Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to DC Volts Set meter to measure DC Volts
Remove connectors X2 and X20 from the PCB
WARNING! - Mains voltage is expected during test follow
TOPs P4 live testing procedure
Mains Power On

Measurement:

Test 1:
Measure the DC voltage between the small soldered point marked "5V" just to the bottom left of connector X20 and a suitable earth.
Expect approximately 5 vdc.
Test 2:
Measure the DC voltage between terminals
8 and 9 on the incoming mains terminal strip.
Expect approximately 22 vdc.