09-11-2016, 07:48 PM
All voltages look ok. Bear in mind that tube equipment isn't like transistor gear in that the difference of a 1/2 volt can cause problems. Tube gear is much more forgiving. The measurement made back in '31 where made with a meter that loads the circuit a bit like 1000 ohms between the probes. Your modern meter meter is in the order of 20meg ohms.
The SG voltage on the mixer is unknown as you changed the value of #9. The voltages around the 2nd det are unknown as they don't tell you if they are with the detector is oscillating. According to the tube manual -16v is just dandy for the 42's control grid w/250v on the plate. 4.5v seems pretty low and would cause the 42 to draw more plate current than necessary. It is also possible that your 36 tube has low emission causing not enough current to be drawn though the high value resistors in the circuit. This can be the cause of having the higher voltage readings around the 2nd detector.
In your comments you didn't say of it is working? Is it??
The SG voltage on the mixer is unknown as you changed the value of #9. The voltages around the 2nd det are unknown as they don't tell you if they are with the detector is oscillating. According to the tube manual -16v is just dandy for the 42's control grid w/250v on the plate. 4.5v seems pretty low and would cause the 42 to draw more plate current than necessary. It is also possible that your 36 tube has low emission causing not enough current to be drawn though the high value resistors in the circuit. This can be the cause of having the higher voltage readings around the 2nd detector.
In your comments you didn't say of it is working? Is it??
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got it!
Terry
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