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
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  • 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.
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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.

Here are some obvious examples of when you should not reply to a thread and use the PM system 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.

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.
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  • Spelling and grammar are not rated, but they do make a post easier to read.
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Looking for the dimensions or form factor of the baby AT board

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    Wasn't the IBM 5162 (XT-286) the prototypical baby AT motherboard? That's my memory of it.

    - Alex


      As promised, here are my findings of the dimensions of various boards I have and the coordinates of the most important parts, What do I consider as an important part:
      - the holes
      - the ISA slots
      - the keyboard and cassette connector.
      IMHO the 12-pins connector is not an important part: you can place it almost anywhere on the board and the board will still be functional inside a case. But move the keyboard connector a centimeter to the right or the left and I don't think you can plug a keyboard into it anymore.

      I will give you the images of the boards as I have saved them in Eagle (packages, to be precise) and I will give you the coordinates of the various parts in inches.

      But what to use as base coordinate? To make a long story short, I used the upper-left pin of ISA slot 1 as base.

      I start with my 5160 clone board base.

      The board:
      - left edge of the board: -0.12
      - top edge of the board: 1.0
      - bottom edge of the board: 11.0
      - right edge of the board: 8.38

      The holes:
      - top-left: 0.58 - 0.6
      - top-middle: 3.58 - 0.6
      - top-right: 8.18 - 0.6

      - middle-left: 0.58 - -5.0
      - middle-middle: 3.58 - -5.0
      - middle-right: 8.18 - -5.0

      - bottom-left: 0.58 - -10.8
      - bottom-middle: 3.58 - -10.8
      - bottom-right: 8.18 - -10.8

      Keyboard connector: the middle between the two drill holes: 7.25 - 0.7

      Distance between upper-left pins of ISA slots: 0.8

      The IBM 5160 board is the same with one exception: the middle-right hole is missing.

      The 5150 board is the same as the 5160 clone board except:
      Keyboard connector: 6.85 - 0.7
      Cassette connector: 5.95 - 0.7
      Distance between upper-left pins of ISA slots: 1.0

      The AT clone board is the same as the 5160 clone board except:
      It is wider, left edge of the board: -0.17
      Keyboard connector: the middle between the two drill holes: 7.45 - 0.7

      The library with the packages is free.
      With kind regards / met vriendelijke groet, Ruud Baltissen


        Back in the day I bought a 286-12 board that dropped nicely into a clone XT case. The only problem was that I managed to pull the timing crystal out of the motherboard first time around. It hung up on the left drive cage. I put the crystal back in backwards, but the dealer was kind enough to point out my error. The second time around it went in easy peasy once I knew what to watch out for.


          Crystals have polarity? Maybe you meant XCO (crystal controlled oscillator)?
          Reach me: vcfblackhole _at_ protonmail dot com.


            Originally posted by Chuck(G) View Post
            Crystals have polarity? Maybe you meant XCO (crystal controlled oscillator)?
            Could be. It was back in the 1980s. Sue me.
            All I remember is was silver, rectangular, and had a relatively thick wire lead coming from each corner. I hooked it with the left-hand drive cage while installing the motherboard & pulled it out. I put it back in and nothing happened, so I took it back to the store where I got it. (remember when there were local brick & mortar computer parts stores?) The owner informed me I had put it in wrong fixed it. Got a dirty look too.