Yes, it was where the wire was in a tight bend. I
don't think that was the original cause though. There
were four or five turns and the other turns were not
damaged. I think the wire had a small hole in the
insulation when the transformer was wound. That teflon
is very tough and I think you would break the wire or
the ferrite before you tore the insulation. I also
wonder why it decided to short after all this time.
The radio had been sent back to Tentec by a former
owner and had the finals replaced. Maybe the short was
interrmitant and caused that failure as well.
Took us some time to track down the short, we figured
it was the finals themselves or one of several bypass
caps, but disconnecting them didn't clear the short.
Who would expect a transformer to short from primary
to secondary, especially one wound with teflon
insulated wire!
73, Dave, VE1ADH
--- Steve Baron - KB3MM <SteveBaron@StarLinX.com>
wrote: > Any pressure on the wire at that spot ?
>
> ----- Original Message -----
> From: "David McClafferty" <ve1adh@yahoo.ca>
> To: "Tentec List" <tentec@mailman.qth.net>; "Tentec
> Reflector"
> <tentec@contesting.com>
> Sent: Sunday, October 05, 2003 13:54
> Subject: [TenTec] Paragon overcurrent fault
>
>
> > My friend Fred ,VE1PBX had a problem with his
> Paragon
> > shutting down on overcurrent even in receive. The
> > finals were drawing the current but they were not
> > defective, they were turned fully on. The bases
> were
> > getting voltage from the driver collector circuit
> > because the interstage transformer was shorted.
> The
> > secondary winding, which is wound with teflon
> wire,
> > had a tiny hole in the insulation where it was
> close
> > to the bottom side of the PC board. We have no
> idea
> > what caused the hole. This teflon insulation is
> very
> > tough. Replacing the wire cured the problem. Fred
> > wanted me to pass this on in case anyone else had
> the
> > same problem.
> >
> > Dave, VE1ADH
> >
> >
>
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