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Thread: Tandy Sound Compatible PCB

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  1. #1

    Default Tandy Sound Compatible PCB

    Hi All

    This design for a simple PCB to provide basic Tandy sound to clones has been sitting in my Eagle CAD folder for a while, but at last it is ready to go to fab. Expect PCBs in the store in about 3 weeks time for those wanting to experiment with the first cut!

    Needs a SN76489AN chip as available from your favorite online auction site

    Last edited by pearce_jj; October 30th, 2016 at 08:15 AM.

  2. #2
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    Default

    This is great! I will want one

  3. #3
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    Neat!

    The problem of enabling audio to use this card still remains, as most software made before 1988 will only enable it by checking model bytes in ROM. Maybe some enterprising person will maintain a page of game patches to force 3-voice audio, or maybe even a utility to help find the detection code (or patch it!).
    Offering a bounty for:
    - The software "Overhead Express" (doesn't have to be original, can be a copy)
    - A working Sanyo MBC-775, Olivetti M24, or Logabax 1600
    - Music Construction Set, IBM Music Feature edition (has red sticker on front stating IBM Music Feature)

  4. #4
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    Took ya long enough for such a simple design

    Not only is do you need to consider the Model Byte detection, you also need to hack around games that rigidly think Tandy Graphics = Tandy Sound. Finally, will setting the card at the addresses used by virtually all games and the 2nd DMA chip in AT systems cause issues?

    The only games with auto detection where you can force an EGA or VGA graphics with Tandy sound are the AGI engine games with interpreter v2.917 or later. Maniac Mansion and Zak McKracken and the Alien Mindbenders have been patched in their low and high resolution versions to always output Tandy sound : http://www.vogons.org/viewtopic.php?...c+pcjr#p342485 But they really sound best with the NCR 8496 clone PSG : http://nerdlypleasures.blogspot.com/...ound-chip.html
    Last edited by Great Hierophant; November 1st, 2016 at 12:26 PM.
    My Retro Computing and Vintage Gaming Blog : http://nerdlypleasures.blogspot.com/

  5. #5
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    Default

    Quote Originally Posted by Great Hierophant View Post
    will setting the card at the addresses used by virtually all games and the 2nd DMA chip in AT systems cause issues?
    Yes. I thought the card targeted 8-bit ISA-slot systems only. (Which is appropriate, as most games with 3-voice audio worth listening to target the 4.77-10 MHz range anyway.)
    Offering a bounty for:
    - The software "Overhead Express" (doesn't have to be original, can be a copy)
    - A working Sanyo MBC-775, Olivetti M24, or Logabax 1600
    - Music Construction Set, IBM Music Feature edition (has red sticker on front stating IBM Music Feature)

  6. #6

    Default

    Correct, also it has 2C0h option (could change that to 1C0h as per Tandy 386(?) but it still technically clashes with 5150 system board reserved range).

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