Re: Video "ringing" with PBXGA but not Mach64 or Elsa Gloria

From: Alan Frisbie (Usenet01REMOVE_at_Flying-Disk.com)
Date: 10/29/03 

Date: Wed, 29 Oct 2003 08:26:33 -0800

Alan Frisbie wrote:

> BINGO! That was it! Even though an ohmmeter showed zero resistance
> between the three analog grounds (pins 6, 7, & 8), a small wire (I
> used 30ga wire-wrap wire) soldered across all three pins cured the
> problem. Now I can use the ZLXp-E2 at all 1280x1024 rates, including
> the most "agressive", setting 13 (80 KHz Horiz, 75 Hz Vert).

Just to be complete, I should add that before adding the wire, I
tried Hoff's suggestion that I test other switch settings (i.e.
different scan rates) on the ZLXp-E2. No matter what the switch
setting, the video ringing still occured.

My guess is that the BNC connection to my monitor (which worked
perfectly) has all three grounds connected together. When I
used the HD-15 connector (directly, through cheaper cable, or
via the KVM switch), I'm guessing that they are not (or that
it somehow requires them to be connected at the video card).
The "floating" ground then resulted in the ringing I saw.

The reason the Elsa and ATI boards did not have the problem is
apparently because all three grounds are connected at the video
card. Now that I have made the fix to the ZLXp-E2, they all
have equally good images.

But, as I mentioned in my previous note, I still would like to
know why the DECwindows "Style Manager - Color" does not allow
me to change colors (the "Modify" button is greyed out) with
the ZLXp-E2, but does allow it with the Elsa and ATI boards?

Thanks,
Alan

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