How to trick an ATI Radeon card into thinking it's plugged in

Hi, I got this computer for free from someone doing a garage sale. He didn't have a cable handy. https://en.wikipedia.org/wiki/DMS-59

Until the store that i've ordered from gets it's order in, which they say could take up to a month, what can I do in the meantime? Is it possible to think it's plugged in, even though VGA is being used?

I saw a trick with resistors, but I only have 300 ohm resistors, i'm not sure if that might overload it or something.

What is the point in doing this?
I would consider it highly impractical.