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Re: [midatlanticretro] Re: Mark 8

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  • David Larsen
    Hi Evan - Thank you for the info. I hope the video and photos are a help. Dave ... -- David Larsen LCF Group, Floyd Virginia 1-540-763-2321 1-540-745-2322
    Message 1 of 6 , Feb 26 11:47 AM
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      Hi Evan - Thank you for the info. I  hope the video and photos are a help. Dave

      On Tue, Feb 26, 2013 at 2:15 PM, Evan Koblentz <evan@...> wrote:
       

      I emailed Titus. He said he's happy to help us with any technical matters about the restoration. Also said he'll send us a copy of all the documentation.




      --
      David Larsen
      LCF Group, Floyd Virginia
      1-540-763-2321
      1-540-745-2322
      Amateur Radio KK4WW
      Historical Computer Collector &
      Historian
      www.microcomputermuseum.com
      www.littlefamilyfarm.com
      www.floydfolks.org
      www.chantillyfarm.com


    • B Degnan
      Evan/Mouse/Corey, The code for blinking lights that I suggested for the Mark 8 is actually a program that interfaces with a TV Typewriter II and displays
      Message 2 of 6 , Sep 19, 2013
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        Evan/Mouse/Corey,

        The code for “blinking lights” that I suggested for the Mark 8 is actually a program that interfaces with a TV Typewriter II and displays random images on the TV screen.  In short It’s not a random front panel lights program.  You need a tv typewriter II to use the program.  He do have one, but we have not tested the I/O of the Mark 8. 

         

        If you’re going to attempt to operate the machine please review the docs on vintagecomputer.net/mark8/ so you can get acquainted with the machine BEFORE you start using it for an extended period. I strongly suggest that you not leave the machine running for more than 45 minutes at a time, it has not been tested other than for power supply ripple.  Seems OK, but it’s not really a production machine.  

         

        It worked enough to deposit and retrieve memory when Ian and I tested it last.  That’s all we know.

         

        Bill

      • Evan Koblentz
        ... We have two :) but I see your point. ... Will do. Jeff J. and I will spend some time with it tomorrow. ... Wish you d told me that a couple of months ago
        Message 3 of 6 , Sep 19, 2013
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          >> do have one, but we have not tested the I/O of the Mark 8.

          We have two :) but I see your point.

          >> please review the docs on vintagecomputer.net/mark8/ so you can get acquainted with the machine

          Will do. Jeff J. and I will spend some time with it tomorrow.

          >> I strongly suggest that you not leave the machine running for more than 45 minutes at a time

          Wish you'd told me that a couple of months ago before we started leaving it on for hours at a time in the museum (really) ... never had any problem.

          >> It worked enough to deposit and retrieve memory when Ian and I tested it last.

          That'll be sufficient for Maker Faire. We can honestly tell people that it's mid-restoration.
        • mwillega
          There is a small, simple 8008 LED flasher program in the SCELBI 8H users manual that does a fine job blinking LEDs, if that is what you are looking for.
          Message 4 of 6 , Sep 20, 2013
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            There is a small, simple 8008 LED flasher program in the SCELBI 8H users manual that does a fine job blinking LEDs, if that is what you are looking for.


            http://www.scelbi.com/files/docs/manuals/SCELBI-8H%20Users%20Manual.pdf 


            Goto page 28


            regards,

            Mike W.



            --- In midatlanticretro@yahoogroups.com, <midatlanticretro@yahoogroups.com> wrote:

            >> do have one, but we have not tested the I/O of the Mark 8.

            We have two :) but I see your point.

            >> please review the docs on vintagecomputer.net/mark8/ so you can get acquainted with the machine

            Will do. Jeff J. and I will spend some time with it tomorrow.

            >> I strongly suggest that you not leave the machine running for more than 45 minutes at a time

            Wish you'd told me that a couple of months ago before we started leaving it on for hours at a time in the museum (really) ... never had any problem.

            >> It worked enough to deposit and retrieve memory when Ian and I tested it last.

            That'll be sufficient for Maker Faire. We can honestly tell people that it's mid-restoration.
          • jeff_s_jonas
            re: the Mark 8 I found this to be the most useful documentation: http://vintagecomputer.net/mark8/RE_Mark-8_Const-NEW.pdf (an account on Degnan s server is
            Message 5 of 6 , Sep 20, 2013
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              re: the Mark 8


              I found this to be the most useful documentation:

              http://vintagecomputer.net/mark8/RE_Mark-8_Const-NEW.pdf

              (an account on Degnan's server is required).
              Pg 6-8 describe the console switches.

              I'm afraid something came loose. I could view and set RAM for a while, but after a while it kept failing the same way.
              a) trying to load 0x00 into hi addr gave 0x04 (above the 1k ram)
                  trying to load 0xff gave 0xF7
              b) trying to load 0x00 into low addr gave 0x0e,
                  trying to load 0xff gave ff (yay!)

              Once the 74193s are loaded, "exam" increments them fine.
              I suspect the 74193 chips need to be reseated (open inputs?)
              ALL the chips are socketed using bare clips instead of plastic sockets,
              so perhaps the issue is not to push them too far in?

              My notes on viewing/setting RAM
              1) set run/step to STEP to halt the CPU
              2) set int/jam to JAM for front panel to take control of memory bus

              3) set upper address byte on toggle switches
              press "LAH" to load into upper address register.
              The RAM card is fully populated with 4 by 8 1101 chips for 1k

              4) set lower address byte on toggle switches
              Press "LAL" to load into lower address register

              setting or incrementing the address causes an immediate READ
              and displays the ram on the upper right "mem data" LEDs.

              the "exam" pushbutton increments the memory address
              and diisplays that byte on the "mem data" display

              the "dep" pushbutton
              1) loads the RAM location with the 8 toggle switches
              2) increments the RAM address (both hi and low)
              3) displays the RAM at that address

              That means you can view ram by
              - setting all switches to 0
              - LAH (set upper address byte to 0)
              - LAL (set lower address byte to 0)
                you now see the contents of address 0
              - press "exam" to your heart's delight

              if you want to alter the byte you see,
              just toggle it in and press "DEP".

              There's no decrement / step BACK function,
              so to view the byte you just modified, you must re-enter the address.

              Until we can view and alter the RAM, there's no way to test the CPU with even the simplest program such as setting port 0 with various values (port 0 has LEDs on the front panel). I tried "run" mode and the LEDs flickered as the CPU was fed 0xff from RAM or running off the end of memory (addresses don't wrap).

              -- jeffj

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