sine wave into a dead input channel. Use the block diagram and schematic to trace the physical path with an oscilloscope. If the signal is visible before an op-amp but missing after it, you have isolated a dead IC.
Positioned immediately after the preamp on the schematic, this active 18dB/octave filter cuts everything below to eliminate stage rumble. Soundcraft Fx16ii Schematic Diagram
The front end of the schematic dictates the console's noise floor and overall tonal character. sine wave into a dead input channel