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

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

Hi,

> 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!
TING, TINGGG!!

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
sci.electronics.repair.

Cheers,

Wizard

> > -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