Mac Plus SCSI Problems

Discussion in 'Apple Collectors' started by bunnspecial, Jan 24, 2016.

  1. bunnspecial macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #1
    I'm trying to get my Plus to boot off a SCSI HDD, which I know can sometimes be a feat easier said than done.

    I'm working with a generic SCSI enclosure with a 4GB drive, although I also have an OWC enclosure(same size drive) that I could use if need be.

    I initially set the drive up from my 9600 using a "patched" version of the HD SC set-up utility that(I think) came with System 6. The drive was set to ID 4, connected to the 9600 by a 3' long DB-25 to Centronics 50 cable, and a terminator on the other Centronix port. The drive worked fine on the 9600. I set it up with 3 partitions-the first one is 900 and some MB and the others about 1.5gb each. I then put a good, bootable System 6 folder on the 900mb partition.

    I then connected it to the Plus, and the computer is not acting as though it even sees it. The drive does not respond as if the computer is "talking to it" upon booting up, and the same version of HD SC set up I used from the 9600 to format it can't see it.

    I know that Pluses can be "touchy" about their SCSI ports, and I've tried different termination set-ups including a couple of different ones on the second Centronics port and an Apple branded pass-through terminator. I've used a couple of different cables just to rule that out.

    Any ideas of other things I can try, short of paying the inflated prices for a 20SC on Ebay?
     
  2. MacTech68 macrumors 68000

    MacTech68

    Joined:
    Mar 16, 2008
    Location:
    Australia, Perth
    #2
    If you can squeeze a copy of SCSIProbe onto a your boot floppy, have a look and see what it reports. That would be a good start.

    Have you tried connecting the drive WITHOUT an external terminator?

    Of course, you're doing all these SCSI cabling changes with everything switched off. ;)

    Try changing the order of power-on. IE, try turning the hard drive on FIRST - waiting 30 seconds, then turning on the Mac Plus.

    Also, make sure the partitions are HFS and NOT HFS Plus formatted.
     
  3. bunnspecial thread starter macrumors 603

    bunnspecial

    Joined:
    May 3, 2014
    Location:
    Kentucky
    #3
    Thanks for the response.

    Yes, I do have it very thoroughly etched into my brain to manipulate SCSI with the power off(thank goodness for USB and Firewire!). I've used enough external SCSI peripherals that I've also long been in the habit of powering all of the up before powering on the computer. This computer has a Kensington System Saver on it that makes doing this super easy(although admittedly reaching around to the back to flip the switch on the hard drive isn't exactly difficult.

    In particular, I'm careful about this with HDDs. I have an HD20 connected to my 512Ke(I actually suspect that it may be the original companion piece for this Plus, as both were given to me by the same person) and know that I have to give it a fair bit of time to spin up.

    In all honesty, I wish I had another HD20, as it "just works"(until the inevitable day where it doesn't) but am trying to make SCSI work with the Plus since it gives me so many more options.

    This drive is formatted HFS Standard. I formatted it with HD SC set up 7.5.3 from the 9600.

    And, as per your suggestion, I did try without any termination at all. The drive did give some signs of "life" when I booted the computer. The LED on the on the front of the drive changed from red to green, which seems to indicate that the drive is "talking" to the computer, but the orange access light never came on.

    I'll try cramming a copy of SCSI probe onto a disk. I do at least have an external, so I can put on a separate disk from the boot disk.
     
  4. havokalien macrumors 6502a

    havokalien

    Joined:
    Apr 27, 2006
    Location:
    Kelso, Wa
    #4
    Do not use HFS. Use OS 8 or 7 and format Macintosh Format (pretty sure 7.5.5 was the last to really do it but I think 8 could do floppies). HFS did not come out until the compacts were officially unsupported.
     
  5. MacTech68 macrumors 68000

    MacTech68

    Joined:
    Mar 16, 2008
    Location:
    Australia, Perth
    #5
    Actually, the MacPlus ROMs were the first to support HFS. The same ROMs in a 512Ke also support HFS.
     
  6. havokalien macrumors 6502a

    havokalien

    Joined:
    Apr 27, 2006
    Location:
    Kelso, Wa
    #6
    As a rule for boot support a non apple driver should be used to make a zip disk bootable like LIDO or Hard Disk Toolkit as the driver for boot is only supported on Apple Hard drives. Support may be there but the early macs are very stubborn.
     

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