Ameritron AL-572 Dead

Discussion in 'Amateur Radio Amplifiers' started by KA1KA, Apr 26, 2021.

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  1. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

  2. KA1KA

    KA1KA XML Subscriber QRZ Page

    Haha... mee too!!!
  3. G3YRO

    G3YRO Ham Member QRZ Page

    Glad that's all it was ! Nice simple fix. (unlike replacing the relay, which as I mentioned is a common failure, but an awful job on these Amps)

    However, I would still be wondering WHY the choke arced between windings . . . not a very common fault on any Linear Amplifier.

    Roger G3YRO
  4. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    The HV RF choke has a known resonance around 10 MHz, which is why it shouldn't be used on 30 meters (our power limit by regulation here would prohibit its use on 30m anyway).

    But I'm amazed the input circuit did not exhibit a terrible mismatch on 30m with the band switch set to 40m, as it's a low-pass network; the mismatch should have been pretty bad, causing the transmitter to deliver very little drive power.

    But "it happened," I guess.:p The choke was the weak link.

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