[Hallicrafters] SX28 power transformer

[Roy Morgan]

At 04:07 PM 7/28/2005, Todd, KA1KAQ wrote:
...SX28) has been in damp location basement storage for some time,
> > not my basement, and was brought back to life in > stages.

<Soap Box Mode ON>

If "brought back to life n stages" means "bringing it up slowly on a 
vairac" that was your mistake.  That killed the transformer and did not 
bring it back to life.

>  It was receiving CW on 80 at 65 volts. Maybe I
> > should have let it cook at low voltage for a few days.

No.  You should have dried out the transformer and reformed/replaced the 
filter caps and replaced leaky coupling caps first.

> >   Or maybe the transformer was just ready to pack up.

Nope. What you did killed it.

>Most folks don't give it a thought, but transformers will suck up
>moisture like a sponge if left unused for an extended period of time -

True.

>  If the radio has lead a sheltered life... it's not likely to be a problem.
>Anything beyond that is a roll of the dice to just plug - n - play,
>though.

Roll dice.  Get lucky.  Receive a replacement transformer from a Good Guy.
Are you going to blow out the new transformer by doing the same thing to it?

>  It's generally not practical to set the entire rig in the oven
>with its plastic dials, escutcheons, and whatever else. It's
><generally> not a big job to remove the iron and bake it for a while,
>and well worth the effort.

It's also not a big job to arrange a couple of lamps shining directly on 
the transformer to bring it's temperature up to dry-out level.  Ordinary 
desk lamps with 60 watt bulbs work fine.

>Once you get the new power transformer installed and working, pay
>special attention to the audio section before you go much further.

If you have not replaced the coupling caps from the audio driver to the 
audio output tubes, you should begin now looking for a new output transformer.

>... Check your voltages, change the necessary components

No. Replace the caps first.

<Soap Box Mode OFF>

Sorry if I sound harsh. I just hate to see yet another fine old radio blown 
up because of bad restoration methods.

Roy


- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
7130 Panorama Drive, Derwood MD 20855
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