Online search reveals nothing, unless i missed some important clues.
Looks like the BIOS scans for the presence of a ISA graphics card and picks it in favor of the built-in Tandy adapter.
The mode.com mono/co80 and MDA + CGA/EGA/VGA trick does not work obviously.
Any hints ?
Tandy were always strange, I had one with a mono/color switch on the back allowing Tandy video (color) or Hercules (mono) screens to be attached
I would hope you could run an MDA card with Tandy video but it seems like the two overlap if you exceed 640k
https://forum.vcfed.org/index.php?threads/tan … rcules.1233391/
You can get a "Y" cable and have two monitors with the same images. I don't know if at that time, there would be support for "extended desktop". I think only specific programs offered this kind of support, like CAD programs.
Take a look at my blog: http://rikintosh.blogspot.com
My Youtube channel: https://www.youtube.com/channel/UCfRUbxkBmEihBEkIK32Hilg
Utility program called VSWITCH.COM can switch between the built-in Tandy Video and installed ISA video card.
Not quite dual monitor setup, but useful in some situations.
