Bearcat 300 scanner no display, has audio and squelch repair

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  • CapLeaker
    Leaking Member
    • Dec 2014
    • 7990
    • Canada

    #1

    Bearcat 300 scanner no display, has audio and squelch repair

    I found an old Bearcat 300 scanner that had no display, but the audio and squelch worked, over at my workplace. This unit has a lot of hours on it. It had some capacitor replacements and other mods done to it too before I found it. To troubleshoot this problem, the usual is to check the +25v and -30V and replace C98 on the main board. That should fix it. There is also a case of a shorted button board (just unplug that ribbon cable and the display should work again). Spoiler alert! Was not the case on this one.

    My display didn't work, because I had a missing -10V on the display board measured at C215 (page 4, far right, where the T201 transformer is).
    Replaced C211 22uF 16V capacitor with a new one and voila, the old BC300 is going to do another round!
    Another easy scanner fix!
    Attached Files
  • stj
    Great Sage 齊天大聖
    • Dec 2009
    • 30934
    • Albion

    #2
    a bit dated now lots of stuff is digital.
    i got a dm1701 from ali for $40 equiv and flashed it with OpenGD77
    it scans pretty fast - much faster than analog baofeng's
    and it will open DMR streams without knowing the CC,TG etc!

    Comment

    • CapLeaker
      Leaking Member
      • Dec 2014
      • 7990
      • Canada

      #3
      Originally posted by stj
      a bit dated now lots of stuff is digital.
      i got a dm1701 from ali for $40 equiv and flashed it with OpenGD77
      it scans pretty fast - much faster than analog baofeng's
      and it will open DMR streams without knowing the CC,TG etc!
      Of course there is newer better stuff. But all it does is monitoring Aircraft AM band. This fix cost zero dollars and scrunched up that capacitor from the junk pile.
      I think my newest radio is already 12 years old. Maybe I should look into getting some new stuff again.

      Comment

      • stj
        Great Sage 齊天大聖
        • Dec 2009
        • 30934
        • Albion

        #4
        airband is mostly dead in europe now,
        the planes are using some type of digital text messaging that has pre-defined messages.
        the pilot just presses one button to send a message - dumbing it down for some reason.
        only private light aircraft still use voice.

        Comment

        • CapLeaker
          Leaking Member
          • Dec 2014
          • 7990
          • Canada

          #5
          Over here are the frequencies are split between low flying and high flying aircraft. It should be like that in Europe too. There is all kinds of AM Air traffic if you know what to look for and if live in a good region to get the signals. Fortunately for me, I got both. My reception is that good, I can hear everything Air band with the Bearcat scanner and it's antenna down, or no antenna and stick my finger in it. How dat possible? Lucky me!

          Comment

          • stj
            Great Sage 齊天大聖
            • Dec 2009
            • 30934
            • Albion

            #6
            i'm near a BIG airport,
            i can get some ground traffic and emergency stuff, but most signals are digital.
            i dont even know the coding or i may be able to decode it.

            Comment

            • CapLeaker
              Leaking Member
              • Dec 2014
              • 7990
              • Canada

              #7
              stj
              So am I. I can hear ground crews, air to tower traffic, Transatlantic flights and US <-> CAN from different sectors high and low checking in, all on AM. On top of that, I can spit on a relay station too.
              I suppose you can also use Liveatc.net and see what they have in your area.

              Comment

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