[Boatanchors] CG-512

[Carl]

How did you magically find the full primary?

You just have to love these people that enjoy sending private emails 
instead of actually contributing to the group knowledge.

http://www.federalpacific.com/university/transbasics/chapter2.html

Carl
KM1H


----- Original Message ----- 
From: "Barrie Smith" <barrie at centric.net>
To: <WA5CAB at cs.com>; <km1h at jeremy.mv.com>; <boatanchors at mailman.qth.net>
Sent: Sunday, January 11, 2009 1:18 PM
Subject: Re: [Boatanchors] CG-512


Okay, I had a 12 volt transformer on the bench, so I hooked it to one 
secondary winding.  I measured 13.3 volts in, and 5.23 out.

This was using all of the primary, which an off-list person told me 
would be the 500 ohm input.

I don't really know what to do with these numbers now.

Any help appreciated.

73, Barrie, W7ALW
----- Original Message ----- 
  From: WA5CAB at cs.com
  To: barrie at centric.net ; km1h at jeremy.mv.com ; 
boatanchors at mailman.qth.net
  Sent: Saturday, January 10, 2009 6:19 PM
  Subject: Re: [Boatanchors] CG-512


  Barrie,

  I agree with Carl.  Assuming the primary impedance choices are 50, 200 
and 500 as stated previously, I can't come up with a logical scenario 
that matches the resistance readings.  The secondary does.  Or least it 
seems to.  Assuming the two windings have the same number of turns, the 
higher resistance of one could be explained by it being the outer 
winding.  It would have a longer mean turn length and therefore higher 
resistance.  The "F" markings probably stand for Filament.  If you were 
using it with a zero balance tube, you would connect one to each side of 
the modulator tube filaments and use a center tapped filament 
transformer.  But with the 100TH's you'll probably have to use fixed 
bias so tie the two together as you said earlier.

  One way in which to reverse-engineer the primaries would be to attach 
a variac to one of the secondaries and measure the AC on the primaries. 
That will give you the turns ratios.  Square that for the impedance 
ratios and then see whether you can figure a combination that comes out 
in the ratio 50/200/500 or near to that.

  In a message dated 1/10/2009 7:03:49 PM Central Standard Time, 
barrie at centric.net writes:

    >About all I can find is that the specs are the same as the PA-512 
which
    >is the standard version of yours. Still no connection info. However 
that
    >model was around for several decades going back into the 30's.
    >
    >Perhaps Bunker of Doom has one catalog with info.  Or look in old
    >Handbooks, thats a fairly standard line to PP grids item.
    >
    >Those measurements make no sense.
    >
    >Carl

    Carl:

    I just checked the resistances again using a different meter.  Same 
results.

    Could I have a defective transformer?

    73, Barrie, W7ALW



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