[rescue] Perverse Question

[Michael Free]

Ahh, that's what 8 years of not needing information will do (file system
corruption in meatspace).

I wish I could remember if I shunted to ground or 12v or 5v or whatever I
did on that XT.... I've got 2 more just like it that need mods :)

The story from back then goes like this... a friend of mine needed a PC and
didn't have much money to do it with. So, I tookher XT, modded it with a
reset switch (since it was to get windows 3.1, and you *know* that locks up)
and it got a 486sx25 motherboard (no drilling required, but needed spacers
to hold up part of the board) and I made some plates to hold together a
3.5/5.25" combo drive and a CD-ROM for one bay, and just drilled new holes
for the second bay with got a 540 meg second hand hard drive.

Heh, for the first few weeks she was even running the stock XT Hercules
video card before I found her an old EGA Mono card that could use the old
green screen. The Hercules actually gave better resolution, but the software
just dealt better with the EGA, and I *think* it gave it 16 shades instead
of true monochrome.

Heh, reminds me of the times when I got Win 3.1 running on a CGA display
over a composite monitor... and when I got the win98 machine in the computer
lab at college routing .WAV output over the system speaker. Sounded like an
AM radio but I had fun with it :)

Mike Free
Off-topic as it gets.

----- Original Message -----
From: "Dave McGuire" <mcguire at neurotica.com>
To: "The Rescue List" <rescue at sunhelp.org>
Sent: Saturday, June 07, 2003 7:59 PM
Subject: Re: [rescue] Perverse Question


> On Saturday, June 7, 2003, at 07:51 PM, Michael Free wrote:
> > If I remember right, in classic terms (XT, the last time I dealt with
> > it)
> > "SENS" or "Power Good" is an input.... the motherboard can tell the
> > power
> > supply if the power is good. You can route this to ground (iirc) with a
> > momentary switch for a reset button, something the IBM PC and XT was
> > sorely
> > lacking.
> >
> > Luckily they had a little removable panel in the back which made
> > drilling a
> > hole for the switch much, much easier :)
>
>    Actually the "Power Good" signal is an output from the power supply.
> On better supplies it's a logical AND of the output of a group of
> window comparators which check that each output voltage is within
> tolerance.  On cheaper supplies (and all modern PC supplies that I've
> seen) it's simply a signal that goes active after a short delay
> following powerup.  It is the intention that the processor not start up
> until that signal is asserted.
>
>        -Dave
>
> --
> Dave McGuire             "I've grown hair again, just
> St. Petersburg, FL           for the occasion."       -Doc Shipley
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