On Wed, 10 Sep 2008 09:58:27 +0100, "Arfa Daily"
wrote:

However, I don't think that he has the necessary professional
background in service, to be able to run down a problem like this by
disconnecting things, and running alternate grounds ... :-\

Reminds me of an on-site repair job at a Scottish University (on a DVM). The Phd
looking over my shoulder at the circuit points to the 1uF capacitor in the
integrator section and says that will be the problem.
I went for the 10M resistor rather than the polypropylene cap...

Geo