[Amps] 2K Classic X filament issue

[Victor Rosenthal 4X6GP]

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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