By "engage" I mean it switches off the outputs.
I don't quite understand your question?
Amp out is not connected to star ground.
Amp ground (next to Amp out) is directly connected to the jack from both boards.
Star ground is connected to the ground tap of the power inlet (called "IEC" in my last post).
yes, see the picture for the wiring, it works now.
Hope I could clarify things a bit.
Sorry, I didn't mean the Amp Out terminal. I meant the ground terminal from the Amp Out Terminal Block. Yes, I see the picture. What is the purpose of this extra ground connection?
I have the Amp Out ground terminals from both amps to Star Ground.