Everything authoritative (i.e, from Eimac) says that running the
filaments does nothing. I've read from several amp designers that the
3-500Z simply doesn;y leak, so the vacuum remains patent. The only
getter in the tube is the zirconium on the plate of the original 3-500Z
(Z for zirconium). Then the zirconium gets red-hot, it acts as a getter,
so the tube is constantly gettering as it operates. This isn't true of
other transmitting tubes and I don't know about the graphite 3-500ZGs.
Install it, plug in the amp and turn it on. It'll either be fine or it
will flash over.
Kim N5OP
-----Original Message----- From: Al Gulseth
Sent: Sunday, August 03, 2014 8:41 PM
To: TenTec@contesting.com
Subject: [TenTec] OT: Need advice checking out a stored 3-500
(Posting this for a local fellow ham who currently isn't on the web)
As the subject line says, a local ham friend of mine asked me today
about how
to go about checking out/waking up a 3-500 (Z?) that came as a spare
with his
AL-80A when he bought it a few years back. He's not really sure how
long the
tube had been sitting around unused/un-exercised before he bought the
amp.
I've seen conflicting info on how to go about it, and the last time I
had my
hands on something like that was 30+ years ago when I worked in the
broadcast
industry before I switched to a different career. Any suggestions?
Other than
his amp I don't have any way that I know of to check it.
Contact me off list if appropriate.
BTW Ten-Tec connection: he's driving it with an Orion.
TNX/73, Al
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--
Kim Elmore, Ph.D. (Adj. Assoc. Prof., OU School of Meteorology, CCM, PP
SEL/MEL/Glider, N5OP, 2nd Class Radiotelegraph, GROL)
/"In theory there is no difference between theory and practice. But, in
practice, there is." //-- Attributed to many people; it's so true that
it doesn't matter who said it./
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