I am having trouble with a Samson Expedition 1000 that I am trying to fix. The unit has 2 Hypex class D modules for power amps. These are not going. But it appears that the modules are probably being stopped from running by the on/off line from the Hypex power supply. Samson have given me a diagram, but the amps and power supply are shown as blocks. Hypex wont give me information. Bruno, I beleive you work for them. The power supply is supply main rails to the modules, but I dont know the right logic conditions for the on/off and dc fault rails.