Odd issue with a new Model 24

[Dr. Peter Stephenson]

I have had a Model 12 for about a year and just bought a Model 24. I have set it up as per the manual but I find that with four mics plugged in I get signal on the board from all four with the sliders all the way down and each channel muted... What am I doing wrong?

 

[Beat]

Make sure all PFL buttons are out. Also, verify whether the AUX(MON1, MON2 and FX) send knobs are on the leftmost position.