The detection and identification of substances that give rise to aromas and off-odors is often a difficult task. Perception of odors is very subjective and odor detection thresholds vary from person to person. The identification of trace levels of compounds responsible for perceived odors is difficult using conventional analytical tools. This paper will focus on a novel method for sampling and analyzing aromatic volatile compounds using an analytical system specifically designed for odor analysis.

Contamination out gassing is the release of volatile compounds from a solid or liquid, often with the addition of heat. These compounds may condense as thin films on surfaces and cause oxidation, corrosion or contact resistance. Out gassing is more likely to be problematic in system environments in which the temperature is elevated and available oxygen is limited. Moisture in the environment may also be a contributing factor. The paper includes an investigation of three case studies of different types of contamination out gassing that led to system failures. The analytical tools and methods used to determine root cause will be discussed in each case. The first case study examines bridging conductive copper dendrites on a system cable used in a PC system related to the cable shipping materials. The second failure to be discussed is the corrosion of Ag conductor traces in a display panel due to out gassing of sulfur compounds from nearby foam cushioning pads. The third case will explore a DC motor failure due to siloxane out gassing from an adjacent foam pad. Prevention of out gassing can be controlled by material selection and supply chain management. There are also standard test methods that can be used to detect out gassing in suspect material. These methods can be used in conjunction with the specification as requirements for qualification of new materials. Two ASTM test methods, ASTM E-595-77/84 and ASTM E1559-03 pertain to contamination out gassing. This paper includes a discussion of both methods and their advantages and disadvantages as part of a test plan.

This paper correlates the reseat failure rates of a PCI option card to the use of thin gold plating across the contact fingers. This failure mechanism results in increased contact resistance and is often misdiagnosed due to its intermittent failure mode. As many new manufactures appear in Asia, the push for global competitiveness to achieve high volume and reduced costs can result in insufficient plating finishes being applied to the contact fingers. Compounding this problem is the fact the many companies use multiple raw board suppliers to meet these volume requirements. Many times the end user of the option card is unaware of the wide variation in contact plating thickness that may be present from one raw board source to another. Intermittent failures are one of the most common defects experienced in high volume assembly. Unless properly diagnosed, these failures can be attributed to finger debris, rework flux, solder paste contamination and even connector related issues. The typical fix, whether approved by the process or not, is for the manufacturing assembler to reseat all of the option cards and memory into the Motherboard connector sockets. Unless the proper troubleshooting approach is followed, isolating the true root cause of the actual failure can be missed. The difficulty in identifying the reseat problem is compounded by the fact that the failures are often intermittent in nature. While reseating may temporarily achieve sufficient mating between the board’s contact fingers and the connector contacts, it provides no long term fix. These unnecessary reseats also reduce the long-term durability of already thin plating affecting customer satisfaction and warranty costs. In the paper, we will expand on the theory behind the XRF plating thickness testing, including: • System theory • Test calibration • Part orientation • Test measurement criteria Additional analysis of metallurgical cross-sectioning was performed to correlate the XRF test readings to the actual plated layers. The measurements were completed by use of a SEM (Scanning Electron Microscopy).