[Amps] 2K Classic X filament issue

[David Gow]

Oops, you are correct.  I must have been thinking of one of my past
SB-220s.  Being series makes it a real mystery.
Dave W7VM

On Tue, Aug 3, 2021 at 11:56 AM Victor Rosenthal 4X6GP <k2vco.vic at gmail.com>
wrote:

> I would have said the same, except that  the filaments are in series.
> That implies that the same current must be flowing through both of them.
> If one set of contacts is dirty, then the current through both tubes
> would be reduced.
>
> 73,
> Victor, 4X6GP
> Rehovot, Israel
> CWops #5
> Formerly K2VCO
> https://www.qsl.net/k2vco/
>
> On 03/08/2021 20:58, David Gow wrote:
> > I had the same on my 2KD-3.  Turned  out the tube socket pins on one
> > socket were a little dirty/corroded.  Cleaned and tightened them and
> > all is well now. Dave W7VM
> >
> > On Tue, Aug 3, 2021 at 10:44 AM Donald Fox via Amps
> > <amps at contesting.com> wrote:
> >
> >> Gents: As you may recall, I have a soft spot for the Henry Classic
> >> consoles. I recently acquired a 2K Classic X console from the
> >> original owner, and want to being it back to life. It's interesting
> >> to note that This 2KX was originally built as a domestic 2KX, with
> >> the smaller plate xformer. The owner eventually purchased the
> >> larger export 1171 plate xformer, and installed it. The amp was
> >> purchased from AES in Wickliffe, Ohio,  back in the early 80's, and
> >> used frequently until the owner left town in 1986. From then on, it
> >> sat unused for 35 years.
> >>
> >> After a thorough cleaning, I am seeing a brightness difference in
> >> the 3-500z tubes. I tried swapping the tubes from front to back,
> >> and the front tube consistently has the weaker filament. I have
> >> also tried a second, known good set of tubes, with the same
> >> results. A visual inspection of the underside of the RF deck
> >> revealed no obvious problems. Filament voltage is around 11
> >> unloaded, as the filaments are in series.
> >>
> >> I have not enabled the HV section as of yet. The bearings in the
> >> blower were semi frozen, such that a new motor was required. That
> >> part is done.
> >>
> >> Thoughts and suggestions please.
> >>
> >> TIA
> >>
> >> Don    N8ECH _______________________________________________ Amps
> >> mailing list Amps at contesting.com
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> >>
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