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Thread: IBM EGA Card Memory Expansion Boards

  1. #11
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    Quote Originally Posted by modem7 View Post
    I receive a HTTP 404 error for that link.
    Same here. Try it this way: here

  2. #12
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    Quote Originally Posted by ab0tj View Post
    Same here. Try it this way: here
    Got it.

    Where in the PDF, it shows "12.70", I measure 13 mm, so close enough there.

    However, the two holes in the IBM EGA card are 4 mm diameter.

  3. #13
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    Quote Originally Posted by modem7 View Post
    Got it.

    Where in the PDF, it shows "12.70", I measure 13 mm, so close enough there.

    However, the two holes in the IBM EGA card are 4 mm diameter.
    12.7mm = 1/2 inch. So makes sense.

  4. #14
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    Quote Originally Posted by modem7 View Post
    Got it.

    Where in the PDF, it shows "12.70", I measure 13 mm, so close enough there.

    However, the two holes in the IBM EGA card are 4 mm diameter.
    Thanks for checking on this. Looks like the holes in the expansion card would need to be 4.8mm to support these standoffs, and they would fit in the 4mm holes of the EGA card. I'll keep looking but if I can't find standoffs that are 4mm on both ends, it looks like there's room in the expansion card design to enlarge the holes a bit.

  5. #15
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    The photos at [here] show how close the IBM Graphics Memory Expansion Card comes to the adjacent card in an IBM 5170.
    Clearly, that is why the IBM Graphics Memory Expansion Card has a protective sheet over its solder side.

    (The photo is not of my 5170's normal slot configuration. I normally leave an empty slot next to the IBM EGA card.)

  6. #16
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    Default Good news and bad news...

    So the good news is... It works. I soldered it together and it required zero rework. Always nice when that happens.
    The bad news is there's some fitment issues. The holes for the standoffs had to be drilled out a bit... Not sure yet if that was a design problem or if I just hit the maximum size the board house can drill. Also I think I need a longer pin header to connect to the EGA card, because I have to bend the board in order to plug it in completely if using the standoffs.

    Overall not too bad for a prototype!
    Attached Images Attached Images

  7. #17

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    Nice job on the board!

  8. #18

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    outstanding!

  9. #19
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    You might be able to just use a M-F header to extend the pins and get the proper board spacing.

  10. #20
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    Quote Originally Posted by mikey99 View Post
    You might be able to just use a M-F header to extend the pins and get the proper board spacing.
    Good thinking. Though that may add too much length, really only need another 4mm or so

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