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cobra 29 low dead key

Discussion in 'General CB Services Discussion' started by fnkycoldmedina, Aug 7, 2007.

  1. fnkycoldmedina Well-Known Member

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    a friend brought this front mic cobra 29 over for me to buy .befor i buy it i need to find out what was done and reverse it .this radio only keys 2 watts and i need more .swings 16 or so but the key is too low for me .looking inside i see something that doesnt look factory on d17.....one leg of the diode was lifted and a resistor added to it .could this be the low key problem?thats all i see on that side .lets look on the solder side now.there is a black wire jumper going from the ground leg of l21(a dual core double can)to the leg of c105...whats this?is it there from factory?anybody got a picture of the solder side of a front mic 29?if you do send to "joe3857@aol.com"same goes for the component side if you have ,thanks.


     
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  2. fnkycoldmedina Well-Known Member

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    i went ahead and removed the resistor added to d17 but this did not bring the dead key back up.this radio has been clipped as well and even though it has you must speak into the power mic pretty loud to get it to swing.it sounds loud over my monitor radio and the talkback but being clipped you should get full swing with a whisper.this radio has 1969 final too.
     
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  3. Master Chief Guest

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    Generally, you want a low dead key and swing up from there. Why do you need a higher dead key?
     
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  4. sounds like the radio was set up to drive a texas star 2 or 4 pill or something with similar drive requirements .or maybe a larger amp with a built in driver .
     
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  5. Switch Kit Active Member

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    He just wants a tuned radio ,which a 29 should do roughly 5 to 6 watt DK with anywhere from 20 to 30 watt pep swing ,especially if this radio carriers a 1969 final. (Even though there's a little more to it then just adding the 1969 to this radio.) What it sounds like he has here is a hack job which he would like to put back as close as he can get to normal operations. There's also NO need for the audio limitier in this radio to be clipped !! VR 4 should adjust to all the audio one would need on these radios. The low dead key "should already" give this radio off the scale audio as long as vr 4 has not been adjusted , (he said he was having problems with the audio as well) he is saying that the DK can not be adjusted from the 2 watts , this means there's something inline that is locking the DK in place ? kind of like a swing kit mod that will also lock the DK in place but yet still give the pep swing from the lower DK , from what FNKY is trying to say here , there are many variables to look at to figure out what's really going on with this radio.For me , they are sometimes easier to figure out what somebody else has done to a radio when the radio is in front me , and even then , I couldn't promise you anything. :oops:
     
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  6. fnkycoldmedina Well-Known Member

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    MC...i want to run this in my work van as a barefoot radio.thats why i need more than 2 watts.any good 29 should do 5-6 watt key.theres something done in here that isnt obvious to my eye .where should i start looking?if i cant figure this out i,ll either give it back or offer it for sale ..its a number 8 earnhart radio by the way......hhhmmm.....any takers ?
     
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  7. KC2OST BANNED

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    Is there a cap and resistor on jp36? (by the final)

    If so, remove it and replace the jumper.
    They usually put the resistor on the back of the board.
     
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  8. freecell BANNED

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    "He just wants a tuned radio ,which a 29 should do roughly 5 to 6 watt DK with anywhere from 20 to 30 watt pep swing ,especially if this radio carriers a 1969 final."

    if you're only getting 5 - 6 watts out of a 1969 in a 29 then you have a large degree of mismatch between both the output of the driver transistor (2314 or 1957) and the 1969 input and additional mismatch in the tank output of the 1969.
     
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  9. fnkycoldmedina Well-Known Member

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    after getting a on the air report this radio will have to go back to its owner.it sounds bad ..even sounds off freq they said,but here on my monitor radio it says its on freq.something is amis in this radio.i wont even offer it for sale .back to the owner it goes.there was nothing on jp36 either.like i said nothing my eye could pick out and ive seen the insides of alot of 29`s.oh well nothing lost nothing gained.thanks anyway guys ....
     
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  10. lords Active Member

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    there is a resistor mod some do to it...you need to check to see if that is done( don't know off hand will check notes if needed)
    and sounds like the driver or pre driver transistors are screwed..
    the coil shouldn't be jumped...did you see if there was a variable
    on it...or the coils in the back messed with?
    theres a lot more then meets the eye on a 29 :)
    P.S. most that put a swing mod in it change d17 diode to a 4001 or better...
     
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  11. KC2OST BANNED

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    Never heard of that one.
     
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