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.
73
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.
73
