I've made this circuit to detect de zero cross but in out pin (pin 7) the voltage are about 3,7V fix. I've already measured pins 5 and 6 and the delta voltage ( vin+ and vin-) are inverting. I had inverted pins 5 and 6 and in this case pin7 is fixed in 0V.
Oscilloscope measurement problem:
I've already tried to measure with other Scope (TDS 2002B) add caps on various places in this circuit. I will try to put this signal on uC INT pin to see if is a osc problem or a circuit one.