Cb microphone don't work correctly

I believe to wire a Sadelta M3 microphone to a Cobra 29 LTD Classic CB radio:

The Sadelta M3 microphone has four wires: white, shield (bare wire), red, and black. The Cobra 29 LTD Classic CB radio's microphone jack also has four pins: Pin 1 (Audio), Pin 2 (Ground), Pin 3 (Transmit), and Pin 4 (Receive).

To wire the Sadelta M3 to the Cobra 29 LTD Classic, you need to connect each wire from the microphone to its corresponding pin on the microphone jack. The white wire carries the audio signal from the microphone's element to the radio, the shield wire provides a ground connection, the red wire activates the radio's transmit function when the microphone is keyed, and the black wire is used for receive audio.
Here are the specific steps to follow:

1. Cut off the existing microphone plug on the Sadelta M3 microphone cord.
2. Strip about 1/4 inch of insulation from each of the four wires in the Sadelta M3 microphone cord.
3. Connect the wires to the pins on the microphone jack as follows:

• White wire to Pin 1 (Audio)
• Shield (bare wire) to Pin 2 (Ground)
• Red wire to Pin 3 (Transmit)
• Black wire to Pin 4 (Receive)

1. Solder each wire to its corresponding pin on the microphone jack. You may want to use a multimeter to verify that each connection is solid and that there are no shorts or open circuits.
2. Once you have soldered all the wires, test the microphone by speaking into it and checking that the radio's TX meter moves as you speak. Also, check that you can hear audio through the radio's speaker when receiving signals.
3. If the microphone is working correctly, use heat shrink tubing or electrical tape to cover the soldered connections and provide strain relief for the wires.

Note that some microphones, including the Sadelta M3, may have additional features such as a built-in amplifier or power supply that require additional wiring.

It might not seem obvious but on many, if not all, current CB radios have separate wires coming from the microphone for RX and TX. It seems like the mic wire for TRANSMIT may be open. It is a common failure.

very easy,replace the diode you just burnt and hook your power up correctly and you should have no problem.

you have a wire crossed or a cold solder.

Check first your microphone

• check if TX is engaging when PTT is pushed.


• check for continuity ( mic and cable )



If you have not done these steps,

try it first, or borrow other compatible mic for Cobra 148GTL

from your friends on air.

A great mic is the RK56 $39.99+tax in Temple, TX on Hwy 95.. And comes with a 4pin for cobras but can be wired for any radio

is this same antenna as before. you should always check the SWR's to see if set correctly.. other than that. bad grounds, bad microphone can make any radio squeal..

Hi there,

It sounds like a microphone problem! I am a C.B. & Ham radio Tech. Try changing the microphone to another one and make sure the Microphone is the right one for the radio. If the microphone is not the right one for the radio it will not work right or when you plug it in it will automatically key up and transmit and the red TX light will come on and it will try to transmit somthing and that would be the thumping everyone hears!! Try that first and let me know if you have any other questions then you can E-mail me at [email protected]

Dennis

Hi dstrand, sorry you are having a problem. I will need some more info if you can. Is this radio in a base situation or mobile? Have you had any work don recently? Have you changed anything on the system? (Microphone, antenna, coax, etc)

Haave you checked your swr recently/ If yes, did you use a seperate meter or did you use one built in the radio?

Hope to hear from you soon.

Tom

Hello Darren, Yes it sounds like the mic is wired bass ackwards,,! A cobra 25 mic wiring is
PIN #1- Shield or ground wire
PIN#2- Audio or Transmit modulation
PIN #3- Transmit or Dead Key
PIN #4- Receive Audio.
When your keying the mic, the RX wires are being connected to make the RX work,,,
*** Let me know how you get along with it. Either buy a new mic wired for your radio or you or someone comfortable with soldering needs to resolder the correct wires back on the mic plug,,,Like I said, let me know and have a great day,, Mechanic is back quiet!