[Boatanchors] CG-512

[Barrie Smith]

----- Original Message ----- 
From: "Carl" <km1h at jeremy.mv.com>
To: "Barrie Smith" <barrie at centric.net>; <WA5CAB at cs.com>; 
<boatanchors at mailman.qth.net>
Sent: Sunday, January 11, 2009 4:57 PM
Subject: Re: [Boatanchors] CG-512


> How did you magically find the full primary?

He sent me a copy of an exchange on the AMFone mail list from 1998.

I don't know who he is.  I tried to respond to his mail, but it came back as 
undeliverable.
>
> You just have to love these people that enjoy sending private emails 
> instead of actually contributing to the group knowledge.

That is a problem.

Anyway, if the resistance numbers I came up with don't make sense, what 
about the voltage readings?

73, Barrie, W7ALW
>
> 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
>
>
>
>  Robert & Susan Downs - Houston
>  wa5cab dot com (Web Store)
>  MVPA 9480
>
>