I just got a  DEC 3000/600

When it starts up the monitor display a sort of graphic tests then nothing
happens I Expect to see hte SRM console prompt but the block white
cursor goes in the lower left corner and nothing happens even if I type
on the keyboard. Anyone could suggest me anything ??
THen how is this workstation?? is it better or worse than dec3000/300 ??
thanks

Rick