Steve, I would try leaving the mod. Floating 10 ohms from ground is not much different from 0 ohms, and direct coupling of caps is not much of a change. It may add a little sensitivity but may introduce a little bit of ¡°squeaky¡±. Try it.
Albert
Hallicrafters Rehabs
On Sunday, September 18, 2022, 9:20 PM, Steven Reed via groups.io <reedsteve@...> wrote:
Glad to have found this group!
I've got an S-40 on the bench -- a restoration project for a friend. ?The receiver belonged to his grandfather (who was licensed), then was passed on to him. ?For the most part, the receiver appears to be all factory, which is always helpful. ?However, his grandfather had been into the radio, and I've found a circuit alteration on V-2 that I'm uncertain about. ?This is a 2nd revision model of the S-40, by the way. ?
The attached schematic shows V-2 and the area around it as originally designed by Hallicrafters. ?Have a look at pin 5 (grid #1) -- the alteration I'm seeing is off of there. ?Here are the changes:
- R30 (10 ohms) is eliminated
- C16 connects directly from pin 5 to S/IF
- C26 connects directly from pin 5 to ground
So, the modification puts three connections on pin 5 -- R7 to ground, C26 to ground, and C16 to S/IF.
Before deciding whether to revert this back to factory, I'm curious as to why this might have been done. ?I've searched online and can't find this modification anywhere. ?
73 - Steve, KW4H
