Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to DC Volts Set meter to measure DC Volts
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Measure the DC voltage between pin 6 (red) of X8 and a suitable earth.
Expect approximately 5 VDC.
Is the voltage measured as expected?