[NJARC] Dim eye tubes

[john ruccolo]

Hi Nick/Folks,

Years ago, there was an article in ARC where the
author claimed to have had some success rejuvenating
eye tubes. I beleive it was written by Jim Farago, the
noted jukebox amp specialist. I think there was
another article along similar lines years later.

I'll have to see if I can find them. Nick, just for
ha-has, put the dim eye tube in a tube tester and run
it at least 50% over-voltage on the filament (9 or 10
volts) for a half-hour or hour. See if that improves
anything. There's really two senarios 1) the phosphour
target is wearing out (like Mike C. said) OR, 2) if
you're really lucky, cathode emission is down, in
which case you might be able to rejuvenate the tube to
a point. I'm gonna have to try this at home in the
Johnnytronics lab.

Regards,

JR


--- michael s christiansen <kb2vrm at juno.com> wrote:

> Visit our web site - See http://www.njarc.org
> _______________________________________________
> Hi guys, That's why they have screen savers on
> computers. I've seen old
> monitors with text actually burned into the CRT. And
> now on to something
> completely different, Girl Scout Cookies will be
> delivered the night of
> the party to those folks who purchased them at the
> last clinic   Thanks,
> Mike Christiansen
> On Wed, 6 Dec 2006 15:51:54 -0800 (PST) Jim
> Whartenby
> <antqradio at sbcglobal.net> writes:
> > Visit our web site - See http://www.njarc.org
> > _______________________________________________
> > Greetings Nick
> > I don't know the exact cause.  The phosphor
> coating either wears 
> > out,
> > wears off or get contaminated by the electrons
> bombarding it.  The 
> > same
> > thing appears to happen to CRTs.
> > 
> > I visited a TV shop in Bound Brook, NJ to pick up
> a donation of 
> > vacuum
> > tubes for the club at least 8 or so years ago.  In
> talking with the
> > owner, he mentioned that he had noticed that this
> problem happened 
> > to a
> > TV CRT he used to align video camcorders.
> > 
> > He had adjusted a TV so that the top portion of
> the CRT displayed 
> > the
> > sync bar and never changed the settings. It stayed
> this way for 
> > years. 
> > When he needed the set for another type of test,
> he readjusted the
> > controls and noticed that the area that had been
> black, that is not
> > exposed to the electron beam, showed much brighter
> colors then the 
> > rest
> > of the screen.  So it appears that the phosphors
> don't last forever.
> > 
> > Lud Sibley experimented with trying to rejuvenate
> eye tubes with no
> > success.   He even put a tube or two in the
> microwave oven!  Nice
> > sparks but no joy.
> > Regards,
> > Jim
> > 
> > --- Nick Senker <ns539 at earthlink.net> wrote:
> > 
> > > Visit our web site - See http://www.njarc.org
> > > _______________________________________________
> > > Why do eye tubes (eg 6U5, 6E5, etc) lose their
> brightness?  Is it 
> > a
> > > failure of the phosphor coating?  I checked one
> that had good
> > > emmision, yet it was very dim. Nick Senker
> > > _______________________________________________
> > > NJARC mailing list
> > > NJARC at mailman.qth.net
> > > http://mailman.qth.net/mailman/listinfo/njarc
> > > 
> > 
> > _______________________________________________
> > NJARC mailing list
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> > 
> > 
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> 



 
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