F12 is a communication error between your display module (behind the facia) and your main module (back of machine). They are connected using a 5 wire cable with a plug at each end. Unplug the machine from the mains and remove this cable at the display and main boards. Now nip the plugs with your fingers and push back on. If this does not sort the problem, call us on 0115 9652118. Tony EMW Electronics
www.emwelec.co.uk
November 2012