whats up with my radio?

[VETE76]

Jumped in my plane, took off from my private grass strip and flew to get gas on my way to my part in a memorial fly over for a Viet Nam vet, called into to land and my radio wouldn't transmit. I could hear everthing fine. Got home and tried the intercom, nothing. Had a friend with his radio talk to me fine but he said I only sent a carrier and no modulation. Any thoughts?
Thanks
Fred

[Mel]

Originally Posted by VETE76

I only sent a carrier and no modulation. Any thoughts?
Thanks
Fred

Bad modulator?
Seriously, it sounds like it may be a mike problem. Did you try another headset?

[VETE76]

tried 2 dif headsets. even switched front with rear seat.
no luck
fred

[Mel]

If you are getting no modulation through the intercom or radio, it almost has to be either the headset or wiring. If you get voice through the intercom but not the radio, then it must be the radio, or again wiring.

[VETE76]

no modulation(voice) thru radio or intercom

[kentb]

A month ago I noticed that I could hear the side tone. I could hear other planes transmit, but no one would reply to my 'radio check'.

When I got on the ground I tried the other headset and though that it was working. Remove my phone plug to make sure that they weren't shorted.

Anyway, long story short, I could transmit from my headset, but not hear and could hear on the PAX headset, but not transmit.

Strange....

I eventually noticed that the intercom had been set in the 'isolate' position. Flipped it back to 'all' and it all works.

So when the avionics shop wired my panel they must have crossed over the phone plug wires between the two so that the pilot and PAX ear speakers are on the wrong side.

Kent

[Ironflight]

Fred,

Since you're keying the radio, you know that the Mic "key" line works. You also know the "audio line works, as you can hear. The only question is if you have a continuous conductor from your mike to the radio's "Mic" in. I have had the contacts in the standard audio and Mic jacks get bent just a little so that they don't contact the plug conductors properly. If you can reach th back side of the jack, pull the headset plugs out, and give the jack contacts a little squeeze (pushing them all towards the center. Put the plug back in and see if you restored contact.

I know - sounds unlikely, but I have had it happen!

Paul

[breister]

However unlikely, if the above doesn't fix your problem then try your headphones in another plane to verify that the mic cords haven't shorted internally.

I'm betting on the mic line to the intercom, though...

[VETE76]

an avionics shop said intercom failure.
head sets work fine in other plane. contacts for the plugs in my plane ok. i told him the problem, he asked a few questions and my answers narrowed it right down to intercom. especially when i described the intercom and its wiring as i didn't know the make. when i told him about the 12 pin block and the wire colors, he said yep, intercom flew south w/o me.
thanks everyone for helping. great forum.
fred

[VETE76]

broken mic wire! soldered! working!
f