[Hallicrafters] HT-3x transformers

[Ray, W2EC]

The problem seems to be the sequence of operation of the power switch,
not the transformer itself. When you flip from one mode over to standby
using the power switch, it is VERY easy to pass right thru standby and
into the power off position. The first instinct is to just flip right
back to standby. For whatever reason, this rapid "break/make" of the
power switch applies some inrush stress to the transformer to the point
where it breaks down. I've never looked into the actual cause, but in
checking with different people who have had transformer failures, it
seems to have usually occurred just after one of these "break/make"
episodes. My old HT-32B is still on its original power transformer but I
took GREAT care not to flip the power back on instantly although I have
had occasion where, even knowing better, I passed right thru standby to
power off. The key seems to be to prevent that urge to instantly flip
the power back on.

And I can't help mentioning that I would MUCH prefer to have selected
"Reply To All:" so that this tidbit got to the whole list, as there is
no way to easily reply ONLY to Bob without "cut and past". The whole
purpose of "Reply To:" and "Reply To All:" is to allow the sender to
decide the relevance of the response and who to respond to. By locking
both "Reply To:" and "Reply To All:" into always sending to the list, we
are being told, in effect, we are too dumb to make decisions like this
and they have to be made for us.

73, Ray  W2EC
 

Bob Nickels wrote:
> 
> I've always heard that HT-32 and HT-37s were prone to power transformer failure,
> but I've been lucky.  Can anyone explain what the failure mode is, and why these
> transmitters seem to fail more often than most?
> 
> Is it a good idea to switch from 5R4/5U4 rectifier tubes to solid-state rectifiers
> in order to reduce the overall current drawn from the transformer?
> 
> Thanks and 73,
> Bob W9RAN
> 
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