Forum Rules and Etiquette

Our mission ...

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.
See more
See less

Mistery ATARI ABC 286 in PC4 chassis with PC4LC mainboard...

  • Filter
  • Time
  • Show
Clear All
new posts

    Mistery ATARI ABC 286 in PC4 chassis with PC4LC mainboard...

    Hello, in the german forum a member has posted details about a mistery ATARI ABC 286 PC. Normally ATARI ABC-286 is well known, but this one is special, I have never seen this one before, also the known websites only show the normal ones ( , ). The interesting things are:

    1. It is using the ATARI PC 4 chassis. ABC 286 chassis usually looks different, see
    2. Special mainboard "ATARI PC4LC", LC = Low Cost?
    3. Instead of PC4 without connector for external floppy drive and without connector for the ATARI (ST) busmouse.
    4. It has exactly 640 kB of ram, using 2x 64 KB and 2x 256 kB SIPP modules
    5. EGA 9 pin video connector, but usually available DIP switches for EGA card mode selection not installed

    Original thread in german:
    Detail photos:

    Do you have any details aboutb this special version?

    I don't have anything to add apart from more speculation as I've never seen anything like this before. But in talking with the owner and seeing the pictures, I agree that everything seems to point to it being a low cost version of the ABC 286 made possible by reusing existing parts from the Atari PC4, even going as far producing a PC4 motherboard with as little components and circuitry as possible. I noticed too the SIPP RAM is missing an Atari P/N silkscreened on the PCB, something which the RAM included with the original Atari PC4 does have so it appears they went with the cheapest RAM they could source at the time.

    It's a very interesting PC, very much a hybrid Atari PC/ABC. I find it a little amusing that they didn't even go to the trouble of hiding the fact it was using a Atari PC4 chassis by keeping with the original plastic trim with the large "PC4" molded into it. You think they could of at least incorporated PC4 into the model name so it wasn't that much out of place! Strange decision.

    I should note it's not the first time I've seen some interesting things going on the with the PC4 in Germany as there is of course the Mitac Paragon 286VE which Atari started rebadging and selling as an Atari PC4. Makes me wonder if this is all related somehow? The Mitac rebadged as a Atari PC4 to continue that line which then allows them to shift development focus to the new ABC series and keep costs down by using existing stock of the PC4 chassis which they now have excess of. All purely speculation though....
    Atari PC | IBM Compatible Series


      I still remember the Mitac PC4, I used to have one in the office where I worked in 1990. I t was a rare place where a lot of Atari PCs and (Mega-)ST/E series were used in office for daily business. Even some early TT were there and some first tries with networking.

      By the way, has announced that they got one of these Mitac PC4 recently and will update the website soon.


        This is very unrelated, but years ago on I saw the most lame brained beige and vanilla Atari PC anyone has ever seen. I was thoroughly intrigued! Imagine pulling incriminating name tags off of a 5151 and dropping Atari specific tags in their place. Or really just a standard clone case. I can't remember too many specifics, but I'm lead to believe it had an 8088 duh. Maybe it was just a diabolical ruse. Maybe just maybe it was an early prototype. I'm sorry I didn't bid. Any Canadians into the Atari scene?


          Hmmm. I guess that explains the 102-key PC keyboard I have with the Atari sticker on the back...


            Show me. Show the world.


              Originally posted by Casey View Post
              Hmmm. I guess that explains the 102-key PC keyboard I have with the Atari sticker on the back...
              Is it a Mitsumi KPQ-E99YC? Do you have any photos?
              Atari PC | IBM Compatible Series


                Sorry for not replying sooner. Been working or sleeping.

                Here's a couple of shots:

                It didn't come with a plate for the LEDs so I added notes with a Sharpie. The back only has the one sticker, and it's pretty faded.
                I can't even remember where I got it, except "eBay." It was a long time ago, when you could buy vintage stuff without paying an insane price on eBay.

                {edit} It's a 5-pin DIN. It's either an AT or an autoswitch, given the LEDs. The last computer I used it on was a Compaq Deskpro 286. I honestly don't remember if I ever used it on my PC or XT. On the other hand, the Deskpro 286 seems quite happy with the (8086) Deskpro keyboard I've been using. My helpful friends tossed the Deskpro as well as the Enhanced 102-key keyboard that went with the 286 while I was in the hospital. Sigh.

                I'll have to try plugging it into a couple other systems. It's been a while since I've used it.
                Last edited by Casey; December 10, 2017, 06:29 PM.