After i have changed the parameters written in the preview log - about PS_ON level after start - now the printer put down the PS_ON pin during the start up.

I decided to show you my first success with the proto board:

The yellow LED will turn on when the printer is switched off.

The printer is turned off as long as you do not press the button next to the yellow led.

The relay is not connected yet. When i will connect it, the printer will shut down completely and only the shutdown circuit stay on.