[Hallicrafters] Tube life question

[rdhalste]

> The best tube tester in the world is the unit itself.
> If the tube works fine in the unit, then who cares
> what a tube tester says!  If the tube does not work
> correctly, the same thing!

One thing I found with many tubes that were weak. I'd put them in the tube
tuester and run the filament voltage up about 10% high and keep it there for
15 minutes to half an hour.  That seemed to rejuvinate *some* tubes. It
worked best on Tungsten and thoriated Tungsten, but even on the indirectly
heated thoriated cathodes.

It's not normally considered good for a tube, but in the case of throwing it
out, or giving it a try, I'm willing to give it a try.  I had about a 30 to
50% success rate.

The same is true for gasy tubes. I plug them in with no voltages on the
plate, screen, or grid. Then crank the filament up maybe 5 to 10% over
nominal and let it cook for about two days.  Setting around, unused is one
of the hardest things you can do to some tubes. Particularly the PL172/8295A
used in the HT22 A & B. Not using them at all is harder on them than normal
useage.  I don't think it's as much of a problem with metal/ceramics as it
is with metal/glass

>
> Many of the major electric companies now try to
> maintain 125 volts +/- 2 volts, mainly on the "+" side

It sure isn't around here.  Many of the lines (residential feeds) are so
long that they have to run close to the allowable maximum close to the sub
to make the minimum near the far end.
Here in Michigan and rural Michigan that is particularly true.

> during the summer months when the demand is the
> highest.  I haven't found it to make much difference,
> but some amateurs believe that it does.  If you look
> at the specifications on many of the older units, it
> says 105 - 125 or something similar.

Roger Halstead (K8RI EN73)
www.rogerhalstead.com
N833R World's oldest Debonair? (S# CD-2)
>
> Glen, K9STH
>
>
> --- ARDUJENSKI at aol.com wrote:
> > Glen and group
> > Do you recommend using a quality tube tester to
> > narrow down the culprits and
> > then start tube substitute?
>
> =====
> Glen, K9STH
>
> Web sites
>
> http://home.attbi.com/~k9sth
> http://home.attbi.com/~zcomco
>
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