I removed U4 pins 8-9 and Vf5 now has some peaks!!The schematic shows U4 pins 8-10 as an inverter. In TINA it is probably completely different, maybe it is the mixer.
The schematic shows that the input of U3 pins 5-7 is from one filter. The filter drives only one the display driver, not all of them.If I remove U3 pins 5-7 won't the display circuit mix the filter outputs all together?
U3 pins 5-7 is shown driving only the input of inverter U4 pins 8-10. Both opamps are doing nothing.
The mixer is not shown on the schematic.