The welch allyn spot vital signs non-invasively and automatically measures systolic and diastolic blood pressure, pulse rate, and oxygen saturation (spo2) for adult and pediatric patients.Further, the welch allyn spot vital signs measures temperature invasively in natural body orifices (i.E., mouth and rectum).The spot vs device was returned to welch allyn for investigation.The evaluation and investigation indicated that the failed power supply of the spot vs device was a result of a fire in the input ac receptacle of the power supply cord.When tested, the ac power input cord was removed from the power supply, the power supply was tested and functioned properly.Further testing of the spot vs device and power supply indicated that a definitive root cause of the fire could not be determined due to the level of damage to the ac input receptacle.Examination of the appliance end of the power supply receptacle shows that the cord melted in a manner where the heat source caused the receptacle body material to flow out and down the sides of the receptacle.Two possible causes were identified.Possible sources of a heat source inside the plug body are high contact resistance between the live and neutral conductor wire of the cord and the contact post in the plug receptacle, or something conductive between the ac live and neutral in the receptacle well end of the power supply cable.Disassembly of a new power receptacle overmold shows that the ac contact posts are crimp connected to the ac live and neutral hookup wire of the cable.High contact resistance at the crimp of the ac post and hookup wire could cause heat buildup at this juncture.Additionally, another possible source of conductive material between the ac live and neutral is cleaning fluids.The cleaning specification in the user manual specifies 10 percent chlorine bleach solution is acceptable.During testing the device power supply was applied clorox cleaning solution for 10 minutes to show that the fluid can soak / wick into the material of the overmold on the plug or receptacle and develop a measurable level of resistance which could cause a short.Welch allyn will continue to monitor complaint trends for this type of alleged malfunction.Based on this information, no further action is required.
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