The end of the cord where it goes into the waa charger was melted.The patient implant procedure was performed on (b)(6) 2020, and the patient was on day six (6) of the trial when this event took place.During the complaint investigation for the wearable antenna assembly, waa.The usb connector appeared to be melted due to a short circuit.We dissembled the waa and connected the mfs board externally to our test equipment.The mfs board was fully functional, and it draws the correct amount of current proving that the board did not cause the short circuit.After further evaluating the usb connector under a microscope it appears that the usb connector pins are melted including the guide shield.This suggests the user may have forced the usb connector incorrectly and the vb pin, which supplies current to the board, make contact with the guide shield or another signal pin causing a short circuit.Usb connectors are mistake proof with only one correct way to connect.There may have been excess force when connecting the usb for this failure mode to occur.Investigation also found the device's battery is expanded (battery l/n: 200408).The cause of expanded battery is attributed to material.A thermal image of the internal board of the waa.In addition, a thermal image of the assembled waa using the same charger but different usb cable since the one that came on the rma was (picture attached), the image near the charging area is blue, meaning it is cool, no highest temperature is 77.4 degrees f after 1 hour charging.Based on these images, there is no evidence of overheating due to the waa.Based on this information the waa overheating was not replicated/confirmed.The cause of the waa melted cord is user error.
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