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  • caljer
    Hello, I m the proud owner of a MITS Altair 8800 serial# 222027K acquired sometime in 2003. I got it from a music store in Mountain View, CA. The computer was
    Message 1 of 6 , Feb 27, 2004
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      Hello,

      I'm the proud owner of a MITS Altair 8800 serial# 222027K acquired
      sometime in 2003. I got it from a music store in Mountain View, CA.
      The computer was on display in the store window among various music
      intruments and with its LEDs blinking. I had to look several times to
      make sure it was not some kind of fake computer. Kind of a chock,
      being a member of the Computer History Museum in Mountain View.
      <http://www.computerhistory.com>. I can now brag about it ;-)

      Anyway I have it now and it was sitting in my garage until today. I
      tested it (looks like one bit is stuck in ON when I deposit and
      examine a memory position). It's kind of fun to read the manual and
      play with this toy. Reminds me my early computer day with the PET
      Commodore and the Apple II. Documentation was included with lots of
      notes and schematics.
      I shot some pictures and posted them in the Photos section here.

      Enjoy and let me know waht you think of this baby,

      Jerome
    • Steve
      Thanks for posting the pictures. Your computer looks pretty clean. Was the music store using it for anything other than a blinky-light window dressing? Have
      Message 2 of 6 , Feb 28, 2004
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        Thanks for posting the pictures. Your computer looks pretty clean.
        Was the music store using it for anything other than a blinky-light
        window dressing? Have you been able to run any programs on it yet?
        What's the function of the blue wire wrap board in the pictures
        labeled "MyAltair8800_10" and "MyAltair8800_11"?

        Steve
        ==========================

        --- In altaircomputerclub@yahoogroups.com, "caljer" <caljer@y...>
        wrote:
        > Hello,
        >
        > I'm the proud owner of a MITS Altair 8800 serial# 222027K acquired
        > sometime in 2003. I got it from a music store in Mountain View, CA.
        > The computer was on display in the store window among various music
        > intruments and with its LEDs blinking. I had to look several times
        to
        > make sure it was not some kind of fake computer. Kind of a chock,
        > being a member of the Computer History Museum in Mountain View.
        > <http://www.computerhistory.com>. I can now brag about it ;-)
        >
        > Anyway I have it now and it was sitting in my garage until today. I
        > tested it (looks like one bit is stuck in ON when I deposit and
        > examine a memory position). It's kind of fun to read the manual and
        > play with this toy. Reminds me my early computer day with the PET
        > Commodore and the Apple II. Documentation was included with lots of
        > notes and schematics.
        > I shot some pictures and posted them in the Photos section here.
        >
        > Enjoy and let me know waht you think of this baby,
        >
        > Jerome
      • caljer
        Thx Steve. Exactly, window dressing! I try to run the small addition program from the manual, but as I said in my first post, whatever I deposit in a memory
        Message 3 of 6 , Feb 29, 2004
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          Thx Steve. Exactly, window dressing!
          I try to run the small addition program from the manual, but as I
          said in my first post, whatever I deposit in a memory location has
          bit D4 ON. (i.e. if I Deposit 00 000 000, I get 00 010 000 when I
          Examine) So I have to check the wiring. I already cleaned the edge
          connectors. The wiring is a little more involved...
          Any other idea for this kind of behavior?

          I posted a higher def pic of the wire wrap board. The board has an
          UART TMS 6011 and two 555. I believe that it was wired as a dual
          function tape recorder interface and serial interface. But it's a
          guess based on connectors as well as schematics in the binder.


