Mic Wiring Question

[Raccoon]

I have a Swan Cubic 100MXA that I'm trying to wire a Cobra (coffin styled) stock mic to . If you're not familiar with the radio , it has the phono jack styled microphone jack . I've tried multiple wiring combinations with no luck .

This mic has 5 wires and their colors are :

Red
White
Shield
Black
Yellow

Obviously Cobra didn't use the usual Red for Transmit , and White for Audio , and Black & Shield for Ground ... because that was the first combination I tried . After that I just started desoldering wires and moving them around from pin to pin with no luck . So to save myself from going crazy & pulling out all of my hair , I decided to see if anyone here might know what the Cobra stock mic color code is , or maybe the wiring code . Thanks

 

[Raccoon]

Did I post this in the wrong section ?

 

[Shadetree Mechanic]

Might have to open the mic and see what color goes to what.

 

[Hurricane145]

Might have to open the mic and see what color goes to what.

It is the only way you can be certain what color of wire is for what.

Other than that you could find the schematic for the Cobra rig the mic came from and then you could tell from the connector what pin is for what, but if you removed the mic connector already you can't because you don't any longer know what wire in the mic goes to what pin.

Another thought is that I would first concentrate on getting the mic to key the transmitter. Then after that is figured out move on to the audio part. Accomplish one part of it at a time.

 

[Dmans]

The information below may help. A DMM is your friend here. You only need to identify 3 wires on your Cobra "Coffin" microphone.

The link is where the info came from.


https://qsl.net/g4wpw/date.html

73
David

 

[sunbulls]

In the first place, the Cobra coffin or any other typical 500 ohm mic is not a good choice for that radio. That Swan needs a HI-Z mic. cartridge. An early HI-Z Johnson or Shure mobile mic will work.

 

[Dr_DX]

Don't go by colors. Mic cord could have been changed. What ever wire the bare copper shield is wrapped around should be the audio wire. Connect it to the Ring of the phono plug.

Using a continuity tester, connect the shield and the other wires. Do any of them have continuity with the mic unkeyed? if so, make note. If no wires have continuity, then the bare shield is not being used for RX\TX switching.

Take the Black wire and test the other 2 remaining wires (not the bare shield or audio wire). One of the wires should have continuity with the mic unkeyed. If you key the mic, and the continuity goes away - that is your RX, (don't use that wire) & the black wire is the common for TX\RX switching.

That should leave you with 1 wire left. To confirm it is the TX wire, there is no continuity between the switching common wire or shield and the remaining wire until the mic is keyed. The Tx wire goes to the Tip of the phono plug.

If the shield was switching common, it solders to the phono plug "body".
If the switching "common" wasn't the shield, then solder it and the shield to the "body" of the phono plug.

Radio takes a high Z mic input. A non amplified D104 with the MC320 cartridge will work very well on that radio too.

 

[Eldorado828]

Don't go by colors. Mic cord could have been changed. What ever wire the bare copper shield is wrapped around should be the audio wire. Connect it to the Ring of the phono plug.

Using a continuity tester, connect the shield and the other wires. Do any of them have continuity with the mic unkeyed? if so, make note. If no wires have continuity, then the bare shield is not being used for RX\TX switching.

Take the Black wire and test the other 2 remaining wires (not the bare shield or audio wire). One of the wires should have continuity with the mic unkeyed. If you key the mic, and the continuity goes away - that is your RX, (don't use that wire) & the black wire is the common for TX\RX switching.

That should leave you with 1 wire left. To confirm it is the TX wire, there is no continuity between the switching common wire or shield and the remaining wire until the mic is keyed. The Tx wire goes to the Tip of the phono plug.

If the shield was switching common, it solders to the phono plug "body".
If the switching "common" wasn't the shield, then solder it and the shield to the "body" of the phono plug.

Radio takes a high Z mic input. A non amplified D104 with the MC320 cartridge will work very well on that radio too.

Excellent explanation, makes it so si.ple a caveman can do it!