Hi all. I have a problem with an SE30 in which I assembled a new motherboard from Boll's project. The computer worked from the first boot, however, there is a problem. A few moments after booting, the screen starts to show artifacts in the form of dashes or single pixels. After about two minutes, they stop appearing and are gone until the next cold boot. I have replaced: Video ROM, Video memory, all four F253 (UA8,UB8,UC8,UD8), LS166 (UE8) and UG6 (PAL Beginning). The fault looks like a memory addressing problem. I think I have replaced all the chips that could be responsible for this... Do you have any idea where to look? I forgot to add that despite these problems, the computer runs completely normally and stably.