may be the pcb has failed.turn off machine using the machines on/off switch.select 95 cottons on rotary selector.now press start/pause/cancel button and switch it on using the machines on/off switch whilst still holding start button pressed.might take 3 or 4 seconds but should be in a test mode now and i think something flashes???.each press of the start button now will activate a part of the machine.hopefully this will help you find fault
ck
October 2008