[SGVLUG] Calling the brightest of cal tech and other nerds!

[Matthew Gallizzi]

On 1/2/07, Bryan Backer <bbacker at yahoo.com> wrote:
>
> Matthew,
>
> Since you're ruled out the normal problems, how about something
> from the 'grasping at straws' bucket? :)
>
> Perhaps it's the momentary switch that PCs use for power down?
> It's bad (intermittent short) or very sensative to static so
> the switch is causing a power down? Depending on the
> physical design of the box, the switch could be
> exposed outside your case so static is affecting it.
>
> If you disconnect the momentary switch from the motherboard
> (the switch is in the case of course - attached via a header
> to your MB) and instead use two jumper wires to turn on/off, do you
> still experience the problem?
>
> No idea if it will help, but you could try your current setup but
> with reset switch and power switch not connected to MB headers.
> With the case open, use a wire or something to short th MB power ON/OFF
> momentary switch to turn the computer on, then close the case.
> Now try your various status electricity tests to see if you can
> get the machine to shut down. If you can, forget my suggestion. :)
> If the machine now stays up, perhaps try swapping out
> power switch/headers/connectors. If nothing, try the same with
> reset switch/header/connector.
>
> For the record, I've never had a static problem like this, but
> I did have a similar problem once when cramming a small form
> factor MB into a wooden box and my home-made power connector
> kept getting bumped - power on. power off. power on. power off.
>
> bb
>
> --- Matthew Gallizzi <matthew.gallizzi at gmail.com> wrote:
>
> > On 12/22/06, John E. Kreznar <jek at ininx.com> wrote:
> > >
> > > > ... static electricity keeps shutting down a computer we recently
> > > > built ...
> > >
> > > What do you mean "shutting down"?  Does it simply freeze as though
> > > something is going into a tight loop, or does power get shut off?
> >
> >
> > It just shuts off. I rub socks on carpet, touch front of case, system
> > completely shuts off. Doesn't freeze. Last motherboard I tried would
> > restart.
> >
> > Have you probed anything with a 'scope?  If the power supply is
> > > turning off, it must be being commanded to do so, and it would be
> > > interesting to investigate the source of the command.
> >
> >
> > Probed with a scope? Hm, don't think so.
> >
> > I once added memory (256 KB to a Microdata 3200 -- big stuff in the
> > > '70s) which turned the computer into a veritable noise detector --
> > > extremely sensitive to static discharge.  Turned out to be a design
> > > flaw in the CDC memory.  I fixed it by rebuilding the refresh
> > circuit.
> >
> >
> > I tried with a different motherboard + different RAM ... still did
> > it.
> >
> >
> >
> > --
> > Matthew Gallizzi
> >
>
>
> -- bbacker at mail.yahoo.com
>



-- 
Matthew Gallizzi
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