[NJARC] Hallicrafters SX-16 PS

[John Ruccolo]

Ouch! Somehow, it appears that the B+ shorted to
ground. Or the rectifier tube failed.

The 690V sounds reasonable to me, Scott. Don't forget,
it's a *full* wave rectifer (half the HV winding
working at a time) so it's really only 345 vols. And,
that's without a load, so it's probably closer to 300.

But what the heck happened? If the *transformer*
failed that would *not* cause the recitifer tube to
melt down. Somehow, you shorted the B+, I think.

With the power OFF, try measuring resistance from the
main B+ bus from the rectifier socket to ground. If
you get a really low reading (near zero or just a few
ohms) something is very wrong. A stray clip lead? A
solder blob, or bit of wire?

Measure the resistance from each side of the xformer
plate winding (power OFF, please!) to the center tap.
If they're close, you porbably didn't damage the
transformer.

Check resistance across the filter caps. HEY, YOU
DIDN'T LEAVE THE OLD FILTER CAPS IN THE CIRCUIT, DID
YOU?

Regards,

John

--- Scott Roberts <ng19delta at yahoo.com> wrote:

> Visit our web site - See http://www.njarc.org
> _______________________________________________
> Just took a look at tthe tube: it is partially
> shrapnelized
> inside- large round bits of melted metal, and one of
> the
> conductors blown out. I Think It's Dead Jim.
> 
> And so I checked the transformer output: close to
> 690VAC at the
> tube. I think that is a BIT high... And there is
> transformer wax
> melted out of it underneath.
> 
> Thoughts?
> 
> Scott
> 
> 
> --- Scott Roberts <ng19delta at yahoo.com> wrote:
> 
> > Visit our web site - See http://www.njarc.org
> > _______________________________________________
> > ARRRGGGHHHHH!!!
> > 
> > I just went to warm up the set to do some
> troubleshooting of
> > the
> > BFO, and got something completely unexpected: a
> veritable
> > lightning storm in the rectifier tube! It was
> glowing purple
> > and
> > yellow, with  electrical charges jumping all over
> the place
> > inside- looked like one of those Tesla balls, and
> heated up
> > very
> > fast. I switched it off after a couple seconds.
> Hope the tube
> > is
> > ok- I will check it after it cools off...
> > 
> > I am suspecting a transformer issue... Any
> thoughts? I have it
> > switched off, and unplugged, although I tried to
> get a reading
> > from the empty rectifier socket, all I got was
> real high: I
> > need
> > to figure out the transformer ower connections,
> and what should
> > be where...
> > 
> > Frustrating- get one thing straight, another
> decides to go to
> > ...
> > 
> > Scott
> > 
> > 
> > --- John Ruccolo <jr6v6gt at yahoo.com> wrote:
> > 
> > > Visit our web site - See http://www.njarc.org
> > > _______________________________________________
> > > Hi Scott,
> > > 
> > > Good work! You're learning the troubleshooting
> > > process.
> > > And, yes, sometimes luck plays a role in
> > > troubleshooting -- thought we don't always like
> to
> > > admit it. ;-)
> > > 
> > > Pretty soon, you will graduate from student to
> > > instructor at our clinics. We can always use
> more
> > > "experts" at the clinics.
> > > 
> > > 
> > > Regards,
> > > 
> > > John
> > > 
> > > 
> > > --- Scott Roberts <ng19delta at yahoo.com> wrote:
> > > 
> > > > Visit our web site - See http://www.njarc.org
> > > >
> _______________________________________________
> > > > Just thought I'd update those paying attention
> to my
> > > > latest
> > > > efforts...
> > > > 
> > > 
> > > > 
> > > > Anyway, I thought it wasn't too bad for a
> first try
> > > > after major
> > > > work! Should be on top of my game for the next
> DX
> > > > contest... ;)
> > > > 
> > > > Scott
> > > > 
> > > > 
> > > >      
> > > >
> > >
> >
>
____________________________________________________________________________________
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> > > > 
> > > >
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>      
>
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