Wondering if someone can enlighten me as to the function of the slide switch on the aft of the Narco MK-12D. I've looked on-line in several Narco MK-12D manuals but haven't seen any reference to it. I had to pull my radios recently and upon reinstalling, I had xmit issues with one of them. When I pulled it to troubleshoot, noticed that this slide switch wasn't fully engaged in one of the 3 positions and so matched it to the 2nd radio (MS-1) position and xmit issue was fixed but wondering what the switch actually does..... This is my first post, so I have tried to attach a photo (not sure if it will be visible in the thread or not, but the switch has 3 possible positions (MS-1 T, (a blank position in the middle), Other). Thanks.