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Cobra 29 ltd classic staying keyed up?

Discussion in 'CB Radio Modifications' started by 805 california, Mar 21, 2017.

  1. 805 california

    805 california Active Member

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    So I have a 2016 cobra 29 ltd classic and when I turn the radio on it shows 4 watts without keying the mic and the tx/rx light stays green. I key the mic and the tx/rx light turns red and I have good modulation. I release the mic, the light goes back green and I still have 4 watts on the meter. The pa works and I hear static coming from receiver. I tried different mics and a new stock final and same thing. I gave it a good visual and no scorched compenets or anything like that. Any idears? I also tried two different meters. Thanks


     
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  2. nomadradio

    nomadradio Analog Retentive

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    Sure sounds like TR21 has shorted. If pulling it out restores the receiver, good chance it will check bad.

    73
     
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  3. 805 california

    805 california Active Member

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    Yeah I replaced c117 and same thing, then I replaced TR21 and the radio is working like a fine Swiss watch now. Thanks for your help!
     
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  4. Msredneck

    Msredneck New Member

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    Where and how do I buy and replace the TR21
     
  5. nomadradio

    nomadradio Analog Retentive

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    Hmm. Where to buy "just one" 2SA733 transistor?

    I would got to Ebay and type "2SA733" in the search box.

    Everybody else who sells that part will have a minimum order amount.

    Odds are that all the Ebay search hits will be for a quantity of five or more.

    The days when you could walk into a local parts distributor and buy just one transistor are pretty well gone.

    As for how to replace?

    There must be some YouTube vids about replacing a 3-legged transistor in a radio.

    73
     

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