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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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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.


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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.


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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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A Tale of Two Luggables (IBM 5155)

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    A Tale of Two Luggables (IBM 5155)

    Greetings -

    So, I drove an hour for a Facebook market posting showing an IBM 5155.

    When I got there in person and powering it on... the floppy drives were not reading. He said, "oh... I have another one" ... so we powered that one on and the monitor was dead but I could hear the floppy drives reading... well, long story short, I made an offer for both (not knowing he had two) and left with both! He said when he moved into the house, he and found them in the attic - and thought they were suitcases at first (both in their zippered carrying cases).

    LUGGABLE 1
    --------------
    The one that wasn't recognizing the floppy drives didn't have a screw holding the card in, so somehow it was loose. Pop it back in... all appears to be in good working condition... computer, screen and drives.

    IMG_1524.jpg

    IMG_1522.jpg

    LUGGABLE 2
    --------------
    The built in monitor is just dead... no flickering, no images, no signs of life whatsoever... but hooking up a TV shows the computer and drives are also in good working condition.

    IMG_1526.jpg

    IMG_1523.jpg

    So, a few questions...

    1) Are there any troubleshooting methods for the dead monitor? I'm definitely not qualified to go digging around in CRT guts.

    2) Are there any quantifiable differences between the two motherboards and processors? (pictured above: one Intel branded CPU with white switch box and the other NEC branded CPU with blue switch box)?

    3) Lastly, any advice overall is certainly welcome.

    Thank you for your time and help!

    #2
    Originally posted by phonophan View Post
    2) Are there any quantifiable differences between the two motherboards and processors? (pictured above: one Intel branded CPU with white switch box and the other NEC branded CPU with blue switch box)?
    No functional differences.
    IBM used different part suppliers (e.g. price competition, no single line of supply).

    Originally posted by phonophan View Post
    --------------
    LUGGABLE 2
    --------------
    The built in monitor is just dead... no flickering, no images, no signs of life whatsoever... but hooking up a TV shows the computer and drives are also in good working condition.

    ...

    1) Are there any troubleshooting methods for the dead monitor? I'm definitely not qualified to go digging around in CRT guts.
    - Verify, that like machine #1, the video cable from the CRT display unit is connected to connector P1 on the CGA card ([photo]).

    - To identify a possible faulty CGA card, try swapping the CGA cards between the two machines.

    - Per the photo at [here], the CRT display unit is powered by +12V from the power supply, via the dedicated connector of P12. Try re-seating that connector. And verify that +12V is present on it.

    Comment


      #3
      Originally posted by phonophan View Post
      LUGGABLE 2
      --------------
      The built in monitor is just dead... no flickering, no images, no signs of life whatsoever... but hooking up a TV shows the computer and drives are also in good working condition.
      I know this sounds silly, but have you tried turning up the brightness knob next to the monitor?

      Comment


        #4
        This was beyond my repair ability... but was worked on by someone else.

        First was testing for voltage issues, replaced a resistor and transistor to no avail.

        Attach01(2).jpg

        Replacing the horizontal output transistor did produce an image but the vsync was off.

        Attach01(3).jpg

        Replaced resistor capacitor to still no avail ... and unfortunately accidentally broke the tube during repair.

        Can't believe a new old stock tube was found, but installed it and voi-la... working luggage.

        Screenshot_20200501-205849_Video Player.jpg

        Just thought i'd share!

        Comment


          #5
          Originally posted by phonophan View Post
          Can't believe a new old stock tube was found, but installed it and voi-la... working luggage.

          [ATTACH=CONFIG]60601[/ATTACH]

          Just thought i'd share!
          Hurray! Thanks for coming back to this thread to share the happy news.

          How on Earth did you find a replacement tube and, if you don't mind my asking, how much did it cost to resurrect your 5155?

          Comment

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