Radio issue: constantly transmitting

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ulflang
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Radio issue: constantly transmitting

Post by ulflang »

Hello,
I have my DA40XLS since 5 years - and now a special issue ....
6 months ago and now again my radios were suddenly constantly transmitting - on both radios!
First time when it happened I was on a taxiway.
Nothing helped: pushing both PTT-switches more than 50 times, switching of the main switch for reset .... still transmitting on both radios after the G1000 came back.
I had to change the frequency that I did not block all others.Taxied back and next day came back with an A&P and started the G1000 - the issue was gone ... for 6 months.
Yesterday it happened again, this time while talking from the left seat - last time my friend was talking from the right seat.
Again both radios were transmitting constantly. We dialed a frequency, which didn't affect anybody and flew with the handheld radio to our avionicshop. There we switched everything of to shut down the engine .... and the issue was gone again. So the guys from the avionicshop couldn't do anything - and I'm now flying around with a bad feeling and a handheld radio on my lap.
Has anybody an idea????
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Boatguy
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Re: Radio issue: constantly transmitting

Post by Boatguy »

Have you contacted Garmin? Their email is horrendously slow, but they have an AOG phone number.
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BRS
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Re: Radio issue: constantly transmitting

Post by BRS »

Both radios in TX at the same time or when you switched between radios. Did you try changing headsets? Could be a short on the key wire in the mic plug of the headset. Do you have the same issue it you plug into the right and use the right key button?
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ulflang
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Re: Radio issue: constantly transmitting

Post by ulflang »

Both radios not at the same time, just that one, that I switched on.
Constantly TX even without any headset connected.
We are just travelling through Florida and are blocked at Daytona.
Here is a Diamond Servicecenter - hope they have an idea.
Thanks for your help.
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Rich
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Re: Radio issue: constantly transmitting

Post by Rich »

Since it's only the selected radio, it could be a short in either pilot or copilot PTT circuit OR the hand mike circuit. I would check the connector for the hand mike first. I had one of these types of plugs used in the headset connectors come a bit loose and it shorted out, causing a constant squeal in the headset. All it took was tightening the plug and the problem went away. That was years ago.
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Rick
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Re: Radio issue: constantly transmitting

Post by Rick »

Another thing you could try when it gets into this state is the Pilot Isolate button, and then also the Copilot Isolate. If the right PTT button is stuck, for example, activating PIlot isolate should disconnect that button and stop the TX. And vice versa for the left PTT. I"m not sure if either affects the handheld mic jack, though, if that's where the problem lies.
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ulflang
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Re: Radio issue: constantly transmitting

Post by ulflang »

Thanks to all!
I hope, that Daytona Aircraft Services fixed it ....
They found a problem behind the audio panel: the cables were packed so tight, that two connectors touched each other in that way, that the PTT-switch was closed. That caused the radios to transmit permanently. I really hope, that this was the issue - lets see.
So far I can strongly recommend their services!
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