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SE/30 Screen Shaking
Posted by: George on 2021-10-12 09:54:00 Hello everyone, nice to meet you. I got a bad Macintosh SE/30. At first, it had no chime, but OS was run. And The screen has like checkered pattern. First image is that state. So, I recaped logic board. SE/30 got chime, but screen didn`t change. I tried to wash logic board. Then chime add noise, and screen was shaking. :< 2nd movie is that state. I got SE/30's schematic, and searched a circuit disconnect. I repair some disconnects, then SE/30's chime was clear! Next, I removed UA8 - UG8, and resoldering, then I got SE/30's screen without checkered pattern! But, screen shaking was there. 3rd movie is that state. A part of floppy was indicated. 4th image is that state. I have good Macintosh SE. And I connected SE's logic board to SE/30's analog board and PSU, CRT, the screen was not shaking. Then, I connected SE/30's logic board to SE's analog board and PSU, CRT, the screen was shaking SE/30's PSU can output over 5v & 12v voltage. So I think, logic board's issue. I searched a circuit disconnect about vsync. But I couldn't find. I'm stuck. I'm sorry I'm not good at English, so maybe you can't understand to my information. But please help me.
Posted by: George on 2021-10-25 06:18:18 Hello everyone. I don't give up yet. And there was a change in the situation. I clean up ROM SIMM's terminal and slot carefully . Then, SE/30's screen shake was gone! 🙂 But, SE/30's screen got stripe line. image2 is that state. I cleaned up around video logic,but did not change state. So, I want to get screen shot, and ask to advice in this forum. This time, SE/30 got good screen at once. image0 is that state. But, that state was only one time. My SE/30's screen is image2's state right now. Please tell me the solution of this issue.
Posted by: joshc on 2021-10-25 07:19:34 That garbled pattern is caused by bad VRAM chips.
Posted by: joshc on 2021-10-25 08:18:09 On second thought (actually, because someone who knows better than me saw my post and messaged me about it) this is more likely a bad address line to the muxes - the traces around there may be damaged from the capacitors leaking previously. Check all the connections for the muxes to see if there's a bad trace there.
Posted by: Byrd on 2021-10-25 16:24:46 View attachment 35240 Clean these chips very well - I just resurrected my 2 x SE/30 boards with video issues cleaning this entire site with IPA, Windex and a very soft toothbrush.
Posted by: George on 2021-10-26 02:24:56 On second thought (actually, because someone who knows better than me saw my post and messaged me about it) this is more likely a bad address line to the muxes - the traces around there may be damaged from the capacitors leaking previously. Check all the connections for the muxes to see if there's a bad trace there. View attachment 35240 Thanks. Maybe, 2nd advice is right. Because, I have another VRAM chip, and I changed before. But didn’t change state. I checked these connections before, but the situation was changed. So, I will try it again.
Posted by: George on 2021-10-26 02:59:06 Clean these chips very well - I just resurrected my 2 x SE/30 boards with video issues cleaning this entire site with IPA, Windex and a very soft toothbrush. Thanks. I will try it!
Posted by: George on 2021-10-29 20:49:35 Hello everyone. My SE/30 is back! UD8 to A0 pattern was disconnected, so I bypassed to UE10. Then, SE/30's screen was clear. Thank you very much!
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