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Re: IMSAI 8080

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  • DanielB
    ... Thanks! Guess I didn t look very hard :)
    Message 1 of 61 , Apr 2 4:25 PM
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      --- In midatlanticretro@yahoogroups.com, Jeff Galinat <jgalinat@...> wrote:
      >
      > On 4/2/2013 6:54 PM, DanielB wrote:
      > >
      > >
      > > Thanks for the input. Neither my front panel nor CPU board (except the
      > > Z80 add-on) are socketed so no issue with tarnished pins, but I will
      > > have to check that on the other boards.
      > >
      > > I seem to have it running small programs ok now, but it looks like I
      > > have a problem with the 8212 latch on the front panel that is used to
      > > drive the LEDs that can be written to on IO port FF. All the input
      > > signals look ok, even checked the timing with a logic analyzer, but I
      > > still get no output to the LEDs. I am guessing that is no an easy chip
      > > to get a replacement for.
      > >
      > >
      > >
      > Hi Daniel,
      > Actually the 8212 is fairly easy to get. It is $5 at Unicorn
      > Electronics <http://www.unicornelectronics.com/IC/8000.html> It is $1.49
      > at Anchor Electronics (not a labeled 8212 but an equivalent 74S412) .
      > Anchor does not have a on line ordering system but the printed catalog
      > is here <http://www.anchor-electronics.com/weblist.pdf> and the
      > 8212/74S412 is listed under 8000/8200 series mid page on the left side
      > on page 8.
      >
      > They are also available on eBay at 3 for $10 with $2 shipping
      > <http://www.ebay.com/itm/Lot-of-3-Intel-P8212-Integrated-Circuits-S1002-1982-Date-Code-NOS-/261191784891?pt=LH_DefaultDomain_0&hash=item3cd03e59bb>
      >
      > Regards,
      > Jeff
      >

      Thanks! Guess I didn't look very hard :)
    • 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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