Tommy Posted May 8, 2015 Report Share Posted May 8, 2015 I have managed to hunt down the source of static whine on my KX175BE. It goes away when I pulled the "fone cb" but nothing was turned off when I pulled it. So what is it for? Quote Link to comment Share on other sites More sharing options...
Jerry 5TJ Posted May 8, 2015 Report Share Posted May 8, 2015 It could be a remnant of an old headphone/speaker amplifier system. If you still have the KMA20 audio panel that CB may be connected to an intercom, or what was an intercom. Attached is a partial schematic for the KX175B from the installation manual. There is often a lot of orphaned wiring in our older planes. KX175 Schematic Snip.pdf 1 Quote Link to comment Share on other sites More sharing options...
FlyDave Posted May 8, 2015 Report Share Posted May 8, 2015 Tommy, I had one of these in my previous J (N1160N). Believe it or not It was for an "Air Fone" (satellite phone) - in a Mooney 201! The CB was connected to a 12 - 24 volt converter in the avionics bay. This converter was still in the plane but the "Air Fone" equipment had been removed. On my way back from Oshkosh in 2012 I was in the clouds at 8,000' and hit a bump. I heard a chirp in my headset and smelled a puff of smoke - yikes! I waited a few seconds, then a few more and a few more. Everything seemed OK so I cautiously continued to my next stop. On descent to my fuel stop I hit another bump and got another chirp and puff of smoke. I told the controller I wasn't declaring an emergency but I needed lower NOW - which he gave me and put me in VMC 2 miles from my destination. I began troubleshooting as soon as I landed. What I found was the "Fone" CB popped and if I turned the avionics master on with "Fone" CB in it would pop. So I figured out what it went to and disconnected the cable from the converter in the avionics bay and left the CB pulled for the remainder of the flight home. I didn't have any more problems after that. Let us know if you have the same thing in your avionics bay and if disconnecting it fixes your static issue. Dave 1 Quote Link to comment Share on other sites More sharing options...
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