Re: Monitor Discharging

Thanks Rodger! Now I know why I co-authored the ORIGINAL cap kit docs with you!
Best explaination I've ever seen (Zonn's was good as well). Would you guys mind
if I included this in the cap kit docs? Believe it or not, it's the question I
get the most from people ("Where does the charge go?").

Thanks to all,

-Al-

Rodger Boots wrote:

> OK, I've read the entire thread now and it's time for my 2 cents worth.
>
> For quite a few reasons, the discharge path must be to the outer surface (the
> aquadag coating) of the tube. Since this is connected to the metal monitor
> chassis, THAT'S where you discharge to, the chassis.
>
> When you have a high voltage breaking down an air gap to form an arc you end
> up with a brief high current with a very fast risetime. Due to inductance in
> any wiring this current passes through you will have a momentary voltage drop
> in the wiring. And the high current pulse will generate a magnetic field that
> will induce this pulse into any close conductors. This is a very small-scale
> and very localized version of the EMP pulses generated by nuclear bombs.
>
> If you are discharging back to the power cord ground you will have quite a bit
> of inductance in the return path and will briefly drop several hundred volts
> across what you would normally think of as a low resistance path. This will
> also induce surge currents into other lines along the path. The risk of
> damaging solid-state electronics via this practice is unacceptably high. And
> that assumes that you don't have a bad connection somewhere that would make
> the pulses even worse.
>
> The moral? Discharge ONLY to the immediate ground point of the CRT, the
> monitor chassis itself. You could discharge to the aquadag coating, but the
> chassis is safer since it connects to a larger area of the coating. Arcing
> directly to the coating could damage it.
>
> saint wrote:
>
> > I had understood, and I am uncertain if this applies equally to vector and
> > raster monitors (meaning I hope I'm on topic! :) ) that when discharging a
> > monitor quickly, you go from annode to monitor chassis. I believe in fact
> > someone was quite adamant that you *not* go from annode to a ground in the
> > wall.
> >
> > I ran across this site that takes completely the opposite point of view:
> > http://www3.50megs.com/todd1814/capkit/capkit.htm
> >
> > It also goes on that discharging to the chassis is a good way to fry your
> > PCB.
> >
> > Anyone in the know care to comment? Is this web site correct, or grossly
> > in error?
> >
> > Thanks!
> >
> > --- saint
>
> --
> Windows:
>
> 32 bit graphical interface for a
> 16 bit patch for an
> 8 bit operating system written for a
> 4 bit processor by a
> 2 bit company that can't stand
> 1 bit of competition.

--
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-=               Al Warner batlzone@cyberenet.net                    =-
-= Learn how to install a Cap Kit in your video game's monitor and   =-
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