how to kludge a 486 PC into thinking it has a video card?

From: Scott Stevens <>
Date: Sun Feb 20 21:54:30 2005

On Sun, 20 Feb 2005 14:17:32 -0800
"Steven Canning" <> wrote:

> Subject: Re: how to kludge a 486 PC into thinking it has a video card?
> > On Fri, 18 Feb 2005, Jules Richardson wrote:
> >
> > > Far as I know the BIOSes of the time would check for MDA / CGA /
> > > EGA / VGA adapters at boot time, but 'not fitted' wasn't usually
> > > an option. I wonder if there's a clever way involving a minimum of
> > > circuitry in such a case for the BIOS checks to work...
> Why not just through a $2 Hercules Graphics card in an ISA slot and be
> done with it ? For troubleshooting you can spew graphics or text if
> needed....

Actually, these days, a 'Hercules Graphics card' is becoming a 'scarce
vintage item.' The junk cards everybody has too many of are ISA VGA
cards. The monitor to plug into said 'Hercules Graphic card' has also
become quite rare. Most of that early stuff is long-ago recycled. The
'junk' these days is 486 to Pentium II based.

I have an original IBM-AT that I still haven't ever powered up, because
it has all original IBM innards, including the IBM EGA card. I know how
to jumper the card to work with a 'TTL monochrome' monitor (EGA
monochrome is a highly usable mode, with high resolution 1 bit
graphics), but have neither a Mono or an EGA monitor to check it out.
I've been holding off on 'corrupting' it by putting in a clone ISA VGA

We're awash in a sea of castoff VGA monitors these days. I watch for a
TTL mono monitor at every auction and sale I go to, and haven't found
one since acquiring the IBM-AT.

Received on Sun Feb 20 2005 - 21:54:30 GMT

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