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johnklos

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  1. johnklos

    Original Hackintoshy Thing

    http://www.maccaps.com/MacCaps/Repair_books_files/Macintosh Repair and Upgrade Secrets.pdf Page 168 and on describe the adapter. It's just a 74LS14, which is just an inverter with a Schmitt trigger, which just cleans up the signal so superfluous changes aren't reflected on the output. The board in the first picture has a 74F253, which may be used to decode address bits or something like that for... a hard drive LED? It'd seem strange to have so much circuitry for just that, but I don't see any other hardware in there that would make use of this...
  2. johnklos

    Full 68040 for Quadra 605

    You know, one of my Q605 motherboards has a MC88916DW80. When I find that specific motherboard, I'll try that out. I bought, I think, half a dozen MC88916DW80 and only used one, so this would be good to know. I find it interesting that because of the amount of time spent using the bus, my QuadDoubled machines running at 50 MHz with a 25 MHz memory bus are, for many uses, slower than a 40 MHz overclocked Q605. Good, solid, true 40 MHz overclocks would be very nice, particularly when I start to build my Q605 cluster
  3. johnklos

    Full 68040 for Quadra 605

    If I remember correctly, stuff (no idea what) won't run at the full 40 MHz. Don't know if memory is too slow, or if some of the peripheral chips won't run at 40 MHz, or what. So the idea is to run the motherboard at 33 MHz, then remove a surface mount resistor to disconnect a clock going to the CPU's clock generator (the MC88920), then wire the output of the 20 MHz oscillator to the pad which leads to the CPU's clock generator. It's outlined here: Quadra 605 overclock to 40 MHz using crystal oscillator I've done this on many Q605 boards, and they typically don't run at 40 MHz, according to Clockometer, but they run close - usually around 38 MHz. I don't know how this works this way, but it does
  4. johnklos

    Full 68040 for Quadra 605

    BTW - all m68040s, with the only possible exception being 1990 engineering samples, were made from the same batches that made 40 MHz parts, so pretty much all of them can run at 40 MHz with good cooling, and all of them can certainly run with no issues at 33 MHz with a heat sink. Running a Quadra 605 or Performa 475 system at 40 MHz, though, requires a 20 MHz crystal oscillator and a wee bit more soldering.
  5. johnklos

    Quadra 650 & 800 Logic board differences

    There are no speed or component differences between Quadra 650 and Quadra 800 models. The Centris 650, though, ran at 25 MHz, and some came with LC040 FPU-less CPUs and without motherboard ethernet.
  6. johnklos

    Full 68040 for Quadra 605

    Most m68040 CPUs in Macs are XC because Motorola took so darned long to "qualify" the '040 to make an official MC part: Official MC mask announcement Original XC68040s (D43B, D50D, D98D, E31F) run hot and are .8um masks, but will run fine at 33 MHz with a heat sink. The E26A is an XC part with a .65um mask, which might be a little cooler. Starting with the E42K mask, they are fully qualified MC68040 parts with .65um masks. Then K63H reduced the mask to .57um. Finally, the latest / last version is the L88M, which is also .57um, but runs cooler than the K63H according to some sources. This version is usually made by Freescale and has their logo in place of the Motorola M. Some eBay sellers scrub the markings off of older m68040s and print newer markings on them to sell them for more money. Unlike the m68060 which has bits in a status register which identify clearly the revision of the CPU, there's no easy way to find out whether you have a real, proper, newer mask. If you have a good thermometer and/or can measure your 5 volt current draw, you can compare the old CPU with the replacement, but other than writing some tricky code to look for specific errata in certain models, there's no straightforward way in software to see what you've got, so try to go with sellers that have high seller ratings.
  7. Eight slots means you can have up to 8 gigs of memory. It's not all that picky, but I've found lots of older memory which won't properly run at the full 400 MHz. Considering how cheap the memory is these days, though, you should be able to get matching sets for really not much.
  8. johnklos

    Sci drive not working

    You can use any disk formatting software with SyQuest, but if you use the wrong kind, it won't necessarily support changing cartridges properly without restarting. The SyQuest extension will poll the drive for disk changes.
  9. johnklos

    68030 PDS: implimentation inconsistencies?

    I have a few machines which are running off of +5 and +12 volts. The only thing that doesn't work is the sound.
  10. johnklos

    China Ebay 68040 processor

    My kitty will volunteer one for you. If you have a good thermometer, measure the idle and busy temperatures of the CPU before you replace. I got a few m68040s which were supposed to be the newest mask which got just as hot as an old early 1990s mask before I finally got a real new one.
  11. johnklos

    Bad caps leading to slow performance ?

    The only time I've seen caps affect speed is when the SCSI bus was affected and got lots of errors due to capacitor problems. I couldn't see any issues in Mac OS, but in NetBSD I'd get SCSI errors in a constant stream. Recapping fixed the SCSI, and disk access went from painful to what we typically expect (mediocre).
  12. There's only a 2 TB limit. While the SCSI chips support drives larger than 2 TB, the limit comes from using just 32 bits worth of blocks (four billion 512 byte blocks). SCA isn't a problem so long as you get adapters with high line termination, like so: https://www.ebay.com/itm/SCA-80-Pin-to-IDC-50-IDC-Male-Adapter-with-High-Line-Termination/233090532398 Likewise, 68 pin SCSI drives with 68 to 50 pin adapters work fine so long as termination is for all 68 pins, like so. The 50 pin motherboard connector has an adapter to go to 68 pin, and the 68 pin drive (SCSI to IDE) and terminator are both 68 pin.
  13. johnklos

    640x480 on LC II?

    Welp. I tried on my LC II, too. I even found a monitor adapter with switches, set the screen depth to 1 bit, and removed the VRAM. I get the grey screen and that's all. The machine boots, but I can't see anything. While looking for the monitor adapter with switches, I came across a 512K VRAM SIMM, so I guess I don't need to do this anyway, but I was definitely curious
  14. johnklos

    Best way to bootstrap LC II without floppy?

    Just posting for future reference. I eventually got everything working on a 250 meg CompactFlash card in the PCD-50B by using a SCSI2SD set to the same number of sectors as the CF card. For some reason, the CF card in the PCD-50B fails when I try to initialize it using Drive Setup or HD SC Setup (both patched, of course). The SD card in the SCSI2SD worked fine, so I initialized, copied the System Folder and programs, then used dd to copy the SD card to the CF card. The nice thing is that I can just connect the CF card to my Mac, chown my user /dev/disk2 (or whatever it comes up as in diskutil list), then give /dev/disk2 to Basilisk II, then access the CF card right from Basilisk.
  15. johnklos

    640x480 on LC II?

    After seeing mention about how the LC and LC II can do monochrome video when no VRAM is installed, I tried it. It didn't work. Then again, my multiscan adapter only works with my LC II in 512x384 mode. So, even though the machine booted, nothing beyond the boot grey appeared on the screen (the boot grey is unlike other models - it comes on immediately on power up). After checking in Apple Service Technical Procedures, I see that it is only supposed to work in 640x480 mode (Basics, 1.18): Does anyone know what I'd have to do to make the LC II run at 640x480? Do I need a diode across pins 7 and 10 of the video connector, like in the first diagram here?
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