[Hallicrafters] HT-3x transformers

[Ray, W2EC]

Hi Bob,

It is certainly reasonable to expect that if the driver stages are out
of alignment, it could affect the output. First though, double check the
actual voltages of the final stage under load, and also check the
current draw. Determine what the actual power input of the final amp is.
Then compare it to the output power and see what kind of efficiency you
are getting. If real low, then it's probably in the final stage, maybe
soft tubes, leaky caps etc. 

As for alignment difficulty, as I recall (years ago so this is subject
to brain fade) the critical path of the alignment was the SSB/audio
section. I think you can safely and without difficulty align the driver
section to get all the RF stages peaked up without risk of making things
worse instead of better. When it comes to aligning the audio section
(SSB supression, alignment of the oscillator etc) that is where it gets
real critical. But again, this is from many years ago, last time I had
to do anything like that on an HT-32B, so it is subject to loss of
memory :-)

73, Ray  W2EC


Bob Nickels wrote:
> 
> Thanks for the thoughtful replies regarding the HT-32 and HT-37 HV transformer
> ailments.  The best theory seems to be that the increased failure rate is due to
> something unique to the winding method and insulation used, which makes the
> transformer prone to breakdown from the HV winding to the filament winding.  Solid
> state rectifiers allow an transformer with such an internal short to continue to
> be used, but such a replacement should take into account the increase in voltage
> that will occur.
> 
> Another question on these fine old transmitters...
> 
> My HT-32B has low output, and the tubes check good.   My next step was going to be
> a complete alignment, which is fairly complicated and time consuming, but the
> manual warns against doing so unless there is a known problem in these stages.
> So my question is, would it be reasonable to expect "low output" to be caused by
> misalignment?  Or would I be better off looking for a problem in one or more
> stages?
> 
> Thanks and 73,
> Bob W9RAN
> 
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