Re: S-40 Restoration - Oddity around V2
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Steve...
?
It looks like elimination of R30 would increase the Local Oscillator
injection level.? I¡¯m not sure why this would be a good idea?
?
73,
ART
W6REQ
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From: Steven Reed via groups.io
Sent: Sunday, September 18, 2022 6:32 AM
Subject: [HallicraftersRadios] S-40 Restoration - Oddity around
V2
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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
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C16 connects directly from pin 5 to S/IF
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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
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