[Hallicrafters] S40A Help


Richard Knoppow 1oldlens1 at ix.netcom.com
Sat May 21 00:21:44 EDT 2011


----- Original Message ----- 
From: "Mike Everette" <radiocompass at yahoo.com>
To: "R Bottomley" <rbottomleysr at dslextreme.com>; 
<hallicrafters at mailman.qth.net>; "Ronald W. Evans" 
<cosmos41 at ix.netcom.com>
Sent: Friday, May 20, 2011 7:18 PM
Subject: Re: [Hallicrafters] S40A Help


>I don't think the dial color is an indicator of S-40 vs 
>S-40A.  I have a Canadian S-40, or at least an S-40 with a 
>Rogers Majestic tag on the back, that has the green dials. 
>And an 80 rectalfire.
>
> I've seen a few S-40 receivers on eVilbay with amber 
> dials, but they are definitely in the minority.
>
> The only difference between the 90 and 5Y3 is the base; 4 
> pins for the 89 vs the octal on the 5Y3.  Unless maybe the 
> early S-40s used a field coil speaker, like their parent 
> S-20R?  My Canadian S-40 has a PM speaker.
>
> Does the Rogers Majestic tag indicate that the radio was 
> actually built in Canada, or merely imported by Rogers 
> Majestic?  I've seen an SX-28 with such a tag as well, but 
> no other models.
>
> I have all 3 S-40 schematics -- S-40, 40A and 40B; and I 
> can't find any obvious difference between the 40 and 40A 
> other than the 80 vs 5Y3.
>
> The schematics came from a CD that I bought on eVilbay a 
> long time ago.  I don't think all 3 -- actually there were 
> 4, because it also included the "mil-spec" original S-40 
> manual -- were on BAMA when I got it; and the scans are 
> better than BAMA.  But I think they are now all on BAMA.
>
> (All Halli's manuals should have been as good as that 
> original S-40 book... oh well.)
>
> The 40B has some definite electrical, and mechanical 
> differences from the earlier models; for one thing, it has 
> one less tube.
>
> The S-40 actually is a reasonably decent radio; except 
> it's broad as a barn door and a little deaf on the upper 
> range especially by the time you get to 10 meters.  A 
> Heathkit QF-1 Q multiplier plugged into the accessory 
> connector on the back really does a lot for its 
> selectivity.  A preselector, maybe an RME DB-23, in front 
> of it would materially boost the sensitivity.  And then 
> you'd have enough knobs to keep you very busy!
>
> 73
>
> Mike
> W4DSE
>
     Check at Nostalgi Air for a Rider's manual for the 
S-40. This manual has schematics for three versions of the 
receiver. The original used a Type 80 rectifier and had a 
field coil speaker using the field coil as a smoothing 
choke. The first revision continued to use the Type-80 but 
with a PM speaker and a 1500 ohm resistor in place of the 
field coil, it also had a revised detector-first AF circuit 
using grid-leak bias for the first audio, the original used 
cathode bias and floated the entire detector circuit at 
cathode level to eliminate distortion. Another variation was 
whether the speaker was connected via a plug. There is a 
Sam's sheet on BAMA but is very similar to the late circuit 
in the above. All use the type 80. Its possible very late 
S-40's used the 5Y3 but I suspect someone changed it. One 
clue may be the way the socket is fastened, it is screwed or 
riveted, the originals were riveted. Of course, its possible 
a careful worker might have riveted a replacement but more 
likely it was mounted with screws.
     Other than the socket and envelope the 80 and 5Y3 are 
identical.


--
Richard Knoppow
Los Angeles
WB6KBL
dickburk at ix.netcom.com 



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