litriSE's latest activity
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LlitriSE replied to the thread Mac Plus 820-0174-A: pulsating vertical-line pattern, no bong, good sync — TSM and LAG cleared via custom PAL exerciser. Where next?.Hello eifeldude! No, I have not made additional progress on this board. I plan to work on it again over the next coming weeks. I'll...
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LlitriSE replied to the thread Mac Plus 820-0174-A: pulsating vertical-line pattern, no bong, good sync — TSM and LAG cleared via custom PAL exerciser. Where next?.I pull the last three remaining chips in the jellybean section - 74LS257 U2G, 74LS393 U1F, 74LS393 U1G. The 74LS257 in U2G was bad and...
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LlitriSE replied to the thread Mac Plus 820-0174-A: pulsating vertical-line pattern, no bong, good sync — TSM and LAG cleared via custom PAL exerciser. Where next?.I continue to struggle to clear the 02FFFF error. I've replaced all four 74F253s. I also pulled the 74LS257 at U2F — it tested clean on...
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LlitriSE replied to the thread Mac Plus 820-0174-A: pulsating vertical-line pattern, no bong, good sync — TSM and LAG cleared via custom PAL exerciser. Where next?.Update: Mac Plus 820-0174-A — pulsating vertical lines, no bong Located and replaced a faulty 74F253 mux (confirmed via DMM —...
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LlitriSE posted the thread Mac Plus 820-0174-A: pulsating vertical-line pattern, no bong, good sync — TSM and LAG cleared via custom PAL exerciser. Where next? in Compact Macs.Mac Plus 820-0174-A: pulsating vertical-line pattern, no bong, good sync — TSM and LAG cleared via custom PAL exerciser. Where next? Hi...
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LlitriSE replied to the thread Running a Mac Plus logic board on an SE analog board/PSU — anyone done this?.Update: it's fully working. Full writeup below with final measured values, in case it's useful to anyone else attempting this...
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LlitriSE replied to the thread Running a Mac Plus logic board on an SE analog board/PSU — anyone done this?.Update: found the actual mismatch, working on a fix. Scoped VSYNC directly at the connector on both boards for a real apples-to-apples...
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LlitriSE replied to the thread Running a Mac Plus logic board on an SE analog board/PSU — anyone done this?.Update: got it working (mostly)! Connected a known-good Macintosh Plus logic board (1MB RAM, booting off BlueSCSI) to a known-good...
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LlitriSE posted the thread Running a Mac Plus logic board on an SE analog board/PSU — anyone done this? in Compact Macs.I'm looking at running a Macintosh Plus logic board off a Macintosh SE's analog board, CRT, and PSU, instead of the Plus's own analog...
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LlitriSE replied to the thread Macintosh SE Checkerboard pattern with random speckled dashes, no boot chime.SOLVED: Checkerboard/noise turned out to be two separate faults — bad ROM LOW chip + a loaded reset line Wanted to close the loop on...
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LlitriSE replied to the thread Macintosh SE Checkerboard pattern with random speckled dashes, no boot chime.Do we know what drives the 68000 Reset to high?
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LlitriSE replied to the thread Macintosh SE Checkerboard pattern with random speckled dashes, no boot chime.Update: RESET/HALT stuck low regardless of switch state — chasing what's actively driving it A fellow member, GreenBarOn, suggested...
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LlitriSE replied to the thread Macintosh SE Checkerboard pattern with random speckled dashes, no boot chime.Update: Macintosh SE checkerboard/noise — continuity testing complete, need advice on scope approach or component swapping Following...
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LlitriSE posted the thread Macintosh SE Checkerboard pattern with random speckled dashes, no boot chime in Compact Macs.I have a Macintosh SE 820-0176-B, 1986, 630-4125 logic board that shows a checkerboard pattern with random noise/static (speckled...
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