Question about Cobra 18 Wx St Ii Mobile Cb Radio

1 Answer

Radio sticks in TX mode after I let go of the button on the mic

I changed mics, tried three different antennas, sent it back to Cobra twice and they say there is nothing wrong with it. I used my swr meter on it and went to a professional and had him check the swr's.

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  • williamhicks Mar 17, 2009

    Do you have a part number so I can replace it myself. I paid $69.00 dor this unit new and I already spend $36.00 in shipping it back to Cobra Corp. twice.

  • williamhicks Apr 06, 2009

    Do you have the relay part number so I can tell Cobra. The unit is still under a 2 year warranty. Or I can change it myself.



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Hello williamhicks,

There is a relay in side of the cb that might be sticking. The problem is that this situation might be environmental. You say that you sent it back to Cobra twice for repairs. I think that the place you are sending it to differs enough environmentally so that the problem does not manifest itself. You can test this by exposing the unit to different temperatures, to determine if the internal relay is sensitive to variations in temperatures.

If you do find that the relay has become tempurature sensitive, you can order the part from Cobra, or strangly enough from Radio Shack, since they do carry the same part just by a different part.

I hope this helps,

Thank you,


Posted on Mar 11, 2009

  • Henry McKelvey
    Henry McKelvey Apr 07, 2009


    I believe it's a solid state relay, It's been awhile, I tried looking for my copy of the schematic but I could not find it. Call Cobra, give them the model number and they should be able to find the part number for you.

    I hope this helps,

    Thank you,




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