[Boatanchors] SB-220 with parasitics

[Kenneth Grimm]

To the best of my knowledge, glass tubes such as the 4-400, 3-500, 3-1000,
etc. were never candidates for rebuilding in which elements were replaced
and a new vacuum was pulled.  However ceramic tubes definitely
were...particularly those with handles!  For those, there still exist
rebulders, for example, Econco and Kennetron.  As broadcast stations
eventually all convert to solid state, even these two may cease rebuilding
vacuum tubes.  If I'm not mistaken one of the prime rebuilders of
yesteryear, Richardson, has already ceased rebuilding.

73,
Ken - K4XL

On Sat, Dec 25, 2021 at 5:14 PM KA2PTE <ka2pte at 3950.net> wrote:

> A shame these cant be rebuilt somehow. I have a 4-400A I broke the glass
> near the anode.
>
> Western Electric in Ga is I think the only tube maker left in the US, and
> they wont
> get involved with these large RF transmitting tubes.
>
> I hear China is trying to get in to making some, but the longevity quality
> is terrible
> as they are copies with cheap material used. When you think how old these
> tubes are,
> going back to the 1950's and they are still going - its an engineering
> marvel.
>
> --
> Steve Hearns [ KA2PTE ]
>
> > I have a dozen or so failed 3-500Z's in a box that I have tried all the
> > rejuvenation tactics, to no avail. They are reserved for future testing
> of
> > any technique for revival. The bent plate may be only good for target
> > practice.
> >
> > 73 Bill N4LG
>
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-- 
Ken - K4XL
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