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Re: [midatlanticretro] Re: IMSAI 8080

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  • Jeff Galinat
    ... It also appears that Jameco has it for $5.95 although they have it mis-labeled as I/O Port with timer.
    Message 1 of 61 , Apr 2, 2013
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      On 4/2/2013 7:20 PM, Jeff Galinat 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
      It also appears that Jameco has it for $5.95 although they have it mis-labeled as I/O Port with timer.
      <http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_52468_-1>
      Jeff
    • 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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