On Thu, May 12, 2011 at 2:35 PM, MikeS <email@example.com> wrote: > AFAIK the old 2001 had the video RAM connected directly to the CG ROM > (unlike the newer ones which had a latch in between), so if one or more bits > of the video RAM were unstable (or you had an intermittent socket) which > caused the data to change part way through a character line, wouldn't you > then get corrupted characters as the CG switched back and forth? You could, but in order for that to be stable, it would need to be synchronized with the pixel clock. If the symptom was random pixels/no visible character shapes, I'd be willing to suspect the SRAMs. > I just thought it'd be an easy and worthwhile thing to try, especially since > someone on the VCF PET forum just fixed a 'flickering snow' problem by > replacing one of the video RAMs. I can see how snow could be an SRAM problem because it's not tied to the same pixels changing in the same characters in the same way frame after frame - that is one way I'd expect random addressing of the CG ROM to manifest itself. -ethan Message was sent through the cbm-hackers mailing listReceived on 2011-05-12 19:00:15
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