Chosen Solution

The motherboard dosen’t seem to have any damage. Maybe its the powersuply?

The first thing to do on this model is replace the PRAM battery. See step#3 of the teardown. It’s purple on this one Completely Revamped Macintosh Color Classic for its 25th Anniversary (Mac Mini inside) Completely Revamped Macintosh Color Classic for its 25th Anniversary (Mac Mini inside)