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Thread: Interesting memory board...

  1. #1

    Default Interesting memory board...

    Does anyone know what this is? And can point me to dip settings?
    This came from a Corona PC-400 and appears to fill the gap from 8000H to AFFFH (yielding 704K memory on bootup).
    No brand name, and no part number on the board. And only 8 out of the 18 IC slots filled....

    20200528_172614000_iOS (2).jpg

  2. #2

    Default

    I don't know this board but maybe I can answer some questions:
    - If it filled the gap starting from 8000h to 0B000h, only 192 KB are needed. And that number fits inside one bank of 256 KB.
    - There is only one dip "up", number 5. 5, 6, 7 and 8 could make "1000" = 8. Could these four bits be the starting address? Just a guess...
    With kind regards / met vriendelijke groet, Ruud Baltissen

    www.baltissen.org

  3. #3
    Join Date
    Feb 2010
    Location
    Russia, St.Petersburg
    Posts
    225

    Default

    82S137 is an EPROM implementing decoder and address selection
    https://datasheetspdf.com/pdf/551116/NXP/82S137/1

    9'th chip is a parity

  4. #4

    Default

    Thanks guys. Definitely good things to look at.. Guess experimenting it is!

    And yeah, I figured there was no parity enabled on this board...

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