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RCI 2970 (old style, not DX)

Steve B

Member
Sep 6, 2009
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Trying to troubleshoot problem. No AM audio. Good carrier signal. SSB starts to modulate then pegs meter? Microphone checked as OK.

Any help appreciated! Steve B
 

Check the 2SB754 regulator transistor that's mounted behind the audio chip. It'll be labelled B754. If you have no AM audio, but have a deadkey, it's possible this regulator transistor has gone fault. If memory serves me right, I think it does also affect SSB too. Let us know how you get on.

Oh, if the radio has a "swing" or "NPC" mod done to it, have it removed. These mods can potentially damage this transistor.

Good luck!
 


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  • @ Geoexplorer69:
    Coax question. I just put up a new Sirio monsoon base antenna with 100’ of rg8u coax testing with myMFJ antenna analyzer shows 1.4 swr at 26.965mhz and a 1.1 at 27.405 mhz . When I checked the ohms it’s steady a 30 ohms across the entire bandwidth.
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    Is 30 ohms worth worrying about in a 100’ run of rg8u ?


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