[Collins] Seeking 75S-3B T7 audio output transformer.

[Dr. Gerald N. Johnson]

On Sun, 2009-02-22 at 22:28 -0500, Kim Herron wrote:
> You have another alternative here if need be.  Contact Phil at Heyboer
> Transformer in Grand Haven MI. Check the website for contact info.  They can
> build them if you have the specs, and the manual should give it to you.
> They are always looking for this type of stuff.  You might also contact Jeff
> Weinberg of Harbach Electronics.  He might have a lead as well. 
> 
> Kim Herron W8ZV 
> www.goldenradioservice.com
> kim.herron at sbcglobal.net
> 1-616-677-3706
> 
Another source to check. Harbach has Peter W. Dahl's name and formulas
and some time ago PWD wanted $125 for that transformer. But Harbach does
not show the audio output transformer on their current price list, but
they do show it in their catalog of possibilities.

> COLLINS 75S-3B AUDIO OUTPUT P/N 667-0302-00
> CORE) EI-050 X .5 STYLE #) 01 E-I LAMINATED CORE
> PR) 70 VAC 100-3000 HZ 2500 OHMS (PLATE-B+)
> S1) 0-2.8-31.3 VAC, 4/500 OHMS @ 1.9 WATTS
> DM) HT = 1.393 WT = 1.705 DT = 1.200 MD = 0.000 MW = 2.000 WEIGHT) LBS
> 
As far as I know, I don't need one. Jefferis needs one and searching the 
internet with google found mostly unanswered requests.

There are several ways to solve the need from using two stock transformers 
to modifying the windings on a readily available ($12.63) power transformer
to rewinding from the remains, to acquiring the materials and winding from 
scratch. I'm sure Hammond, Harbach, or Heyboer can wind from scratch cheaper
than I can, but their price may not get decent until they wind them in 
quantity. So I'm exploring a little to see what there might be for a market
to be supplied by a one man shop, as a retirement business.

-- 
73, Jerry, K0CQ, Technical Advisor to the CRA
All content copyright Dr. Gerald N. Johnson, electrical engineer