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MSI/88 1802 computers from Electronic Goldmine

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  • Lee Hart
    I ordered ten of the MSI/88f data terminals from Electronic Goldmine. They have dropped the price to $1.99 each! The order came in today, and they look very
    Message 1 of 7 , Mar 3, 2003
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      I ordered ten of the MSI/88f data terminals from Electronic Goldmine.
      They have dropped the price to $1.99 each! The order came in today, and
      they look very promising.

      They are apparently running out of stock, as there are several different
      types. All are well-made and compact, 2.25" thick by 3.5" wide and
      7.625" long. They all have a 16-character alphanumeric LED display (they
      were sold out of the ones with LCD display), and a 27 or 28 key keypad.
      Model numbers are MSI/88, MSI/88e, and MSI/88f. The MSI/88f came with
      batteries and displays "JEC POE 1051 E.2" and then "FUNCTION _".

      I took one apart. There are two allen screws at the top, and one hidden
      phillips screw under the center of the "Do Not Remove" sticker at the
      bottom of the battery box. Inside, are a neat stack of 5 boards,
      interconnected with 0.025" square pins and sockets.

      top: keyboard, 28 key locations, but some have a double ENTER key
      2nd: LED display, two 8-digit "british flag" LED displays and logic
      3rd: 10k/12k RAM board; this one had five Hitachi HM6116LP-4 2k RAMs
      4th: CPU board; has CDP1802ACE, 28-pin ROM, and 15-pin I/O connector
      the 1802 is running at 2 MHz
      bottom: 16k22k RAM board; this one had eleven house-marked RAMs
      (probably more HM6116 2kx8 RAMs or equivalent)

      My plan is to "sacrifice" one and cut the chips off so I can trace out
      the circuit. Unfortunately, none of the chips are socketed. I'll keep
      you all posted!
      --
      Lee A. Hart Ring the bells that still can ring
      814 8th Ave. N. Forget your perfect offering
      Sartell, MN 56377 USA There is a crack in everything
      leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
    • Stewart <stew_m_3@yahoo.com>
      Lee, before you sacrifice a usable unit, I have the boards out of a couple of others I bought which had bad keyboards. I can send you them to cut up if you
      Message 2 of 7 , Mar 3, 2003
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        Lee, before you sacrifice a usable unit, I have the boards out of a
        couple of others I bought which had bad keyboards. I can send you them
        to cut up if you like. I was just going to hold them over the torch to
        salvage the chips anyway. Let me have your address again, and I will
        drop them in the mail to you.

        Stew

        --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@e...> wrote:

        > My plan is to "sacrifice" one and cut the chips off so I can trace out
        > the circuit.
      • Lee Hart
        ... That would be fine, too. As I recall, your memory boards were different; they had MWS5114 1Kx4 RAMs instead of the 2Kx8 RAMs that mine has. Perhaps there
        Message 3 of 7 , Mar 4, 2003
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          Stewart wrote:
          > Lee, before you sacrifice a usable unit, I have the boards out of a
          > couple of others I bought which had bad keyboards. I can send you them
          > to cut up if you like. I was just going to hold them over the torch to
          > salvage the chips anyway. Let me have your address again, and I will
          > drop them in the mail to you.

          That would be fine, too. As I recall, your memory boards were different;
          they had MWS5114 1Kx4 RAMs instead of the 2Kx8 RAMs that mine has.
          Perhaps there are other differences. For example, there were half a
          dozen missing ICs in various places, and a few cuts and patches. My
          mailing address is in all my signature lines.
          --
          Lee A. Hart Ring the bells that still can ring
          814 8th Ave. N. Forget your perfect offering
          Sartell, MN 56377 USA There is a crack in everything
          leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
        • erd_6502
          ... I got my four today, too. ... Really? I thought they were down to just the MSI/88e. All four of mine are that model. ... I know. I wanted to play with
          Message 4 of 7 , Mar 4, 2003
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            --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@e...> wrote:
            > I ordered ten of the MSI/88f data terminals from Electronic
            > Goldmine.

            I got my four today, too.

            > They are apparently running out of stock, as there are several
            > different types.

            Really? I thought they were down to just the MSI/88e. All four
            of mine are that model.

            > They all have a 16-character alphanumeric LED display (they
            > were sold out of the ones with LCD display)

            I know. I wanted to play with the LCD version (possibly by
            putting a larger display on there - I have up to 20x4).

            > Model numbers are MSI/88, MSI/88e, and MSI/88f. The MSI/88f came
            > with batteries and displays "JEC POE 1051 E.2" and then
            > "FUNCTION _".

            Any idea what the differences are?

            All of mine beeps in OPER mode and display "ERR 1" in PROG mode.
            Randomly punching buttons gets an "ERR 2 8000".

            > I took one apart...

