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Quantum Q540/MFM cabling question

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  • Richard Cini
    All ï I got a CompuPro Disk3 controller and Q540 36MB (!!!) hard drive for my IMSAI, so I may try to piece together a hard drive system for it. I have a set
    Message 1 of 4 , Mar 2, 2014
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      All —

      I got a CompuPro Disk3 controller and Q540 36MB (!!!) hard drive for my IMSAI, so I may try to piece together a hard drive system for it. I have a set of ST506 cables for it (I think), but I wanted to ask about the cabling. The control cable (34-pin) has a twist in it between the C and D connectors. I didn’t count the wires but it looks like the same kind of drive_select twist as in the IBM floppy cables. Is this normal for this kind of cabling?

      Also, the drive didn’t come with a terminating resistor pack. I think it’s a 220/330 pack, but if anyone has a Bourns part number for it, I’d appreciate it.

      Thanks!


      Rich

      --
      Rich Cini
      Collector of Classic Computers
      Build Master and lead engineer, Altair32 Emulator
    • Dave McGuire
      I m just on my mobile phone at the moment, so I will be brief, can provide more info later, but for now...no, it is NOT the same cable. MFM control cable
      Message 2 of 4 , Mar 2, 2014
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          I'm just on my mobile phone at the moment, so I will be brief, can provide more info later, but for now...no, it is NOT the same cable.  MFM control cable twists different pin numbers.  I seem to recall "in 5, flip 5" for MFM control cables but I don't have the pinouts in front of me.  Don't power it up with a floppy cable!

          Incidentally the Quantum Q540 is one of two drives DEC sold as the RD52.  I love the chitter-chitter sound those drives make.

                         -Dave

        -- 
        Dave McGuire, AK4HZ
        New Kensington, PA


        On Mar 2, 2014, at 10:17 AM, Richard Cini <rich.cini@...> wrote:

        All —

        I got a CompuPro Disk3 controller and Q540 36MB (!!!) hard drive for my IMSAI, so I may try to piece together a hard drive system for it. I have a set of ST506 cables for it (I think), but I wanted to ask about the cabling. The control cable (34-pin) has a twist in it between the C and D connectors. I didn’t count the wires but it looks like the same kind of drive_select twist as in the IBM floppy cables. Is this normal for this kind of cabling?

        Also, the drive didn’t come with a terminating resistor pack. I think it’s a 220/330 pack, but if anyone has a Bourns part number for it, I’d appreciate it.

        Thanks!


        Rich

        --
        Rich Cini
        Collector of Classic Comput ers
        Build Master and lead engineer, Altair32 Emulator
      • Richard Cini
        Thanks Dave. The connectors are labeled │C▓ and │D▓ and the twist is │5 in flip 5▓ between the two. I did power the drive up without cables (since
        Message 3 of 4 , Mar 2, 2014
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          Thanks Dave. The connectors are labeled “C” and “D” and the twist is “5 in flip 5” between the two. I did power the drive up without cables (since I don’t have the controller working) — it’s a great sound.

          Rich

          --
          Rich Cini
          Collector of Classic Computers
          Build Master and lead engineer, Altair32 Emulator

          From: Dave McGuire <Mcguire@...>
          Reply-To: MARCH-Post <midatlanticretro@yahoogroups.com>
          Date: Sunday, March 2, 2014 at 10:27 AM
          To: MARCH-Post <midatlanticretro@yahoogroups.com>
          Subject: Re: [midatlanticretro] Quantum Q540/MFM cabling question

           


            I'm just on my mobile phone at the moment, so I will be brief, can provide more info later, but for now...no, it is NOT the same cable.  MFM control cable twists different pin numbers.  I seem to recall "in 5, flip 5" for MFM control cables but I don't have the pinouts in front of me.  Don't power it up with a floppy cable!

            Incidentally the Quantum Q540 is one of two drives DEC sold as the RD52.  I love the chitter-chitter sound those drives make.

