David-Thanks for the information - since posting my query I have gone through every wire on the control board using the electrical data sheets posted by denford and labelled their function. I found that the motor spindle control fuse was blown and now have the spindle turning under the potentiometer...

I have recently been given a starturn -1985 manufacture- in a clearout at my school. The BBC computer and software have long disappeared and I don't think the lathe has actually ever been used at all -its as clean as a whistle ! Plugging in the machine only -the cooling fan starts up -but nothing el...