I just tried the monitor with one of my other older Macs (Performa 6200CD) and the monitor (and Performa) works fine.

The Mac II was in the basement but it's not a soggy musty place. The Mac II purrs like it did years ago, just a blank screen. The monitor does not even flicker when it gets a green light.

All the monitor cable pins and pin sockets (on the card) look good, too. The HDD sounds like it is booting like the good ol' days.