Low Pass Filter problems

[DrRobin]

Hi,

I have bought 3 off digital filter ICs but have one problem and a question.

E-Field Problem
When I select the LP filter on the E-field I just see loads of 50Hz noise.  Clearly there is an open circuit on the LP filter output, but I have been all round the chip and all connections are okay.  I am thinking it is further on in the circuit. 

Has anyone had this problem and could suggest where the open circuit might be? Alternatively I can trace the signal if I had a circuit and layout diagram.  I am an electronics engineer and have access to a full workshop with lots of test kit.

H-field question
I installed LP filters on H1 and H2, they are working great and set to 16kHz, they cut my noise from 60mV to 16mV.  However, I expected the thresholds to reduce, but they haven't, so whilst I have really low noise, I actually detect less signals as the signal peaks have been smoothed a little and now don't make the thresholds.

I am running in auto mode, should I be in manual and are there any suggested settings?

Thanks

Robin