It would appear that you have never replaced the capacitors on your SE/30 motherboard. Having the most powerful PSU in the world won't rectify that problem. You need to replace the caps. And if you have, then perhaps you didn't adequately clean up the leaked fluid when you changed the caps. Leaked fluid cannot always be easily seen.

It could also be an eaten PCB trace. Even if you cleaned the board well and correctly changed out the caps, a bad trace would cause the Simasimac pattern you are seeing. Those are a pain in the fanny. I have a board like that. I've spent hours trying to resurrect it, but so far it still gives me the SimasiMac lines.