On Thu, May 12, 2011 at 1:21 PM, MikeS <dm561@torfree.net> wrote: > Have you tried replacing the video RAM? Besides the fact that I did test (and mark) all the 6550s, bad video RAM is not likely to cause pixel-level defects in the video... that tends to be a fault around the chargen and attached shift register or with the timing chain of flip-flops and such. I was able to test the SRAMs in another board using a Fluke 9010A (it plugs into the CPU socket and sees whatever the CPU would see), so I'm confident that the SRAMs are good. What I was *not* able to successfully test with that board was those same SRAMs at $8000-$83FF. It looked to me that there was some problem in the path between the 6502 socket and the SRAMs. This is in addition to any visible rendering problems. -ethan Message was sent through the cbm-hackers mailing listReceived on 2011-05-12 18:00:25
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