Hi Jeff,
-
I've received some broadcast transmitter tubes with
recommended warm up times of 10 plus min, some
as high as 30 minutes min.
-
A fellow broadcaster (now an SK) never paid
much attention to the pre power warm up time
especially the first install.
-
He called me over one night to source a
breaker trip problem which was traced back
to the tube, which was not allowed the
recommended pre start filament idle time.
-
After 30 min, I applied power and the everything
worked as expected, the transmitter was back
on the air.
The program director went back to defcon
level 3 spazz level (some of you broadcasters
can appreciate that remark).
-
>From memory, Econco was our rebuilt tube
supplier of choice (great people), the pentode
with handles was one of the more fussy
animals (5cx1500a) and of course I was
working on the first Sparta 602/680 off the
assembly line.
-
20 to 30 min of warm up time is relatively
cheap. I believe the recommended warm up
time was mentioned in the Econco paper
work, although I do it as a rule of thumb.
-
Interested parties could call Econco
in Woodland, CA if they wanted more
detailed information.
-
cheers
skipp
-
--------- Forwarded message ----------
From: "Jeff Maass" <jmaass@columbus.rr.com>
To: "Amps Mailing List" <amps@contesting.com>
I have a pair of 4CX800A tubes that have been on
the shelf here for a few years (and for an unknown
period before I got them). I'm about to swap them
into one of my Alpha 91b amps.
Is there a recommendation to let these tubes run
without HV for a period before pressing them into
full service?
I did a search of the archives, and it seems that
there is no consensus on the need for this procedure
for any but the largest "tubes with handles".
73,
Jeff Maass K8ND
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