my sparc won't display?

[forrest]

i've got a sparc classic that i just got in the mail. it's got a sun/vga adapter, so i can plug in my standard monitor to it. so, i plug that sucker in (the guy who sent it to me said, it boots to a promt), i turn on the monitor, the light stays green, the light on the sparc turns on, and i can hear the hard drive spinning and crunching in a booting manner.. the light on the monitor stays on still, it just never displays anything.

help?

it's a Sparc Classic