Even without the Video Rom and Rom Simm, an SE/30 typically shows horizontal lines ( so fake Simasimac ).

It's probably a broken trace somewhere or a dead CPU as the board really doing nothing.

However there are so many traces to check if one wants to test the complete video and power circuit that I probably not going to begin with it.

I don't have a scope, I would buy one if I had the money...

Would one with the help of a scope find the cause faster ?