At 02:09 AM 11/02/1999 , OConnell, Jerry wrote:
>Hi folks,
>
>I am trying to diagnose a display problem on an old AST PC and I'm not
>totally sure of it's history, here's the deal;
>
>1. On-board ATI Rage Pro graphics card - P200MMX, 32MB RAM, sound, CD-ROM
>etc.
>2. On boot up it will display nothing (in DOS) - blank screen, however it is
>booting.
>3. It will then happily go into Windows at 640x480
>4. It will not open a full screen DOS box from windows (goes blank) but will
>open a windowed one.
>5. It will go blank if I change to 800x600
>6. But strangely, it will display in windows at 1024x768.
>
>I tried adding a different PCI graphics card, an S3 and I only got a repeat
>of the same problem, so it kinda eliminates the graphics card from the
>equation.
>
>Has anybody got any ideas, because as is, it looks like I can't access the
>BIOS settings or do any DOS mode configuration.


This is an intriguing issue, so much so that I decided to dig around on
AST's web site.   It would be helpful if you supplied us with the model
number or some number on the motherboard to distinguish the motherboard.

The only thing I can garner from reading on AST's web site about this
particular video onboard chipset is that it has an automated disable
function of the onboard video if you plug-in a secondary card, like your
S3 card.   The interesting thing about this is if the chipset is going bad,
disabling the low end vga portion of the video display for the Post procedure,
it might also have disabled the auto-recognition portion to disable the
video when you plugged in the S3 card.

In this case, if as you have said even adding a second video card does not
solve it, I would tend to believe the motherboard needs to be replaced as it
is not only giving you the problem with onboard video, but the auto-recognition
in the chipset is probably gone bad also.  This one is very interesting and I
hope you post your final solution.

    Bob Wright

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