          Jerome


          --- In altaircomputerclub@yahoogroups.com, "Steve" <alltare@y...>
          wrote:
          > Thanks for posting the pictures. Your computer looks pretty
          clean.
          > Was the music store using it for anything other than a blinky-light
          > window dressing? Have you been able to run any programs on it
          yet?
          > What's the function of the blue wire wrap board in the pictures
          > labeled "MyAltair8800_10" and "MyAltair8800_11"?
          >
          > Steve
          > ==========================
          >
          > --- In altaircomputerclub@yahoogroups.com, "caljer" <caljer@y...>
          > wrote:
          > > Hello,
          > >
          > > I'm the proud owner of a MITS Altair 8800 serial# 222027K
          acquired
          > > sometime in 2003. I got it from a music store in Mountain View,
          CA.
          > > The computer was on display in the store window among various
          music
          > > intruments and with its LEDs blinking. I had to look several
          times
          > to
          > > make sure it was not some kind of fake computer. Kind of a chock,
          > > being a member of the Computer History Museum in Mountain View.
          > > <http://www.computerhistory.com>. I can now brag about it ;-)
          > >
          > > Anyway I have it now and it was sitting in my garage until today.
          I
          > > tested it (looks like one bit is stuck in ON when I deposit and
          > > examine a memory position). It's kind of fun to read the manual
          and
          > > play with this toy. Reminds me my early computer day with the PET
          > > Commodore and the Apple II. Documentation was included with lots
          of
          > > notes and schematics.
          > > I shot some pictures and posted them in the Photos section here.
          > >
          > > Enjoy and let me know waht you think of this baby,
          > >
          > > Jerome
        • Larry T.
          ... Jerome In my experience, the most likely causes of this kind of behavior are: 1) a bad memory chip 2) a bad buffer chip The only way to tell for sure is to
          Message 4 of 6 , Mar 1 8:15 AM
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            --- In altaircomputerclub@yahoogroups.com, "caljer" <caljer@y...>
            wrote:
            > Thx Steve. Exactly, window dressing!
            > I try to run the small addition program from the manual, but as I
            > said in my first post, whatever I deposit in a memory location has
            > bit D4 ON. (i.e. if I Deposit 00 000 000, I get 00 010 000 when I
            > Examine) So I have to check the wiring. I already cleaned the edge
            > connectors. The wiring is a little more involved...
            > Any other idea for this kind of behavior?

            Jerome

            In my experience, the most likely causes of this kind of behavior are:
            1) a bad memory chip
            2) a bad buffer chip
            The only way to tell for sure is to know the layout of the memory
            board. If there is more then one bank of ram chips and you know the
            size of the chips, pick an address that would be in a different bank
            of ram chips and see if the same bit is still 'stuck' after you
            deposit data. If there are more then two banks of chips, try this
            with each seperate bank. If it is a bad ram, only bad banks will
            show the problem, and if more then one bank is bad, the may well have
            the problem with a different bit. Be sure to test will all 0's AND
            all 1's! You might have problems such that you will always get a 0 no
            matter what data you poke! If you have mulitple memory boards, be
            sure to try all of the boards. If is is a buffer chip, all memory on
            the same board will have the problem. If all boards have the problem,
            then it is likely a buffer on the cpu board (I don't remember the
            Altair from panel having buffers for the data lines, but if so the
            problem may be there).

            Larry
          • Erik Klein
            Which store in Mountain View was it? I work off of Castro and would be curious if I d ever passed it and missed the old box. I ve seen similar memory issues
            Message 5 of 6 , Mar 1 9:04 AM
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              Which store in Mountain View was it? I work off of Castro and would be curious if I'd ever passed it and missed the old box.

              I've seen similar memory issues on my machines before. One possible issue could be a simple short in the bus. If one of the memory lines is shorted to another tied high or low then you might see a "stuck bit' situation.

              BTW, only some of the messages in this thread are making it to my inbox for some reason. I never did see your original post. . .

              Erik Klein
              www.vintage-computer.com
              www.vintage-computer.com/vcforum
              The Vintage Computer Forum


              caljer <caljer@...> wrote:
              Thx Steve. Exactly, window dressing!
              I try to run the small addition program from the manual, but as I
              said in my first post, whatever I deposit in a memory location has
              bit D4 ON. (i.e. if I Deposit 00 000 000, I get 00 010 000 when I
              Examine) So I have to check the wiring. I already cleaned the edge
              connectors. The wiring is a little more involved...
              Any other idea for this kind of behavior?

              I posted a higher def pic of the wire wrap board. The board has an
              UART TMS 6011 and two 555. I believe that it was wired as a dual
              function tape recorder interface and serial interface. But it's a
              guess based on connectors as well as schematics in the binder.


