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radio troubleshooting

R

rwarre

Well Known Member
Was flying to Longmont, CO today IFR all was fine until my radio stopped transmitting. Need a plan now to troubleshoot the system. I have two radios, neither would transmit. Could receive on both radios but could not here a side tone. Radio showed it was keyed when I press the "press to talk switch". Suggestions on troubleshooting procedure please.
 
The best place to ask that question is the Aeroelectric list. Suggest you sign up & ask there; you'll get a lot more good info than just radio troubleshooting.

If neither radio transmits but both receive, it's not the radio. Check the mic line from your [intercom? audio panel?] to the radio(s). If you have separate intercom & audio panel, check the mic line from intercom to audio panel, or the audio panel itself.


If you have an audio panel with the older style edge connector for the tray, the 1st step should probably be to remove it, clean the contacts & reinstall.

Charlie
 
Yeah, my assumption was that intercom functions were ok, but since there was no info given on type of plane, equipment, etc, that was the best I could do.
 
Similar to me

I had a similar situation only I could transmit but not receive. Turned out to be an issue with my intercom. The radios would also work perfectly when I unplugged the headsets.
 
If the radio was saying that you were transmitting, maybe its not a radio issue and an issue with the intercom system? I would do the same as someone else mentioned, try plugging in on the other side. do you have a portable radio to determine if you are indeed transmitting?
 
I see you have a Piper

If it's the problem with the piper than you have no way of knowing if the alternator is on line or failed unless you seee the amp gauge at zero. When an alternator fails and battery starts lower, the transmitter is the first to go.
Below about 11 volts.
John
 
Thanks for the tips

Appreciate the help. I run a 7A with PS Eng 7000 audio panel, Garmin 430, and MGL V10 radios. I will try different headsets and switching sides first. Thanks again.
 
Another possibility, though unusual, is the avionic bus voltage being lowered to the point of not transmitting when the ptt is pressed (the radio will draw more current when trying to transmit). I experienced this on my RV due to a bad, high resistance, avionics master switch. It took some time for me to discover.
 
If you do have to dive under the panel, you might consider adding a pair of radio-only headphone/mic jacks somewhere you can reach them in flight. That way you can bypass any intercom/audio panel issues, if needed.
 
Simple tests first

The other simple test is to turn the PS7000 to OFF.

This is the failsafe mode that connects the pilot headset directly to COM 1.

If that lets you transmit it isolates the problem to the intercom.
 
And I have yet to figure out my recieve but won't transmit issue ,only when Nav lights on. The radio stuff can be tricky.
 
Fixed?

Took the 327 from the tray, cleaned the contacts with electronic cleaner and reinstalled. Flew for 30 minutes without any problems, talked to several pilots who received my transmission fine. Cross my fingers.
 
rwarre said:
Took the 327 from the tray, cleaned the contacts with electronic cleaner and reinstalled. Flew for 30 minutes without any problems, talked to several pilots who received my transmission fine. Cross my fingers.
Click to expand...

Are you saying pulling the transponder fixed your com radio problem?
 
Yeah, those edge connectors pretty much define 'certified aviation quality'. They really are the 1st place to look when you have an audio or comm problem.

Charlie
 
Lesson learned

I solved the faulty radio transmission problem and kick my self for poor judgement. I remember when working until the panel with the ADS-B installation that one of my ground crimps didn't feel right even though I did a pull test. I double checked several crimps and sure enough the audio panel ground was loose and came right out of the connector. Even though I have used my crimper for the whole build of my rv, I have decided to invest in a better crimper.
 
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