If you are using the built-in composite and RGBI digital outputs, yes. However, you will see the same image from both outputs (although the color and the sharpness will be different through composite,)
I would expect that VGA would conflict with the onboard video. MDA might work, but you would still need special software to actually do anything with it.
A Tandy 1000 *X will disable its onboard video if a VGA or EGA card is installed. Finding a PLUS-style card for the EX or HX is a much more difficult proposition.
Has anyone tried to install an MDA/Hercules card in a Tandy 1000, SX or TX? There is no hardware reason why it should not work, but I wonder whether there is BIOS support for MDA. *Ls have MDA/Hercules built in.
A Tandy 1000 *X will disable its onboard video if a VGA or EGA card is installed. Finding a PLUS-style card for the EX or HX is a much more difficult proposition.
Has anyone tried to install an MDA/Hercules card in a Tandy 1000, SX or TX? There is no hardware reason why it should not work, but I wonder whether there is BIOS support for MDA. *Ls have MDA/Hercules built in.
Nope. VGA on a EX or HX is impossible. System does not detect a different video card installed.