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IBM EGA Card Memory Expansion Boards

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    IBM EGA Card Memory Expansion Boards

    Hi all. One of the projects I have been working on lately is recreating the PCB for the IBM EGA memory expansion board (part number 6480099). I'm going to have board made either way to expand my own system, but I was wondering if there was a need out there and I should get extras? They seem to be hard to find. You'd have to source your own components to solder on the board.

    #2
    Originally posted by ab0tj View Post
    Hi all. One of the projects I have been working on lately is recreating the PCB for the IBM EGA memory expansion board (part number 6480099). I'm going to have board made either way to expand my own system, but I was wondering if there was a need out there and I should get extras? They seem to be hard to find. You'd have to source your own components to solder on the board.
    man you and I have a lot of overlapping interests, I'd probably want one or at least the file to get my own if you release it

    Great Heirophant had expressed interest as well

    Comment


      #3
      Originally posted by maxtherabbit View Post
      man you and I have a lot of overlapping interests, I'd probably want one or at least the file to get my own if you release it

      Great Heirophant had expressed interest as well
      Apparently we do. Luckily enough this one isn't difficult since the schematics are already available. I just had to transcribe it into KiCad
      I am definitely willing to share the design files when they're done. Economy of scale helps the costs when ordering PCBs so if others are interested it's nice to make one big order.

      Comment


        #4
        Saw one of these go cheap on eBay recently: https://www.ebay.com/itm/IBM-MEMORY-...4/264537735855
        Once upon a time, the internet sucked because it came through the phone. Now the phone sucks because it comes through the internet.

        Comment


          #5
          IBM EGA Adapter Memory Expansion.jpg

          Comment


            #6
            By the way, if someone has one of these and could provide some measurements (namely overall dimensions, spacing and diameter of the holes, standoff length) that would be helpful. Otherwise I'll figure it out when my EGA card shows up

            Comment


              #7
              Originally posted by ab0tj View Post
              By the way, if someone has one of these and could provide some measurements (namely overall dimensions, spacing and diameter of the holes, standoff length) that would be helpful. Otherwise I'll figure it out when my EGA card shows up
              See [here].

              Hole diameter is 4 mm.

              Comment


                #8
                Originally posted by modem7 View Post
                See [here].

                Hole diameter is 4 mm.
                Awesome, thank you!

                Comment


                  #9
                  Originally posted by modem7 View Post
                  See [here].

                  Hole diameter is 4 mm.
                  The standoffs look exactly like this - is the hole in the expansion slightly larger than the one in the EGA card?

                  Comment


                    #10
                    Originally posted by ab0tj View Post
                    The standoffs look exactly like this ...
                    I receive a HTTP 404 error for that link.

                    Originally posted by ab0tj View Post
                    ... is the hole in the expansion slightly larger than the one in the EGA card?
                    I will get back to you on that; I have a few things to do now.

                    Comment


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

                      Comment


                        #12
                        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.

                        Comment


                          #13
                          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.

                          Comment


                            #14
                            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.

                            Comment


                              #15
                              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.)

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