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MARCH IBM PC 5150 rev A Restoration Project Notes

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  • B. Degnan
    Hi all. I have been able to get MARCH s IBM PC 5150 rev A up and running. I will post detailed notes on my web site. This is the 16K-64K original IBM PC
    Message 1 of 3 , May 22, 2008
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      Hi all.

      I have been able to get MARCH's IBM PC 5150 rev A up and running. I will
      post detailed notes on my web site. This is the 16K-64K original IBM PC
      model with original black power supply. Very rare rev "A" model and worthy
      of a museum.

      In summary
      -there is bad RAM, but I was able to get a 32K contiguous to function,
      enough to boot DOS 1.1, but not enough for DOS 2.x or higher. I need to
      find and replace the bad 4116 chip(s) so that the system is using a full 64K.

      -BASIC ROM C 1.0 - (cassette basic 1.0). Note that with 32K RAM, there is
      still 28K available for BASIC. This is due in part to the CGA card having
      it's own memory. I have a good article on the IBM PC in the CISC367
      directory of my web site if you're interested in more details.

      -the original mono display card was bad, replaced with a CGA monitor
      card. Looking for a replacement monochrome. changed settings for color card.

      -the one diskette works - switch settings OK

      -the dip switches indicated the presence of a 8077 co-processor, but none
      was present. Changed switch to "no co-processor"

      Pictures (not renamed yet, but re-sized)
      http://vintagecomputer.net/ibm/5150/5150_A/

      I am working on some sort of display for the MARCH exhibit of this computer.

      More news soon. I took notes of the entire restoration "logic"

      NEXT: replace the RAM, find an IBM monochrome card. more cleaning.

      Bill
    • Evan Koblentz
      Thanks for the update, Bill. ... That is because it was given to an IBM employee directly from Big Blue. Part of the first batch. I ll look up the email from
      Message 2 of 3 , May 22, 2008
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        Thanks for the update, Bill.

        >>> Very rare rev "A" model and worthy of a museum.

        That is because it was given to an IBM employee directly from Big Blue.
        Part of the first batch. I'll look up the email from the person who donated
        it but that will take me a while to locate.




        -----Original Message-----
        From: B. Degnan [mailto:billdeg@...]
        Sent: Thursday, May 22, 2008 11:29 PM
        To: midatlanticretro@yahoogroups.com
        Subject: [midatlanticretro] MARCH IBM PC 5150 rev A Restoration Project
        Notes


        Hi all.

        I have been able to get MARCH's IBM PC 5150 rev A up and running. I will
        post detailed notes on my web site. This is the 16K-64K original IBM PC
        model with original black power supply. Very rare rev "A" model and worthy
        of a museum.

        In summary
        -there is bad RAM, but I was able to get a 32K contiguous to function,
        enough to boot DOS 1.1, but not enough for DOS 2.x or higher. I need to
        find and replace the bad 4116 chip(s) so that the system is using a full
        64K.

        -BASIC ROM C 1.0 - (cassette basic 1.0). Note that with 32K RAM, there is
        still 28K available for BASIC. This is due in part to the CGA card having
        it's own memory. I have a good article on the IBM PC in the CISC367
        directory of my web site if you're interested in more details.

        -the original mono display card was bad, replaced with a CGA monitor
        card. Looking for a replacement monochrome. changed settings for color
        card.

        -the one diskette works - switch settings OK

        -the dip switches indicated the presence of a 8077 co-processor, but none
        was present. Changed switch to "no co-processor"

        Pictures (not renamed yet, but re-sized)
        http://vintagecomputer.net/ibm/5150/5150_A/

        I am working on some sort of display for the MARCH exhibit of this computer.

        More news soon. I took notes of the entire restoration "logic"

        NEXT: replace the RAM, find an IBM monochrome card. more cleaning.

        Bill




        ------------------------------------

        Yahoo! Groups Links
      • Mike Hatch
        ... will ... IBM PC ... worthy ... need to ... full 64K. I should have a few of those if you want them, let me know. ... there is ... having ... color card.
        Message 3 of 3 , May 23, 2008
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          --- In midatlanticretro@yahoogroups.com, "B. Degnan" <billdeg@...> wrote:
          >
          > Hi all.
          >
          > I have been able to get MARCH's IBM PC 5150 rev A up and running. I
          will
          > post detailed notes on my web site. This is the 16K-64K original
          IBM PC
          > model with original black power supply. Very rare rev "A" model and
          worthy
          > of a museum.
          >
          > In summary
          > -there is bad RAM, but I was able to get a 32K contiguous to function,
          > enough to boot DOS 1.1, but not enough for DOS 2.x or higher. I
          need to
          > find and replace the bad 4116 chip(s) so that the system is using a
          full 64K.

          I should have a few of those if you want them, let me know.


          >
          > -BASIC ROM C 1.0 - (cassette basic 1.0). Note that with 32K RAM,
          there is
          > still 28K available for BASIC. This is due in part to the CGA card
          having
          > it's own memory. I have a good article on the IBM PC in the CISC367
          > directory of my web site if you're interested in more details.
          >
          > -the original mono display card was bad, replaced with a CGA monitor
          > card. Looking for a replacement monochrome. changed settings for
          color card.
          >
          > -the one diskette works - switch settings OK
          >
          > -the dip switches indicated the presence of a 8077 co-processor, but
          none
          > was present. Changed switch to "no co-processor"

          Possibly the co-processor as well but i need to look.


          >
          > Pictures (not renamed yet, but re-sized)
          > http://vintagecomputer.net/ibm/5150/5150_A/
          >
          > I am working on some sort of display for the MARCH exhibit of this
          computer.
          >
          > More news soon. I took notes of the entire restoration "logic"
          >
          > NEXT: replace the RAM, find an IBM monochrome card. more cleaning.
          >
          > Bill
          >

          Mike.
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