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.

This forum has been around in this format for over 15 years. These rules and guidelines help us maintain a healthy and active community, and we moderate the forum to keep things on track. Please familiarize yourself with these rules and guidelines.

Rule 1: Remain civil and respectful

There are several hundred people who actively participate here. People come from all different backgrounds and will have different ways of seeing things. You will not agree with everything you read here. Back-and-forth discussions are fine but do not cross the line into rude or disrespectful behavior.

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.

This should be obvious but, just in case: profanity, threats, slurs against any group (sexual, racial, gender, etc.) will not be tolerated.

Rule 2: Stay close to the original topic being discussed
  • If you are starting a new thread choose a reasonable sub-forum to start your thread. (If you choose incorrectly don't worry, we can fix that.)
  • If you are responding to a thread, stay on topic - the original poster was trying to achieve something. You can always start a new thread instead of potentially "hijacking" an existing thread.

Rule 3: Contribute something meaningful

To put things in engineering terms, we value a high signal to noise ratio. Coming here should not be a waste of time.
  • This is not a chat room. If you are taking less than 30 seconds to make a post then you are probably doing something wrong. A post should be on topic, clear, and contribute something meaningful to the discussion. If people read your posts and feel that their time as been wasted, they will stop reading your posts. Worse yet, they will stop visiting and we'll lose their experience and contributions.
  • Do not bump threads.
  • Do not "necro-post" unless you are following up to a specific person on a specific thread. And even then, that person may have moved on. Just start a new thread for your related topic.
  • Use the Private Message system for posts that are targeted at a specific person.

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.

Here are some obvious examples of when you should not reply to a thread and use the PM system instead:
  • "PM Sent!": Do not tell the rest of us that you sent a PM ... the forum software will tell the other person that they have a PM waiting.
  • "How much is shipping to ....": This is a very specific and directed question that is not of interest to anybody else.

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.

Reporting problematic posts

If you see spam, a wildly off-topic post, or something abusive or illegal please report the thread by clicking on the "Report Post" icon. (It looks like an exclamation point in a triangle and it is available under every post.) This send a notification to all of the moderators, so somebody will see it and deal with it.

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
  • Use Google, books, or other definitive sources. There is a lot of information out there.
  • Don't make people guess at what you are trying to say; we are not mind readers. Be clear and concise.
  • Spelling and grammar are not rated, but they do make a post easier to read.
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Identifying XT clone mainboard

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    Identifying XT clone mainboard

    Recently I restored an old XT mainboard, it's a 5160 clone with a bit different ROM selection circuit, and I wonder who made such boards, what for (was there a system?) and when, in my unit components are from 1984-85 (chips are made by TI and Nec). It does not look like a simplified Taiwanese clone. In typical clones, chips were soldered into board and in best cases the only info on silkscreen was type of ROMs.
    In this mainboard, all chips are in sockets, types are printed on silkscreen, component values (including passives and connector types!) and DIP settings are printed too. There is also some breadboard in a corner. Making such board is far from a cheap clone.
    The ROM is a modified 08/16/1982 IBM's burned to EPROM (came without sticker, so no info from it). There is a logo behind NPU socket which looks like stylish S with a resistor symbol in it.
    And the male ISA connector on the edge of the board - what is it, is it for some kind of riser?
    ROM circuit allows to connect not only ROM, but also to connect /MEMW to some sockets R/W pin like for SRAM. Additionally IRQ2 can be connected to ROM socket pin 2 (usually A12). Was there a configuration involving RAM in ROM area?
    Thanks in advance

    Originally posted by MCbx View Post
    And the male ISA connector on the edge of the board - what is it, is it for some kind of riser?
    Likely a "diagnostics port" used only in production/test of the motherboard. It's a common practice in several PCB's.


      Or an option for additional ISA slots. There were 11 and 13 slot cases made for industrial use at the time.
      Reach me: vcfblackhole _at_ protonmail dot com.


        Thanks for reply!
        It is certainly ISA expansion as it has all signals for it, tested it with ohmmeter.
        I got some more information and there indeed was such option to connect SRAM in ROM area, but it was not compatible with anything except some specialized software.


          That looks like a Display Telecommunications Corporation "Megaboard":

          It was one of the earlier "parts only" PC clone motherboards.


            That's it! And I also have a IBM BIOS copy. My unit has holes for reset button, but no button soldered in, only reset jumper which is not present in another unit. There is also no logo, so it may be an early one, late one or clone, but it's generally this design.
            Knowing the name I found a nice assembly information in a PC Mag article.
            Thank You for this information!.


              Very similar in shape and design to my 8088 board in a "wedge technology" clone. Only difference is the chip manufacturer being a mix of AMD, Intel, and Mitsubishi rather than NEC,