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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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Conduct yourself as you would at any other place where people come together in person to discuss their hobby. If you wouldn't say something to somebody in person, then you probably should not be writing it here.

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Rule 4: "PM Sent!" messages (or, how to use the Private Message system)

This forum has a private message feature that we want people to use for messages that are not of general interest to other members.

In short, if you are going to reply to a thread and that reply is targeted to a specific individual and not of interest to anybody else (either now or in the future) then send a private message instead.

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Why do we have this policy? Sending a "PM Sent!" type message basically wastes everybody else's time by making them having to scroll past a post in a thread that looks to be updated, when the update is not meaningful. And the person you are sending the PM to will be notified by the forum software that they have a message waiting for them. Look up at the top near the right edge where it says 'Notifications' ... if you have a PM waiting, it will tell you there.

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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If you are unsure you may consider sending a private message to a moderator instead.


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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unknown 512k memory expansion card ibm 5150

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    unknown 512k memory expansion card ibm 5150

    Hello,
    I have acquired a nice 5150 in quite a good state. It came with a RAM expansion card, from which I haven't been able to find any information about online. I wonder if any of you have any idea about this card. It came with only one bank filled (with TI 4164-12 ic's), as seen in the picture. The SW2 in the mainboard was configured for 128kb in total (64kb on board + 64 kb on the card). I decided to take the risk and got some chinese memory ICs, which look very similar to the ones installed, and should have the same specs. I populated one bank and had the enormous luck to configure the right card dip switch settings to make the bios recognize the added memory. I changed the SW2 in the mainboard to 192kb total. So far so good. I had more ICs available so decided to try my luck again and populated 2 banks more. This time I had no luck. Tried various combinations but nothing worked and when no memory related error came on POST then a keyboard error happened. Very weird.
    192 kb are working well. However, it would be great if I could expand to full capacity, now that the ICs I recently acquired seem to work fine (at least in one bank ). Do you have any idea of the possible dip switch settings for this card? The card comes with only one switch bank with 6 dip switches. In my guess, dip sw 1 and 2 seem to define the starting RAM amount. They were 1=off, 2=on and 3 to 6 = on in the original configuration. The change to 192 kb that I just made worked by having 4 = off. I have been looking everywhere for a hint, but it is very difficult. Any help is greatly appreciated.
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    #2
    The brand i dont know

    But it seems the previous person used it as a conventional back fill card.
    THE BIOS MASTER

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      #3
      That is a Twinhead CT-6080a. But I don't see switch setting info for that model in any of the usual places.

      The closest I see out there is this: https://www.arvutimuuseum.ee/th99/i/S-T/53468.htm

      Perhaps the settings are similar.

      Comment


        #4
        Many thanks for the useful tips. I will explore the settings as explained in the link posted by SomeGuy. It indeed seems close enough to this card. I will revert with the result soon.

        Comment


          #5
          Sadly no luck with this card. Jumper settings appear to be quite different from the CT-6280... If anybody has any tip on the possibility of doing some 'reverse engineering' to find out the correct jumper settings it would be great. Otherwise will just try to get another card.

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