[Boatanchors] CG-512

[Barrie Smith]

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



  Robert & Susan Downs - Houston
  wa5cab dot com (Web Store)
  MVPA 9480 
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