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Revisiting the 20
#5

Patrick 
Yes it would be nice to separate the dual pots for testing. Tune in a station and listen whilest turning separate controls. 

And you could do the three card monte with the 24 tubes. 

What Radioroslyn said the bias section of the pot can't lower the gain enough to mute the radio. So the 5k section of the pot attenuates the input signal from the antenna at the same time. You should be able to measure the 5k pot between the chassis ground and the antenna connector. Don't forget to turn the pot while measuring. 

On the other part try watching the bias voltage to see if it changes smoothly or full of glitches. 

You could sneak in a germanium diode in and make an AVC control. 

I just got the part about cross wired the pots so one is going up while the other is going down. Yea they need to work together.

!!!!!!!!!!!!!!!!!!!RESISTANCE IS FUTILE!!!!!!!!!!!!!!!!!!!!!!  
                           /\/\/\/\/\/\/\/\/\
                                                     
                                 [Image: http://philcoradio.com/phorum/images/smi...on_eek.gif]  Chris


Messages In This Thread
Revisiting the 20 - by Patrick - 05-13-2021, 02:48 PM
RE: Revisiting the 20 - by Radioroslyn - 05-13-2021, 04:50 PM
RE: Revisiting the 20 - by Steve Davis - 05-13-2021, 09:37 PM
RE: Revisiting the 20 - by morzh - 05-13-2021, 11:32 PM
RE: Revisiting the 20 - by OZ4 - 05-13-2021, 11:36 PM
RE: Revisiting the 20 - by morzh - 05-13-2021, 11:46 PM
RE: Revisiting the 20 - by OZ4 - 05-13-2021, 11:58 PM
RE: Revisiting the 20 - by morzh - 05-14-2021, 12:18 AM
RE: Revisiting the 20 - by OZ4 - 05-14-2021, 12:29 AM
RE: Revisiting the 20 - by OZ4 - 05-14-2021, 01:05 AM
RE: Revisiting the 20 - by Patrick - 05-14-2021, 05:33 AM
RE: Revisiting the 20 - by morzh - 05-14-2021, 10:25 AM
RE: Revisiting the 20 - by Patrick - 05-14-2021, 10:37 AM
RE: Revisiting the 20 - by radio1 - 05-14-2021, 08:16 PM



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