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Thread: AT&T PC 6300 Revisited

  1. #1
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    Default AT&T PC 6300 Revisited

    I acquired an AT&T PC 6300 recently; it arrived yesterday. Having owned one back in the 1980s I am "sorta" familiar with it, but back then it was just an office appliance. The farthest I got into the hardware was to add a DTC controller and a Conner HD. I passed it on a few years later for a newer PC with 3.5 inch drives and a color display.

    So now I have a survivor of that era, and I have gotten as far as removing the CPU's top cover. Already I am asking questions:

    In addition to the video card and 2 half-height 5.25 FDDs there are two 8-bit cards in the backplane: One is a Plus HardCard 20, which I'm guessing is an HD on an ISA card.
    Anyone got documentation for that?

    The other card is a DAK VG-100 and appears to be related to video; there are two RCA jacks labeled video in and video out. No idea.
    Anyone recognize this?

    I know the motherboard is upside-down under the backplane that holds the cards and that the video card is a connector for the two. I would like to check for dead battery and possible cap leaks.
    Can I remove the bottom-half cover or will I have to remove all the internal components to access the motherboard?

    The keyboard is missing one key cap and switch (lower right corner, RETURN as I recall).
    What is the switch mechanism, and does anyone know of a source for spares?

    Thanks for your replies.

    -CH-

    Pics:

    IMG_2335.jpg IMG_2338.jpg
    Last edited by clh333; April 20th, 2017 at 09:39 AM.

  2. #2
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    Yes, the mainboard is "downstairs" and you have to check the battery. The keyboard is special, you won't get spare parts for it, except of from another same keyboard. The Plus HardCard 20 should be a harddisk (so called filecard), I guess it is having 20 Megabytes, but that is not original AT&T/Olivetti part, but some kind of third party add on.

    You can download all service manuals etc. from the following sites:
    - https://sites.google.com/site/att6300shrine/Home
    - http://www.olivettim24.hadesnet.org/download.html

    Please note, that AT%T 6300 is originally an Olivetti M24. And Xerox 6060 and Logabax Persona 1600 are the same as well. So you can use software, drivers, manuals, etc. from all of them to learn about this machine.
    -

  3. #3

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    Can't say much about those cards, but to access the underside, just remove the two captive flat head screws on the back bottom corners and the bottom part of the case should slide off. To remove the motherboard, remove the screws and standoffs holding it in place, take out the video card that came with it, and I believe unscrew the thick red and black power cables, and the it should come out without a problem. I don't think much is on the underside of the motherboard, so just removing the bottom case should reveal everything you want to check without taking out the whole board.

  4. #4
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    Quote Originally Posted by 1ST1 View Post
    Yes, the mainboard is "downstairs" and you have to check the battery. The keyboard is special, you won't get spare parts for it, except of from another same keyboard. The Plus HardCard 20 should be a harddisk (so called filecard), I guess it is having 20 Megabytes, but that is not original AT&T/Olivetti part, but some kind of third party add on.

    You can download all service manuals etc. from the following sites:
    - https://sites.google.com/site/att6300shrine/Home
    - http://www.olivettim24.hadesnet.org/download.html

    Please note, that AT%T 6300 is originally an Olivetti M24. And Xerox 6060 and Logabax Persona 1600 are the same as well. So you can use software, drivers, manuals, etc. from all of them to learn about this machine.
    -
    Thanks for your reply.

    I know (now) that the 6300 was a re-branded Olivetti. I had never seen the add-in cards contained within and still don't have any idea what the DAK card was for, but apparently somebody listed another one on eBay for $200. I'm pretty sure he doesn't know what to do with it either.

    I have a bad habit of saving useless stuff for "someday" so I have the original manuals for the AT&T and also the original distribution disks, containing MS-DOS 3.x and the AT&T utilities and help files. Including the mouse driver there are eight disks in all. So I diskcopied the boot disk and booted the machine; all systems passed POST. So far, so good.

    Thanks again for your input.

    -CH-

  5. #5
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    Anyhow, check the battery and take it out. It only holds the date/time, nothing more. But these batteries tend to leak and destroy the board.

  6. #6
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    Good Lord, a DAK board--from Drew Kaplan during his heyday, nonetheless. I used to love to browse his catalogs and actually bought some stuff from him back in the day. Here's a sample catalog

    The VG-100 card doesn't ring any bells, but you can drop a line to Sol (who took over from Drew when he retired) at dak.com. If Sol doesn't remember, maybe Drew will.

  7. #7
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    Quote Originally Posted by Chuck(G) View Post
    Good Lord, a DAK board--from Drew Kaplan during his heyday, nonetheless. I used to love to browse his catalogs and actually bought some stuff from him back in the day. Here's a sample catalog

    The VG-100 card doesn't ring any bells, but you can drop a line to Sol (who took over from Drew when he retired) at dak.com. If Sol doesn't remember, maybe Drew will.
    I was wondering of that was the same company... the logo looked familiar. What the hell were they doing manufacturing PC cards?

    I used to get their catalogs all the time, too. I probably bought something from them but I can't remember what.

    Thanks for the link; I'll ask.

    -CH-

  8. #8
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    Quote Originally Posted by 1ST1 View Post
    Anyhow, check the battery and take it out. It only holds the date/time, nothing more. But these batteries tend to leak and destroy the board.
    Motherboard Rev. P4, ROM Rev. 1.43, 8087 on board, battery had leaked but perhaps not enough to damage the traces.

    Thanks for your assistance.

    -CH-

  9. #9
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    Fortunately, the battery is "upside down", which makes it a bit more likely that leakage will affect the motherboard less than in "normal" designs. I replaced mine with a lithium coin cell in series with a schottky diode (lower forward drop than a normal silicon diode). Works just fine.

  10. #10
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    Quote Originally Posted by Chuck(G) View Post
    Fortunately, the battery is "upside down", which makes it a bit more likely that leakage will affect the motherboard less than in "normal" designs. I replaced mine with a lithium coin cell in series with a schottky diode (lower forward drop than a normal silicon diode). Works just fine.
    Good to know, although I will do without the battery for now.

    Found that Plus Card 20 was the second offering from a wholly-owned Quantum subsidiary who pioneered the drive-on-a-card product in the mid-80s. Found a link to some docs and software utilities here: http://ibm-pc.org/firmware/other/plu...20hardcard.htm. Appears I have BIOS version 5.x; second version of the board.

    No reply from Sol or DAK yet.

    Thanks,

    -CH-

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