[Hallicrafters] sx101a

[Mark K3MSB]

Jack --

I had this happen to my 101A last month.   If the fuse is gone, you
should still get audio,  but since the oscillator is not working,
you'll hear static only.

Pretty easy to test;  if the 1/4 amp fuse is gone, the 12BY7A will be
cold and dark.  Save the sleve over the 1/4 amp fuse;  a new 3AG type
will go in it nicely.

Mark K3MSB

On 11/21/05, k0ewu at juno.com <k0ewu at juno.com> wrote:
> HI- there is an extra filament tx (T10) for the local oscillator, it is
> fused on the primary. The fuse(/4 a) is hidden in a length of sleeving
> making it hard to find,
> this fuse also feeds  3.3k 10 watt resistor (R69) mounted next to a
> sheild by the local oscillator.
> It's purpose is to  keep the osc circuits warm to minimize warm up drift.
> These components are on all of the time that the set is plugged in- not
> switched.
> If perchance the fuse has blown you will not have voltage to the osc tube
> heater.
> Sometimes the fuse just opens from old age.
> old jack
>
>
> On Fri, 18 Nov 2005 06:29:02 -0600 "Ross Stenberg" <k9cox at charter.net>
> writes:
> > There is a heater element (resistor) used to supply constant
> > filament
> > voltage to the LO that can open up over time and the receiver will
> > appear as
> > you describe. It is easy to overlook one tube not lighting up when
> > all the
> > others do.
> >
> >         73 Ross K9COX
> >
> >
> > >>>Strange question from someone who has a degree in electronics but
> > here
> > goes. My sx101a worked fine on the vintage net this past Sun. but
> > the next
> > time I turned it on there was nothing. No sound & no s meter
> > movement.
> >
> > All tubes seem to lite up. Changed both audio output tubes but
> > still
> > nothing. Thought I'd ask before I take it out of its bottom cover.
> >
> > Thanks Jack
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