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Sometimes you just can't trust your lyin' eyes. NCL2000 crock.

Discussion in 'Amplifiers' started by nomadradio, Nov 27, 2018.

  1. nomadradio

    nomadradio Analog Retentive

    Apr 3, 2005
    Likes Received:
    Sometimes you just can't believe your lyin' eyes.

    This resistor should have a green third band, as in "brown-black-green".

    But somebody looked at the old one after it had overheated and burned that green band black.


    Before you replace a resistor with a black third band, consider what color it used to be, especially in tube-type equipment.

    This resistor is in a National NCL-2000 amplifier. It serves to shut the amplifier down in receive mode. One section of the antenna relay shorts across it when the amplifier is keyed, activating the tubes. This 10-ohm part would have caused the tubes to cook along at full idle current on standby and when keyed, both. Sure would have caused it to run hot even if you never keyed it. The correct 1-megohm part blocks the voltage to the screen grids of the tubes, and puts them in standby mode.

    And I probably would not have noticed it if Kopcicle hadn't asked about this section of this model amplifier. I suppose dumb luck is better than bad luck.



  2. Low_Boy

    Low_Boy Well-Known Member

    Jan 21, 2010
    Likes Received:
    Good catch
  3. Handy Andy

    Handy Andy Do Your Research First, Then Decide...

    Apr 23, 2018
    Likes Received:
    Wow! It' literally looks like a 10 ohm OEM part.

    1 Meg eh?

    Good to see you on the job!
    packrat likes this.
  4. kopcicle

    kopcicle Sr. Member

    Feb 17, 2016
    Likes Received:
    ...your welcome. More like even I stumble across something once in a while :ROFLMAO:

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