Facing same issue as you. If your problem is acting the same as mine: I discovered that if you boot into "safe" you will continue seeing the video, gui is gone, running on level 3, but once logged in you can type "yast" at the prompt and get text version of yast.
This didn't do me any good though.
/etc/X11/xorg.conf is where video stuff is defined. Messing with that didn't help either.
I have discovered that there is graphical login interface that runs just at the spot that my screen dies. I haven't determined yet if xdm is what suse uses or not, but my current goal is to find that out and look for possible video settings in its conf file. If that doesn't work, then its back to xorg and/or some other conf file that is as yet undiscovered.
I have not tried the solution offered by reddazz, but as I have never run sax2 before I think it will be worth it, if for nothing more than the exposure.
One last thing: I have a kvm between the cpu and the monitor. Could it be that the kvm is introducing some confusion?
I hope that this post helps a little. Please notice I am pure rookie.