TDS Sensor not working

Hi,

I got the TDS analog sensor for the Arduino, but this one isn't working.

I have done some measurements with a Oszilloscope and something is strange.

The signal out from the LMV324 (A) towards the pobe pin2 is only between 200mV and 750mV, but it should be between -3V and +3V - right?

The output frequency from the CD4060BM is 2,5 kHz.

The operating voltage is +3,3V and -2,7V, but should be +-3V, right?

The analog output of the board is constant at ~300mV and incresing by 50mV only if the probe is in water.

Has anybody some hints, I asume the LMV324 isn't working.

Thanks

uwe