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quorten

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  1. So close... I have to say I have high hopes about this. Relating to the previous discussion about the BBU pinout, it looks like it's all correct on the actual board design, Sprint Layout's misclassification of MBRAM and ROW2 was due to the fact that these are connected to pull-up resistors. Also, another note, I did find the SE PDS pinout and verified it was correct in my retrace of the schematic (one rename but otherwise good).
  2. Wow, really? So Uniserver just copied the BOMARC schematics and put a price tag on them? I do have to agree, though, there seems to be a heck lot of copying for the schematics but not very many folks putting effort to improve quality on them, so I guess I shouldn't be too surprised if this is what you mean.
  3. I've noticed the note #4 at page 1 erroneously says "RDB" instead of "ADB". Now that I'm getting more into redrawing the Macintosh SE MLB schematics, I'm also looking to the redrawn SE/30 MLB schematics for reference. Though the original SE/30 scans are not nearly as illegible or as incomplete as the SE MLB schematics, looks like there are still a number of small fact/quality checks and improvements remaining. I might see what I can do to carefully eye through it the way I've done for the only page of the SE MLB schematics that is scanned, as in any case it would be a good learning experience for me too. As a side note, I've noticed that @uniserver also happens to have some redrawn SE/30 schematics on his personal website that have purportedly been around for much longer. It requires payment through PayPal, though, and I'd guess his way of running the site requires him to manually send an E-mail to you after the payment is received, which may not be guaranteed if he's no longer very active with his site. Also, It's been years since he's last been on 68kMLA. Has anyone ever bought/used Uniserver's schematics? I'm curious to hear what you thought about them.
  4. Judging from the 1/3 in the bottom right corner and the tiny text above it that appears to say "SHT" (sheet) in scans of other pages, I'd assume page 3 of the main logic board schematic is also missing, unless you've turned up something for that. At least we have some hints about which components go on which pages based off of the numbers in parenthesis on the arrows to connections on other pages. I'm feeling pretty confident now about my retrace of page 1, I'll be able to move to drawing up full MLB schematics in KiCad soon. I still need to check the PDS pinout with a second source since I had trouble finding it. Could someone provide a link? My work is up here on GitHub. https://github.com/quorten/macsehw Link straight to the redrawn PDF. The BBU pinout is definitely helpful! Where did you get it? It uses a slightly different terminology than the original deciphered schematic. Also there are a few technical differences that I've spotted. Possibly some of these might be a (deliberately) introduced error on the original schematic? RDO0, RDO1, RDO2, ... (instead of RD0, RD1, ...) 11 *ENTD1K mystery symbol (indicate inverted signal, replace EXTPDS placeholder) 12 *EN245 (indicate inverted signal) 13 ROW2 (RAM configuration pin, instead of generic VCC, though maybe it's really the same thing) 17 MBRAM (RAM configuration pin, instead of *EOP for 53C80 SCSI controller) 32 *IRQ (indicate inverted signal) 44 C16MRSF2 (16 MHz clock descriptive label instead of FCLK) 45 *SELSCC (indicate inverted signal) 50 SNDRST (SNDRES) (replace PB7 placeholder) 53 VIDPG2 (replace PA6 placeholder) 52 *EAREN (replace EXTPDS placeholder) 82 C2M (2 MHz clock for 74F257 chip select, as opposed to EN257 label) 60 *HSYNC (indicate inverted signal) 61 *VSYNC (indicate inverted signal) An important point, the Reddit you've linked for a replacement RTC does indeed have a minor error, the time in seconds should be separate from the 256 bytes of PRAM. It's worth cross-checking this source code with the corresponding source in a few different software emulators before sticking one of those chips in a real hardware system, not to mention that it still does need a bit of work as originally mentioned. I started making a few changes in the copy in my GitHub repo with the schematics. Really, both the RTC and the BBU, neither of these are hard to re-implement, it's just that... it requires a bit more understanding on the software side of affairs. @Kai Robinson One important thing missing from the printed circuit board reproduction thus far: looks like you forgot the B1 reference designator. Sure, here on 68kMLA we all know it by its much more affectionate name, the PRAM battery, but nothing quite completes the experience of removing and replacing those beasties without the unapologetic reference designator to assign an ID number to yet another nameless battery.
  5. So I decided to split up modernizing the Macintosh SE main logic board schematics into two stages. The first stage is for my own proof that I can actually read anything meaningful off of the original scans: trace over vector graphics and typed text on the original schematic image. It's almost finished, but not quite, it has a few text transcription errors (due to the difficulty of reading), but this is what I have so far. Fortunately, there is a certain degree of redundancy in the text labels, and seeing the big picture clearly really helps too. As it turns out, the reverse engineering on the PCB layout will indeed be helpful in correcting minor errors. Like, resistor identifiers and values, having zero ambiguity on that. Also, other things can easily be solved by consulting other tech specs like datasheets, the PDS slot documentation, and so on. retrace_se_mlb_schem.pdf
  6. Looking at the fuzzy Macintosh SE schematic right now, a first try at a grayscale conversion and gamma-adjusted image rescaling seems to make at least some parts easier to read, albeit at reduced resolution. I'm looking to try my hand at redrawing this if I think I can see sufficient detail from the originals.
  7. +1, I would also agree. I'm guessing probably the main reason for doing otherwise would be as part of the first stage of Tindie sales to recoup the costs. But otherwise, for the publicly available designs, definitely I would prefer 1:1 so that we can emulate the good old feeling of retrofitting unoriginal capacitors.
  8. Wow, I feel like I've come late to seeing this development. 1/2 what I was wishing would happen. The other half, modern schematics for the Macintosh SE. Well, I've seen what @elemenoh has done for the SE/30 schematics and these two separate projects together really makes me want to go and do likewise for the Macintosh SE, if no one else has yet stepped up to the task. Interesting that I thought the sequence of events would happen the other way around, but well, some things just turn out a bit more chaotic than ideal.
  9. quorten

