Set Appliance State:

Isolate Mains Power to appliance as per TOPs P4
Set Multimeter to DC Volts Set meter to measure DC Volts
Gain access to PCB (use Insulation Mat as required)
NO Demands
WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure
Mains Power On

Measurement:

Test 1:
Measure the DC voltage between Pin 12 (Green) on X25 and a suitable earth. Expect approximately 1.6 Vdc
Test 2:
Isolate Mains Power to appliance as per TOP's P4
Remove the DC fan connector (4 wire) and make safe.
Mains Power On
Allow fan to run (fan will run at maximum speed)
Measure the DC voltage as above again.
Expect approximately 3.7 Vdc
Note: Each pin on the PCB connector is numbered.