Set Appliance State:
Mains Power Off
Set Multimeter to DC Volts 
| WARNING! Mains voltage is expected during test, follow TOPs P4 live testing procedure |
Measurement:
TEST 1:
Measure the voltage across M6 pins C & D Blue and Brown while connected to the main PCB.
Expect Approx 28Vdc
TEST 2:
Turn on a hot tap and measure the voltage across M6 pins C & D Blue and Brown while connected to the main PCB.
Expect 0Vdc
Measure the voltage across M6 pins C & D Blue and Brown while connected to the main PCB.
Expect Approx 28Vdc
TEST 2:
Turn on a hot tap and measure the voltage across M6 pins C & D Blue and Brown while connected to the main PCB.
Expect 0Vdc
Isolate as per TOPs P4
and refit as necessary