagnet to control the turning off or on within a circuit. The contacts are of magnetic material and the electromagnet acts directly on them without requiring an armature to move them. Sealed in a long, narrow glass tube, the contacts are protected from corrosion and are usually plated with silver, which has very low resistivity but is prone to corrosion when exposed, rather than corrosion-resistant but more resistive gold as used in the exposed contacts of high-quality relays.
Gideon Analytical Labs received three failed Kapton based flex circuits with opens in the trace lines. The origin of the open was not known. The opens in the trace lines were traced down on the Kapton to several eyelets where contact was supposed to be made.
No areas were distinguished and no anomalies were found suggesting a trace copper foil problem on any of the circuits received. A cross-section of the above trace line and eyelet demonstrates the trace line (the line in the middle) either has been dislodged from the barrel or was never connected.
Gideon Analytical Laboratories received one static transfer switch (STS) Main Logic printed circuit board (PCB) assembly with two chips onboard digital signal processor (DSP)’s that were non-functional. The thought was the DSPs may have ball grid array (BGA) solder joint integrity issues causing the failures.
Analysis ensued. The three DSPs were removed from the PCB and immersed into the green dye and the DSP was pried from the main circuit board to reveal any cracked solder BGAs.
Gideon Analytical Laboratories received 19 multilayered ceramic capacitors (MLCCs). MLCCs have a ceramic dielectric, a ceramic or lacquered coating, a metalized electrode, and connecting terminals. Ceramic capacitors, in particular, MLCCs, are ubiquitous in all kinds of electrical equipment. Some of the MLCCs Gideon received were to test quality control, some were to test process evaluation immediately after wave solder, and some were failures in the field. The objective was to determine where these failures were entering the product and the cause of the failures.
Gideon Analytical Laboratories received several PCBs with MLCC capacitors mounted near the circuit board edge. The capacitors had a polyurethane conformal coating passing class 2 IPC-A-610 inspection. Several of the capacitors had less than 3000 ohms leakage current when measured on an IR meter. The coating was removed and the samples were potted and cross-sectioned for further analysis. The capacitor shown is typical of a lot of failures.
These are flex cracks caused by PCB flexing or bending.
Gideon Analytical Laboratories received a PCB with possible failed capacitors in several positions. PCBs are used to mechanically support and electrically connect electronic components. They are used in almost every all but the simplest electronic devices, from GPS systems to laptops, from cell phones to microwave ovens. Several MLCC capacitors on this PCB had failed, and the goal of Gideon Analytical Laboratories was to diagnose the cause of the failure.
Gideon Analytical Laboratories received 100 capacitors and directed to analyze them via cross-sectional analysis. Capacitors store charges and frequently appear on PCBs. There are many types of capacitors; electrolytic capacitors are tantalum capacitors are fairly common. The goal was to discover any abnormalities or determine if there were no abnormalities.
Each capacitor was cross-sectioned and observed 15 to 20 times under 40-72x magnification during the sectioning process. At some point during the cross-sectioning process, pictures were taken to depict the internal quality of the ceramic structure and any cracks (mechanical, knit, Kirkendall voiding or other defects) that may be present.
Gideon Analytical Laboratories performed failure analysis on two printed circuit board assemblies (PCB) with fractured solder joints on the Hall Sensor interconnect. The assemblies were taken apart and the conformal coating was removed to reveal the solder joints of the Hall Sensor. Five out of six of the Hall Sensors were mounted flush against the Valox 457 mounting block.
A Hall Effect Device detects magnetic flux density and is used in both movement and position sensing.
