Need Help with Comms Testing

After 2 days, I have run out of ideas to test so I am posting in hope of some insight.

I have a GTN-650 Comm 1 and a Skyview Comm 2 with a 5000EX audio panel.

The problem is that I get no voice transmit on either comm radio from the copilot mic. I get no sidetone either. Its like the mic is dead. But the mic works fine on the intercom.

The transmit light lights up on the radios and on the audio panel when I push the PTT button on either side so I know my PTT switch is working, but I am not actually putting out any voice because I cannot hear anything on my handheld radio.

I can transmit from the pilot mic no problem. I can hear my transmissions on my handheld radio. Since the pilot side works, the radios must be wired correctly to the audio panel.

Also the intercom works fine on both pilot and copilot so I know the mic is working and I assume it must be wired correctly for it to work with the intercom.

I have ohmed out the wires from all the jacks and they are correct. I have removed the jacks from the panel to make sure they are not grounded. I have tested the wires for shorts and found none.

I am testing with the same headset on each side and also a different headset on each side, so it is not the headset.

My next step is to contact PS Engineering and see if my audio panel is bad. I don't know what else to test.

Any thoughts would be appreciated.
Thanks.

My guess is that you have inadvertantly wired the copilot mike to the #3 or #4 passenger mike input. Put the intercom into "crew" mode. If the intercom no longer works, then the diagnosis is confirmed.

Thanks for the reply, Bob.
I tried the intercom in crew mode this morning and it still works.

My experience is limited to the Dynon SV COMM. When the intercom is on, you will hear pilot and copilot microphones in the headsets. With the intercom off, and have the side tone set correctly, you will only hear the pilot microphone when you are transmitting. There is no side tone feedback in the copilot headphones when transmitting. I believe it is designed that way, because you don't have to have an intercom for the radio to work, and the radio is only set up to have one primary channel for the pilot side that feeds back to the headphones. My guess is that the Garmin is also designed similarly.

Are you certain you have the pilot PTT switch wired to the "Pilot Mic PTT" (J1-34) and the copilot PTT switch wired to the "Copilot Mic PTT" input (J2-33) on the 5000EX? If both were wired to the Pilot Mic PTT it would do as you say.

Problem solved!
I feel like an idiot, but will blame it on old age.

Sparky was almost correct, but it was even simpler.

Turns out the problem was me, not the panel.

I have a removable copilot stick with a disable switch on the panel.

I had been doing all my testing with the pilot PTT thinking it did not matter which switch to control the transmit function. Sparky reminded me that each PTT is wired to a different pin on the audio panel.

So I put in the copilot stick and surprise, everything works fine.

Thanks for the replies and thanks Sparky for setting me on the right path.

Bruce, I think what you described is my audio panel failsafe mode. If you power off the audio panel, comm1 will still function. I have my comm1 wired through my emergency bus so if I have a power failure I can connect my GTN-650 direct to the battery and still have comm capability for a short while. The SV's have the backup battery for the panels, but not the SV comm2.

That was my last panel test, so now I can rivet the forward skin on.

Bob,

I'm glad you got it sorted out and that I helped in some way.