                           -Dave

          -- 
          Dave McGuire, AK4HZ
          New Kensington, PA


          On Mar 2, 2014, at 10:17 AM, Richard Cini <rich.cini@...> wrote:

          All —

          I got a CompuPro Disk3 controller and Q540 36MB (!!!) hard drive for my IMSAI, so I may try to piece together a hard drive system for it. I have a set of ST506 cables for it (I think), but I wanted to ask about the cabling. The control cable (34-pin) has a twist in it between the C and D connectors. I didn’t count the wires but it looks like the same kind of drive_select twist as in the IBM floppy cables. Is this normal for this kind of cabling?

          Also, the drive didn’t come with a terminating resistor pack. I think it’s a 220/330 pack, but if anyone has a Bourns part number for it, I’d appreciate it.

          Thanks!


          Rich

          --
          Rich Cini
          Collector of Classic Comput ers
          Build Master and lead engineer, Altair32 Emulator

        • Dave McGuire
          That s a hard drive cable then. I found my very old notes about this...For a floppy drive, starting from pin 1, in 9, flip 7 . For an MFM control cable, you
          Message 4 of 4 , Mar 2, 2014
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            That's a hard drive cable then. I found my very old notes about
            this...For a floppy drive, starting from pin 1, "in 9, flip 7". For an
            MFM control cable, you start from the other end, pin 34, and it's "in 5,
            flip 5".

            *chitter chitter*

            -Dave

            On 03/02/2014 10:53 AM, Richard Cini wrote:
            > Thanks Dave. The connectors are labeled “C” and “D” and the twist is “5
            > in flip 5” between the two. I did power the drive up without cables
            > (since I don’t have the controller working) — it’s a great sound.
            >
            > Rich
            >
            > --
            > Rich Cini
            > Collector of Classic Computers
            > Build Master and lead engineer, Altair32 Emulator
            > http://www.classiccmp.org/cini
            > http://www.classiccmp.org/altair32
            >
            > From: Dave McGuire <Mcguire@... <mailto:Mcguire@...>>
            > Reply-To: MARCH-Post <midatlanticretro@yahoogroups.com
            > <mailto:midatlanticretro@yahoogroups.com>>
            > Date: Sunday, March 2, 2014 at 10:27 AM
            > To: MARCH-Post <midatlanticretro@yahoogroups.com
            > <mailto:midatlanticretro@yahoogroups.com>>
            > Subject: Re: [midatlanticretro] Quantum Q540/MFM cabling question
            >
            >
            >
            >
            > I'm just on my mobile phone at the moment, so I will be brief, can
            > provide more info later, but for now...no, it is NOT the same cable.
            > MFM control cable twists different pin numbers. I seem to recall "in
            > 5, flip 5" for MFM control cables but I don't have the pinouts in front
            > of me. Don't power it up with a floppy cable!
            >
            > Incidentally the Quantum Q540 is one of two drives DEC sold as the
            > RD52. I love the chitter-chitter sound those drives make.
            >
            > -Dave
            >
            > --
            > Dave McGuire, AK4HZ
            > New Kensington, PA
            >
            >
            > On Mar 2, 2014, at 10:17 AM, Richard Cini <rich.cini@...
            > <mailto:rich.cini@...>> wrote:
            >
            >> All —
            >>
            >> I got a CompuPro Disk3 controller and Q540 36MB (!!!) hard drive for
            >> my IMSAI, so I may try to piece together a hard drive system for it. I
            >> have a set of ST506 cables for it (I think), but I wanted to ask about
            >> the cabling. The control cable (34-pin) has a twist in it between the
            >> C and D connectors. I didn’t count the wires but it looks like the
            >> same kind of drive_select twist as in the IBM floppy cables. Is this
            >> normal for this kind of cabling?
            >>
            >> Also, the drive didn’t come with a terminating resistor pack. I think
            >> it’s a 220/330 pack, but if anyone has a Bourns part number for it,
            >> I’d appreciate it.
            >>
            >> Thanks!
            >>
            >>
            >> Rich
            >>
            >> --
            >> Rich Cini
            >> Collector of Classic Comp ut ers
            >> Build Master and lead engineer, Altair32 Emulator
            >> http://www.classiccmp.org/cini
            >> http://www.classiccmp.org/altair32
            >
            >
            >
            >


            --
            Dave McGuire, AK4HZ
            New Kensington, PA
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