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Display Telecommunications Corporation "Megaboard".

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    Display Telecommunications Corporation "Megaboard".

    Ok, have been exploring this early-ish clone board lately, here is what I have found:


    This is a Display Telecommunications Corporation "Megaboard". I don't know if it was always called that, or if they referred to it differently when part of a complete OEM system. It is not labeled as such.

    The DTC "Megaboard" is an early ~1983 IBM XT clone motherboard. Note this is not the same "DTC" that produced hard disk controller. Also do not confuse with "DTK".

    It was the first product of Display Telecommunications Corp. It was sold to OEMs and individuals as bare boards, kits, or assembled. It was used by hobbyists, experimenters and high-tech handypersons.

    There is an Infoworld article comparing it to other boards here:

    One ad lists:
    Display Telecommunications Corporation
    4100 Sprint Valley Rd, #400
    Dallas Tx 75234
    Bare board $99
    Socketed: $249.95
    Assembled $599.95

    DTC did sell cases and other parts for it.

    After clipping a shorted -12v tantalum capacitor, the board works great. Going by the chip dates, this specific board was manufactured in 1984.

    The ROMs contains a bootleg of the IBM 5160 11/08/82 BIOS with BASIC. From my research, it normally should have come with its own "megabios". Also from what I have read, supposedly the manual gave instruction how to copy the IBM ROM in to it, which some considered inappropriate.

    This board uses the same power supply interface as the PC/XT/AT. A standard AT supply works fine with it.

    The board is physically larger than an XT board. It will not fit in an XT or Baby AT case. The Keyboard plug does not line up and the board needs extra space for its reset switch. Still, it is mostly an XT clone and uses the 5160 ISA spacing.

    The board itself feels a little flimsy. All chips are socketed. On the one hand, socketed chips can be a bit less reliable, but on the other hand, could be easier to fix. I haven't looked up all of the part numbers, but It uses only basic 74LS chips to interface the main chips. (No PAL programming needed?)

    An odd implementation on this board, it has little metal divider shields between the main sections. While that was common on some earlier computers, I don't believe I have seen that on other IBM PC clone boards.

    Over all, this is a "no frills" motherboard, but it does have some developer-friendly aspects.

    Most visibly, it has perfboard area where one can their own custom circuitry. It features a reset switch next to the keyboard port.

    This board supposedly "features" slot 8 support identical to the IBM XT. Although, what was that ever used for? The board also has a card-edge connector that seems to extend the ISA slots.

    Jumpers permit ROMs to be configured in a variety of ways.

    By cutting/soldering jumper wires, the board can be configured to use either 16k, 64k, or 256k, RAM chips. This board contains a full 640k, although the Infoworld article suggests it would be limited to 256k.

    This board has also been maxed out with an NEC V20 and a math co-processor.

    Booting it, and throwing software at it, it seems perfectly IBM PC XT compatible. It passes all the diagnostics I have thrown at it. It works fine with VGA, XT keyboards, and an 8-bit 1.44mb floppy controller. Of course, remember this has an IBM BIOS in it.

    The only real issue with this motherboard is that it does not physically fit a standard XT case.

    Any rate, I think this in an interesting addition to my collection of early PC clone and parts.

    It's nice. Just get out the hacksaw. I have a rather largish Wang case I'd sell you cheap. You can go to town making a mess of that.


      I didn't realize copying the IBM Basic ROMS was so common, this XT clone board I have
      also came with a copy of IBM Basic.



        Growing up, our first computer was a DTC Megaboard clone. In fact, this machine is still in my parents' attic, so someday I will attempt to restore it.

        We had the OEM case which fit the board nicely. It had an oval-shaped cutout for the keyboard and reset switch (similar to PC 5150), and the lid was hinged so it opened up rather than sliding off. The front bezel was designed to look like an IBM only it had horizontal decorative lines instead of the vertical ones on the IBM. It had a rear power switch, and a black "Fortron"-branded power supply. I'm fairly certain it was all bought from DTC that way. I don't have any pics of it, as it's 1000 miles away.

        We had the "MegaBIOS" with it when we got it, however it was replaced at some point down the road with an ERSO BIOS probably due to some hardware compatibility issue (HD floppy drive, video card, maybe?), and unfortunately the original MegaBIOS chip was set aside and is probably gone forever now. I have a clear memory of the POST test booting up with the message "TESTING MEMORY /" (with a / \ flashing back and forth).

        I still have the original OEM manual and documentation for it. It goes into great detail about the theory of operation (logic diagrams, scope readings, etc) and also has the listing for the infamous "IBM MEMORY to INTEL HEX CONVERTER" BASIC program that allegedly lets you copy IBM BIOS ROMs (have never tried it) in order to "facilitate patching".

        Here's a few pics of some of the pages from the book:


        There doesn't seem to be a lot of info out there about the company beyond what you posted. I assume they probably stayed mostly a mail-order clone company, and just couldn't afford the R&D to stay competitive and eventually folded up. If anyone has any more story about what they did after this, I'd be really curious too.



          Update - I managed to get the case out of storage and snapped some photos. The hard drive is of course non-functional, and those floppies need servicing but that original PSU started right up with good voltages on all rails. Interestingly the company, Fortron (not to be confused with Fortran or Voltron) is still in the power business today.

          The switched, standard AC outlets on the back were a nice feature so you could plug in a non-IBM monitor and I think we plugged in our printer too (before the days when we knew we should have a surge suppressor strip).

          I'm really interested to find an image of the original "MEGA-BIOS" bios chip, just to make it all complete. If anyone has that actual chip, would love to get a dump of it for archival purposes.

          Attached Files
          Last edited by frankiekat; August 24, 2021, 06:16 AM. Reason: added link to Fortron


            There's something awry with the PM's. I got you PM's frankiekat and see a sentence or so in the notification email. When I go to the forum to read them they just show as blank (although yesterday I was able to read one of them). The one you sent with those pics shows the pics but no text. The text must be there somewhere. I can confirm that my case appears identical to yours. PSU is branded differently but also looks like it might be the same.

            Hmmm, just looked again the the PM's are no longer blank. Will reply now.
            I'm Chris. I have a small collection of old IBM compatibles and a getting-rather-large collection of Sinclair QL related hardware and software items. Always on the look out for QL stuff if anyone has anything.


              Originally posted by Chr$ View Post
              There's something awry with the PM's. I got you PM's frankiekat and see a sentence or so in the notification email. When I go to the forum to read them they just show as blank (although yesterday I was able to read one of them). The one you sent with those pics shows the pics but no text. The text must be there somewhere.
              That is a known ongoing issue that has been occurring since the hosting software (vBulletin) was upgraded at the VCF in April.
              Discussed in a few threads within the 'Vintage Computer Forum Support' section.
              Appears to be related to PM's with still-under-moderation members.