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Old 14th Nov 2021, 3:13 pm   #2
orbanp1
Heptode
 
Join Date: Nov 2009
Location: London, Ontario, Canada
Posts: 639
Default Re: BC-348-Q. Receiver.

Hi Robert,

The 6SK7 is a remote-cutoff pentode, controlling the screen voltage does control the transconductane of the tube. Look up the data sheet of the tube.
Screen control is generally associated with AGC.

May be they wanted to change the gain of that RF-amplifier stage?
Using a pot there, not as a variable resistor but as a voltage divider, with other resistors, one can implement manual RF-gain adjustment.

I would restore the radio to factory wiring, and then see if it performs as expected.

Your calculations for a separate screen resistor seems to be in the ballpark, in case you want to go that route.

Regards, Peter
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