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Flex 6300 Not Keying Amp

After working great for a long time, my Flex isn't keying my KPA500 amp. When I read across the RCA cable coming from TX, I get about 30 ohms and it doesn't change when I key CW.

It's been years, but I remember that TX needs to be enabled in the settings. Looking at the settings, RCA TX is 0. Should I change this to a 1 or is there somewhere else it needs to be enabled?


Steve, W6SDM

Best Answer

  • Alan
    Alan Member ✭✭✭
    Accepted Answer

    Yes. Needs to be set, per band and RCA TX connection, in the "TX Band Settings". Mine is set up for transverters.

    Alan. WA9WUD


  • Steve W6SDM
    Steve W6SDM Member ✭✭


    Strange... all of my TX settings were not checked. I'm not sure how it worked before unless somehow those settings got cleared in software. I re-checked all bands from 160 to 6 meters and now it's keying.

    Also, is settings under TX, RCA TX1 is zero. Should that be a one? Even with a 0 in the box, everything is working now and the amp is keying.

    Thanks for your help!


  • Alan
    Alan Member ✭✭✭

    In the Radio Settings, TX tab, those RCA setting are time delay in milliseconds, for the delay between when you push the MOX (RF out), until the PTT to the amp changes.

    A one millisecond delay would not be noticeable. Some will set the delay more like 30ms when the amplifier must first tune itself, before the PTT closes in.


  • Steve W6SDM
    Steve W6SDM Member ✭✭

    Got it. I am relieved that it wasn't a relay that gave out. I got my Flex 6300 when they first came out and have been using it constantly since then, so it wouldn't surprise me if something did wear out.

    Thanks again,


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