Investigation: distribution history: the complaint product was manufactured at csi on 11/feb/2020.Manufacturing record review: device history record was reviewed, and no non-conformities related to the complaint condition were noted.Incoming inspection review: incoming inspection record review not applicable to this product.Service history record : service history not applicable for this product.Historical complaint review: a review of the 2-year complaint history did not show similar reported complaint conditions.Product receipt: the complaint product has not been returned to coopersurgical as this is a field service complaint.Visual evaluation: this is a field service complaint, there was no product returned for evaluation.If further information becomes available at a later date this investigation will be amended accordingly.Functional evaluation: this is a field service complaint, there was no product returned for evaluation.If further information becomes available at a later date this investigation will be amended accordingly.Root cause: this is a field service complaint, there was no product returned for evaluation.If further information becomes available at a later date this investigation will be amended accordingly.Likely root cause can be attributed to modern low voltage electronic equipment which is most commonly powered by switching power supplies (psus) (e.G.Laptop/tablet power supplies, usb chargers, etc).These are often ungrounded types, which means that there is no direct connection to earth.Protection against electric shock is provided by means of isolation between the mains input and the low voltage output, instead of by using an earth connection.As there is no direct connection to earth, a charge can build up on the output of the power supply.Depending on the design of the power supply, this can be to a sufficient level to cause a tingling sensation, or a similar sensation to a static electricity shock when initially touching a conductive part of the device (or a connected device).Corrective action: the action is to change the tablet power supply and usb hub to an alternative type (surface pro docking station).Subsequent measurements, using the surface pro docking station, indicate that the level of charge is low enough not to be felt by the user.Coopersurgical will continue to monitor this complaint condition for any trends.
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