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Re: [Altair Computer Club] Parts, boards, suggestions wanted...

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  • Steve
    The SIO-B has a TTL interface. It was manufactured for the sole purpose of being one half of the 2-board 88-ACR (Audio Cassette Recorder) set. Essentially,
    Message 1 of 28 , Jun 13, 2005
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      The SIO-B has a TTL interface. It was manufactured for the sole
      purpose of being one half of the 2-board 88-ACR (Audio Cassette
      Recorder) set. Essentially, it's a SIO-C without the RS232
      circuitry. A modem board was mounted piggyback style onto the SIO-
      B.

      The board should work as a stand-alone, without the modem board, but
      you would have to add some TTL-to-RS232 converter circuitry.

      steve
      =======================
      --- In altaircomputerclub@yahoogroups.com, Craig Landrum
      <craigl@m...> wrote:
      > >Be advised that the SIO-C is a teletype (20ma current loop)
      interface
      > >board. If you want to use an RS-232 terminal, you'll need the SIO-
      A
      > >board, or a newer 2SIO.
      > >
      > Thanks for the info, Steve - I'll look for an SIOA. What about
      > an SIOB that someone has offered??
      >
      > --
      > Craig Landrum
      > Chief Technical Officer
      > mindwrap, inc.
      > Phone: (540) 675-3015 x 229
      > Fax: (540) 675-3130
      > email: craigl@m...
    • Steve
      Bob, The 2SIO can be configured either for RS232 OR 20 ma current loop, in case you didn t know. steve ... board, ... 148X ... just ... interface ... SIO-A
      Message 2 of 28 , Jun 13, 2005
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        Bob,

        The 2SIO can be configured either for RS232 OR 20 ma current loop, in
        case you didn't know.

        steve
        =================================

        --- In altaircomputerclub@yahoogroups.com, "UEOGUY-H.E.ROBT"
        <ueoguy@y...> wrote:
        > Craig, the SIOB is a TTL level board, if you can't find a 232
        board,
        > it's pretty easy to add a rs-232 rec/drvr chip to the board like a
        148X
        > series
        > to covert to and from. I have a need for a C board, myself, and I
        just
        > found an extra 88-2SIO, so you may be in luck!
        >
        > Just Bob!
        >
        > Craig Landrum wrote:
        >
        > >>Be advised that the SIO-C is a teletype (20ma current loop)
        interface
        > >>board. If you want to use an RS-232 terminal, you'll need the
        SIO-A
        > >>board, or a newer 2SIO.
        > >>
        > >>
        > >>
        > >Thanks for the info, Steve - I'll look for an SIOA. What about
        > >an SIOB that someone has offered??
        > >
        > >
        > >
      • UEOGUY-H.E.ROBT
        Thanks Steve! It s just that there is not a real easy way to go from one to the other, without rewiring the board, so I was looking for an SIOC to (borrowing
        Message 3 of 28 , Jun 13, 2005
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          Thanks Steve! It's just that there is not a real easy way to go from
          one to the other, without rewiring the board, so I was looking for an
          SIOC to (borrowing from the future),...plug n' play! But in any event,
          I have a 2 SIO if Craig should need it?

          Just Bob! ...who wishes to change the past!

          Steve wrote:

