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Cobra 25 LTD Repair

Discussion in 'General CB Services Discussion' started by Happy_Hamer, Jul 14, 2008.

  1. Happy_Hamer

    Happy_Hamer Administrator Staff Member

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    I bought a nice looking Cobra 25 at a garage sale.

    It powers up nicely, when I connect the mic I get a rapid and loud thud thud thud thud coming over the speaker. I thought it was the mic so I tried 4 other Cobra mics and same thing, as soon as a mic is connected the noise starts. Hooked it up to 2 other power sources and still the same thing.

    Anyone ever encounter this?



    Any thoughts where to start?
     
    #1
  2. Happy_Hamer

    Happy_Hamer Administrator Staff Member

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    Anyone?
     
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  3. pathfinder259

    pathfinder259 Member

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    Could be a shorted audio chip.Have you did a p.a. test??Is the signal meter
    detecting signal??I know you will not be able to hear the receive audio
    without the mic connected.But you can put the radio on say channel 19
    and see if the signal meter is detecting signal..Also as i say do a p.a. test..
    Put the radio in p.a. mode.Plug an external speaker into the p.a. jack
    Then connect your mic.Then plug your mic in,and see if you are getting
    audio through the p.a. stage.This test will tell you if the audio chip
    is functioning properly.If when you plug the mic in.In the p.a. mode,You
    get the same loud thudding sound through speaker.Then you probably
    have a shorted audio chip..Or it could be one of the large elect. caps
    beside the audio chip..The audio chip will be the 10 legged i.c. bolted
    to the right side of the chassis rail.Radio facing you,component side up.
    The audio i.c. part number is TA-7222AP
     
    #3
  4. Switch Kit

    Switch Kit Active Member

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    what 259 said, tell us more. I'd like to hear that rapid thud thud thud , Good luck Hamer
     
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  5. RUDEDOG369

    RUDEDOG369 Member

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    NOISE

    I HAD THE SAME THING HAPPEN WITH A DAK9 IF THE RADIO IS QUIET WHEN YOU UNPLUG THE MIC IT PROBALY NEEDS TO BE WIRED FOR MIC,OR MIC NEEDS WIRED.
     
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