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Cromemco System Three

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  • B. Degnan
    Today I picked up a donation consisting of a Cromemco System Three Model with dual 8 drives (PerSci) CS3 S/N: 31856. The condition is excellent. There are few
    Message 1 of 6 , Oct 26, 2007
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      Today I picked up a donation consisting of a Cromemco System Three Model
      with dual 8" drives (PerSci)
      CS3 S/N: 31856. The condition is excellent.
      There are few scratches, color nice, etc. The system came with the Cromemco
      desk (same desk as seen in the brochure), the computer fits in the desk.

      Hazletine 1510 - The display. Appears to work, display is in great shape.
      Keyboard good, a tiny bit of screen burn, but strong display tube, no mold.
      s/n: 213442-001 model: 4DTD155255

      Texas Instruments Omni 800 / 810 RO Terminal
      Very Good Cond.
      part number 0994293-0002
      s/n 04711 42035
      parallel

      Fortran IV and a CDOS boot disk, data disks. 8".

      I was told $15000 was spent on this system in 1979. The owner was moving
      out of his estate, a good 20+ acres at least on the top of a hill. A
      pretty expensive personal computer!

      NOTE: The three pieces of hardware were cabled together and the comptuer
      fit into the desk when I arrived. I made notes so that I could cable the
      system back together when I got the system home. I am unsure the last time
      this system was last used. There appear to be disks with labels indicating
      backups as late as 1990. The whole thing is now set up in my living
      room. I have an understanding wife.

      I decided to power it on after checking all of the cards and re-seating the
      chips on the cards. (ZPU, etc...the standard stuff that comes with the
      System Three.) Powers up at apparently full strength. I was careful to
      smell for fire/smoke.

      It's the 1979 model with PerSci dual drives using one one drive cable, and
      one drive belt. Weird, must be a mechanical problem to explain why I can't
      get drive A to engage a disk..I have the system cabled up exactly like it
      was used, same equipment and cables. The drive mechanism, working or not,
      is pretty cool...when you insert the disk, a motor engages the head and
      holds the disk in place, no manual levers needed. When you push the
      corresponding drive letter button (only "B" works) the motor pops the disk
      out again. I never used an S-100 system with that kind of luxury. Because
      drive B can engage and eject a disk, I get a the clue of what drive A
      should be doing, and that helps analyze the problem.

      If I was to guess, I'd say the drive is bad, and/or the controller
      card. I can't access RDOS, and I have the dip switch settings correctly
      set for both the processor card and the disk controller card. The RDOS
      docs state that I should be able simply to hit enter a few times to get a
      RDOS monitor prompt. I can't rule out the terminal as a problem, but I
      assume once this set up, as-is, worked.I will try the terminal with another
      system to rule that out..

      There's just a little screen burn, but you only notice it in the high-res
      photos, not when actually using it.

      I have some pics. Note that the computer is removed from the bay and sits
      on top of the desk.

      http://www.vintagecomputer.net/cromemco/system_three/

      I reviewed Herb's related pages, and continue to work on the system. Any
      any suggestions are appreciated. I will send an abbreviated post to cctech.

      Looks cool anyway.

      Bill
    • jack99rubin
      ... You and who else? I ve got a couple System Three s in _my_ living room too, not because my wife is understanding (though of course she is) but because I
      Message 2 of 6 , Oct 27, 2007
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        :
        >
        > Today I picked up

        You and who else? I've got a couple System Three's in _my_ living
        room too, not because my wife is understanding (though of course she
        is) but because I can't move them myself! (ok, I could if I had too
        but they are very heavy and I imagine the desk is no lightweight
        model either)

        a donation consisting of a Cromemco System Three Model
        > with dual 8" drives (PerSci)
        > CS3 S/N: 31856. The condition is excellent.
        > There are few scratches, color nice, etc. The system came with the
        Cromemco
        > desk (same desk as seen in the brochure), the computer fits in the
        desk.

        Welcome to the wonderful world of Persci drives. These fantastic
        monsters are voice-coil driven with a unique high performance
        construction. You did, of course, insert the shipping cards or
        otherwise immobilize the heads before moving it, right? When not
        energized, the heads/coils are free to move and can be easily damaged.

        Check Herb's manuals but if the drives don't work, you've a got a
        great class project for several semesters. Barry Watzman (you can
        find him at comp.os.cpm) has done a lot with these drives over the
        past few years and Herb and Dave Dunfield might be able to help as
        well.

        Sounds like a beautiful system - definitely top-end for the time.

        Jack
      • Dan Roganti
        nice catch , Bill ! [ I do not fear computers. I fear the lack of them ] [ Pittsburgh --- http://www2.applegate.org/~ragooman/ ] B. Degnan wrote: Today I
        Message 3 of 6 , Oct 27, 2007
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          nice catch , Bill !