          >Bob,
          >
          >The 2SIO can be configured either for RS232 OR 20 ma current loop, in
          >case you didn't know.
          >
          >steve
          >=================================
          >
          >--- In altaircomputerclub@yahoogroups.com, "UEOGUY-H.E.ROBT"
          ><ueoguy@y...> wrote:
          >
          >
          >>Craig, the SIOB is a TTL level board, if you can't find a 232
          >>
          >>
          >board,
          >
          >
          >>it's pretty easy to add a rs-232 rec/drvr chip to the board like a
          >>
          >>
          >148X
          >
          >
          >>series
          >>to covert to and from. I have a need for a C board, myself, and I
          >>
          >>
          >just
          >
          >
          >>found an extra 88-2SIO, so you may be in luck!
          >>
          >>Just Bob!
          >>
          >>Craig Landrum wrote:
          >>
          >>
          >>
          >>>>Be advised that the SIO-C is a teletype (20ma current loop)
          >>>>
          >>>>
          >interface
          >
          >
          >>>>board. If you want to use an RS-232 terminal, you'll need the
          >>>>
          >>>>
          >SIO-A
          >
          >
          >>>>board, or a newer 2SIO.
          >>>>
          >>>>
          >>>>
          >>>>
          >>>>
          >>>Thanks for the info, Steve - I'll look for an SIOA. What about
          >>>an SIOB that someone has offered??
          >>>
          >>>
          >>>
          >>>
          >>>
          >
          >
          >
          >
          >
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          >--- Steve, your group moderator
          >
          >Yahoo! Groups Links
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          >
        • Craig Landrum
          ... just ... Perhaps we could trade my SIOC for the 2SIO? -- Craig Landrum Chief Technical Officer mindwrap, inc. Phone: (540) 675-3015 x 229 Fax: (540)
          Message 4 of 28 , Jun 14, 2005
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            >Craig, the SIOB is a TTL level board, if you can't find a 232 board,
            >it's pretty easy to add a rs-232 rec/drvr chip to the board like a 148X
            >series
            >to covert to and from. I have a need for a C board, myself, and I
            just
            >found an extra 88-2SIO, so you may be in luck!
            >
            >Just Bob!
            >

            Perhaps we could trade my SIOC for the 2SIO?

            --
            Craig Landrum
            Chief Technical Officer
            mindwrap, inc.
            Phone: (540) 675-3015 x 229
            Fax: (540) 675-3130
            email: craigl@...
          • Craig Landrum
            All; I m deep in the process of building/restoring an Altair 8800 and welcome any words of wisdom the members may have. I had an original 8800 D/C board
            Message 5 of 28 , Jun 22, 2005
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              All;

              I'm deep in the process of building/restoring an Altair 8800 and
              welcome any words of wisdom the members may have. I had an
              original 8800 D/C board (obtained years and years ago) and I
              recently acquired a case and (separately) an original power
              supply board. I've also acquired four 16K static boards,
              a PROM board, a serial board, and PIO, the two-board disk
              set, and what appears to be an Altair cabinet with dual 5.25
              drives (it has two MITS mini-drive buffer boards inside). I
              also acquired an original 1K memory board with the original
              256 bytes of RAM on it. All boards are MITS. Managed to find
              a replacement "MITS 8800" aluminum strip also.

              So far, I replaced all the electrolytics on the power supply
              board, rewired the transformers and the power supply seems
              to check out with the right voltages.

              I just finished wiring up the D/C board to the bus - man that
              sure is a treat. I finally found a clean way of doing this
              by positioning the bus upside down and using a shaving mirror
              to insert the individual wires from underneath and soldering
              on the top (the bottom of the bus). By working from 53 - 99
              and then 3-49 in order, it made for a nice clean looking job
              and I could keep the wires short and neat.

              I'll be wiring the D/C board and bus power lines to the
              terminal strip tonight and doing an initial smoke test with a
              Vector Graphics CPU card I have floating around.

              The front dress panel looks pretty good - just a few missing
              portions of the screen-printed letters. I plan to try my
              hand at creating stencils to fix up the damaged letters using
              home-made silk-screen stencils (see http://www.photoez.us/ ).
              This worked well for me in another project where I restored an
              old Chataqua Roller Organ.

              Once I pass the smoke test and can store and examine memory,etc
              I'll start adding and checking out the other boards. The biggest
              hurdle I'm likely to have is talking to the disk drives via
              those "mini drive buffer boards" and the two-board floppy
              set. Any help or hints here would be welcome.

