I am working on a Stewart Warner model 525 battery radio. I am ready to replace the interstage transformers and have a question about the detector tube.
If you look at the schematic it shows the grid leak resistor connected to the +A side of the filament supply and not to ground, this would provide a low positive voltage to the grid.
The tube layout shows the detector tube to be a 00A, a gas type tube.
My question is if a 01A tube will work in this location?
Thank you,
Mitch
Yes the detector grid should be biased toward positive filament pin. This is opposite of other stages in a radio.
An 01A will work in place of 00A, No changes necessary. If you decide to try 00A set plate voltage very low. Gas tubes will ionize and stop operating with high plate voltage.
Norm
:Hello everyone,
:
:I am working on a Stewart Warner model 525 battery radio. I am ready to replace the interstage transformers and have a question about the detector tube.
:
:If you look at the schematic it shows the grid leak resistor connected to the +A side of the filament supply and not to ground, this would provide a low positive voltage to the grid.
:
:The tube layout shows the detector tube to be a 00A, a gas type tube.
:
:My question is if a 01A tube will work in this location?
:
:Thank you,
:
:Mitch
:
I had to be sure as i have been trying to get the radio to play with Warrens help. The radio is not passing RF and i thought it might have been the detector tube design.
Mitch
Have you checked continuity of the audio interstage transformers? They are sometimes open. Do you have a signal up to the detector?
Norm
::Hi Mitch
::
:: Yes the detector grid should be biased toward positive filament pin. This is opposite of other stages in a radio.
::
:: An 01A will work in place of 00A, No changes necessary. If you decide to try 00A set plate voltage very low. Gas tubes will ionize and stop operating with high plate voltage.
::
::Norm
::
:::Hello everyone,
:::
:::I am working on a Stewart Warner model 525 battery radio. I am ready to replace the interstage transformers and have a question about the detector tube.
:::
:::If you look at the schematic it shows the grid leak resistor connected to the +A side of the filament supply and not to ground, this would provide a low positive voltage to the grid.
:::
:::The tube layout shows the detector tube to be a 00A, a gas type tube.
:::
:::My question is if a 01A tube will work in this location?
:::
:::Thank you,
:::
:::Mitch
:::
::
::
:Thank you Norm,
:
:I had to be sure as i have been trying to get the radio to play with Warrens help. The radio is not passing RF and i thought it might have been the detector tube design.
:
:Mitch
:
I have checked both interstage transformers, one is open. I have changed both of them. Best move. The RF curcuit seems to be dead. I could make the radio work as a crystal type from the grid resistor so I new the radio worked through the AF section.
Now all three grid supression resistors were open in the RF section. I replaced them with 810 ohm 1/2 watt resistors.
The battery eliminator connections were correct.
The radio is now playing correctly.
Warren has helped me reach this success through his advice and constant support.
Thanks to all on this site,
Mitch