Cobra 29 NW LTD

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turbo
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Cobra 29 NW LTD

Post by turbo » Sunday 2nd Dec 2007, 4:49

Radio has no audio on TX . 4 watt dead key , RX is fine , Mic is good .PA dose not work . what could this be ? has any one seen this problem before?

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Rick
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Re: No TX audio Cobra 29 NW LTD.

Post by Rick » Sunday 2nd Dec 2007, 6:29

You should have more than .4 watt so check D8 it sounds like its open circuit. You may also have a bad driver and or final TR15 and TR14

These radios are known to have trouble with cold solder joints, so maybe a good idea re-solder around audio amp and output stage.
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Post by RedEye » Sunday 2nd Dec 2007, 10:51

Was that .4 watt or was it supposed to be four watt deak key? I can't tell if that is a period for the previous sentence or not....

If you meant the radio has a Four Watt dead key with no audio or PA audio,

If RX is ok, but no PA or modulation, possibly the mic or mic input circuit?

turbo
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Post by turbo » Sunday 2nd Dec 2007, 12:08

Yes , that is a typo . should read four watts . Finals appear to be good . tested on a dosy test center . Also radio makes correct frequency per channel .

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Rick
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Re: No audio Cobra 29 NW LTD.

Post by Rick » Sunday 2nd Dec 2007, 12:22

Sorry I read as 0.4 of a watt and PA working well in that case change the audio chip.
Rick.

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frogman296
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Re: No audio Cobra 29 NW LTD.

Post by frogman296 » Sunday 2nd Dec 2007, 20:05

Rick wrote: change the audio chip.
what he said...seems as though a pile of the newer style 29's have that issue

turbo
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Cobra 29 nw ltd

Post by turbo » Saturday 15th Dec 2007, 13:06

well every one , you all were wrong . This what was finaly found . The pot on the dynamike was broke , after changing the ta7222 it still had the same symtom . Now working fine . this concludes this repair 8)

James Unit 198
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Post by James Unit 198 » Saturday 15th Dec 2007, 21:10

before i would have asking any question i would check that all the controls and switches was working a ok. the first post was not very good.
Radio has no audio on TX . 4 watt dead key , RX is fine , Mic is good .PA dose not work . what could this be ? has any one seen this problem before?

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Min
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Re: Cobra 29 nw ltd

Post by Min » Sunday 16th Dec 2007, 13:59

turbo wrote:well every one , you all were wrong . This what was finaly found . The pot on the dynamike was broke , after changing the ta7222 it still had the same symtom . Now working fine . this concludes this repair 8)

And thanks to you too

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