skydvrboy Posted October 4, 2021 Report Share Posted October 4, 2021 (edited) I can no longer hear my #2 radio. It worked when I left my home base and quit before I got to my destination with no hint at what was to come. I have a KMA20 audio panel and the #2 radio is a KX125. As I started testing, I found I can transmit, but not hear. What is the likelihood that this is just a loose wire on the KMA20? That seems to me to be the most likely culprit. Additional testing I didn't think of doing would be to see if I can hear the Morse code on the Nav radio. I'll test that tomorrow morning. I'm pretty sure both the Nav and Comm audio come through the Comm channel on the KMA20. If I can't hear the code, then I'm almost positive the problem lies with the audio panel and not the radio. When I called a well known and highly regarded avionics shop, they wanted me to pull my radio and send it to them for testing. I balked at that and asked them if they could instead get my whole plane in the shop to diagnose the problem. I'm taking it to them tomorrow and will request that they inspect the KMA20 for a loose wire on pin 15 before they remove my #2 radio. Anything else I'm missing here? Other tests I should run to diagnose? Questions I should ask the shop? Edited October 5, 2021 by skydvrboy Quote Link to comment Share on other sites More sharing options...
ArtVandelay Posted October 4, 2021 Report Share Posted October 4, 2021 I assume you tried a different headset and tried the copilot jacks? Quote Link to comment Share on other sites More sharing options...
Yetti Posted October 4, 2021 Report Share Posted October 4, 2021 I've done that a couple of times and found that if I push the plug all the way into the jack it works better. You should pull it out and push it in several times to clean the pins in the back. Also swap one and two. Quote Link to comment Share on other sites More sharing options...
skydvrboy Posted October 5, 2021 Author Report Share Posted October 5, 2021 1 hour ago, ArtVandelay said: I assume you tried a different headset and tried the copilot jacks? Actually, no, I didn't think of this since the #1 radio was working perfectly for both receive and transmit. I'm not sure it's even possible for the headset or jack to be the problem, since there is a single audio out for the entire audio panel, but I'll give it a try. It certainly can't hurt anything! Thanks for the suggestion. Quote Link to comment Share on other sites More sharing options...
ArtVandelay Posted October 5, 2021 Report Share Posted October 5, 2021 Actually, no, I didn't think of this since the #1 radio was working perfectly for both receive and transmit. I'm not sure it's even possible for the headset or jack to be the problem, since there is a single audio out for the entire audio panel, but I'll give it a try. It certainly can't hurt anything! Thanks for the suggestion.Good point. FYI, my audio panel has com and nav audio on different inputs (wires), so if both are silent I guess would suspect the radio. 1 Quote Link to comment Share on other sites More sharing options...
skydvrboy Posted October 5, 2021 Author Report Share Posted October 5, 2021 (edited) I’m at the avionics shop now. Five minutes in and they had the radio pulled and bench tested. Dead audio out on the radio. Per the shop, the KX125 has a single audio out for both Nav and com. You listen to Nav by turning up the Nav volume on the radio. I had both volumes at max, but when one’s dead, they’re both dead. Edited October 5, 2021 by skydvrboy 1 1 Quote Link to comment Share on other sites More sharing options...
skydvrboy Posted October 5, 2021 Author Report Share Posted October 5, 2021 A leaking capacitor on the speaker output fried the circuit board. They’re going to change out the board and remaining old capacitors that are likely to leak and warranty the radio. I could probably get a used one for about the same price or a bit less, but the old capacitors in it would be just as likely to leak. 3 Quote Link to comment Share on other sites More sharing options...
LANCECASPER Posted October 10, 2021 Report Share Posted October 10, 2021 On 10/5/2021 at 9:11 AM, skydvrboy said: A leaking capacitor on the speaker output fried the circuit board. They’re going to change out the board and remaining old capacitors that are likely to leak and warranty the radio. I could probably get a used one for about the same price or a bit less, but the old capacitors in it would be just as likely to leak. Wow a radio shop that actually works on radios - very rare these days. Let me guess - the tech is over 60? Quote Link to comment Share on other sites More sharing options...
skydvrboy Posted October 10, 2021 Author Report Share Posted October 10, 2021 2 hours ago, LANCECASPER said: Wow a radio shop that actually works on radios - very rare these days. Let me guess - the tech is over 60? If I had to guess, he was around 80. I kind of felt sorry for him working so late in life, but he genuinely looked like he was having fun. 1 Quote Link to comment Share on other sites More sharing options...
Marauder Posted October 10, 2021 Report Share Posted October 10, 2021 Wow a radio shop that actually works on radios - very rare these days. Let me guess - the tech is over 60?A lot of the newer avionics are using wave solder technology for attaching components. Most of the older avionics can be serviced if it has through hole components and those components are available. And of course, the tech may need to use, heaven forbid, an oscilloscope to diagnose a problem. Sent from my iPhone using Tapatalk Pro 1 Quote Link to comment Share on other sites More sharing options...
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