003, I follow your logic about the strange artifacts 100%. But I am zealous to investigate their root cause not because I am having problems due to those artifacts, but rather due to these reasons:
(1) In all my many years of using classic Macs as an end user, and as a technician, I never saw those strange artifacts until the year 2006, after having purchased an old Mac off EBAY; and...
(2) Larry Pina puts quite nearly every single screen anomaly seen in his books. Yes, even the checkerboard pattern that tt started this thread with is in Pina's books. But guess what? Those strange artifacts are no where to be found in Pina's books or any other technical books I've read!
003, I know you are saying that *YOU* have seen them before. And by reading the posts in the Applefritter thread you can see that others have seen them too, including myself. But why didn't Pina? The quest to answer that question intrigues me, as I hope it will some of you. I really want to know! And we cannot flippantly say, "Because Pina never tried such-and-such a ROM in his SE/30" because I myself am seeing those artifacts WITH A STOCK SE/30 ROM! Actually, with 3 different kinds of SE/30 ROMs!
Now...
tt, I don't want this discussion to diverge too much from your initial question that started this thread, which centered on your checkerboard pattern problem. But you need to follow the advice I posted for you in that AppleFritter thread, which includes cleaning the ROM contacts and the ROM socket contacts. And if that doesn't solve it, you need to resolder those analog board points I mention. At that point, you need to post back here and let us know how it went. Thanks!
(1) In all my many years of using classic Macs as an end user, and as a technician, I never saw those strange artifacts until the year 2006, after having purchased an old Mac off EBAY; and...
(2) Larry Pina puts quite nearly every single screen anomaly seen in his books. Yes, even the checkerboard pattern that tt started this thread with is in Pina's books. But guess what? Those strange artifacts are no where to be found in Pina's books or any other technical books I've read!
003, I know you are saying that *YOU* have seen them before. And by reading the posts in the Applefritter thread you can see that others have seen them too, including myself. But why didn't Pina? The quest to answer that question intrigues me, as I hope it will some of you. I really want to know! And we cannot flippantly say, "Because Pina never tried such-and-such a ROM in his SE/30" because I myself am seeing those artifacts WITH A STOCK SE/30 ROM! Actually, with 3 different kinds of SE/30 ROMs!
Now...
tt, I don't want this discussion to diverge too much from your initial question that started this thread, which centered on your checkerboard pattern problem. But you need to follow the advice I posted for you in that AppleFritter thread, which includes cleaning the ROM contacts and the ROM socket contacts. And if that doesn't solve it, you need to resolder those analog board points I mention. At that point, you need to post back here and let us know how it went. Thanks!