[Boatanchors] Any Experiance with Early Hally S-19R?

[Al Klase]

Dave,

A long time since I worked on the S-19R I used to have.  It worked 
reasonably well, but I do remember that the cheaper Halli's had coils 
that didn't age well.

While the bands 3&4 oscillator coils don't have have adjustable 
padders., they do have fixed padding caps.  The Riders docs here show 
their values:
http://www.nostalgiaair.org/pagesbymodel/892/M0008892.pdf

Perhaps you can cobble compression trimmers on bands 3&4 so you can do 
the old "trim high, pad low" on them.

It may be helpful to take a stick and attach a powdered iron core to one 
end and a piece of brass to the other.  If you stick the iron in the 
coil it will increase it's inductance, while the brass will decrease the 
inductance.  This may help figure out which way you need to go.  
Possible actions would be to modify the coil or install iron or brass 
permanently.

Personally, I'd try to go the variable padder route.

Good luck,
Al

On 9/19/2018 10:10 PM, David Stinson wrote:
> Is anyone here familiar with the early version of
> the Hallicrafters S-19R? It's the one with the
> 6K7G 1st IF, 6Q7 1st Audio and type 41 Audio PA.
> Here is the diagram:
>
> https://photos.app.goo.gl/mAdhuBVZ69hZvZdr9
>
> I'm trying to refurb this thing for an old friend,
> but it's a bear.  Bands 1 and 2 are working well,
> but on 3 and 4 the LO has only one cap to tune and
> they simply cannot be made to track. The mixer
> input tuned circuits don't seem capable of
> tracking, either.  I've had to add capacitance at
> both the LO and Mixer tuned circuits on band 3 to
> get them even close.  Band 1 requires the padding
> cap on the mixer coil to be disconnected and any
> cap across it is "too much."  This is the case
> whether the antenna input as a 50-ohm non-reactive
> service monitor, through a 400-ohm series resistor
> as the manual specifies or a random wire antenna.
> Band 2 sounds good but Band 3 is not only
> "untrackable," but has a problem with images.  The
> IF and BFO are aligned properly.  Someone subbed a
> 37 tube in the BFO for the original 76, and that
> does improve things.  I've also added a coupling
> wire to improve the BFO injection and that did
> work well.  Band 4 seems pretty hopeless; focusing
> on 3 for now.  The design sure could have used an
> antenna trimmer.  And it has a microphonic on
> strong signals which seems to be connected to
> mechanical resonances in the tuning cap because of
> the metal freq dial "ringing" like a bell.
>
> Anyone have some tips on this old Hally?
>
> TNX OM ES 73 DE Dave AB5S
>
>
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-- 
Al Klase – N3FRQ
Jersey City, NJ
http://www.skywaves.ar88.net/