Re: Monitor Discharging

I think this is an excellent discussion to be added to your docs - I
understand monitors better than I did now, I think.

One question though - I want to refer people to that person's web site for
different portions of the site - but I'm reluctant to do so if that
particular page on his site is dangerous. It seems to me that his method,
after listening to everyone, might damage your electronics - does it pose
any health risk to the individual attempting his method?

--- saint
    Build Your Own Arcade Controls FAQ
    http://www.arcadecontrols.speedhost.com

On Thu, 9 Dec 1999, Al Warner wrote:

> 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.
>
> --
> =====================================================================
> -= Al Warner batlzone@cyberenet.net =-
> -= Learn how to install a Cap Kit in your video game's monitor and =-
> -= see a whole lot more on my web page at: =-
> -= http://www.cyberenet.net/~batlzone =-
> =====================================================================
>
>
>
Received on Thu Dec 9 15:07:04 1999