On Mon, 7 Aug 2000, Chris Tribo wrote:

> On Sun, 6 Aug 2000, Simon Richter wrote:
> 
> > Hi,
> > 
> > I'm using a DS5000/125 at home, with said graphics card. Since a few
> > weeks, the gfx board's self test fails ("Red screen test"), which keeps
> > the machine from autobooting. Since I'm using a monochrome monitor anyway,
> > I don't see a reason to exchange the graphics board. Is there any way to
> > make the prom ignore the self test failure?
> > 
> >    Simon
> 
> 	Did this error start when you switched to using a monochrome
> monitor or did it just spontaneously happen? If it just happened, you
> might have loose/dirty or a bad SRAM chip on the card. You might try
> swapping board 1 with board 3 and see if you get a blue screen error
> (Ha!) and report back. If it started happening when you switched to a mono
> monitor, then there probably isn't anything wrong with the card, and no,
> you can't make the PROM ignore a default test failure. You may however be
> able to trick the card into thinking that the red signal is attached by
> terminating it, but I don't know the innards of the Bt RAMDACS or if that
> is even the real problem.
> 
> 
> 	Chris
> 
> 

I agree, I would sure try terminating (with a 75 ohm resistor)  the red
(and blue) video out signals, I have seen that error when they were
unconnected. My guess is that the RAMDAC has a comparator on the video
outputs, and by setting the video drive on and checking the comparator,
the PMAGD's firmware can determine if a video monitor is connected...




Peter Wallace
Mesa Electronics