              Eventually, my goal is to have a unit with all-MITS boards
              running CP/M. I've previously restored two IMSAIs and
              wrote CP/M BIOS's driving 8, 5.25, and 3.5 drives in
              double-sided, double density, and can read a schematic, so
              there's some hope here. Probably won't be able to
              do double-density with the Altair board set. If anyone has any
              source code that shows how to format drives and talk to drives
              via the MITS two-board set, I sure would appreciate taking a
              look.

              Any suggestions you might have for setting up the system,
              configuring addresses, etc would be welcome. One of my first
              questions will be whether its possible to have a full 64K RAM
              system and a boot PROM on the PROM board which can be
              disabled after loading to RAM - sort of like Cromemco's
              16Khz RAM boards and 64FDC floppy controller combo, which I
              can highly recommend if you are doing an IMSAI.
              --
              Craig Landrum
              Chief Technical Officer
              mindwrap, inc.
              Phone: (540) 675-3015 x 229
              Fax: (540) 675-3130
              email: craigl@...
            • Steve
              The Altair cabinet with dual 5.25 drives is most likely the 8800bDM (8800b Turnkey computer with internal Dual Minis). You could use a full 64K with the model
              Message 6 of 28 , Jun 22, 2005
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                The Altair cabinet with dual 5.25 drives is most likely the 8800bDM
                (8800b Turnkey computer with internal Dual Minis).

                You could use a full 64K with the model B while booting from the B's
                Turnkey board (if it was properly modified), but not with the
                8800/8800A, There was a mod to disable the top 2K of a 16K static
                RAM, to make room for the 2K PROM board. Since no MITS software
                required the full 64K, it was never much of a problem to forfeit the
                top 2K.

                If you plan to use a lot of boards in your 8800, you might have power
                supply problems with a big load on the original wimpy supply. Any
                chance you can use the supply from the bDM? It's MUCH beefier.

                steve
                =============================

                --- In altaircomputerclub@yahoogroups.com, Craig Landrum
                <craigl@m...> wrote:
                >
                > All;
                >
                > I'm deep in the process of building/restoring an Altair 8800 and
                > welcome any words of wisdom the members may have. I had an
                > original 8800 D/C board (obtained years and years ago) and I
                > recently acquired a case and (separately) an original power
                > supply board. I've also acquired four 16K static boards,
                > a PROM board, a serial board, and PIO, the two-board disk
                > set, and what appears to be an Altair cabinet with dual 5.25
                > drives (it has two MITS mini-drive buffer boards inside). I
                > also acquired an original 1K memory board with the original
                > 256 bytes of RAM on it. All boards are MITS. Managed to find
                > a replacement "MITS 8800" aluminum strip also.
                >
                > So far, I replaced all the electrolytics on the power supply
                > board, rewired the transformers and the power supply seems
                > to check out with the right voltages.
                >
                > I just finished wiring up the D/C board to the bus - man that
                > sure is a treat. I finally found a clean way of doing this
                > by positioning the bus upside down and using a shaving mirror
                > to insert the individual wires from underneath and soldering
                > on the top (the bottom of the bus). By working from 53 - 99
                > and then 3-49 in order, it made for a nice clean looking job
                > and I could keep the wires short and neat.
                >
                > I'll be wiring the D/C board and bus power lines to the
                > terminal strip tonight and doing an initial smoke test with a
                > Vector Graphics CPU card I have floating around.
                >
                > The front dress panel looks pretty good - just a few missing
                > portions of the screen-printed letters. I plan to try my
                > hand at creating stencils to fix up the damaged letters using
                > home-made silk-screen stencils (see http://www.photoez.us/ ).
                > This worked well for me in another project where I restored an
                > old Chataqua Roller Organ.
                >
                > Once I pass the smoke test and can store and examine memory,etc
                > I'll start adding and checking out the other boards. The biggest
                > hurdle I'm likely to have is talking to the disk drives via
                > those "mini drive buffer boards" and the two-board floppy
                > set. Any help or hints here would be welcome.
                >
                > Eventually, my goal is to have a unit with all-MITS boards
                > running CP/M. I've previously restored two IMSAIs and
                > wrote CP/M BIOS's driving 8, 5.25, and 3.5 drives in
                > double-sided, double density, and can read a schematic, so
                > there's some hope here. Probably won't be able to
                > do double-density with the Altair board set. If anyone has any
                > source code that shows how to format drives and talk to drives
                > via the MITS two-board set, I sure would appreciate taking a
                > look.
                >
                > Any suggestions you might have for setting up the system,
                > configuring addresses, etc would be welcome. One of my first
                > questions will be whether its possible to have a full 64K RAM
                > system and a boot PROM on the PROM board which can be
                > disabled after loading to RAM - sort of like Cromemco's
                > 16Khz RAM boards and 64FDC floppy controller combo, which I
                > can highly recommend if you are doing an IMSAI.
                > --
                > Craig Landrum
                > Chief Technical Officer
                > mindwrap, inc.
                > Phone: (540) 675-3015 x 229
                > Fax: (540) 675-3130
                > email: craigl@m...
              • Craig Landrum
                ... I haven t actually cracked the case on the drive chassis yet, but if I recall the eBay pics, there is no bus but there are two loose mounted MITS mini
                Message 7 of 28 , Jun 22, 2005
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                  On Wednesday, June 22, 2005 at 1:28 PM, Steve sent:

