11-21-2021, 12:52 PM
Steve,
Thank you for responding.
I did not attempt to operate the radio in its "as is" state. It had been "restored" by someone but they did a very poor, sloppy job and I opted to not even try it.
I have done this octal conversion before, on a 38-14, and had no issues whatsoever.
Just for fun, I tried different capacitors in parallel with the oscillator section of the tuning capacitor. Using a 150 pF put me in the ballpark as far as getting the tracking correct is concerned. 180pF also worked but was a bit too much. This is why I was thinking perhaps something about the oscillator coil's characteristics has changed.
I'm baking the oscillator coil now, and I may try a different 12A8GT. I currently have a tested used tube in that socket. i do have a few NOS 12A8GTs. As you say, the characteristics of both it and the 6A7 are very similar.
Thank you for responding.
I did not attempt to operate the radio in its "as is" state. It had been "restored" by someone but they did a very poor, sloppy job and I opted to not even try it.
I have done this octal conversion before, on a 38-14, and had no issues whatsoever.
Just for fun, I tried different capacitors in parallel with the oscillator section of the tuning capacitor. Using a 150 pF put me in the ballpark as far as getting the tracking correct is concerned. 180pF also worked but was a bit too much. This is why I was thinking perhaps something about the oscillator coil's characteristics has changed.
I'm baking the oscillator coil now, and I may try a different 12A8GT. I currently have a tested used tube in that socket. i do have a few NOS 12A8GTs. As you say, the characteristics of both it and the 6A7 are very similar.
--
Ron Ramirez
Ferdinand IN
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