I can't get my 755 to power on without using the 12V trigger. i recently had to put a yamaha receiver in the place of the 990 and the Yamaha does not have a trigger output. I disconnected the 12v trigger wire thinking the amp would just stay powered up when both the master switch and standby switch are in the "on" position. However, i cannot get the amp to respond. The green button on the front lights up, but I don't get the "Click" that I normally get when the amp is ready to use. Obviously, there is no sound. When I put current on the 12v trigger, the amp fires right up. Any thoughts?