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Thread: IBM Professional Graphics Controller not working

  1. #11


    This does not relate specifically to your cards, but, if a RAM IC fails in the video ram storage area (or fails to produce an output), it will produce a geometric array where the pixels can be turned on (or possibly stuck off). The pattern I think would depend on the way the hardware storage was arranged.

    I have attached a photo of an example where just one video RAM IC was removed from a bank of 16 IC's in a video card with a 256 x 256 pixel array (this is Matrox's first S-100 graphics card) , so its outputs are interpreted as logic high. As you can see it produced 16 lit lines as one might expect. The boxes or checkerboard are plotted as 20 pixels x 20 lines as a reference from a simple program I wrote to test the card. And it is somewhat reminiscent of your screen image. So clearly you have some faulty RAM and it looks like you have found them already.
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