> Thanks for the help Dieter.
>
> I have noticed that the problem only happens when connecting the
> A101-1 to the modules on the MIDDLE row of my 9u cabinet. I have
> removed all the modules from the middle row and tried them
> individually and the problem still occurs.
>
> The excessive noise from the filter happens if I connect the
> filter to ANY point on the middle row. It does not happen on the
> top or bottom rows.
>
> I am concerned that it may be the power supply or would you still
> suggest that the filter is faulty.
>
> Many thanks
>
> Carter

What kind of 9U cabinet is used If there's only one power supply in the
cabinet it should make no difference. Double check if one of the supply
connections (between PSU und bus boards) is loose or broken.

Is the noise like a white noise (e.g. like the A-118) or hum noise with
50/60Hz

Best wishes
Dieter Doepfer