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Re: IMSAI 8080

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  • DanielB
    ... I ve been tracing the circuit for the Dutronics board that was in my IMSAI 8080. The loose wire connects to the MREQ signal on the Z80. Any idea where the
    Message 1 of 61 , Mar 8, 2013
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      --- In midatlanticretro@yahoogroups.com, joshbensadon <no_reply@...> wrote:
      >
      > --- In midatlanticretro@yahoogroups.com, corey986 wrote:
      > >
      > > You don't happen to have documentation for the Dutronics board? I have one and have no clue how it hooks up. I only see where you plug it into the 8080a slot and a single wire that comes out that is supposed to hook up to something...
      > > email me directly at corey@ so I can ask you more questions about it.
      > >
      > > Thanks,
      > > Corey
      >
      > Sorry, I don't have schematics for the board, but I've studied the idea of creating 8080A signals from the Z80A. I have a good idea of how that board is suppose to work but I would love to see some schematics for it.
      >
      > There is a good chance that I might be able to recreate the schematics by following the visible traces on your board. Would you be willing to put your board on a scanner and send me scans of the top & bottom? Pull out the CPU if the socket is an open frame type.
      >
      > There is a header on the lower right side, that outputs the STATUS signals and should some how be connected to the S100 bus. The single wire is quite possibly the Memory Refresh signal from the Z80A, this was not a feature of the 8080A. But that's just a guess.
      >
      > Cheers,
      > Josh
      >

      I've been tracing the circuit for the Dutronics board that was in my IMSAI 8080. The loose wire connects to the MREQ signal on the Z80. Any idea where the other end of this wire should connect?
    • DanielB
      Yep, front panel is working good now. One odd thing I have run into is that from the Zapple monitor I can write to the SMB s onboard RAM, but I cannot write to
      Message 61 of 61 , May 14, 2013
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        Yep, front panel is working good now. One odd thing I have run into is that from the Zapple monitor I can write to the SMB's onboard RAM, but I cannot write to the RAM on the memory board but I can write to the memory board from the front panel.

        Dan

        --- In midatlanticretro@yahoogroups.com, joshbensadon <no_reply@...> wrote:
        >
        >
        >
        > --- In midatlanticretro@yahoogroups.com, "DanielB" <danlb_2000@> wrote:
        > >
        > > After bad chips I finally got the front panel working, and after a couple bad tantalum caps on the SMB I also got that working. Very exciting when I got the Zapple monitor prompt!
        > >
        > > https://lh6.googleusercontent.com/-uQShOzInDeE/UZFoWnYYpsI/AAAAAAAACII/80vupyb6Psc/w883-h662-no/IMG_3933.JPG
        > >
        >
        >
        > Daniel,
        >
        > That's looking great! Very well done :)
        >
        > Can you now Examine/Deposit via the front panel?
        >
        > :)J
        >
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