Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to AC Voltage Set meter to measure AC Volts
Gain access to PCB (use Insulation Mat as required)
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure the voltage between the terminal marked L and terminal marked N at the PCB on connector X1.