                  >The Altair cabinet with dual 5.25 drives is most likely the 8800bDM
                  >(8800b Turnkey computer with internal Dual Minis).

                  I haven't actually cracked the case on the drive chassis yet, but
                  if I recall the eBay pics, there is no bus but there are two loose
                  mounted "MITS mini driver buffer boards". I'll open it up
                  tonite and see for sure.

                  >
                  >You could use a full 64K with the model B while booting from the B's
                  >Turnkey board (if it was properly modified), but not with the
                  >8800/8800A, There was a mod to disable the top 2K of a 16K static
                  >RAM, to make room for the 2K PROM board. Since no MITS software
                  >required the full 64K, it was never much of a problem to forfeit the
                  >top 2K.

                  Yeah, I had to sacrifice the top 4K in one of my IMSAIs so I'll
                  probably do the 16K board mod - was this documented in the 16K
                  board manual? (I don't have a copy yet).

                  >
                  >If you plan to use a lot of boards in your 8800, you might have power
                  >supply problems with a big load on the original wimpy supply. Any
                  >chance you can use the supply from the bDM? It's MUCH beefier.

                  Yeah, I was noticing the wimpy supply - a miracle it drives anything.
                  I'd like to keep it original as long as it will drive the boards,
                  but if it starts going south I'll see if I can find a larger supply.
                  A number of pics I've seen of 8800 insides show what appears to be
                  voltage regulators or other parts offloaded from the cap board and
                  bolted to the chassis. What up with that?

                  Thanks for the advice Steve!!

                  Also - for those of you who have kit built units, be advised that
                  I thought my unit did not have a serial number sticker until I
                  disassembled the chassis - the serial number sticker was stuck to
                  the underside of the flat metal chassis plate that the power supply
                  bolts onto :-)

                  --
                  Craig Landrum
                  Chief Technical Officer
                  mindwrap, inc.
                  Phone: (540) 675-3015 x 229
                  Fax: (540) 675-3130
                  email: craigl@...
                • UEOGUY-H.E.ROBT
                  Craig, the Drive controller board set, was it included with the 5.25 drives, or obtained separately? As I recall, the mini-disk used a different disk-2
                  Message 8 of 28 , Jun 22, 2005
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                    Craig, the Drive controller board set, was it included
                    with the 5.25 drives, or obtained separately?

                    As I recall, the mini-disk used a different disk-2 controller
                    board than the 8 inch floppies,? (Steve keep me honest here)

                    Just Bob!

