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Curbell medical engineering conducted an analysis of the returned pillow speaker device.This unit was returned for an alleged thermal event where the volume buttons were excessively hot, around 154f as reported by the customer.Curbell medical engineering confirmed that everything in the unit was operating as expected, except the microphone for talkback.It was also observed that the volume buttons (or at least the area near these buttons) was hot to the touch.With the unit intact and unassembled, the unit was connected and at rest for 30 minutes.The temperature measured around the volume buttons peaked around 160f.The unit was then removed from service and opened for internal review.It was discovered the c15 capacitor (the 100uf line leveling output capacitor for the main 5v regulator) had its leads broken away from the main body of the capacitor, free of the printed circuit board, and was now able to move within the case enclosure.The heat source was generated by the 3.3v regulator that takes its power from the 5v regulator.This 3.3v regulator was removed and replaced and full functionality of the device was confirmed.Therefore, it is our belief that the device was exposed to an extreme mechanical impact significantly outside of the scope of normal operating conditions because the c15 capacitor did not have a cold solder joint (a cold solder joint is a weak comprised joint), but rather, the capacitor leads were physically severed from the main body of the capacitor component; thus allowing the main body component to move freely within the case enclosure.Moreover, the removal of c15 capacitor from the circuit made the 5v regulator extremely unstable which affected the 3.3v regulator to the point where it became damaged.Consequently, this caused the source of heat to be produced.To date, (b)(4) gen iv pillow speaker devices have been sold and this is the only known occurrence of this type of incident.Finally, our pillow speaker devices have been validated to the ul 1069 standard which includes drop testing 100 cycles of the pillow speaker unit from a height of 4 feet onto a hard surface.Curbell medical pillow speakers have been successfully validated to this standard.
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