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Re: [Altair Computer Club] Altair 680 expander boards

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  • Martin Eberhard
    Not really. Mine works great with the original power supply. I have 2 16K SRAM boards and a UIO. I checked out the voltage regulation, and it looks fine. It is
    Message 1 of 15 , Sep 12, 2013
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      Not really. Mine works great with the original power supply. I have 2 16K SRAM boards and a UIO. I checked out the voltage regulation, and it looks fine.

      It is possible that if you had the 680-PCI board (with a bunch of relays) and also had a low-line condition on the 120V input, you might have a problem.

      My 680B actually had the 2nd transformer hack. But it was so hokey that I took it out, never imagining that this was an official factory hack :-)

      Martin


      On Thu, Sep 12, 2013 at 2:35 PM, B Degnan <billdeg@...> wrote:
       

      A separate transformer would be needed to power three additional cards.  Right?

      Bill

      Sent from AOL Mobile Mail


      -----Original Message-----
      From: eberhard <eberhard@...>
      To: altaircomputerclub <altaircomputerclub@yahoogroups.com>
      Sent: Thu, Sep 12, 2013 05:07 PM
      Subject: RE: [Altair Computer Club] Altair 680 expander boards




      Kip,

      The Altair 680 was a low-cost product with limited expansion capability. In its base configuration, it had just one  expansion socket, which was intended only to take an "expansion board" - which was sold separately. Many (most?) Altair 680s and 680bs were sold without this expansion board, and were thus limited to 1K RAM, and 1 serial port.

      As far as I know, the excellent Grant Stockley replica is just that - a true-to-the-original replica of the original Altair, including the connector that would take an expansion board. I don't think Grant offered an expansion board for sale with his kit, (and I am sure someone here will educate me if I am wrong on this).

      Because so many 680s were originally sold without expansion boards, they are pretty scarce. This is why I decided to create a copy of the original Altair 680b expansion board. I am pretty sure that my expansion board, just like an original expansion board, will work perfectly in Grant's replica, just as it does in a real Altair 680 or 680b.

      With an expansion board, the Altair 680 - Grant's replica or original - will have 3 expansion sockets. I know of the following option boards that were made available for the 680b:

      680-KCACR cassette interface
      680-BSM 16K static RAM
      680-PCI Process Control Interface
      680-UIO 2 serial plus 2 parallel ports

      There was rumor of a floppy controller for the 680b, but to my knowledge, such a board was never offered for sale by MITS. (I think it is even doubtful that the 6800 processor, running at 500 KHz as it does in the Altair 680b, can even keep up with even a minidisk data rate.)

       



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

      Hi Guys!

      I have been a longtime admirer of the Motorola line of microprocessors and when I saw the discussion of the Altair 680 expander boards,  I thought interesting.  Hmmm, I would like to know want it would take to build a complete 680b computer system with expansion capabilities using the newest technology available.  I’m not really aware of what is currently available for the 680b and maybe later a 6809 or 6309 version.  I have seen 680b replicas before, that although very well done, had everything on one PCB with no expansion capabilities.  This design for the 680b did not interest me.  However, with the talk of expansion boards, I am again interested.  Any help with this endeavor will be much appreciated.  Thank you in advance.

      Kip

       

      From: altaircomputerclub@yahoogroups.com [mailto:altaircomputerclub@yahoogroups.com] On Behalf Of eberhard@...
      Sent: Wednesday, September 11, 2013 7:34 PM
      To: altaircomputerclub@yahoogroups.com
      Subject: [Altair Computer Club] Altair 680 expander boards

       

       

      Since the subject of 680 replicas came up again, I thought I'd bring this up:

      A while back, I designed and fabricated a small run of replica expander boards (backplanes) for the Altair 680. They are a pretty close replica, and have decent gold plating on the fingers, both top and bottom. You can see photos of my expander board in the Files section, under "Altair 680b Expander Board".

      These work great - that's what I have in my own 680b. with brand-new edge connectors, all of the usual flakiness problems of my 680b went away.

      I still have a few of these left, if anyone wants to buy one. I will sell them for $30 each without the edge connectors installed - they take the same edge connectors as all other Altair backplanes.

