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Re: Lobo floppy drives

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  • s100doctor
    ... I agree. When you flip over the drives, check the PC boards for a PC board number. Then you ll know which set of schematics you ll need. They look like
    Message 1 of 40 , Nov 14, 2012
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      Bill Degnan:
      > >
      > > Yup. Shugart 800 or 801s.

      I agree. When you flip over the drives, check the PC boards for a PC board number. Then you'll know which set of schematics you'll need. They look like Shugart 800/801 to me but there will be more identification on them. I have organized my Shugart 800 docs based on PC board numbers:

      http://retrotechnology.com/herbs_stuff/s_drives.html#f8.0

      and there may be manuals specific to your drive versions on various PDF archive Web sites too. The 801 was simply an 800 with jumpers set to provide decoding of hard-sectored sector pulses. There's actually a 800/801 named jumper.

      Lobo made products for TRS-80's and I think they had some kind of S-100 interface for another Z80 system in the era. But it doesn't matter: they simply wrapped a case around a manufacturer's drives. I imagine if you Google search their Infoworld magazine archive, you'll likely see some Lobo advertizing.

      Herb Johnson
    • Mike Loewen
      ... Here s the service manual for the Tandom TM-848, with the schematics in the back: http://bitsavers.trailing-edge.com/pdf/tandon/TM848_service_1982.pdf
      Message 40 of 40 , Dec 15, 2012
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        On Sat, 15 Dec 2012, joshbensadon wrote:

        > --- In midatlanticretro@yahoogroups.com, Mike Loewen <mloewen@...> wrote:
        >>
        >> The double-sided drives have a 2S signal on pin 10 of the interface
        >> connector to indicate single or double-sided media. The outputs of the
        >> respective pulse-shaping ciruitry for each sensor is essentially ORed to
        >> form a single Index pulse output.
        >
        >
        > Cool, so I can imagine the two sensor signals going to an RS flip flop
        > to provide the 2S signal and as you said to an OR gate for the index.

        Here's the service manual for the Tandom TM-848, with the schematics in
        the back:

        http://bitsavers.trailing-edge.com/pdf/tandon/TM848_service_1982.pdf

        Knock yourself out. :-)

        > Hmm, thinking about why, I guess the design was to create a hardware
        > error if a user placed a DS disk into a SS drive. As Rich found, the
        > lack of index pulses caused a drive not ready. Correct me if I'm wrong,
        > but in later 5.25" drives, they did not change the index sensor
        > location. Then I suppose the errors created would be software
        > generated?

        The 5.25" drives only had a single index hole aperture.

        > I vaguely remember hearing a discussion about how computers switched
        > from hardware solutions to software solutions, then back to hardware.
        > I just don't know the dates, could this 8" to 5.25" be part of that
        > switch?

        I couldn't say. Certainly Woz did a lot in software for his Apple II
        disk controller design. Another odd thing about the 8" drivers vs the
        5-1/4" drives was that the 8" drives had a write-enable notch, while the
        5-1/4: drives had a write-protect notch. Very confusing.


        Mike Loewen mloewen@...
        Old Technology http://sturgeon.css.psu.edu/~mloewen/Oldtech/
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