Trying to use this old head set mic to place in my 213fIS. I see the ground copper and the power which must be the green but, is there a coating on the power (green) that I must some how scrape off ? I have tried like it is and does not work. Issue is these wires are so tiny and unless I use a chemical or something can't see getting the green off. Checked the audio settings and all is good and on as far as other posts I have seen on this topic.