[Hallicrafters] HT-32 to HT-37

[David C. Hallam]

I think the transformer short problem in the HT32/HT37 transmitters is 
primarily related to the HV 5R4 rectifier rather than the 5V4. The HV 
shorts to the transformer steel through the 5R4 filament winding.  
That's not to say that the 5V4 could not fail and cause a problem.

David
KW4DH


On 10/1/2012 3:26 PM, K4PRF, B. L. Pratt wrote:
> Lesson learned the hard way.  If you have one of these fine transmitters
> and if it is still using the 5V4 low voltage rectifier, your power
> transformer is in danger.  If I remember correctly the problem is caused
> by a cathode to plate short in the 5V4 which opens the high voltage
> winding in the PT.  These transformers are very hard to find and
> expensive if you can find one.  I purchased a beautiful HT-32A several
> years back knowing that the PT was bad.  I was able to order a
> replacement PT from the Peter Dahl Co.  Expensive but a perfect
> replacement and runs very cool.  I replaced that 5V4 with a 5R4 in this
> and my HT-37.  I am told that those 5V4s have killed many a transformer
> and some call it a "death tube."  You might while you are in there
> replace the selenium bias rectifier with a silicon rectifier.  There
> have been many articles dealing with these modifications on the HT-32s
> and HT-37s.
>
> Burt  K4PRF
>
>
> ______________________________________________________________
> Hallicrafters mailing list
> Home: http://mailman.qth.net/mailman/listinfo/hallicrafters
> Help: http://mailman.qth.net/mmfaq.htm
> Post: mailto:Hallicrafters at mailman.qth.net
>
> List Administrator: Duane Fischer, W8DBF
> ** For Assistance: dfischer at usol.com **
>
>
> This list hosted by: http://www.qsl.net
> Please help support this email list: http://www.qsl.net/donate.html
>

-- 
A democratic government is the only one in which those who vote for a tax can escape the obligation to pay it.
Alexis de Tocqueville