                    Craig Landrum wrote:

                    >All;
                    >
                    >I'm deep in the process of building/restoring an Altair 8800 and
                    >welcome any words of wisdom the members may have. I had an
                    >original 8800 D/C board (obtained years and years ago) and I
                    >recently acquired a case and (separately) an original power
                    >supply board. I've also acquired four 16K static boards,
                    >a PROM board, a serial board, and PIO, the two-board disk
                    >set, and what appears to be an Altair cabinet with dual 5.25
                    >drives (it has two MITS mini-drive buffer boards inside). I
                    >also acquired an original 1K memory board with the original
                    >256 bytes of RAM on it. All boards are MITS. Managed to find
                    >a replacement "MITS 8800" aluminum strip also.
                    >
                    >So far, I replaced all the electrolytics on the power supply
                    >board, rewired the transformers and the power supply seems
                    >to check out with the right voltages.
                    >
                    >I just finished wiring up the D/C board to the bus - man that
                    >sure is a treat. I finally found a clean way of doing this
                    >by positioning the bus upside down and using a shaving mirror
                    >to insert the individual wires from underneath and soldering
                    >on the top (the bottom of the bus). By working from 53 - 99
                    >and then 3-49 in order, it made for a nice clean looking job
                    >and I could keep the wires short and neat.
                    >
                    >I'll be wiring the D/C board and bus power lines to the
                    >terminal strip tonight and doing an initial smoke test with a
                    >Vector Graphics CPU card I have floating around.
                    >
                    >The front dress panel looks pretty good - just a few missing
                    >portions of the screen-printed letters. I plan to try my
                    >hand at creating stencils to fix up the damaged letters using
                    >home-made silk-screen stencils (see http://www.photoez.us/ ).
                    >This worked well for me in another project where I restored an
                    >old Chataqua Roller Organ.
                    >
                    >Once I pass the smoke test and can store and examine memory,etc
                    >I'll start adding and checking out the other boards. The biggest
                    >hurdle I'm likely to have is talking to the disk drives via
                    >those "mini drive buffer boards" and the two-board floppy
                    >set. Any help or hints here would be welcome.
                    >
                    >Eventually, my goal is to have a unit with all-MITS boards
                    >running CP/M. I've previously restored two IMSAIs and
                    >wrote CP/M BIOS's driving 8, 5.25, and 3.5 drives in
                    >double-sided, double density, and can read a schematic, so
                    >there's some hope here. Probably won't be able to
                    >do double-density with the Altair board set. If anyone has any
                    >source code that shows how to format drives and talk to drives
                    >via the MITS two-board set, I sure would appreciate taking a
                    >look.
                    >
                    >Any suggestions you might have for setting up the system,
                    >configuring addresses, etc would be welcome. One of my first
                    >questions will be whether its possible to have a full 64K RAM
                    >system and a boot PROM on the PROM board which can be
                    >disabled after loading to RAM - sort of like Cromemco's
                    >16Khz RAM boards and 64FDC floppy controller combo, which I
                    >can highly recommend if you are doing an IMSAI.
                    >
                    >
                  • Steve
                    Craig, If the auction didn t end too long ago, can you tell us the item # of the dual drive cabinet? If I can see a picture of it, I ll be able to ID it. Or
                    Message 9 of 28 , Jun 22, 2005
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                      Craig,

                      If the auction didn't end too long ago, can you tell us the item # of
                      the dual drive cabinet? If I can see a picture of it, I'll be able
                      to ID it. Or can you post an image?

                      To the best of my knowledge, MITS' only dual-mini enclosure was that
                      of the 8800bDM computer. By the way, they also made a single mini
                      version, the 8800bSM. Aside from these two examples of internal 5"
                      drives, the only other configuration was an external/stand-alone
                      cabinet containing a single drive and "buffer board", using the same
                      case as the 680b computer. The bDM and bSM computers were nicknamed
                      the "Dual Foley" and "Single Foley", for the department store chain
                      for which they were originally developed. The Foleys were sweet
                      systems: when loaded with static RAM and the very reliable 5" drives,
                      they were relatively trouble free.

