Testing an electret microphone?

[[email protected]]

My radio stopped working. I'm transmitting, but with no audio. I think it's probably the mic, but there are some other components between the mic and the radio. Is there some way I can test my electret mic to confirm it's actually the mic before I order a replacement? From what I understand electret microphones need power from a pre-amp.

This is an old ICOM HS-15 boom mic, with a 3.5mm 3 ring plug.

Thanks!
Tom

[Two Shoes (Judson Knowles)]

On Wednesday, May 7, 2014 8:39:17 AM UTC-6, wrote:
> My radio stopped working. I'm transmitting, but with no audio. I think it's probably the mic, but there are some other components between the mic and the radio. Is there some way I can test my electret mic to confirm it's actually the mic before I order a replacement? From what I understand electret microphones need power from a pre-amp.
>
>
>
> This is an old ICOM HS-15 boom mic, with a 3.5mm 3 ring plug.
>
>
>
> Thanks!
>
> Tom

Might try this: http://en.wikipedia.org/wiki/Electret_microphone. May require a little power, (see sidebar circuit) but should be able to use a single battery and run a meter across to see changes as you speak into it.

[Two Shoes (Judson Knowles)]

Also: http://askville.amazon.com/multimeter-microphone-element-works/AnswerViewer.do?requestId=52795258

Good luck. Easiest is to swap with known good to test other items in the system (if available).

[Soartech]

Before bothering to buy a new mic you should carefully check continuity of all wires leading from the mic element to the radio.
Electret mic elements are very reliable and almost never fail. But wires and solder joints do break fairly often.
Chances are (like most electrical failures) there is a broken connection somewhere.

[Two Shoes (Judson Knowles)]

On Wednesday, May 7, 2014 10:48:05 AM UTC-6, Soartech wrote:
> Before bothering to buy a new mic you should carefully check continuity of all wires leading from the mic element to the radio.
>
> Electret mic elements are very reliable and almost never fail. But wires and solder joints do break fairly often.
>
> Chances are (like most electrical failures) there is a broken connection somewhere.

Great point Soartech, I jumped the gun... First things first

[[email protected]]

On Wednesday, May 7, 2014 12:48:05 PM UTC-4, Soartech wrote:
> Before bothering to buy a new mic you should carefully check continuity of all wires leading from the mic element to the radio.
>
> Electret mic elements are very reliable and almost never fail. But wires and solder joints do break fairly often.
>
> Chances are (like most electrical failures) there is a broken connection somewhere.

Yes, tried this, but the set screw holding the mic element case together was corroded, tried to drill it out with no success, so I can't get to the wiring inside the mic.

But I'll give it another shot.

[JS]

Another possibility, now you mention rust:
Condenser microphones are not happy with moisture.
Jim

[[email protected]]

On Wednesday, May 7, 2014 2:14:05 PM UTC-4, JS wrote:
> Another possibility, now you mention rust:
>
> Condenser microphones are not happy with moisture.
>
> Jim

Right I think this may be the issue... the glider was tied out for awhile before a hangar became available. I think the constant Florida heat and humidity killed the mic.

However, I did finally get it opened and the wiring looks intact. I can't get to the actual mic element, it's buried too deeply in the microphone head. However, I did find this great video about testing an electret mic. It's actually pretty easy.

https://www.youtube.com/watch?v=LycH4cXgx7Q