VOGONS

IBM Color Graphic - display problems

Topic actions

First post, by demyx

Posted on 
User metadata
Rank Newbie
Rank
Newbie

Hi everyone!
Months ago I bought a non-working IBM 5150, with some cards inside.
Over time I managed to fix the motherboard that was reporting errors on the memory, so I started testing the cards.
The IBM CGA gives me display problems as in the photos.
The visible defects appear only when the image is moving, for example while displaying the contents of a directory, while with a still image no anomaly is found.
I also tried the card with the Landmarks diagnostics, but the test passed...
Also tried on a 386sx, but the situation does not change.
Does anyone have any idea where the problem could be?
Thank you very much!!!

Reply 1 of 2, by Grzyb

Posted on 
User metadata
Rank l33t
Rank
l33t

That's CGA snow - perfectly normal.
To avoid the snow, software must only write to the video memory during retrace - old software does take care of that, newer doesn't.

You can try this - http://www.oldskool.org/pc/cgacomp - it should only display the snow in the "CGA Snow" option.

Nie rzucim ziemi, skąd nasz root!

Reply 2 of 2, by demyx

Posted on 
User metadata
Rank Newbie
Rank
Newbie

Thanks Grzyb for your reply, I have found that it is a common defect of this card.
I was not aware of this fact, all experience that enters...
As soon as I have some time I'll take the test.
Good afternoon!

Go to top of page Go to top of page
Back to General Old Hardware
Close window
Close window