Set Appliance State:

Mains Power Off
Set Multimeter to AC Volts Set meter to measure AC Volts
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure the AC voltage between pins 8 (black) and 10 (blue) on connector J3.
Expect mains voltage.
Is the voltage measured as expected?