              Jerome


              --- In altaircomputerclub@yahoogroups.com, "Steve" <alltare@y...>
              wrote:
              > Thanks for posting the pictures. Your computer looks pretty
              clean.
              > Was the music store using it for anything other than a blinky-light
              > window dressing? Have you been able to run any programs on it
              yet?
              > What's the function of the blue wire wrap board in the pictures
              > labeled "MyAltair8800_10" and "MyAltair8800_11"?
              >
              > Steve
              > ==========================
              >
              > --- In altaircomputerclub@yahoogroups.com, "caljer" <caljer@y...>
              > wrote:
              > > Hello,
              > >
              > > I'm the proud owner of a MITS Altair 8800 serial# 222027K
              acquired
              > > sometime in 2003. I got it from a music store in Mountain View,
              CA.
              > > The computer was on display in the store window among various
              music
              > > intruments and with its LEDs blinking. I had to look several
              times
              > to
              > > make sure it was not some kind of fake computer. Kind of a chock,
              > > being a member of the Computer History Museum in Mountain View.
              > > <http://www.computerhistory.com>. I can now brag about it ;-)
              > >
              > > Anyway I have it now and it was sitting in my garage until today.
              I
              > > tested it (looks like one bit is stuck in ON when I deposit and
              > > examine a memory position). It's kind of fun to read the manual
              and
              > > play with this toy. Reminds me my early computer day with the PET
              > > Commodore and the Apple II. Documentation was included with lots
              of
              > > notes and schematics.
              > > I shot some pictures and posted them in the Photos section here.
              > >
              > > Enjoy and let me know waht you think of this baby,
              > >
              > > Jerome



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            • Steve
              Jerome, Your guess about it being a tape interface makes sense to me. One of the quirks of Yahoo is that only the person who posted a photo and the group
              Message 6 of 6 , Mar 1 10:38 AM
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                Jerome,

                Your guess about it being a tape interface makes sense to me.

                One of the quirks of Yahoo is that only the person who posted a photo
                and the group moderator are able to see the full size image.
                Everyone else has to live with a so-called "screen size" image that's
                usually only about 400 pixels wide. You can get around this by
                posting your image in the FILES folder rather than the PHOTOS
                folder. I've created a folder in FILES called JEROME, and I've put
                the full size image there.

                Besides doing the checks that Larry discussed, take the time to read
                through the message archives about other memory problems. You might
                find something useful. Also, check the white wires that run from the
                first mother board to the front panel. It's common to have one or
                more of them break off where they're soldered. Your computer was
                built a little differently than most. Usually, the first mother
                board was installed fully to the right side (as viewed from the
                front) of the computer. The 2nd, 3rd, and 4th mothers would then be
                added to the left of the 1st one. Your builder started in the
                middle. There's nothing wrong with that, but it does leave the white
                wires a little more vulnerable and messy than would otherwise be the
                case. Look at pictures of other 8800s and you'll see what I mean.

                You probably already know this, but let me give this warning anyway.
                When you're troubleshooting, NEVER pull a board out of the buss with
                the computer powered up. You'll most likely cause catastrophic
                damage. This has been discussed in the archives too.

                Steve
                ========================

                --- In altaircomputerclub@yahoogroups.com, "caljer" <caljer@y...>
                wrote:
                > Thx Steve. Exactly, window dressing!
                > I try to run the small addition program from the manual, but as I
                > said in my first post, whatever I deposit in a memory location has
                > bit D4 ON. (i.e. if I Deposit 00 000 000, I get 00 010 000 when I
                > Examine) So I have to check the wiring. I already cleaned the edge
                > connectors. The wiring is a little more involved...
                > Any other idea for this kind of behavior?
                >
                > I posted a higher def pic of the wire wrap board. The board has an
                > UART TMS 6011 and two 555. I believe that it was wired as a dual
                > function tape recorder interface and serial interface. But it's a
                > guess based on connectors as well as schematics in the binder.
                >
                >
                > Jerome
                >
                >
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