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Dog Cow

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  1. Dog Cow

    ROMBUS - 64 MB flash interface for Mac Plus

    By "spots" do you mean "bytes" ? Off the top of my head, I can name the "Stolen from Apple Computer" icon as something that could be overwritten. Or at the tail end of the ROM are several sets of initials which could be overwritten. A little more obscure are the Toolbox traps for resource references. Basically nobody used references, according to Apple, and they were deprecated in the 128K ROM. Thus the code could be overwritten for your purposes. The resource reference traps may have been completely removed in the 128K ROM. I'd need to do some more checking on this. By the way, you probably already know this, but the ROM has a 4 MB address space, however on the 128K/512K motherboard, there's only enough address lines to the sockets to address 128K of ROM. Perhaps this fact could be used to advantage on 64K ROM machines...
  2. It may be Microsoft Chart, or it may not be anything. It could be a mockup screenshot merely to promote the Plus as a business-class machine.
  3. Dog Cow

    Discharging a CRT - video

    When working on the Mac at some point you will need to plug it for testing and when doing so you will have charged up the CRT. If the issue you are attempting to resolve remains unresolved, I don't need to do any testing while I wait for the CRT part to arrive in the mail. I already did my testing, determined what part(s) I needed, and my Mac remains powered off while they arrive. I install the part(s), then power on the Mac again and it is fixed.
  4. Dog Cow

    Mac 512K with Hyperdrive 20 having issues

    Your Sad Mac error 0F0064 means that the Mac's boot loader in ROM found the boot blocks on disk, but wasn't able to load the System file. Stick to 400K disks for now. The single-sided 400K drive can read 800k disks, but only the bottom side, meaning the Mac's ROM will find the boot blocks on your 800K disk, but then will show Sad Mac 0F0064 as it can't load the System file from the top side of the disk.
  5. Dog Cow

    Imagewriter II ribbon cartridge sources?

    After I posted that link, I was wondering if that's actually what you wanted. And now I'm not wondering. I bought a black ribbon from one of these suppliers probably about 8 years ago. Don't remember which one, but it is still working fine.
  6. Dog Cow

    Imagewriter II ribbon cartridge sources?

    Take your pick; plenty of suppliers for black ribbons
  7. The list of Sad Mac codes says "4 = Memory test - Mod3 test"
  8. G10, G6, F9, F8, F6, and F5.
  9. Dog Cow

    SE/30 does not boot

    Suggested experiment: Attach the drive's SCSI cable only. Power on the Mac SE/30. When the question-floppy icon appears, plug the power cable into your SCSI drive. Report back what happens.
  10. When you say "via software," you're probably referring to the Mac SE and newer machines which use the Startup CDEV to set the boot device, and retain this setting in PRAM.
  11. Dog Cow

    killing Plus keyboard with proper cable?

    Maybe. Depends on if you believe in hot-plugging or not. ADB is not supposed to be hot-plugged, but I've done it and had it work. But I've also ruined a Mac LC ADB port by hot-plugging. The keyboard port on a Mac 512K or Plus is probably not supposed to be hot-plugged either, but I've done it and had it work too. But maybe next time I try it, it will fry a keyboard or something on the motherboard.
  12. Dog Cow

    The 2020 Experience

    Post here if your Mac thought it was 1920 instead of 2020. :-P My Mac 512K with System 2.0/Finder 4.1 recognizes that it's 2020, but my SE/30 with 7.5.3 thinks it's 1920.
  13. Dog Cow

    Discharging a CRT - video

    Yep. Usually what I do is wait for whatever replacement part to arrive in the mail, and during that waiting period, I do not switch on the Macintosh.
  14. Dog Cow

    Macintosh 512k sad Mac error help

    Because the ROMs are socketed, the solution could be as simple as reseating them.
  15. Dog Cow

    Developing a portable user-land AppleTalk stack

    cheesestraws, There was some AppleTalk networking code written for Unix systems back in 1984-85 at Stanford and other universities. Look up the SUMMacC, EFS, and SEAGATE projects. Towards the bottom of this AppleTalk article in the section "AppleTalk Overview" are some links to get you started. There are other projects as well, so look around and I think you'll find that a lot of the groundwork is already done for you.