      If you want to buy edge connectors, I will place an order for them - they cost about $12 each, the last time I looked, and they take several weeks to be delivered.

      Let me know if you are interested.




    • wtsnet
      A Computer Notes article describes how to add a second transformer. I was told the transformer is no longer available. The clone 680 has a new back panel
      Message 2 of 15 , Sep 12, 2013
      • 0 Attachment

        A Computer Notes article describes how to add a second transformer. I was told the transformer is no longer available. The clone 680 has a new back panel design for use with a switching supply.



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

        A separate transformer would be needed to power three additional cards.  Right?
        Bill

        Sent from AOL Mobile Mail


        -----Original Message-----
        From: eberhard <eberhard@...>
        To: altaircomputerclub <altaircomputerclub@yahoogroups.com>
        Sent: Thu, Sep 12, 2013 05:07 PM
        Subject: RE: [Altair Computer Club] Altair 680 expander boards




        Kip,

        The Altair 680 was a low-cost product with limited expansion capability. In its base configuration, it had just one  expansion socket, which was intended only to take an "expansion board" - which was sold separately. Many (most?) Altair 680s and 680bs were sold without this expansion board, and were thus limited to 1K RAM, and 1 serial port.

        As far as I know, the excellent Grant Stockley replica is just that - a true-to-the-original replica of the original Altair, including the connector that would take an expansion board. I don't think Grant offered an expansion board for sale with his kit, (and I am sure someone here will educate me if I am wrong on this).

        Because so many 680s were originally sold without expansion boards, they are pretty scarce. This is why I decided to create a copy of the original Altair 680b expansion board. I am pretty sure that my expansion board, just like an original expansion board, will work perfectly in Grant's replica, just as it does in a real Altair 680 or 680b.

        With an expansion board, the Altair 680 - Grant's replica or original - will have 3 expansion sockets. I know of the following option boards that were made available for the 680b:

        680-KCACR cassette interface
        680-BSM 16K static RAM
        680-PCI Process Control Interface
        680-UIO 2 serial plus 2 parallel ports

        There was rumor of a floppy controller for the 680b, but to my knowledge, such a board was never offered for sale by MITS. (I think it is even doubtful that the 6800 processor, running at 500 KHz as it does in the Altair 680b, can even keep up with even a minidisk data rate.)

         



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

        Hi Guys!

        I have been a longtime admirer of the Motorola line of microprocessors and when I saw the discussion of the Altair 680 expander boards,  I thought interesting.  Hmmm, I would like to know want it would take to build a complete 680b computer system with expansion capabilities using the newest technology available.  I’m not really aware of what is currently available for the 680b and maybe later a 6809 or 6309 version.  I have seen 680b replicas before, that although very well done, had everything on one PCB with no expansion capabilities.  This design for the 680b did not interest me.  However, with the talk of expansion boards, I am again interested.  Any help with this endeavor will be much appreciated.  Thank you in advance.

        Kip

         

        From: altaircomputerclub@yahoogroups.com [mailto:altaircomputerclub@yahoogroups.com] On Behalf Of eberhard@...
        Sent: Wednesday, September 11, 2013 7:34 PM
        To: altaircomputerclub@yahoogroups.com
        Subject: [Altair Computer Club] Altair 680 expander boards

         

         

        Since the subject of 680 replicas came up again, I thought I'd bring this up:

        A while back, I designed and fabricated a small run of replica expander boards (backplanes) for the Altair 680. They are a pretty close replica, and have decent gold plating on the fingers, both top and bottom. You can see photos of my expander board in the Files section, under "Altair 680b Expander Board".

        These work great - that's what I have in my own 680b. with brand-new edge connectors, all of the usual flakiness problems of my 680b went away.

        I still have a few of these left, if anyone wants to buy one. I will sell them for $30 each without the edge connectors installed - they take the same edge connectors as all other Altair backplanes.

        If you want to buy edge connectors, I will place an order for them - they cost about $12 each, the last time I looked, and they take several weeks to be delivered.

        Let me know if you are interested.



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