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| SE/30 video issue, half simasimac pattern |
Posted by: LeSpameur on 2025-12-14 13:46:57
The board is clean and has been recapped. I already replaced all the SMD video chips (F253, LS166, and LS393), but no luck. The picture is from an SE/30 listed on eBay, which has the exact same issue. Any idea? To me, the video circuitry doesn’t seem to be fully initialized. I haven’t probed anything yet. It'll be fun. The sound is also glitched, but that’s another story (or maybe another broken trace). |
Posted by: David Cook on 2025-12-14 14:18:40
The picture is from an SE/30 listed on eBay Does your screen also show part of the floppy disk? If so, good news! That means the CPU, ROM, and main RAM are working.
Here is a tutorial for fixing it:
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Posted by: LeSpameur on 2025-12-14 22:39:33
Thanks. It’s most likely a broken trace between UE8 and UC6/7. |
Posted by: LeSpameur on 2025-12-30 13:11:40
Does your screen also show part of the floppy disk? If so, good news! That means the CPU, ROM, and main RAM are working.
Here is a tutorial for fixing it:
I forgot to mention something ; when I remove the ROM, the Simasimac pattern is normal, no vertical lines ! |
Posted by: LeSpameur on 2026-01-03 03:49:37
Fixed it! It was a broken via between UD8 and the video ROM on address line 0. It also fixed the sound issue 😀 |
Posted by: David Cook on 2026-01-03 09:47:44
Congratulations!!! |
Posted by: LeSpameur on 2026-01-03 10:04:05
Congratulations!!! Thanks!! What a relief after all this time spent probing and checking traces… |
Posted by: GreenBar0n on 2026-01-03 12:21:36
Fixed it! It was a broken via between UD8 and the video ROM on address line 0. It also fixed the sound issue 😀 Nice work! That's exactly what I'm seeing on mine too, missing pin 4 on UD8, A0 - but also pin 12, A1, a new F253 will be here Monday . Congrats! |
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