Forum Rules and Etiquette

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This forum is part of our mission to promote the preservation of vintage computers through education and outreach. (In real life we also run events and have a museum.) We encourage you to join us, participate, share your knowledge, and enjoy.

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Rule 5: Copyright and other legal issues

We are here to discuss vintage computing, so discussing software, books, and other intellectual property that is on-topic is fine. We don't want people using these forums to discuss or enable copyright violations or other things that are against the law; whether you agree with the law or not is irrelevant. Do not use our resources for something that is legally or morally questionable.

Our discussions here generally fall under "fair use." Telling people how to pirate a software title is an example of something that is not allowable here.

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New user moderation

New users are directly moderated so that we can weed spammers out early. This means that for your first 10 posts you will have some delay before they are seen. We understand this can be disruptive to the flow of conversation and we try to keep up with our new user moderation duties to avoid undue inconvenience. Please do not make duplicate posts, extra posts to bump your post count, or ask the moderators to expedite this process; 10 moderated posts will go by quickly.

New users also have a smaller personal message inbox limit and are rate limited when sending PMs to other users.

Other suggestions
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IBM 5170 Extended Memory Card Mystery

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    Final update in regards to this issue. No other SIMM in my current possession will work in this PC-AT save for the single pair of 1MB Hitachi SIMMs, in either memory adapter. I have surrendered in the fact that I cannot stuff more memory into this system without investing in a matched set of IBM-proprietary 256K pairity SIMMs, but that is far from a current priority of mine.

    I did however learn much about the memory adapter that came with it, so that's a plus! It's a shame no one ever considered keeping the original manuals that came with such hardware.

    Thanks again for everyone's input! It finally put this 13-year mystery to bed.


      i've got these... 1.jpg

      they're 512K each.


        Found my card ! it was in the AT sitting right on my garage workbench

        I checked the card and the original switch setting I had posted is correct:

        1,2,3,5,7,8 on
        4,6 off

        The memory count at boot goes up to 2560 KB
        Running the diagnostics diskette, indicates 128 KB is used to backfill the base memory to 640 KB
        This leaves 1920 KB extended memory.


          Originally posted by chulofiasco View Post
          i've got these...

          they're 512K each.
          Cool ! I like the look of these SIMMs , very vintage !


            Originally posted by ArchieX View Post
            Hmm. I also just found this link which also refers to a "Memory Expansion Adapter" that sounds like my card,
            The card quoted in that magazine article has to be different to the "Memory Expansion Adapter" found by yuhong. Why? Because of the dates of the two magazine articles.
            AUG86: "... last week introduced the Memory Expansion Adapter ..."
            SEP87: "... Was introduced last week ..."

            And it gives a different name to the card:

            AUG86: "... Memory Expansion Adapter ..."
            SEP87: "... Enhanced Memory Expansion Adapter ..."

            And the maximum RAM per card:

            AUG86: "... with as much as 3 megabytes ..."
            SEP87: "... memory adapter that provides up to 12 megabytes of memory ..."

            Originally posted by ArchieX View Post
            ... and mentions the fact that you would need five of these cards to reach a maximum of 15MB.
            That sentence can be interpreted differently.

            Originally posted by ArchieX View Post
            I think I'm starting to see a picture here. This card should be populated with 9-chip 256KB modules to give me 3MB, whereas for some reason I have a lucky set of 1MB modules that happen to work to give me 2MB; my other 1MB modules will not be seen by the system regardless of which memory adapter I use.
            Could it be that you have the 'Enhanced Memory Expansion Adapter', and that card is quite picky about the 1MB modules that it can use ?


              An 'Enhanced Memory Expansion Adapter' sold on eBay at [here].
              Has photos, including one of box.


                Originally posted by modem7 View Post
                Could it be that you have the 'Enhanced Memory Expansion Adapter', and that card is quite picky about the 1MB modules that it can use ?
                Very possible. I've read many sources that cite the 5170 was exceedingly picky with the memory it would recognize, but even in that case, I don't have other memory that will work in it for the time being. And along the lines I stated before, twelve IBM-propriety 9-chip 1MB 30-pin parity SIMMs is probably hard enough to locate as to be virtually impossible, and not a high priority of mine.

                But the info is nice to know!
                Last edited by ArchieX; March 15, 2016, 02:37 AM.


                  Originally posted by modem7 View Post
                  An 'Enhanced Memory Expansion Adapter' sold on eBay at [here].
                  Has photos, including one of box.
                  Very interesting, the box says that card is for the AT and XT ..... maybe this is for the XT-286


                    Originally posted by mikey99 View Post
                    Very interesting, the box says that card is for the AT and XT ..... maybe this is for the XT-286
                    That would be strange having an 8-bit/16-bit memory card. Are you sure the box should be paired with that card?


                      Originally posted by mikey99 View Post
                      the box says that card is for the AT and XT
                      Do I detect the slightest hint of a next character right at the edge of that picture? Maybe it says XT 286?


                        Originally posted by bobba84 View Post
                        Do I detect the slightest hint of a next character right at the edge of that picture? Maybe it says XT 286?
                        How about:


                          Originally posted by modem7 View Post
                          How about:

                          There it is! Mystery solved, I believe!


                            So, I'll do y'all one better

                            First off, I can confirm that the card that the OP is describing is in fact an IBM Enhanced Memory Expansion Adapter for the PC-AT and PC/XT 286. My own EMEA card has the same "ASM 55X3543" inscribed on it, and the picture on inscribed "ASM 30F5368" also appears to be an EMEA card.

                            And now, drumroll please, the end of a very old internet mystery. What about the Operator's Guide? I wrote to the IBM Corporate Archives and asked them to send me whatever materials they still had on the EMEA card. They replied by sending me OCR'd PDFs of the following documentation:

                            IBM Enhanced Memory Expansion Adapter: Guide to Operations - G570-2237
                            IBM Enhanced Memory Expansion Adapter: Technical Reference Manual - G570-2240
                            IBM Enhanced Memory Expansion Adapter: Specification Sheet - G571-0106
                            IBM Enhanced Memory Expansion Adapter: Presentation FOILS - B184-F8
                            IBM Enhanced Memory Expansion Adapter: Presentation Guide - 2-19-D-3-B184-F8
                            They were unable to find the Brochure (G571-0107), and the Hardware Maintance and Service manual (G570-2239). But having the Owner's Manual, Technical Reference Guide, product spec sheet, and the salesman's pitch with slides... that should be enough to get any of us started.

                            That being said, the 1MB memory DIMMs I purchased online still don't work in the card, even with the correct DIP switch settings. I suspect that the EMEA card is just picky about what memory DIMMs it takes.

                            1. Guide to Operations - G570-2237
                            2. Technical Reference Manual - G570-2240
                            3. Specification Sheet - G571-0106
                            4. Sales Presentation FOILS (presentation deck) - B184-F8
                            5. Sales Presentation Guide - 2-19-D-3-B184-F8
                            Last edited by djfitzgerald; September 13, 2021, 02:22 PM.


                              Originally posted by djfitzgerald View Post
                              So, I'll do y'all one better
                              Thank you.
                              I have added the documents to, specifically, [here] and [here].