Lou Franklin's test mic

[2FB327]

I'm trying to make a test mic using a coffin style 4 pin cobra as per Lou's book, understanding and repairing cb radios (page 9).
It states: A test mic with clip leads is very handy. Take a good mic and remove the plug.
Jumper the audio line across the PTT switch so it's always hot.
Cut off the tx/rx switching wires since you won't need them.
Install a clip on the shield and audio wires.

What am I missing here? The PTT is in the head of the mic. Can someone help me out?

 

[222DBFL]

He is saying inside the mic to jump the audio line across the PTT switch. You might need a piece of wire to do this. And the wiring code for a 4 pin cobra is:
So pin 2 wire would get soldered across the PTT switch. Use a piece of wire if needed.
Pin 2 is the white wire. Take a piece of wire and this wire and solder them together then take that wire and solder it across the PTT switch. Does that make sense??
The TX wire pin 3 is the red wire and the RX wire pin 4is the black one. All that is left is the audio out and ground/shield wires. Again, hope this helps.

 

[2FB327]

I think I got it. Open up the mic and solder the audio wire and solder across the PTT.
there are 5 pins on the switch?
The audio(pin 2) is yellow?
I understand that in the end I will have a clip on the shield wire, and a clip on the audio wire.
Just not sure how to make the PTT switch hot, I'll experiment more.

 

[LeapFrog]

I think I got it. Open up the mic and solder the audio wire and solder across the PTT.
there are 5 pins on the switch?
The audio(pin 2) is yellow?
I understand that in the end I will have a clip on the shield wire, and a clip on the audio wire.
Just not sure how to make the PTT switch hot, I'll experiment more.

If you really had to get this going, you honestly could get by with electrical tape wrapped around the mic and keeping the switch pressed in.

222DBFL explained it well, you might have to open the "jack plug" up to see what color wire is at pin 2, or just look at the internals of the mic when it's opened up to find the audio wire.

 

[loosecannon]

i have used a variation on this idea in the past and found it very helpful.

make up the mic plugs like he suggests, except use alligator clips on the wires.

then make up the mic like he says. cut off the RX and TX wires, and only leave the audio wire and it's shield coming out of the cord. solder alligator clips to those wires.

inside the mic you can either move the audio wire to the "receive" side of the switch, or leave it as is, but you will have to key the mic in order to talk into it. jumpering across the switch means that the audio will come through whether the button is pressed or not.

using this setup, you can "key" a radio, or make it receive by jumping alligator clips together.
then you can either inject a tone into the audio and shield wires, or hook your special mic up and send the audio tone through it.

if you make up a cobra 5 pin, a cobra/galaxy 4 pin, a realistic 5 pin DIN, and a ranger 8 pin plug you should be able to cover pretty much any radio that will come across your bench.
(on the cobra 5 pin, be sure to jumper the RX and TX wires to pin 4 which is the RX/TX switching ground, and not pin 2 which is the audio shield)
LC

 

[2FB327]

Thank you.