Teach Me About Headphone/Mic Jacks

NealRomeoGolf

NealRomeoGolf

Final Approach
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My copilot side headphone jack has had issues since I bought it. Copilot can hear but they cannot be heard on either the intercom or the radio. So something about the contact in the jack. I have taken it to the avionics shop twice. They fiddled a little with it. They say all of their headphones work. They tried one of mine and it doesn't. They shrugged.

Is it just a contact thing? I have tried multiple DC headsets in there and 2 different Bose headsets. None of them have worked for me.

Easy solution would be to put a new jack in but it is situated right above all of the circuit breakers so getting to it is a problem. Any ideas what else I could do? Is the tip just not contacting the back of the jack to open the mic circuit? I really don't understand audio stuff so I am clueless.
 
The Jack should be held in by a nut on the front. If you think that you can get the wires loose enough to be able to un-screw the Jack and work on it in front of the panel, it is as simple as soldering the wires onto the new Jack.

But having just replaced a radio myself, it was crappy work dealing with about 1,276 wires going who knows where, working on my back at times curled up like a fetus in a cramped aluminum torture box.

So super easy if you can just get the wires free enough to bring out from under the panel. Or it will be many hours of cleaning up 60 years of loose and dead end wires, rusty crusty wire clamps, old zip ties, etc.
 
I had a similar thing happen to me recently. Bose X and Zulus worked fine on the pilot side. Tried a set of DC One-X and got nothing on the intercom. Plugged them into the copilot side and they worked fine. Other headsets worked fine on the copilot side. My best guess is that nothing was wrong with the headset or the jacks, but the nuts that held the jacks in the panel were installed slightly differently on the pilot side than on the copilot side, such that the mic plugs engaged slightly differently.
 
Matthew Rogers said:
The Jack should be held in by a nut on the front. If you think that you can get the wires loose enough to be able to un-screw the Jack and work on it in front of the panel, it is as simple as soldering the wires onto the new Jack.

But having just replaced a radio myself, it was crappy work dealing with about 1,276 wires going who knows where, working on my back at times curled up like a fetus in a cramped aluminum torture box.

So super easy if you can just get the wires free enough to bring out from under the panel. Or it will be many hours of cleaning up 60 years of loose and dead end wires, rusty crusty wire clamps, old zip ties, etc.
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I see the lock nut. Will have to see if I can get to it with it embedded in the plastic panel.

20201205_071730.jpg
 
The way I understand it is as follows:

-The tip or broken contact in your picture is for the push to talk. That contact normally switches a relay for the transmit part of the com. That contact has nothing to do with the intercom

-That being said I would think it is a problem with the wiring to the intercom/auto panel. Or a problem with the intercom
 
AKBill said:
The way I understand it is as follows:

-The tip or broken contact in your picture is for the push to talk. That contact normally switches a relay for the transmit part of the com. That contact has nothing to do with the intercom

-That being said I would think it is a problem with the wiring to the intercom/auto panel. Or a problem with the intercom
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Intercom is brand new and it didn't work with the old one or the new one. If it were wiring, why would the shop's headset work? Head scratcher.
 
My guess would be it's your headset. Cold solder joint, broken wire etc.
 
NealRomeoGolf said:
Intercom is brand new and it didn't work with the old one or the new one. If it were wiring, why would the shop's headset work? Head scratcher.
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That is the problem with wiring. A broken wire can make the problem intermittent. Vibration can cause it to make contact or not make a contact. Troubleshooting can be hard. One way to check it would be to run a new wire from the jack to the intercom
 
another way would be to wire a new mic jack (does not need to be installed in the panel). And hook it up to the intercom
 
The DC headests had those multiple-ringed plugs that sometimes didn't work with the simpler jacks. In the picture you see two rings; most headsets have just one. The audio ring on yours might not be contacting the jack's contact; try moving the plug in and out a little to see if it works in some other slightly different position.

It might be easier to get the shop to put the single-ring plug on the cord.
 
I found a workaround today. I had a splitter sitting in the hangar. Plugged that in and then put the headset on the splitter. Mic works that way.
 
One thing about all headphone jacks is that the work with very low voltages so the slightest resistance can cause big problems. However, twisting the plug back and forth each time you insert the plug can often polish off that slight corrosive film causing the resistance. In fact I have thus restored jacks that have not been used for years but it took a lot of twists.
 
NealRomeoGolf said:
I found a workaround today. I had a splitter sitting in the hangar. Plugged that in and then put the headset on the splitter. Mic works that way.
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Weird. Why did you have a mic splitter? Not much use for one of those. Most people only split the headset/speaker stuff.

The mic jack is an oddball size and not readily available outside of aviation.

Have it lying around from the old “bring your own intercom” days long ago? :)
 
denverpilot said:
Weird. Why did you have a mic splitter? Not much use for one of those. Most people only split the headset/speaker stuff.

The mic jack is an oddball size and not readily available outside of aviation.

Have it lying around from the old “bring your own intercom” days long ago? :)
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My Archer, when I bought it, only had headphone jacks for the front. The previous owners had splitters for people in the back to be on the intercom.
 
cgrab said:
Just for fun, measure the length of the jacks to see if the one that works is longer.
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We did that in another thread here recently. Well the person that had the problem posted a photo of two side by side. But that was the headphone side and not the mic. Usually the mic jacks are identical. The headphone side often has differences between mono and stereo plugs that don’t always tickle the jack where it wants to be tickled.
 
NealRomeoGolf said:
Copilot can hear but they cannot be heard on either the intercom or the radio.
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Is there a volume knob that is turned all the way down?

It has happened to me. My back-seat passengers couldn't hear us speaking in the front. I swapped headsets and they still couldn't hear us. I asked a shop to look at it, and they said there's no problem. I later discovered that it was all my fault -- a knob on the audio panel was turned all the way down, it was for the (back-seat) passengers, and I hadn't even noticed. Duh!!

Your problem is slightly different, involving the copilot's mic instead of the passengers' ability to hear. But if there's a knob for the copilot's mic ...
 
Matthew Rogers said:
it was crappy work dealing with about 1,276 wires going who knows where, working on my back at times curled up like a fetus in a cramped aluminum torture box.
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I haven't tried it, but that's exactly what I would expect.

You know, I've wondered why anybody would want to do avionics installations. It really does sound miserable.
 
NoHeat said:
I haven't tried it, but that's exactly what I would expect.

You know, I've wondered why anybody would want to do avionics installations. It really does sound miserable.
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Not really that bad if one avoids too many devices. I have done all my installations. In fact I built my own intercom. I just got done hand digging a long trench for a gas line, now THAT'S miserable!
 
Agree with a previous poster. Sounds like your headset jack on the headset itself is not seating fully in the plug. This could also explain why the shops headset works if it is able to fully engage and make all connections. I've fixed many pilot intercom gripes in the military by just reaching in and pushing the plug into the jack a little more firmly. Other possibilities could be a corroded/oxidized jack on the headset cord but it sounds like you're experiencing this problem with multiple headsets so I go back to the idea that something is preventing it from fully seating on your copilot side.
 
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