            > top: keyboard, 28 key locations, but some have a double ENTER key
            > 2nd: LED display, two 8-digit "british flag" LED displays and
            > logic

            I can't take mine apart where I am (no tools in my desk)... what
            are the model numbers on the LED displays? Are they raw or do
            they appear to be "ASCII" displays?

            > 3rd: 10k/12k RAM board; this one had five Hitachi HM6116LP-4 2k
            > RAMs

            Hmm... I was hoping for some 5114s in mine... I have buckets of
            8K-wide SRAMs. Guess I'll find out eventually.

            -ethan
          • Stewart
            ... Yeah, ditto for both of mine (one is LCD model). Same error messages and nothing else. ... Lee, I just boxed up the loose boards and they will go out to
            Message 5 of 7 , Mar 4, 2003
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              --- In cosmacelf@yahoogroups.com, "erd_6502" <erd_6502@y...> wrote:
              > All of mine beeps in OPER mode and display "ERR 1" in PROG mode.
              > Randomly punching buttons gets an "ERR 2 8000".

              Yeah, ditto for both of mine (one is LCD model). Same error messages
              and nothing else.

              > > 3rd: 10k/12k RAM board; this one had five Hitachi HM6116LP-4 2k
              > > RAMs

              Lee, I just boxed up the loose boards and they will go out to you in
              the morning. The RAM board I am sending has some surface mount RAM on
              it. The board looks quite a bit newer than the rest of the MSI/88.
              Probably an upgrade when the thing was being serviced at some point.
              Both my 88's have service tags in them from as late as 1993. Good luck
              with the reverse engineering!

              Stew
            • Lee Hart
              ... I ve compared an MSI/88e and an MSI/88f. They are identical except for having a 27-key or 28-key keyboard, and a different program ROM. ... They are just
              Message 6 of 7 , Mar 4, 2003
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                Lee Hart wrote:
                >> Model numbers are MSI/88, MSI/88e, and MSI/88f.

                erd_6502 wrote:
                > I got my four today, too. Any idea what the differences are?

                I've compared an MSI/88e and an MSI/88f. They are identical except for
                having a 27-key or 28-key keyboard, and a different program ROM.

                > what are the model numbers on the LED displays? Are they raw or do
                > they appear to be "ASCII" displays?

                They are just an array of LEDs, with no "smarts" in them at all.
                Probably configured as a 16x16 diode matrix, with all decoding done in
                software.

                > Hmm... I was hoping for some 5114s in mine... I have buckets of
                > 8K-wide SRAMs. Guess I'll find out eventually.

                The pinouts for the HM6116 (24-pin 2Kx8), 8Kx8 (28-pin), and 5114
                (18-pin 1Kx4) are all different, so they won't be interchangeable.

                What are the 8K parts you have? I may have a use for them myself for
                another project.
                --
                Lee A. Hart Ring the bells that still can ring
                814 8th Ave. N. Forget your perfect offering
                Sartell, MN 56377 USA There is a crack in everything
                leeahart_at_earthlink.net That's how the light gets in - Leonard Cohen
              • erd_6502
                ... Now that I can check for myself, they are MAN2815s. ... Probably. ... But it s more complicated than that. On the display board, there are a pair of 74C374
                Message 7 of 7 , Mar 5, 2003
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                  --- In cosmacelf@yahoogroups.com, Lee Hart <leeahart@e...> wrote:
                  > > what are the model numbers on the LED displays?
                  >
                  > They are just an array of LEDs, with no "smarts" in them at all.

                  Now that I can check for myself, they are MAN2815s.

                  > Probably configured as a 16x16 diode matrix

                  Probably.

                  > ...with all decoding done in software.

                  But it's more complicated than that.

                  On the display board, there are a pair of 74C374 Octal D flip-flops
                  (latches) that gang to a pair of DS8867s, next to a pair of
                  74C164 shift registers that are attached to three 75492 hex display
                  drivers (six segment drivers per package).

                  It looks like the 74C374/DS8867 circuit handles one axis, and the
                  74C164/75492 circuit handles the other axis. I was not able to
                  locate any specs on the MAN2815 or the DS8867s, but I found
                  something for the 75492:

                  http://thayer.dartmouth.edu/%7Eengs032/datasheet/75491.pdf

                  > > Hmm... I was hoping for some 5114s in mine... I have buckets of
                  > > 8K-wide SRAMs...
                  >
                  > The pinouts for the HM6116 (24-pin 2Kx8), 8Kx8 (28-pin), and 5114
                  > (18-pin 1Kx4) are all different, so they won't be interchangeable.

                  Naturally. I _have_ 24 and 28 pin SRAMs. I don't have any CMOS
                  18-pin SRAMs.

                  > What are the 8K parts you have? I may have a use for them myself for
                  > another project.

                  That's a typo. I meant to write "8-bit wide SRAMs"... I have a
                  few 6264s, but a lot more 2016s and 6116s.

                  -ethan
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