Hello again, I could find a solution There is no "Inhibit Switch for NTSC" or "NTSC enabled Switch" inside the Commander. The thing to do is close contact W142 and open contact W142 on the Mainboard. After that playing NTSC Laserdisc's ist possible
I'd just remove the top metal plate for side B laser movement from the parts machine with the rail on it and swap it with the one in the H9. All DVL players have the same part.