just had the same fault. It is the brushes! Saved me a new door lock as that is what I was going to change. You can check by putting the machine on its side (remember to unplug) and remove the brushes (will need a 5.5mm socket). They should be pretty worn. You can check it is the brushes and get a couple of extra days by pulling the carbon centres until they move out a couple of millimetres from where they stopped previously and refitting (worked for me)
TomShaw, June 2010
my wt741 was flashing f-12 now theirs nothing wont switch on HELP
MRS HENDERSON, June 2010
motor brushes need replaced. very unlikely to be a door lock problem