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Avionics guru's. Carrier only, no voice suddenly.....

Ofitz

Member
Avionics guru's. Carrier only, no voice.....SOLVED

I tried to take my son flying the other night and while taxiing for fuel, we noticed that the intercom was crackling and he was having trouble hearing me. I tried to ask the tower a question and was getting carrier only, no voice. It was an all the sudden type problem.

After fueling, I unplugged everything and turned off the intercom. When I turned on the avionics master, I could transmit. Once I turned on the intercom though, same thing. Carrier only, no voice.

It has since gotten worse. I can hear everything on the radio, but nothing on the intercom, and I cannot transmit my voice, but I do see the transmit T in the bendix king....

I took out the intercom and played with the wires, checked the breakers, etc. Nothing obvious.

Sigtronics panel mount with Bendix King KX-155 radio.

Any ideas??
 
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I agree with Kahuna - nine times out of ten, a sudden change like that occurs at a connection that has moved - and the most likely candidate is the microphone jack. Plugs get bumped and contacts bent.
 
If you could transmit fine with the intercom off then 99% chance its the intercom. With the intercom off its in fail safe mode and voice is routed directly to the radio and not thru the unit.
 
I tried the front and back headset jacks with the same effect so I don't think it's that...

As it stands now, even with the intercom OFF, I still cannot transmit. I'm going to try again tomorrow.

I'm guessing the intercom is toast also...
 
After fueling, I unplugged everything and turned off the intercom. When I turned on the avionics master, I could transmit. Once I turned on the intercom though, same thing. Carrier only, no voice.

Any ideas??

You say it works with intercom off here...

As it stands now, even with the intercom OFF, I still cannot transmit. I'm going to try again tomorrow.

I'm guessing the intercom is toast also...

But now you say it doesn't work here, I give up :confused:
 
@Walt: Don't give up yet! :)

@Doug: I'll try a new headset again to rule that out for certain.

I'm going to look at it again today. The problem is sort of intermittent in that sometimes I can make the radio work again, but yesterday I ran out of time. When I left, I could not transmit. It doesn't seem to follow a pattern that I can discern.

I may need an avionics guy to look at it. I'll let everyone know the outcome.
 
At the moment with what we know based on your report, Walt is likely spot on here (that being if it works with the avionics switch off). Most intercoms are made to fail over directly to the radio when power is removed...therefore if you shut it off, your jacks effectively are wired directly to the radio - which typically explains why they will work when the intercom is off, but not when it's on.

If it were a jack wiring it would either work all the time or not work all the time...that's the nice thing about that.

You definitely need to figure out whether it IS or is NOT working without power and with power before worrying about any other troubleshooting. Once that step has been completed, then you can look at headsets, jack wiring, etc..

Cheers,
Stein
 
I had a similar problem...

Just some input from personal experience. When I was wiring up the Mockingbird last year in Creswell Oregon for the x-country flight back to Winder, I had a transmit problem. Only after switching headsets with help from Gary Ludeke, did I find my electret element in the David Clarks had gone south from shipping out to west coast. After a quick trip to Pacific Coast Avionics for a new mike element, problem solved. Hope this helps.
 
SOLVED!!

At first it was intermittent, then it failed all together.

So, I decided to start again at the beginning, I was using my new Clarity Aloft headset, so I went back to my old work horse DC 13.4's

Voila... Problem solved. It is an issue with the Clarity aloft... Not sure why, I have to call them. Probably the mike as was just stated.

When I had my son try to transmit from the back seat with the DC's, I ruled out the headset as the problem as he could not transmit either. Apparently, I ruled it out too soon. When the DC is the only headset plugged in, everything is fine! Once I plug in the clarity aloft, everything acts up!

Thanks for the help guys! At least it was simple AND cheap....
 
Ok then

Good job David, I learned the hard way, don't bang around the electret element. We used the old fashioned bullet proof carbon mics back in my Navy days as they were more durable. In fact if they weren't working, one solution was to rap them in the palm of your hand to loosen up the carbon element.:D
I assume the element in the clarity aloft is rather fragile.
 
At first it was intermittent, then it failed all together.

So, I decided to start again at the beginning, I was using my new Clarity Aloft headset, so I went back to my old work horse DC 13.4's

Voila... Problem solved. It is an issue with the Clarity aloft... Not sure why, I have to call them. Probably the mike as was just stated.

When I had my son try to transmit from the back seat with the DC's, I ruled out the headset as the problem as he could not transmit either. Apparently, I ruled it out too soon. When the DC is the only headset plugged in, everything is fine! Once I plug in the clarity aloft, everything acts up!

Thanks for the help guys! At least it was simple AND cheap....

I had the same issue with my wife's Clarity Aloft and our Garmin 340 audio panel. They replaced the headset and it worked fine for about 5hrs of flying then it happened again. Reluctantly we returned them and she went back to her Zulu's.

:(
 
That's funny because it worked for about 5 hours for me too. That is why I was thinking it was something OTHER than the headset.

I am past the 30 days though. Might have to sell it online....
 
Is the Garmin 340 configurable in any way for the mic input? Perhaps Clarity Aloft and Garmin could put their heads together on this one. This is just electronics - anything can be fixed properly.
 
Clarity Aloft

Posting for Bill from Clarity Aloft ... please read below ....

We are not aware of a problem with the Garmin 340, as we have many headsets in use with that audio panel. If there is an incompatiblity problem we would be very interested in working with Garmin to resolve it. Could you make a post that we would appreciate hearing directly from anyone who has the problem? Especially the guy who says his 30 trial period has expired. We will do whatever it takes to satisfy him.

any help you could give would be appreciated.

Regards,

Bill

Bill Waterman, Aloft Technologies
612 325-9602
[email protected]
 
That's funny because it worked for about 5 hours for me too. That is why I was thinking it was something OTHER than the headset.

I am past the 30 days though. Might have to sell it online....

Ofitz,
Our team has jumped in to help. Clarity is one of our partners and here to help. Call Bill. He is the man to help you. Holler if you need further assistance.
 
Ofitz,
Our team has jumped in to help. Clarity is one of our partners and here to help. Call Bill. He is the man to help you. Holler if you need further assistance.

Wow! That is awesome! And I really love the headset so I hope I can get it to work. I'm glad I posted here! I thought I was outta luck. I'll call him tomorrow!

Great work guys! Love it!

Dave
 
Hello everyone,
I've been contacted by Bill and we've unfortunately to my knowledge not had any problems with this part of the circuit with any other headsets. however we're going to work with them to see if we can figure out what is going on and are working to see about getting some of these for testing.

stand by,
 
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