Hi Guys, and thanks for your advice. I too have run out of ideas, which is why I posted the plea for help!

It's going to be something simple - many of these things are - and I guess I will have to go back to basics and check the wiring right through from start to finish and not assume anything is right!

The fact that none of you, with your combined experience, have knowledge of any similar board problem is encouraging. My own "gut" feeling is the connector, but I may well be wrong! Aren't we all at some time?