Set Appliance State:

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

Observation:

Measure the voltage between pin 12 (blue) and pin 11 (orange) at M3 on the PCB.
Expected voltage approximately 15V DC.
Note:
Some or all of the pink wires on M3 may not be present depending on the exact model you are working on.