Set Appliance State:

Mains Power Off
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 for DC volts across pin 3 (yellow lead) connector X2 and a suitable earth connection.
Expected voltage approximately 4.8 Vdc.
Note.
Pins are numbered on the connectors.