          [ "I do not fear computers. I fear the lack of them"     ]
          [ Pittsburgh --- http://www2.applegate.org/~ragooman/    ]
          
          


          B. Degnan wrote:
          Today I picked up a donation consisting of a Cromemco System Three Model 
          with dual 8" drives (PerSci)
          CS3 S/N: 31856. The condition is excellent.
          There are few scratches, color nice, etc. The system came with the Cromemco 
          desk (same desk as seen in the brochure), the computer fits in the desk.
          
            
        • B. Degnan
          ... my wife helped, but I am a bass player, used to moving large objects (amps and speakers) to and from a car. ... True confession, I did not. I was very
          Message 4 of 6 , Oct 27, 2007
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            At 12:15 PM 10/27/2007 +0000, you wrote:
            >:
            > >
            > > Today I picked up
            >
            >You and who else? I've got a couple System Three's in _my_ living
            >room too, not because my wife is understanding (though of course she
            >is) but because I can't move them myself! (ok, I could if I had too
            >but they are very heavy and I imagine the desk is no lightweight
            >model either)

            my wife helped, but I am a bass player, used to moving large objects (amps
            and speakers) to and from a car.


            >a donation consisting of a Cromemco System Three Model
            > > with dual 8" drives (PerSci)
            > > CS3 S/N: 31856. The condition is excellent.
            > > There are few scratches, color nice, etc. The system came with the
            >Cromemco
            > > desk (same desk as seen in the brochure), the computer fits in the
            >desk.
            >
            >Welcome to the wonderful world of Persci drives. These fantastic
            >monsters are voice-coil driven with a unique high performance
            >construction. You did, of course, insert the shipping cards or
            >otherwise immobilize the heads before moving it, right? When not
            >energized, the heads/coils are free to move and can be easily damaged.

            True confession, I did not. I was very careful however, I removed the
            computer from the desk and placed it in the passenger seat. I only had a 2
            mile drive to get home. But no, I did not think to put in the shipping
            card (there was only one).

            >Check Herb's manuals but if the drives don't work, you've a got a
            >great class project for several semesters. Barry Watzman (you can
            >find him at comp.os.cpm) has done a lot with these drives over the
            >past few years and Herb and Dave Dunfield might be able to help as
            >well.

            I read the conversation Herb recorded from various sources. I learned that
            yes, this could be a long project. My immediate goal is to get to the RDOS
            prompt.

            >Sounds like a beautiful system - definitely top-end for the time.
            >
            >Jack


            Bill
          • Herb Johnson
            ... learned that ... the RDOS ... You ought to be able to get the RDOS prompt irrespective of the drive s condition. I agree that s the first thing. But if the
            Message 5 of 6 , Oct 27, 2007
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              "B. Degnan" <billdeg@...> wrote:

              >
              > I read the conversation Herb recorded from various sources. I
              learned that
              > yes, this could be a long project. My immediate goal is to get to
              the RDOS
              > prompt.
              >
              > >Sounds like a beautiful system - definitely top-end for the time.


              You ought to be able to get the RDOS prompt irrespective of the
              drive's condition. I agree that's the first thing. But if the drives
              are trying to seek or whatever that's good too. You can ask the
              original owner what is supposed to happen at bootup. There may be
              notes around in whatever you got with it. YOu didn't change the dip
              switch settings did you? Check to see what character RDOS wants to see
              on start-up - it makes a difference, the baud rate is set by a
              specific character's ASCII binary pattern.

              I'd make sure the terminal was operational, by connecting the
              terminal's transmit and receive connections; and see if the terminal
              echos whatever is typed. Chances are those are pins 2 and 3 on the
              DB25 connector, but check the docs of whatever card is running the
              serial port; or the terminal docs. I doubt it is running current loop
              mode. You ought to get one of those RS-232 devices which has red and
              yellow LED's and DB25 connectors, to show activity on key RS232 pins.
              (I use a 'scope or an analog meter myself.)

              MAke sure the S100 cards are seated OK. Use a DC voltmeter to check
              the operating DC voltages on the S-100 side.

              The Cromemco CPU is a decent card but it will fail with age. You may
              have to test each card on another Cromemco system, I recall you have a
              few. Enjoy your new system!

              herb johnson
            • B. Degnan
              Update: I have returned the system to the original configuration for a bare-bones system. I can now get to the RDOS prompt. I have version 1. ? I can check
              Message 6 of 6 , Oct 31, 2007
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                Update:

                I have returned the system to the original configuration for a bare-bones
                system. I can now get to the RDOS prompt. I have version 1. ? I can
                check memory, assign drives, and jump to memory locations, it's a pretty
                straight-forward monitor program. I cannot use RDOS to tell the computer
                to boot from the apparently working B drive. I wonder if there are dip
                switches on the drives that allow a person to flip A to B. I will find out
                soon enough.

                I am convinced that there's a mechanical/electrical problem with the PerSci
                drive. I have the schematics, etc. and I will let you know how it
                goes. Once I get the drive working, I'd like see if I can get the original
                Cromemco CP/M working. 1.??




                Bill
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