                      There were some mods to the 8800 power supply to support greater
                      loads. A (Radio Shack) transformer was added for one of the 12V
                      supplies. You'll often see this upgrade in pictures of ebay sales.
                      And of course there were a lot of homebrew upgrades too. Many people
                      seemed to just install bigger capacitors, which works OK until you
                      really start loading down the transformer(s).

                      The "62K mod" was documented separately from the official 16MCS
                      manual.

                      steve
                      =============================

                      --- In altaircomputerclub@yahoogroups.com, Craig Landrum
                      <craigl@m...> wrote:
                      >
                      > On Wednesday, June 22, 2005 at 1:28 PM, Steve sent:
                      >
                      > >The Altair cabinet with dual 5.25 drives is most likely the
                      8800bDM
                      > >(8800b Turnkey computer with internal Dual Minis).
                      >
                      > I haven't actually cracked the case on the drive chassis yet, but
                      > if I recall the eBay pics, there is no bus but there are two loose
                      > mounted "MITS mini driver buffer boards". I'll open it up
                      > tonite and see for sure.
                      >
                      > >
                      > >You could use a full 64K with the model B while booting from the
                      B's
                      > >Turnkey board (if it was properly modified), but not with the
                      > >8800/8800A, There was a mod to disable the top 2K of a 16K static
                      > >RAM, to make room for the 2K PROM board. Since no MITS software
                      > >required the full 64K, it was never much of a problem to forfeit
                      the
                      > >top 2K.
                      >
                      > Yeah, I had to sacrifice the top 4K in one of my IMSAIs so I'll
                      > probably do the 16K board mod - was this documented in the 16K
                      > board manual? (I don't have a copy yet).
                      >
                      > >
                      > >If you plan to use a lot of boards in your 8800, you might have
                      power
                      > >supply problems with a big load on the original wimpy supply. Any
                      > >chance you can use the supply from the bDM? It's MUCH beefier.
                      >
                      > Yeah, I was noticing the wimpy supply - a miracle it drives
                      anything.
                      > I'd like to keep it original as long as it will drive the boards,
                      > but if it starts going south I'll see if I can find a larger supply.
                      > A number of pics I've seen of 8800 insides show what appears to be
                      > voltage regulators or other parts offloaded from the cap board and
                      > bolted to the chassis. What up with that?
                      >
                      > Thanks for the advice Steve!!
                      >
                      > Also - for those of you who have kit built units, be advised that
                      > I thought my unit did not have a serial number sticker until I
                      > disassembled the chassis - the serial number sticker was stuck to
                      > the underside of the flat metal chassis plate that the power supply
                      > bolts onto :-)
                      >
                      > --
                      > Craig Landrum
                      > Chief Technical Officer
                      > mindwrap, inc.
                      > Phone: (540) 675-3015 x 229
                      > Fax: (540) 675-3130
                      > email: craigl@m...
                    • Craig Landrum
                      ... That was the first thing I tried :-) Its off of eBay now. I ll try and post a few pictures of my own in the next few days. -- Craig Landrum Chief
                      Message 10 of 28 , Jun 23, 2005
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                        >If the auction didn't end too long ago, can you tell us the item # of
                        >the dual drive cabinet? If I can see a picture of it, I'll be able
                        >to ID it. Or can you post an image?

                        That was the first thing I tried :-) Its off of eBay now. I'll
                        try and post a few pictures of my own in the next few days.

                        --
                        Craig Landrum
                        Chief Technical Officer
                        mindwrap, inc.
                        Phone: (540) 675-3015 x 229
                        Fax: (540) 675-3130
                        email: craigl@...
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