Explain the NeXTStation "dim monitor" problem, etc...

From: jpero_at_sympatico.ca <(jpero_at_sympatico.ca)>
Date: Tue Apr 16 15:42:18 2002


> Phosphors do lose efficiency but I dont think that is the main
> problem. I think mainly the cathode loses emission. This can temporarily be
> improved by CRT rejuvinators or raising the heater voltage (I'm old enough to
> remember the old cylindrical autotranformer picture tube brightenters that you
> stacked on the old B-W TV CRTS: they basically raised the heater voltage a
> little bit, squeezing a little more life out of the CRT)

I know phosphors becomes fried slowly from long use but I'm referring
to cathode emissions:

I wondered whom is right?

cathode oxide or
heater coating?

I think this is heater coating.

I see this frequently on zeniths and zenith tubes clones for TVs
since it used same socket and pinout. I used the rejuvenator so many
times with those tubes to brighten them up and blow shorts out.
Glowing bright orange and Crackling (lightening in a bottle)!!
Sometimes you have to really hammer the guns w/ plastic tool to
dislodge hard enough that tube sings to get shorts blown off. Ting!

Shorts does kill transistors if they're not robust enough which is
much about that because I fix TVs and monitors. And when a tech
finds a dud transistor and swaps it, that tv comes back with same
part blown because tube arc'ed again. Can be a day, days or weeks.
Always small transistors (typically TO-92), rarely extends to
expensive jungle IC. Now you know why I always blow shorts out on
those tubes. This was from infos according to other techs on



> > -Douglas Hurst Quebbeman (DougQ at ixnayamspayIgLou.com) [Call me "Doug"]
> > Surgically excise the pig-latin from my e-mail address in order to reply
> > "The large print giveth, and the small print taketh away." -Tom Waits
> >
> Peter Wallace
Received on Tue Apr 16 2002 - 15:42:18 BST

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