The dial can be turned by hand, but does not rotate under it's own power. I cannot see how to get it apart to find out what is causing this. I have a technical background and am quite aware of how to dismantle things like this without electrocuting myself, just need to know how to get the cover of without damaging it.

C. Phillips, November 2008

Turn off power supply there is a black electrical cover on the underside remove screw this will enable you to pull and lift upwards clock off it's pins
Would think replace than repair

a, November 2008