Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to AC Volts 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 A/C voltage across brown and blue connections of connector 100 on the PCB.
Expected voltage, mains voltage.
Note.
Ensure a good connection is made or misdiagnosis will occur.