    SE/30 worth repairing ?

    Oh wow! Not sure why I had trouble linking across the forum in a durable means before, but in any case looks like 68kMLA now has a reliable means to do so. This is what I found chasing around.
  10. quorten

    Question mark over checkerboard pattern on SE

    Ah, yes, link hacking magic, the working link has been restored. Yes, it's an SE/30 instead of an SE. But I see there is SE/30 on your exterior case from the photo. (No mention of checkerboard here actually, but helpful advice.) https://68kmla.org/forums/index.php?app=forums&module=forums&controller=topic&id=58398
  11. quorten

    Question mark over checkerboard pattern on SE

    Elsewhere on the forum I believe mention of a similar problem with checkboard pattern pointed to bad address multiplexers. You could try replacing the address multiplexers and see if that works, but I'd defer to looking at that forum post first. Here is the link to the forum post I saved on my personal blog, but alas, the link is broken! Go fish and see if you can search it out of the forum. https://68kmla.org/forums/index.php?/topic/58398-se30-vertical-stripes-death-chimes/
  12. Nice! If I don't get any more info about anyone who's started a PCB layout, I might create a simple pull request so that we can get something simple started that would at least be helpful for an interactive BOM and recapping projects. But, before that, probably the first pull request I may make would simply be to polish the repository structure, documentation, etc. so that it is comparable with other KiCad projects out on GitHub.
  13. Wow, really nice work @elemenoh, this is just what I was hoping to see happen sometime. Definitely I'd like to see these schematics make their way into a better information repository than Google Drive, like the 68kMLA wiki, etc. I'd offer that probably the best way to go about maintaining/improving the schematics would be to put them in a GitHub repo or anything more proper of a revision control system than Google Drive. Sounds like @Bolle may have started on laying out the footprints as a first step in creating the printed circuit board layout. Even without complete PCB traces, this would allow for the creation of an "interactive BOM" which can be helpful for guiding a recap operation, for example. For sure, it would be interesting to see this go further and include other Macintosh models too. As I'm also familiar with KiCad, I'd also be willing to chip in to the PCB design.
  14. quorten

    3D printed programmer switch

    Yeah, I've made that Thingiverse model using SLA printing as-a-service from dirtypcbs.com. It's pretty cheap there, and the buttons appears to work well, I've taken it out and put it back in a few times and had no trouble other than it is a bit stiffer than the original, so it seems, but otherwise it seems to bend back and forth okay and I'm not concerned about it being brittle and breaking... just concerned about accidentally double-triggering it because of the stiffness. Also, I'm mildly annoyed that it doesn't strive to be a more physically accurate replica of the original, but hey, what can we complain for a part that was designed to work fairly well with FDM?
  15. quorten

    The 2020 Experience

    My Macintosh SE with System 6.0.7 correctly recognizes the year as 2020. Interesting that the newer system software has that defect, you'd think it would be the reverse.
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